msc_thesis/thesis.org

#+TITLE: Cavitation Erosion in Blended Stellite Alloys
#+AUTHOR: Vishakh Pradeep Kumar





Since the 1930s, investigations on cavitation erosion have sought to quantiy the cavitation erosion resistance of materials, establish correlations with mechanical properties (yield & tensile strength, strain energy, elastic modulus, and hardness), and formulate phenomenological models that describe the cavitation erosion process.

Materials grouped by similar microstructure show a trend of increasing cavitation erosion resistance with increasing hardness, although this trend does not necessarily hold across disparate materials \cite{HANDBOOKCAVITATIONDAMAGE}. In addition to the original hardness of the material, cavitation erosion resistance appears to be resistant to the ability of a metal to be work hardened \cite{HANDBOOKCAVITATIONDAMAGE}.

<SHOW GRAPH OF HARDNESS VS CAVITATION EROSION OF ALL YOUR REVIEW HERE. SHOW INCREASING HARDNESS INSIDE MATERIAL GROUPS>

<Strain energy being a good indicator and why Thiruvengadum's erosion strength is cool>.
Strain energy and its evolution to erosion strength because of how stellite shows phase transformation effects.

Steller \cite{} noted the poor agreement beween

Steller [72,73] observed that often there was poor agreement between cavitation resistance of materials measured in different types of test rigs and this proved to be a stumbling block in the prediction of material performance in the prototype.


* Phase Transformation

The Cr7C3 carbide is unstable at high temperatures and transforms to M_{23}C_{6} upon heat treatment. Under further temperature and time, Cr_{23}C_{6} partially transforms to Cr_6C \cite{mohammadnezhadINSIGHTMICROSTRUCTURECHARACTERIZATION2018}.

2M_{7}C_{3} + 9M \rightarrow M_{23}C_{6}

M_{23}C_{6} + 13M \rightarrow 6M_{6}C





* Grain size

ASTM E112
Heyn Lineal Interceot Procedure


* Stellite Introduction

mp-1221498



Chromium provides superior hot oxidation and corrosion resistance by forming resilient Cr2O3 scales.

many cobalt-based alloys, most of its service strength relies on generating and controlling MC, M7C3, and M23C6 carbide particles within grains, interdendritic spaces, and grain boundaries.


M7C3 is a metastable pseudo-eutectic carbide typically formed at lower carbon-chromium ratios and effectively transforms into secondary M23C6 upon heat treatment according to the following reactions: [4]

$$ 23Cr_{7}C_{3} \rightarrow 7Cr_{23}C_6 + 27C $$
$$ 6C + 23Cr \rightarrow Cr23C6 $$



* FCC to HCP Transformation

# I *love* this paragraph
# https://doi.org/10.1016/j.surfcoat.2018.11.011
# The ε-Co and γ-Co phase are the main phases in Co alloys [39]. According to the phase diagram, the ε-Co phase is more stable at room temperature [40]. However, the γ-Co to ε-Co transformation rarely occurs under normal cooling conditions, and as a result, the γ-Co phase is generally retained at room temperature [39], as we found in the as-deposited Stellite 6 coatings. Nevertheless, this transformation can be triggered athermally (e.g. quenching from temperature of γ-Co) [25,41], isothermally (e.g. aging at temperatures between 650 °C and 950 °C) [35,42,43], or by strain [30,31]. In this study, the thermal fatigue process was achieved by quenching, with heating temperatures of up to 650 °C, and the crack tip introduced severe plastic deformation, all conditions that promote the γ-Co to ε-Co transformation.


* Strain Energy

As cavitation erosion is caused by consecutive bubble impacts over a duration of time, similar to fatigue phenomenon, with accumulte86d strain energy is natural tothe ability of the material to


# Ultimate resilience (also called unit rupture work) is the amount of energy absorbed per unit volume of material as it is taken from zero load to rupture, in tension. In the context of a tensile stress-strain curve, ultimate resilience is the area under the curve.


Thiruvengadum defines erosion strength as the energy absorbed per unit volume of material up to fracture under the action of the erosive force in various environments \cite{thiruvengadamConceptErosionStrength1967}.

| Thiruvengadam, Thiruvengadam and Waring [65,66]

Thiruvengadum \cite{thiruvengadamUnifiedTheoryCavitation1963, thiruvengadamMechanicalPropertiesMetals1966}

Steady state erosion rate \propto \frac{1}{SE}


CavitationErosionBehaviourSteelPlateScroll



* Karimi and Leo

The Karimi and Leo phenomenological model describes cavitation erosion rate as a function of

Karimi and Leo

* Hoff and Langbein equation

Hoff and Langbein proposed a simple exponential function for the rate of erosion, representing the normalized erosion rate requiring only the
A simple exponential function for the rate of erosion was proposed by Hoff and Langbein,

$$ \frac{ \dot{e} }{ \dot{e_{max}} } = 1 - e^{\frac{-t_i}{t}} $$

$\dot{e}$ - erosion rate at any time t
$\dot{e_{max}}$ - Maximum of peak erosion rate
$t_i$ - incubation period (intercept on time axis extended from linear potion of erosion-time curve)
$t$ - exposure time

* L Sitnik model

$$ V = V_o {\left[ ln\left( \frac{t}{t_o} + 1  \right) \right]} ^ {\beta} $$


$$ \dot{V} = \frac{\beta V_o}{t + t_o} {\left[ ln \left( \frac{t}{t_o} + 1 \right) \right]}^{\beta - 1}$$

V_o > 0
t_o > 0
\beta >= 1




* Timeline latex
Use for cavitation curves models
https://github.com/MLNLP-World/Paper-Picture-Writing-Code/blob/main/latex/imgs/category/timeline.png

* TODO Find out the SEM guy at BITS Pilani

https://www.facebook.com/bitsdubai/posts/-we-are-pleased-to-announce-the-inauguration-of-the-newly-established-advanced-c/291636303624927/

* TODO

Need to get ASTM G32 buttons made by that Chinese CNC dude Tulika showed you


* Project Proposal

** Abstract



Cavitation erosion process is a multifaceted phenomenon that depends not only on the strength characteristics of cavitating bubbles but also on the erosion resistance of materials to the cavitation energy imparted upon them. The loss of material due to cavitation leads to degradation in performance


The aim of this MSc project is to investigate the resistance of blended stellite alloys to cavitation erosion. The cavitation phenomena is simulated by ultrasonic vibrating probes, or sonicators, located at fixed gap from the material.

The synergistic effect existing between cavitation erosion and corrosion erosion is investigated with the help of in-situ electrochemical measurements of corrosion.


# Describe the apparatus
Experiments are to be conducted using an ultrasonic vibratory horn, with fixed frequency 20 kHz and variable peak to peak amplitude.

# Describe the need for scanning electron microscopy
Scanning electron microscopy is to be used to characterize the microstructural characteristics of the cavitated sample surfaces, as well as cross sections of the surface directly underneath cavitation.



** Introduction


# Context
# How well was the project placed in the context of previous work?
# In your case, you really need to underscore Rehan's work on stellites and Ahmed's work on cavitation erosion


# Describe why there is a need to look from both the fluid and solid perspective
Cavitation erosion is a complex phenomenon that results from hydrodynamic elements and material characteristics \cite{Franc2004265}.

# Hydrodynamic POV
From a hydrodynamic standpoint, cavitation erosion results from the formation of and subsequent collapse of vapor bubbles within a fluid medium, due to the local pressure reaching the saturated vapor pressure (due to pressure decrease (cavitation) or temperature increase (boiling)). When these bubbles implode, they emit heat, shockwaves, and high-speed microjets that can impact adjacent solid surfaces, leading to damage to the surface and removal of material due to the accumulation of damage following numerous cavitation events.

The required pressure drop required by cavitation could be provided by the propagation of ultrasonic acoustic waves and hydrodynamic pressure drops, such as constrictions or the rotational dynamics of turbomachinery \cite{GEVARI2020115065}.

# Now do the materials POV
The resultant stress levels, which range from 100 - 1000 MPa, can surpass material resistance thresholds, including yield strength, ultimate strength, or fatigue limit, leading to material removal from the surface and subsequent degradation of industrial sysytems. The high strain rate in cavitation erosion makes it rather comparable to explosions or projectile impacts, albeit with very limited volume of deformation and repeated impact loads. The plastic deformation results in progressive hardening, crack propagation, and local fracture and removal of material, with the damage being a function of intensity and frequency of vapor bubble collapse. The selection of more resistent materials requires investigation of material response to cavitation stresses, with the mechanism of erosion being of particular interest. The resulting reduction of performance & service life and the increased maintenance and repair costs motivate research into understanding how materials respond to the impact of a cavitating material. Cavitation erosion is a major problem in hydroelectric power plants \cite{Romo201216}, Francis turbines \cite{Kumar2024}, nuclear power plant valves \cite{Kim200685,Gao2024}, condensate and boiler feedwater pumps \cite{20221xix}, marine propellers \cite{Usta2023}, liquid-lubricated journal bearings \cite{Cheng2023}, pipline reducers \cite{Zheng2022, Chen201442, Mokrane2019}.

# The commercial wear resistant Stellite alloys are derived from the Co–Cr–W–C family first investigated by Elwood Haynes in early 1900s [1].

# Stellites
Stellite alloys consist of a cobalt (Co) matrix with solid-solution strengthening of chromium (Cr) and tungsten(W)/moblybdenum(Mo), and hard carbid phases (Co, Cr, W, and/or Mo carbides) \cite{Shin2003117, Crook1992766, Desai198489, Youdelis1983379}. The matrix provides execelent high-temperature performance, while the carbides provide strength, wear resistance and resistance to crack propagation \cite{Ahmed2021, Crook199427}.

# Applications
Stellites are typically used for wear-resistant surfaces in lubrication-starved, high temperature or corrosive environments \cite{Zhang20153579, Ahmed2023, Ahmed20138, Frenk199481, Song1997291}, such as in the nuclear industry \cite{McIntyre1979105, Xu2024, Gao2024}, oil & gas \cite{Teles2024, Sotoodeh2023929}, marine \cite{Song2019}, power generation \cite{Ding201797}, and aerospace industries \cite{Ashworth1999243}. Hot Isostatic Pressing (HIP) consolidation of Stellite alloys offers significant technological advantages for components operating in aggressive wear environments \cite{Ahmed20138, Ahmed201470, Ashworth1999243, Yu20071385}. Yu et al \cite{Yu2007586, Yu20091} note that HIP consolidation results in superior impact and fatigue resistance over cast alloys.

# Why are stellites OP at cavitation?
# Stellites have good CE resistance due to the low stacking fault energy of the cobalt fcc phase, which favors planar slip dislocations and increases the number of cycles that leads to fatigue failure.

# Understanding the matrix phase
Understanding the cobalt phase is crucial for studying structural changes in Co-based alloys widely used in industry. Cobalt and Co-Cr-Mo alloys undergo thermally induced phase transformation from the high temperature face-centered cubic (fcc) $\gamma$ phase to low temperature hexagonal close-packed (hcp) $\epsilon$ phase at 700 K and strain induced fcc-hcp transition through maretensitic-type mechanism (partial movement of dislocations) \cite{HUANG2023106170}. At ambient conditions, the metastable FCC retained phase in stellites can be transformed into HCP phase by mechanical loading, although any HCP phase is completely transformed into a FCC phase between 673 K and 743 K \cite{DUBOS2020128812}; the metastable fcc cobalt phase in stellite alloys \cite{Rajan19821161} absorbs a large part of imparted energy under the mechanical loading of cavitation erosion. The fcc to hcp transition is related to the very low stacking fault energy of the fcc structure (7 mJ/m2) \cite{Tawancy1986337}. Solid-solution strengthening leads to increase of the fcc cobalt matrix strength (due to distortion of the atomic lattice with the additino of elements of different atomic radiuses), decrease of low stacking fault energy \cite{Tawancy1986337} due to the adjusted electronic structure of the metallic lattice, and inhibition of dislocation cross slip. Given that dislocation cross slip is the main deformation mode in imperfect crystals at elevated temperature, as dislocation slip is a diffusion process that is enhanced at high temperature, this leads to high temperature stability \cite{LIU2022294}. The addition of nickel (Ni), iron (Fe), and carbon (C) stabilize the fcc structure of cobalt (a = 0.35 nm), while chromium (Cr) and tungsten (W), stabilize the hcp structure (a = 0.25 nm and c = 0.41 nm), although Cr and W increases hot corrosion resistance \cite{Vacchieri20171100, Tawancy1986337}.
# Maybe get the size of atoms and show the mismatch?


# Let's now move into the carbides portion.
In addition to solid-solution strengthening, the precipitation of carbides allows stellites to endure mechanical and thermal stresses at high temperature. \cite{Gui20171271,osti_4809456}




# Novelty
# How well was the novelty of the project expressed?

To date, academic research pertaining to cavitation erosion specifically on HIP'd stellite alloys appears to be absent from the existing literature.


# Novelty - Me jerking off to the novelty of my thesis
Given the detrimental influence of voids and defects on cavitation erosion, the lack of academic investigation into cavitation erosion on HIP (Hot Isostatic Pressing) stellite alloys, underscores the need for further exploration. Moreover, the complexity introduced by blended stellite alloys in the context of cavitation erosion in corrosive enironments adds another layer of intrigue to this research endeavor. By analyzing the interactions between alloy composition, microstructure, and cavitation erosion behavior, this thesis aims to fill a critical gap in the current understanding of material performance under cavitation erosion conditions.





# As-cast cobalt-base superalloys consist of a variety of carbides, which mainly includes coarse primary M7C3, M23C6 and MC




While solid-solution strengthening is a necessary factor in stellites, the most important strengthening mechanism in current alloys is the precipitation of carbides.

Cr guarantees hot corrosion resistance and forms M23C6 carbides, while form MC carbides
\cite{Vacchieri20171100}.






Cavitation erosion of Stellites is material removal through crack propagation through the cobalt matrix through the matrix-carbide interface \cite{Szala2021}, making the solid solution strengthening of the matrix a critical parameter \cite{Heathcock1981597}.

\cite{Zhang2021} find that high hardness

Therefore, the negative effect of porosity is weaker than the positive effect of grain refinement, low dilution ratio and high hardness on cavitation performance. Consequently, SLD coating has better cavitation resistance than LC coating. © 2020 Elsevier B.V.},


Liu et al \cite{Liu2022} find that Stellite 21 has superior CE resistance in seawater due to the formation of compact Cr oxides on erosion pits.





 HIPed Stellite 6 wear behaviour relies on the plastic deformation of cobalt matrix, starting at Cr7C3/matrix interfaces.

 Once the Cr7C3 particles lose from the matrix restrain, they debond from matrix and are removed from the material.

 Carbides detachment creates cavitation pits which initiate cracks propagation through cobalt matrix, leading to further detachment of chunks of material.



# Motivation
# Scope
# Aims




** Aims and Objectives
# Were the aims of the project clearly expressed?
# Were they specific and measurable?
# Were they realistic?
# Were adequate timescales referred to?

** Methodology

Cavitation testing is to be carrier out according to ASTM G32 indirect method, with an ultrasonic titanium tip operating at a frequency of 20kHz and peak to peak amplitude of 50 um.

- The time period for each test was 1 h, except the polarization test, in fresh batch of mediums.
- The standoff distance between the sample and the ultrasonic transducer was kept constant at 2 mm.
- The temperature of the water is to be maintained at room temperature of 22 °C ± 0.5 °C
- The pH of the water is to be maintained at a pH range of 7.5 - 8.5.

test arrangement.


*** Work Packages
Were tangible work packages (activities and steps) defined that would be used to achieve the aims of the project?


Research phase 	Objectives 	Deadline

- Background research and literature review
  - Meet with supervisor for initial discussion
  - Read and analyze relevant literature
  - Use new knowledge to refine research questions
  - Develop theoretical framework
- Research design planning
  Design questionnaires
  Identify channels for recruiting participants
  Finalize sampling methods and data analysis methods
- Data collection and preparation
  Recruit participants and send out questionnaires
  Conduct semi-structured interviews with selected participants
  Transcribe and code interviews
  Clean data
- Data analysis
  Statistically analyze survey data
  Conduct thematic analysis of interview transcripts
  Draft results and discussion chapters
- Writing
  Complete a full thesis draft
  Meet with supervisor to discuss feedback and revisions
- Revision
  Complete 2nd draft based on feedback
  Get supervisor approval for final draft
  Proofread
  Print and bind final work
  Submit




*** Resources
Were the resources needed for the project well-defined? Were they in place already? Was there a statement of the planning needed to put the necessary resources in place?

*** Associated risks
# Were the risks which might affect the success of the project defined?
# Were measures suggested to mitigate these?

Main risk about the dissertation is the time allowed. Indeed, despite of having some basic knowledge in solid mechanics, I’ll need to really understand in depth the physics behind the phenomenon of vibration, to get a complete frame of work principle of BWTs. Moreover, time of simulations is not compressible and based on previous experiences, including SpecEng1 project, 3D simulations can take a long time depending on needed precision. Also, even if I used ANSYS CFX by the past, the software is so complete that it might be long to master it. The creation of the Gantt chart will help managing my time, allocating enough time for each subsidiary objective.

**** Technical Risks

# If your project is based around a technology, technical risks relate to specific challenges to delivering that technology and making it work as expected.

Technical risk pertains to the development and manufacturing of the experimental rig, with focus on the ability of the system to achieve the performance required to meet technical specifications and stakeholder expectations.

- Experimental setup complexity
  Experimental setup could pose unexpected issues due to lack of planning

  Risk mitigation strategies:

    - Detailed Planning and Design in CAD
      The rig is to be designed in CAD to ensure all subsystems meet spatial, power, and I/O requirements.

    - Expert Consultation & Review
      The rig design is to be reviewed by supervisor and other expereinced researchers & engineers. Feedback is to be recorded and designed altered to alleviate concerns. Identified people for review are:
      - Dr Rehan Ahmed
      - Dr Mohammed Al-Musleh
      - Muhsin Aykapaddatu

- Functionality/performance is not as expected or to specification
    - Pilot testing of experimental rig to ASTM G32 standard
      Validation of rig using the known materials and comparing results to existing data.

    - Documenting Procedures and Troubleshooting Protocols
      Maintaining documentation of all components used as reference, in addition to developing a Standard Operating Procedure (SOP) outlining each step of the experimental procedure according to the ASTM G32 standard.

    - Modular Design & Redundancies
      The experimental rig design is modularized, in order to allow for easy modificatino and adjustment of components as needed. Spare parts are to be readily available, either in nearby storage or purchasable through local vendors; rig design is to allow for rapid replacement or repair if necessary.

- Noise exposure
- Chemical Hazards
- Instrumentation Failure

**** Data Acquisition and Analysis

Managing and analyzing large volumes of experimental data, including high-speed imaging and erosion measurements, can be daunting. Ensuring the reliability, accuracy, and consistency of data collection and analysis methods is essential for drawing valid conclusions.

***** Pre-Experiment Preparation:
Develop a detailed data acquisition plan outlining the parameters to be measured, the sampling frequency, and the duration of data collection.
Ensure all data acquisition equipment is properly calibrated and validated before starting experiments.

***** Quality Control Measures:
Implement rigorous quality control measures during data acquisition to minimize errors and ensure data accuracy.
Conduct regular checks to verify the consistency and reliability of measurements throughout the experiment.

***** Data Management Protocols:
Establish clear protocols for data management, including organization, storage, and backup procedures to prevent loss or corruption of data.
Use standardized file naming conventions and metadata documentation to facilitate data retrieval and analysis.

***** Real-Time Monitoring:
Implement real-time monitoring of data acquisition systems to promptly identify and address any issues or anomalies during experiments.
Set up alerts or alarms for out-of-range measurements to prevent data loss or invalid results.

***** Data Validation and Verification:
Validate acquired data by comparing it with theoretical predictions, empirical models, or data from previous studies.
Perform sensitivity analyses and cross-checks to verify the consistency and reliability of results obtained from different measurement techniques or instruments.

***** Statistical Analysis Techniques:
Apply appropriate statistical analysis techniques to identify trends, correlations, and outliers in the acquired data.
Utilize statistical software packages for robust analysis and interpretation of experimental results.

***** Error Propagation Analysis:
Conduct error propagation analysis to assess the impact of measurement uncertainties on the final results.
Quantify uncertainties associated with each measurement parameter and propagate them through the analysis to determine their effect on the overall conclusions.

***** Peer Review and Collaboration:
Seek feedback and peer review from colleagues, advisors, or experts in the field to validate the accuracy and reliability of data analysis methods and results.
Collaborate with researchers with expertise in data analysis techniques to enhance the robustness and comprehensiveness of your analysis.

***** Documentation and Reproducibility:
Document all data acquisition and analysis procedures in detail, including software codes, algorithms, and assumptions used.
Ensure transparency and reproducibility of data analysis by providing comprehensive documentation and making raw data and analysis scripts available to others.


** Other stuff


Issues with integration with other technologies/hardware/software within the project
Failures under test or demonstration conditions
Failure to meet required standards or legislation.

Implementation Risks
To some extent these are inter-related to all the risks you identify, but essentially relate to project management issues during delivery of your project. They might include:
Substantial delays in the tasks
Overspend or other financial issues
Partners leaving, not contributing to the project as intended, or going in to liquidation
Legal issues, such as data protection issues or IP infringement.


Societal & Commercialization Risks are outside the scope of this research proposal.







*** Expected outcomes
Was the anticipated result of the project clearly defined?
Were sensible interim milestones identified?


*** Resources needed

*** Risks anticipated


*** Beneficiaries of work

# Was it made clear who would benefit from the work carried out in the project

# Contribution to knowledge

To finish your proposal on a strong note, explore the potential implications of your research for your field.
Emphasize again what you aim to contribute and why it matters.
For example, your results might have implications for:
Improving best practices for cavitation erosion research at Heriot-Watt University
Comparing models that predict erosion resistance
Challenging popular or scientific beliefs
Creating a basis for future research


* Literature review


# Describe why there is a need to look from both the fluid and solid perspective
Cavitation erosion is a complex phenomenon that results from hydrodynamic elements and material characteristics \cite{Franc2004265}. When components are exposed to sustained cavitation erosion, the component surface is degraded and material is progressively lost. Cavitation erosion is a major problem in hydroelectric power plants \cite{Romo201216}, Francis turbines \cite{Kumar2024}, nuclear power plant valves \cite{Kim200685,Gao2024}, condensate and boiler feedwater pumps \cite{20221xix}, marine propellers \cite{Usta2023}, liquid-lubricated journal bearings \cite{Cheng2023}, pipline reducers \cite{Zheng2022, Chen201442, Mokrane2019}.

# Hydrodynamic POV
From a hydrodynamic standpoint, cavitation erosion results from the formation of and subsequent collapse of vapor bubbles within a fluid medium, due to the local pressure reaching the saturated vapor pressure (due to pressure decrease (cavitation) or temperature increase (boiling)). When these bubbles implode, they emit heat, shockwaves, and high-speed microjets that can impact adjacent solid surfaces, leading to damage to the surface and removal of material due to the accumulation of damage following numerous cavitation events. The required pressure drop required by cavitation could be provided by the propagation of ultrasonic acoustic waves and hydrodynamic pressure drops, such as constrictions or the rotational dynamics of turbomachinery \cite{GEVARI2020115065}. Impurities in the fluid, such as solid particles and nanobubbles with a radius of 500nm can significantly reduce the cavitation threshold leading to increased cavitation intensity. When these bubbles collapse near walls, the concentration of energy on very small areas of the wall result in high stress levels on the wall.

# Let's hyperfocus on the wall for a bit
# In the case of a nucleus situated in the middle of a very confined domain # between two parallel walls, growth is fastest in the directions parallel to the wall. During the subsequent collapse phase, the reverse occurs: there is a rapid equatorial contraction and the bubble takes the shape of an hourglass, before splitting into two symmetric bubbles. Each one then develops a re-entrant jet directed towards the nearest wall.

# The notion that the aggressiveness of cavitation could be
# assessed through a consideration of energy conversion was
# already acknowledged by Hammitt

# Now do the materials POV
The resultant stress levels, which range from 100 - 1000 MPa, can surpass material resistance thresholds, including yield strength, ultimate strength, or fatigue limit, leading to material removal from the surface and subsequent degradation of industrial sysytems. The high strain rate in cavitation erosion makes it rather comparable to explosions or projectile impacts, albeit with very limited volume of deformation and repeated impact loads. The plastic deformation results in progressive hardening, crack propagation, and local fracture and removal of material, with the damage being a function of intensity and frequency of vapor bubble collapse. The selection of more resistent materials requires investigation of material response to cavitation stresses, with the mechanism of erosion being of particular interest. The resulting reduction of performance & service life and the increased maintenance and repair costs motivate research into understanding how materials respond to the impact of a cavitating material.


# The commercial wear resistant Stellite alloys are derived from the Co–Cr–W–C family first investigated by Elwood Haynes in early 1900s [1].

# Stellites

Stellite alloys belong to the cobalt-chromium family, with the addition of tungsten or molybdenum as the main alloying elements.
The matrix in stellite alloys consist of cobalt (Co) with solid-solution strengthening of a substantial amount of chromium (Cr) and tungsten(W)/moblybdenum(Mo), resulting in high hardness & strength at high temperature, with carbide precipitations (Co, Cr, W, and/or Mo carbides) adding strength and wear resistance \cite{Shin2003117, Crook1992766, Desai198489, Youdelis1983379, Ahmed2021, Crook199427}.

# Understanding the matrix phase
# Understanding the cobalt phase is crucial for studying structural changes in Co-based alloys widely used in industry.
Cobalt and Co-Cr alloys undergo thermally induced phase transformation from the high temperature face-centered cubic (fcc) $\gamma$ phase to low temperature hexagonal close-packed (hcp) $\epsilon$ phase at 700 K and strain induced fcc-hcp transition through maretensitic-type mechanism (partial movement of dislocations) \cite{HUANG2023106170}. At ambient conditions, the metastable FCC retained phase in stellites can be transformed into HCP phase by mechanical loading, although any HCP phase is completely transformed into a FCC phase between 673 K and 743 K \cite{DUBOS2020128812}; the metastable fcc cobalt phase in stellite alloys \cite{Rajan19821161} absorbs a large part of imparted energy under the mechanical loading of cavitation erosion. The fcc to hcp transition is related to the very low stacking fault energy of the fcc structure (7 mJ/m2) \cite{Tawancy1986337}.

# Let's talk about the addition of other elements
Solid-solution strengthening leads to increase of the fcc cobalt matrix strength (due to distortion of the atomic lattice with the addition of elements of different atomic radii), and decrease of low stacking fault energy \cite{Tawancy1986337} due to the adjusted electronic structure of the metallic lattice. Dislocation motion in stellites is discouraged by solute atoms of Mo and W, due to the large atomic sizes. Given that dislocation cross slip is the main deformation mode in imperfect crystals at elevated temperature, as dislocation slip is a diffusion process that is enhanced at high temperature, this leads to high temperature stability \cite{LIU2022294}. In addition, nickel (Ni), iron (Fe), and carbon (C) stabilize the fcc structure of cobalt (a = 0.35 nm), while chromium (Cr) and tungsten (W), stabilize the hcp structure (a = 0.25 nm and c = 0.41 nm) \cite{Vacchieri20171100, Tawancy1986337}.

# Maybe get the size of atoms and show the mismatch?

The amount and types of carbides dispersed in the stellite matrix are primarily determined by the carbon content, with higher carbon content encouraging carbides with higher C/M ratios, while the size of carbides is determined by the cooling rate. Carbon content can be used to distinguish between different Stellite alloys: high-carbon Stellites designed for high wear resistance, abrasion, & severe galling, medium-carbon (0.5 - 1.6% wt) Stellites used for high temperature service, and low-carbon (<0.5% wt) stellites used primarily for corrosion resistance, cavitation, & sliding wear \cite{kapoor2013microstructure}. Low-carbon stellites depend primarily of solid-solution strengthening for their mechanical properties. As the carbon content increases, the W/Mo content is usually also increased to prevent depletion of Cr from matrix solid solution strengthening. Chromium is the predominant carbide former, with M7C3 and M23C6 phases, in addition to providing corrosion resistance and strength to the stellite  matrix. Difference between the M7C3 and M23C6 phases is not readily visible under SEM. In tungsten-containing alloys, carbides of type M7C3 and M6C are formed in addition to the matrix. Ahmed et al report on the identification of intermetallic Co3W and Co7W6 phases through XRD, although these phases are not identified in SEM observations.


# Insert table of stellite compositions here

# Why are stellites OP at cavitation?
# Stellites have good CE resistance due to the low stacking fault energy of the cobalt fcc phase, which favors planar slip dislocations and increases the number of cycles that leads to fatigue failure.

# Applications
Stellites are typically used for wear-resistant surfaces in lubrication-starved, high temperature or corrosive environments \cite{Zhang20153579, Ahmed2023, Ahmed20138, Frenk199481, Song1997291}, such as in the nuclear industry \cite{McIntyre1979105, Xu2024, Gao2024}, oil & gas \cite{Teles2024, Sotoodeh2023929}, marine \cite{Song2019}, power generation \cite{Ding201797}, and aerospace industries \cite{Ashworth1999243}. Hot Isostatic Pressing (HIP) consolidation of Stellite alloys offers significant technological advantages for components operating in aggressive wear environments \cite{Ahmed20138, Ahmed201470, Ashworth1999243, Yu20071385}. Yu et al \cite{Yu2007586, Yu20091} note that HIP consolidation results in superior impact and fatigue resistance over cast alloys.



# The heck is a blended stellite alloys
A blended stellite alloy is formed by hot isostatic pressing of a mixture of two stellite powders. The powders are created through gas atomization, in which a stream of liquid stellite alloy is disrupted and atomized into tiny molten droplets by a high-pressure inert gas flow. The free-falling molten droplets rapidly solidify into spherical particles before being collected, forming high quality stellite powders with controllable size. The rapid cooling of the powder during atomization leads to reduced precipitation of carbides and supersaturation of the metallic matrix with other elements, as seen in the reduced proportion of carbide phases detected in the XRD performed on powders, compared to XRD of HIP'd samples. The mixing of powders is conducted in a powder hopper that ensures uniform distribution of powder mixtures. The HIP treatment was conducted at a temperature of 1200 C and a pressure of 100 MPa for a duration of 4 hours, resulting in full dense blended stellite alloys. During the HIP'ing process, carbides are precipitated, in addition to reduction of supersaturation of the matrix.


Depending on the composition of the stellite powders used, the blended alloys could possess uniform microstructure or regions that are similar to the constituent powders. This is due to the different diffusion rates of the added elements - carbon diffuses through the blended alloys while tungsten cannot diffuse due to its high atomic radius.

# Blended stellitttte alloys
# Mechanical alloying has been defined as a process that involves repeated cold welding, fracturing and rewelding of powder particles in a high-energy ball mill. Mechanical alloying is a solid-state powder processing process that combines mixtures of powders in a high-energy ball mill to induce the creation of a homogeneous alloy through repeated cold welding, fracturing, and rewelding. Every time two balls collide, some amount of powder is hit, with the particles plastically deformed and welded together, resulting in composite particles. The process continues until all composite particles contain the starting ingredients in the proportion they were mixed together. As the process does not involve the phase transformation of the constituent powders, mechanical alloying allows for the synthesis of novel blends with composite phases that would be difficult or impossible to produce via traditional casting techniques. The composite particles can be consolidated through sintering or hot isostatic processing to produce Compositionally Complex Materials.








# Let's describe the ultrasonic cavitation setup and go deeper
# Why is thin layer stuff so important?
The ASTM G32 standard defines the study of cavitation performance of materials by placing an ultrasonic sonotrode above a stationary specimen, forming a thin liquid layer between the two solid walls. the sonotrode horn emits an acoustic wave into the fluid and causes cavitation when the pressure amplitude is sufficiently high. Due to the reflection and superposition of ultrasound in the thin liquid layer, the intensity of cavitating bubbles is increased, leading to accelerated cavitation erosion.

#+CAPTION: Parameters defined by ASTM G32
| Parameter              | Value   |
|------------------------+---------|
| Frequency              | 20  kHz |
| Peak-to-peak amplitude | 50 um   |
| Gap                    | 0.5 mm  |
| Horn diameter          | 15.9 mm |

Endo et al \cite{Endo1967229} found that the extent of damage depends upon the thickness of the thin liquid layer, Kikuchi et al \cite{Kikuchi1985211} find that the extent of damage is a function of the reciprocal of the thickness of the liquid layer. For thicknesses $h < 0.5mm$, numerous bubbles coalese into several large bubble clusters in contact with the horn tip and the staionary specimen, while for thicknesses $h > 0.5mm$, the numerous bubbles produced are isolated \cite{Me-Bar1996741,Abouel-Kasem201221702, Wu201775}.








# Why is controlling temperature so important?

The test water temperature affects the degree of cavitation erosion \cite{Singer1979147, Ahmed1998119}, with mass loss rate initially increasing with increase in temperature, peaking at an optimum temperature $T_m$, then decreasing with further increase in temperature \cite{Peng2020}, with bulk liquid temperatures above 50 C not altering erosion rate significantly \cite{Singer1979147, Nagalingam20182883}.


However, it must be noted that the temperature of the liquid film between the ultrasonic tip and sample rises rapidly, regardless of the bulk liquid temperature \cite{Endo1967229, Abouel-Kasem201221702}, with maximum erosion rates observed with film temperatures at temperatures 30-35 C \cite{Singer1979147, Priyadarshi2023}.



Because the test water temperature markedly affects the degree
of erosion, impact pressure, and the number of bubbles as it is
observed by Ahmed

        title = {Investigation of the temperature effects on induced impact pressure and cavitation erosion},




# Describe the experimental rig stuff

Previous results of operation of the stationary specimen method
indicated that the minimum local pressure on the specimen, which
corresponds to the effective cavitation number, depends as
expected on several geometrical and operating parameters. These
parameters include the distance, h, between the stationary speci-
men and the horn-tip surfaces, the driving frequency of the horn,
and/or the amplitude of oscillation.



# Let's talk about seawater, shall we

In seawater (and other corrosive media), the coupling of corrosion and cavitation erosion can cause significant material damage with complex, synergistic mechanisms

# Show how Fe coatings perform worse in seawater while Co coatings perform better, somehow



# Cavitation erosion behaviour

The cavitation erosion rate depends on the duration under cavitation, even when all test parameters are kept constant. with distinct stages: the incubation stage (with little material loss), acceleration stage, deceleration stage, and constant rate stage (with the rate of material erosion reaching a steady-state value).


The incubation stage

Generally, cavitation erosion over time involves two stages, namely, the incubation stage (with little material loss, possibly due to the accumulation of internal stresses) and the erosion stage (with the rate of material erosion reaching a steady-state value).


Impact fracture is the dominating factor during the incubation period, with fatigue fracture being the dominant mechanism during the subsequent stages. \cite{HATTORI2001839}


* Introduction to Cavitation Erosion

# Describe why there is a need to look from both the fluid and solid perspective
Cavitation erosion is a complex phenomenon that results from hydrodynamic elements and material characteristics. [cite:@Franc2004265]

# Now go into the hydrodynamic point
From a hydrodynamic standpoint, vapor bubbles arise when local pressures within a fluid medium reduce to saturated vapor pressure, due to pressure decrease (cavitation) or temperature increase (boiling).
Mechanisms facilitating such pressure differentials include the propagation of ultrasonic waves and hydrodynamic pressure differentials induced by geometric constraints or the rotational dynamics of turbomachinery.
The required pressure drop required by cavitation could be provided by the propagation of ultrasonic acoustic waves and hydrodynamic pressure drops, such as constrictions or the rotational dynamics of turbomachinery. [cite:@GEVARI2020115065]
Moreover, impurities within the fluid, such as solid particles and nanobubbles with a radius of 500 nm, can significantly reduce the cavitation pressure threshold, amplifying the overall cavitation intensity. The subsequent collapse of these bubbles near solid boundaries, the resulting concentration of energy on very small areas of the wall result in high stress levels on the wall.


# Now do the materials point
The resultant stress levels, which range from 100 - 1000 MPa, can surpass material resistance thresholds, including yield strength, ultimate strength, or fatigue limit, leading to material removal from the surface and subsequent degradation of industrial sysytems. The high strain rate in cavitation erosion makes it rather comparable to explosions or projectile impacts, albeit with very limited volume of deformation and repeated impact loads. The plastic deformation results in progressive hardening, crack propagation, and local fracture and removal of material, with the damage being a function of intensity and frequency of vapor bubble collapse. The selection of more resistent materials requires investigation of material response to cavitation stresses, with the mechanism of erosion being of particular interest.

# What is affected by cavitation
Cavitation can occur in hydraulic systems (pumps, injector ports, high temperature liquid flows), marine propellers, and turbomachinery (steam turbines), and liquid metal systems (nuclear reactors, and metallurgical processes), with detrimental effect.

# Put the below in a table
# Many metals and alloys have been investigated under
cavitation erosion conditions; examples are: AI-based
alloys, 11-13 Cu-based alloys, 14,15Ti-based alloys,16,17
cast irons,18,19 stainless steels,20-22 Co and Ni super-
alloys,23-25 cemented carbides,24,26 non-metallic
materials,27,28 composites,29,30 ceramics,31,32 and
concrete and cements.33-35


#+BEGIN_COMMENT
Imagine we've got two main ways things change their phase:
boiling, which is like turning up the heat until water decides it's too hot and wants to become steam;
and cavitation, which is more like giving water so much room to breathe that it gets dizzy and starts forming bubbles.

Now, whether we're heating things up or letting the pressure down, the secret that lets this change happen is when the pressure around our water whispers, "It's time," by hitting the saturated vapor pressure.
So, in a nutshell, it's all about hitting that sweet spot where the water feels just right to jump into its next costume, be it vapor or bubbles.

To make cavitation happen — think of it as getting water to the point where it starts popping bubbles — you can use sound waves that travel through the fluid, making the pressure go down.

Also, if you mess with the path the fluid takes, like squeezing it through tight spots or whirling it around in pumps and propellers, that can also drop the pressure just right. It's like setting up an obstacle course for the fluid; the hurdles and twists help create those bubble-making low-pressure zones.
#+END_COMMENT

#+BEGIN_COMMENT
# Why is cavitation so bad?
# Near-wall collapses of vapour bubbles lead to material fatigue and erosive damage.

# # We can model the flow as inviscid! Go easier simulations
# The compressible wave propagation in cavitation is inertia driven; we can assume that viscous effects are negligible. Because the driving effects behind cavitation erosion are inertia driven (compressible wave propagation), we assume that viscous effects are negligible and apply the compressible Euler equation for mass and momentum conservation.

# Distinguish between cavitation and boiling, for the new kids on the block.
# Cavitation is the process of nucleation in a liquid when the pressure falls below the vapor pressure, while boiling is the process of nucleation that occurs when the temperature is raised above the saturated vapor/liquid temperature.

# Describe the vapor and gas stage
# The first and most obvious difference between the saturated liquid and saturated vapor states is that the density of the liquid remains relatively constant and similar to that of the solid except close to the critical point. On the other hand the density of the vapor is different by at least 2 and up to 5 or more orders of magnitude, changing radically with temperature

#+END_COMMENT








# Describe the sonotrode setup
An ultrasonic horn (hereafter referred to as sonotrode) oscillates with a frequency of 20 kHz and a peak to peak amplitude of 50 um above a counter sample, with a gap width of 0.5mm.

# Describe the simulation case
The domain is rotationally symmetric, leading to the use of a 90 degree segment being modelled to reduce computational effort. As cavitation is three-dimensional and non-periodic, the symmetry walls are modelled as periodic boundaries.

# Grid independence study for fluids
As indicator for grid sensitivity study, we choose the vapor volume fraction integrated over the computational domain, as it describes the cavitating flow.


# Why a shadowgraph
Need to observe the cavitation bubbles being formed.







cavitation erosion resistance of Stellite 6 coatings has also been the object of interest in several works:







* Cavitation Description

# Describe why there is a need to look from both the fluid and solid perspective
Cavitation erosion is a complex phenomenon that results from hydrodynamic elements and material characteristics [cite:@Franc2004265]. When components are exposed to sustained cavitation, the surface is degraded and material is progressively lost.

# List of applications
# Who are our stakeholders, why should we care?
Cavitation erosion is a major problem in hydroelectric power plants [cite:@Romo201216], Francis turbines [cite:@Kumar2024], nuclear power plant valves [cite:@Kim200685][cite:@Gao2024], condensate and boiler feedwater pumps [cite:@20221xix],
marine propellers [cite:@Usta2023], liquid-lubricated journal bearings [cite:@Cheng2023], pipline reducers [cite:@Zheng2022] [cite:@Chen201442] [cite:@Mokrane2019].

# Now go into the hydrodynamic point
From a hydrodynamic viewpoint, vapor bubbles are produced when the local pressure in a originally liquid fluid reaches the saturated vapor pressure, due to cavitation (presure decrease) or boiling (temperature increase).

# Let's talk a bit more about the required pressure drop, seems important.
The required pressure drop required by cavitation could be provided by the propagation of ultrasonic acoustic waves and hydrodynamic pressure drops, such as constrictions or the rotational dynamics of turbomachinery. [cite:@GEVARI2020115065]


# Now do the materials point
A material exposed to such a myriad of micro-bombardment can be severly eroded, as the high stress levels exceed the resistance of the material, such as yield strength, ultimate strength or fatigue limit, leading to removal of material from the surface.

# Let's talk a little more about sub-surface cracks
Bubble collapse can cause surface/sub-surface cracks, which are enhanced at stress risers (voids, defects, notches), leading to micro-cracks. The microcracks propagate

# Witty remark to explain why cavitation erosion is cool? Meh? Remove if unncessary
The high value of the strain rate in cavitation erosion makes it rather comparable to explosions or projectile impacts, albeit with very limited volume of deformation and repeated impact loads.


#+BEGIN_COMMENT
Imagine we've got two main ways things change their phase:
boiling, which is like turning up the heat until water decides it's too hot and wants to become steam;
and cavitation, which is more like giving water so much room to breathe that it gets dizzy and starts forming bubbles.

Now, whether we're heating things up or letting the pressure down, the secret that lets this change happen is when the pressure around our water whispers, "It's time," by hitting the saturated vapor pressure.
So, in a nutshell, it's all about hitting that sweet spot where the water feels just right to jump into its next costume, be it vapor or bubbles.

To make cavitation happen — think of it as getting water to the point where it starts popping bubbles — you can use sound waves that travel through the fluid, making the pressure go down.

Also, if you mess with the path the fluid takes, like squeezing it through tight spots or whirling it around in pumps and propellers, that can also drop the pressure just right. It's like setting up an obstacle course for the fluid; the hurdles and twists help create those bubble-making low-pressure zones.
#+END_COMMENT

When a liquid is subject to ultrasound, tiny bubbles may occur and collapse.
High local pressure, temperature, and velocity fields are formed due to cavitation.

In an ultrasonic cavitation field, the acoustic energy can be divided into two parts:
- acoustic propagation energy $E_{pa}$
  $E_{pa}$ is transmitted in the medium before dissipating into internal energy.
- cavitation energy $E_{ca}$
  The energy absorbed by cavitation bubbles is converted into mechanical energy $E_{me}$


# The cavitation erosion phenomenon is the major problem confronting designers and users
of high-speed hydrodynamic system. It occurs mostly in fluid-flow machinery, for example
pumps, water turbines, marine propellers, also in devices in the chemical and petrochemical
industries, in diesel engines and pipelines [1-7]. Cavitation erosion is a reason of a drop of
efficiency, an increase of noise and a decrease of service life of the systems [2-4,6].
Therefore, an interest of investigations of materials resistant to cavitation erosion remains at
high level from many years.



* Synergy evaluation
Pure erosion (E): Two different methods were employed for the pure
erosion test. Three samples were subjected to erosion performed in 5 L of
triple distilled water for 1 h. And three samples were subjected to
cavitation erosion in 3.5% NaCl solution with cathodic protection for 1 h.
• Pure corrosion (C): Four samples were subjected to in-situ
electrochemical measurements kept at open circuit potential (OCP), and
electrochemical impedances spectroscopy (EIS) analysis were conducted
in 3.5% NaCl solution for 1 h. Two sample materials were also subjected
to potentiodynamic polarization, at a potential range between -1 V to 2 V,
to obtain C by applying Faradaic conversion.
284
• Combined cavitation erosion-corrosion (T): all six samples were cavitated
in 5 L of 3.5% NaCl solution for 1 h while subjected to OCP.


* Experimental procedure


The masses of the samples are to be recorded before and after each experiment with a precision mass balance for gravimetric analyses.


The samples are to be left inside individual clean plastic bags for a week to ensure the formation of air-formed oxide films.



The Q500 Sonicator has an operating frequency of 20 KHz and the output amplitude can be controlled by setting a range from 1 to 100% of the maximum vibration amplitude ASTM G32 55 um.

The tip of the ultrasonic probe, made of niobium alloy
C103, is 12.7 mm in diameter. It is positioned in the center of
the beaker and the distance between the probe tip and the surface
of the water is about 2.0 cm.


The piezoelectric signal of the acoustic sensor is to be acquired by an oscilloscope.


* Experiment monitoring




* Working liquid properties

Kind of liquid (water) applied, tap/distilled
Temperature, °C
pH indicator
contents of dissolved air
contents of undissolved air
other chemical additives



* Research Qurstions


How do the HIP treated Stellite alloys compare with the untreated alloys in terms of:
  - mechanical properties
    - hardness
    - tensile strength
  - Resistance to Erosion-Corrosion
    - Abrasive Wear resistance
    - Adhesive Wear Resistance
    - Erosion Wear Resistance
  - Microstructure
    - Grain size
    - Phase distribution
    - Porosity
  - Homogeneity and Distribution of Elements in blends
  - Performance in harsh environmental conditions
    - High temperature
    - Corrosive Environment
      - Polarization Curves
        Potentiodynamic polarization measurements in accordance with ASTM G5 and G59 in different electrolyte solutions to characterize performance of alloys in terms of open circuit potential, passivation behavior, and pitting potentials.

        A polarization curve is a plot of current density ($i$) versus electrode potential ($E$) for a specific electrode-electrolyte combination. Plots of $log |i|$ vs. $E$ or vs. $(E – Eo)$ are called polarization curves. The polarization curve is the basic kinetic law for any electrochemical reaction.



      - Cyclic Polarization
Cyclic potentiodynamic polarization technique is a relatively non-destructive measurement that can provide information about the corrosion rate, corrosion potential, susceptibility to pitting corrosion of the metal, and concentration limitation of the electrolyte in the system. The technique is built on the idea that prediction of the behavior of a metal in an environment can be made by forcing the material from its steady state condition and monitoring how it responds to the force as the force is removed at a constant rate and the system is reversed to its steady state condition.





* COMMENT Learning Outcomes - Subject Mastery

Understanding, Knowledge, and Cognitive Skills
For the core science/engineering area that is the subject of the project preparation work, the
student should demonstrate:
- A knowledge and an understanding of the subject's scope, terminology, and conventions
- A critical understanding of the subject's principal theories, principles, and concepts, and certain specialist topics within these
- An extensive, detailed, and critical knowledge and understanding that is informed by developments at the forefront of the subject
- A critical awareness of current issues in the subject
- Apply critical analysis, evaluation, and synthesis to issues that are at the forefront of informed by developments at the forefront of a subject/discipline.
- Identify, conceptualize, and define new and abstract problems and issues.
- Develop original and creative responses to problems and issues.
- Critically review, consolidate, and extend knowledge, skills practices, and thinking in a subject/discipline.
- Deal with complex issues and make judgments relevant to the design of research in the absence of complete or consistent data/information.


* COMMENT Scholarship, Enquiry, and Research (Research-Informed Learning)

For the core science/engineering area that is the subject of the project preparation work, the
student should demonstrate the ability to:
- Apply a range of standard and specialized research inquiry techniques, evidenced by a detailed literature review of the relevant subject area
- Plan a significant project of research, investigation, or development, as evidenced in a written project proposal and plan
- The Module will use Microsoft’s MS Project to illustrate how software packages can be used to support the successful planning and management of projects.
- Demonstrate originality or creativity in interpreting prior work on the subject and applying this to the design of his / her research project



Learning Outcomes - Personal Abilities
Industrial, Commercial & Professional Practice

The student should,
- Deal with complex professional issues and make informed judgments on issues not addressed by current professionals and/or practices.
- Demonstrate an awareness of the application of his / her work in an industrial and/or commercial context

Autonomy, Accountability & Working with Others

The student should,
- Exercise substantial autonomy and initiative in planning and managing his / her research
- Take responsibility for his / her work and interaction with others
- Take responsibility for accessing and using a significant range of resources including literature, electronic documents, and software / computational resources.
- Demonstrate initiative by making an identifiable contribution to planning his / her research
- Exercise critical reflection on his/ her own and others' roles and responsibilities. Communication, Numeracy & ICT
The student should be able to use a range of advanced and specialized skills as appropriate to the subject of the project preparation work, including:
- Written communication in the form of a project proposal, literature review, and detailed project plan
- Dialogue with other students, researchers, and academic staff
- Making effective use of software to prepare written work and collect and/or manipulate data.
- Undertake critical evaluations of a wide range of written, numerical, and graphical information




* Flexing with the LitReview list

%@ARTICLE{Lavigne2022,
%@ARTICLE{Hou2020,
%@ARTICLE{Liu2019,
%@ARTICLE{Zhang20191060,
%@ARTICLE{E2019246,
%@ARTICLE{Romero2019581,
%@ARTICLE{Romero2019518,
%@ARTICLE{Lei20119,
%@ARTICLE{Qin2011209,
%@ARTICLE{Ding200866,
%@ARTICLE{Feng2006558,

#+BEGIN_SRC bibtex
@ARTICLE{Wang2023,
author={Wang, L. and Mao, J. and Xue, C. and Ge, H. and Dong, G. and Zhang, Q. and Yao, J.},
title={Cavitation-Erosion behavior of laser cladded Low-Carbon Cobalt-Based alloys on 17-4PH stainless steel},
journal={Optics and Laser Technology},
year={2023},
volume={158},
doi={10.1016/j.optlastec.2022.108761},
art_number={108761},
note={cited By 5},
document_type={Article},
source={Scopus},
}

@ARTICLE{Szala2022741,
author={Szala, M. and Chocyk, D. and Turek, M.},
title={Effect of Manganese Ion Implantation on Cavitation Erosion Resistance of HIPed Stellite 6},
journal={Acta Physica Polonica A},
year={2022},
volume={142},
number={6},
pages={741-746},
doi={10.12693/APhysPolA.142.741},
note={cited By 0},
document_type={Article},
source={Scopus},
}

@ARTICLE{Lavigne2022,
author={Lavigne, O. and Cinca, N. and Ther, O. and Tarrés, E.},
title={Effect of binder nature and content on the cavitation erosion resistance of cemented carbides},
journal={International Journal of Refractory Metals and Hard Materials},
year={2022},
volume={109},
doi={10.1016/j.ijrmhm.2022.105978},
art_number={105978},
note={cited By 3},
document_type={Article},
source={Scopus},
}

@ARTICLE{Mitelea2022967,
author={Mitelea, I. and Bordeaşu, I. and Mutaşcu, D. and Buzdugan, D. and Craciunescu, C.M.},
title={Cavitation resistance of Stellite 21 coatings tungsten inert gas (TIG) deposited onto duplex stainless steel X2CrNiMoN22-5-3},
journal={Materialpruefung/Materials Testing},
year={2022},
volume={64},
number={7},
pages={967-976},
doi={10.1515/mt-2021-2169},
note={cited By 1},
document_type={Article},
source={Scopus},
}

@ARTICLE{Liu2022,
author={Liu, J. and Chen, T. and Yuan, C. and Bai, X.},
title={Effect of corrosion on cavitation erosion behavior of HVOF sprayed cobalt-based coatings},
journal={Materials Research Express},
year={2022},
volume={9},
number={6},
doi={10.1088/2053-1591/ac78c9},
art_number={066402},
note={cited By 5},
document_type={Article},
source={Scopus},
}

@ARTICLE{Sun2021,
author={Sun, J. and Yan, Y. and Li, B. and Shi, Q. and Xu, T. and Zhang, Q. and Yao, J.},
title={Comparative Study on Cavitation-Resistance and Mechanism of Stellite-6 Coatings Prepared with Supersonic Laser Deposition and Laser Cladding},
journal={Zhongguo Jiguang/Chinese Journal of Lasers},
year={2021},
volume={48},
number={10},
doi={10.3788/CJL202148.1002118},
art_number={1002118},
note={cited By 6},
document_type={Article},
source={Scopus},
}

@ARTICLE{Szala2021,
author={Szala, M. and Chocyk, D. and Skic, A. and Kamiński, M. and Macek, W. and Turek, M.},
title={Effect of nitrogen ion implantation on the cavitation erosion resistance and cobalt-based solid solution phase transformations of HIPed stellite 6},
journal={Materials},
year={2021},
volume={14},
number={9},
doi={10.3390/ma14092324},
art_number={2324},
note={cited By 22},
document_type={Article},
source={Scopus},
}

@ARTICLE{Zhang2021,
author={Zhang, Q. and Wu, L. and Zou, H. and Li, B. and Zhang, G. and Sun, J. and Wang, J. and Yao, J.},
title={Correlation between microstructural characteristics and cavitation resistance of Stellite-6 coatings on 17-4 PH stainless steel prepared with supersonic laser deposition and laser cladding},
journal={Journal of Alloys and Compounds},
year={2021},
volume={860},
doi={10.1016/j.jallcom.2020.158417},
art_number={158417},
note={cited By 20},
document_type={Article},
source={Scopus},
}

@CONFERENCE{Cinca202115,
author={Cinca, N. and Lavigne, O. and Ther, O. and Tarrés, E.},
title={Cavitation erosion characterization of cemented carbides},
journal={Advances in Tungsten, Refractory and Hardmaterials<6C>2021 - Proceedings of the 10th International Conference on Tungsten, Refractory and Hardmaterials},
year={2021},
pages={15-31},
note={cited By 0},
document_type={Conference Paper},
source={Scopus},
}

@ARTICLE{Hou2020,
author={Hou, G. and Ren, Y. and Zhang, X. and Dong, F. and An, Y. and Zhao, X. and Zhou, H. and Chen, J.},
title={Cavitation erosion mechanisms in Co-based coatings exposed to seawater},
journal={Ultrasonics Sonochemistry},
year={2020},
volume={60},
doi={10.1016/j.ultsonch.2019.104799},
art_number={104799},
note={cited By 31},
document_type={Article},
source={Scopus},
}

@ARTICLE{Liu2019,
author={Liu, J. and Bai, X. and Chen, T. and Yuan, C.},
title={Effects of cobalt content on the microstructure, mechanical properties and cavitation erosion resistance of HVOF sprayed coatings},
journal={Coatings},
year={2019},
volume={9},
number={9},
doi={10.3390/coatings9090534},
art_number={534},
note={cited By 29},
document_type={Article},
source={Scopus},
}

@ARTICLE{Zhang20191060,
author={Zhang, H. and Gong, Y. and Chen, X. and McDonald, A. and Li, H.},
title={A Comparative Study of Cavitation Erosion Resistance of Several HVOF-Sprayed Coatings in Deionized Water and Artificial Seawater},
journal={Journal of Thermal Spray Technology},
year={2019},
volume={28},
number={5},
pages={1060-1071},
doi={10.1007/s11666-019-00869-x},
note={cited By 29},
document_type={Article},
source={Scopus},
}

@ARTICLE{E2019246,
author={E, M. and Hu, H.X. and Guo, X.M. and Zheng, Y.G.},
title={Comparison of the cavitation erosion and slurry erosion behavior of cobalt-based and nickel-based coatings},
journal={Wear},
year={2019},
volume={428-429},
pages={246-257},
doi={10.1016/j.wear.2019.03.022},
note={cited By 49},
document_type={Article},
source={Scopus},
}

@ARTICLE{Romero2019581,
author={Romero, M.C. and Tschiptschin, A.P. and Scandian, C.},
title={Low temperature plasma nitriding of a Co30Cr19Fe alloy for improving cavitation erosion resistance},
journal={Wear},
year={2019},
volume={426-427},
pages={581-588},
doi={10.1016/j.wear.2019.01.019},
note={cited By 10},
document_type={Article},
source={Scopus},
}

@ARTICLE{Romero2019518,
author={Romero, M.C. and Tschiptschin, A.P. and Scandian, C.},
title={Cavitation erosion resistance of a non-standard cast cobalt alloy: Influence of solubilizing and cold working treatments},
journal={Wear},
year={2019},
volume={426-427},
pages={518-526},
doi={10.1016/j.wear.2018.12.044},
note={cited By 13},
document_type={Article},
source={Scopus},
}

@CONFERENCE{Mutascu2019776,
author={Mutaşcu, D. and Mitelea, I. and Bordeaşu, I. and Buzdugan, D. and Franţ, F.},
title={Cavitation resistant layers from stellite alloy deposited by TIG welding on duplex stainless steel},
journal={METAL 2019 - 28th International Conference on Metallurgy and Materials, Conference Proceedings},
year={2019},
pages={776-780},
note={cited By 1},
document_type={Conference Paper},
source={Scopus},
}

@ARTICLE{Kovalenko2019175,
author={Kovalenko, V.I. and Klimenko, A.A. and Martynenko, L.I. and Marinin, V.G.},
title={Erosion of co-cr-w alloy and coatings on its basis under cavitation in and},
journal={Problems of Atomic Science and Technology},
year={2019},
volume={2019},
number={5},
pages={175-178},
note={cited By 0},
document_type={Article},
source={Scopus},
}

@ARTICLE{E201890,
author={E, M. and Hu, H.-X. and Guo, X.-M. and Zheng, Y.-G. and Bai, L.-L.},
title={Microstructure and cavitation erosion resistance of cobalt-based and nickel-based coatings},
journal={Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment},
year={2018},
volume={39},
number={1},
pages={90-96},
doi={10.13289/j.issn.1009-6264.2017-0357},
note={cited By 7},
document_type={Article},
source={Scopus},
}

@ARTICLE{Ding201797,
author={Ding, Y. and Liu, R. and Yao, J. and Zhang, Q. and Wang, L.},
title={Stellite alloy mixture hardfacing via laser cladding for control valve seat sealing surfaces},
journal={Surface and Coatings Technology},
year={2017},
volume={329},
pages={97-108},
doi={10.1016/j.surfcoat.2017.09.018},
note={cited By 58},
document_type={Article},
source={Scopus},
}

@ARTICLE{Guo2016123,
author={Guo, S. and Zhou, G. and Guo, X. and Yi, Y. and Yao, J.},
title={Influence of scanning velocity on microstructure and properties of Co-based alloy coatings by diode laser cladding},
journal={Jinshu Rechuli/Heat Treatment of Metals},
year={2016},
volume={41},
number={8},
pages={123-127},
doi={10.13251/j.issn.0254-6051.2016.08.028},
note={cited By 2},
document_type={Article},
source={Scopus},
}

@ARTICLE{Ciubotariu201698,
author={Ciubotariu, C.-R. and Frunzəverde, D. and Mərginean, G. and Serban, V.-A. and Bîrdeanu, A.-V.},
title={Optimization of the laser remelting process for HVOF-sprayed Stellite 6 wear resistant coatings},
journal={Optics and Laser Technology},
year={2016},
volume={77},
pages={98-103},
doi={10.1016/j.optlastec.2015.09.005},
note={cited By 44},
document_type={Review},
source={Scopus},
}

@ARTICLE{Ciubotariu2016154,
author={Ciubotariu, C.-R. and Secosan, E. and Marginean, G. and Frunzaverde, D. and Campian, V.C.},
title={Experimental study regarding the cavitation and corrosion resistance of stellite 6 and self-fluxing remelted coatings},
journal={Strojniski Vestnik/Journal of Mechanical Engineering},
year={2016},
volume={62},
number={3},
pages={154-162},
doi={10.5545/sv-jme.2015.2663},
note={cited By 12},
document_type={Article},
source={Scopus},
}

@ARTICLE{Singh201487,
author={Singh, R. and Kumar, D. and Mishra, S.K. and Tiwari, S.K.},
title={Laser cladding of Stellite 6 on stainless steel to enhance solid particle erosion and cavitation resistance},
journal={Surface and Coatings Technology},
year={2014},
volume={251},
pages={87-97},
doi={10.1016/j.surfcoat.2014.04.008},
note={cited By 120},
document_type={Article},
source={Scopus},
}

@ARTICLE{Hattor2014257,
author={Hattor, S.},
title={Recent investigations on cavitation erosion at the university of fukui},
journal={Fluid Mechanics and its Applications},
year={2014},
volume={106},
pages={257-282},
doi={10.1007/978-94-017-8539-6_11},
note={cited By 2},
document_type={Article},
source={Scopus},
}

@CONFERENCE{Depczynski20131045,
author={Depczynski, W. and Radek, N.},
title={Properties of elektro sparc deposited stellite coating on mild steel},
journal={METAL 2013 - 22nd International Conference on Metallurgy and Materials, Conference Proceedings},
year={2013},
pages={1045-1050},
note={cited By 3},
document_type={Conference Paper},
source={Scopus},
}

@ARTICLE{Singh2012498,
author={Singh, R. and Tiwari, S.K. and Mishra, S.K.},
title={Cladding of tungsten carbide and stellite using high power diode laser to improve the surface properties of stainless steel},
journal={Advanced Materials Research},
year={2012},
volume={585},
pages={498-501},
doi={10.4028/www.scientific.net/AMR.585.498},
note={cited By 2},
document_type={Conference Paper},
source={Scopus},
}

@ARTICLE{Romo201216,
author={Romo, S.A. and Santa, J.F. and Giraldo, J.E. and Toro, A.},
title={Cavitation and high-velocity slurry erosion resistance of welded Stellite 6 alloy},
journal={Tribology International},
year={2012},
volume={47},
pages={16-24},
doi={10.1016/j.triboint.2011.10.003},
note={cited By 68},
document_type={Article},
source={Scopus},
}

@ARTICLE{Lei20119,
author={Lei, Y. and Li, T. and Qin, M. and Chen, X. and Ye, Y.},
title={Cavitation erosion resistance of Co alloy coating on 304 stainless steel by TIG cladding},
journal={Hanjie Xuebao/Transactions of the China Welding Institution},
year={2011},
volume={32},
number={7},
pages={9-12},
note={cited By 4},
document_type={Article},
source={Scopus},
}

@ARTICLE{Qin2011209,
author={Qin, C.-P. and Zheng, Y.-G.},
title={Cavitation erosion behavior of a laser clad Co-based alloy on 17-4PH stainless steel},
journal={Corrosion Science and Protection Technology},
year={2011},
volume={23},
number={3},
pages={209-213},
note={cited By 8},
document_type={Article},
source={Scopus},
}

@ARTICLE{Hattori20091954,
author={Hattori, S. and Mikami, N.},
title={Cavitation erosion resistance of stellite alloy weld overlays},
journal={Wear},
year={2009},
volume={267},
number={11},
pages={1954-1960},
doi={10.1016/j.wear.2009.05.007},
note={cited By 68},
document_type={Article},
source={Scopus},
}

@ARTICLE{Ding200866,
author={Ding, Z.-X. and Wang, Q. and Chen, Z.-H. and Zhang, S.-Y. and Zhao, G.},
title={Research on cavitation erosion resistance of spraying and fusing co-based and Ni-based coatings},
journal={Hunan Daxue Xuebao/Journal of Hunan University Natural Sciences},
year={2008},
volume={35},
number={1},
pages={66-70},
note={cited By 0},
document_type={Article},
source={Scopus},
}

@ARTICLE{Feng2006558,
author={Feng, L.-H. and Lei, Y.-C. and Zhao, X.-J.},
title={Cavitation behavior of a Co-base alloy},
journal={Corrosion and Protection},
year={2006},
volume={27},
number={11},
pages={558-560},
note={cited By 0},
document_type={Article},
source={Scopus},
}

@ARTICLE{Garzon2005145,
author={Garzón, C.M. and Thomas, H. and Dos Santos, J.F. and Tschiptschin, A.P.},
title={Cavitation erosion resistance of a high temperature gas nitrided duplex stainless steel in substitute ocean water},
journal={Wear},
year={2005},
volume={259},
number={1-6},
pages={145-153},
doi={10.1016/j.wear.2005.02.005},
note={cited By 33},
document_type={Conference Paper},
source={Scopus},
}
#+END_SRC

* Timetable

** DONE Week 1
CLOSED: [2024-02-26 Mon 19:05] SCHEDULED: <2024-01-15 Mon>
Introduction to the course
Assessment briefing
Canvas, Turnitin
Citing, Referencing, Plagiarism

** DONE Week 2
CLOSED: [2024-02-26 Mon 19:05] SCHEDULED: <2024-01-22 Mon>
Time Management
Why critical analysis

** DONE Week 3
CLOSED: [2024-02-26 Mon 19:05] SCHEDULED: <2024-01-29 Mon>
Taking Ownership of Critical thinking in an academic context
What is critical writing?
The “Park” Group exercise

** DONE Week 4
CLOSED: [2024-02-26 Mon 19:05] SCHEDULED: <2024-02-05 Mon>

The “Park” solution – Class discussion
Literature Searching & the Literature Review
The Philosophy and nature of research

** DONE Week 5
CLOSED: [2024-02-26 Mon 19:06] SCHEDULED: <2024-02-12 Mon>

Creating an annotated bibliography to support writing a literature review
Annotated bibliography -– Class discussion

** DONE Week 7
CLOSED: [2024-02-26 Mon 19:06] SCHEDULED: <2024-02-26 Mon>

Data analysis and presentation

** DONE Week 8
CLOSED: [2024-03-19 Tue 16:45] SCHEDULED: <2024-03-04 Mon>

Risk, Health & Safety
Research Methods – Course Portfolio: Background research

** DONE Week 9
CLOSED: [2024-03-19 Tue 16:45] SCHEDULED: <2024-03-11 Mon>

Research Project Management: Planning & Gantt Charts: MS Project Application (Part 1)
Research Project Management: Planning & Gantt Charts: MS Project Application (Part 2)

* Project Proposal


Grade contribution - 30% total weighting
Word count - approx. 1,000 words which include the word count for the work plan

- [ ] Work Packages
  Was a WBS (activities and steps) defined?
- [ ] Resources
  Were the resources needed for the project well-defined?
  - Were they in place already?
  - Was there a statement of the planning needed to put the necessary resources in place?
- [ ] Associated risks
  - Were the risks which might affect the success of the project defined?
  - Were measures suggested to mitigate these?


** Overview
# This part of the proposal is like an "executive summary" or abstract of what the document contains.
# It should be no more than a single page or even less, double-spaced.
# Essentially it is a "map" that shows the territory through which the reader will be led.
# This section should be written last (as summary) after all other sections have been prepared.

- [ ] Context & Novelty
  - How well was the project placed in the context of previous work?
  - How well was the novelty of the project expressed?

** Background
# BACKGROUND AND GENERAL GOALS OF THE THESIS:
# The major body of the document begins with any background that needs to be understood and helps in understanding what is to be done and why.
# It also explains in general narrative terms the main question or questions that will be addressed and describes broadly the research strategy that will be used to bring together the information needed to answer those questions.

*** Statement of objectives.
# Clearly and concisely, what are the general goals of the thesis. Each thesis may have distinct goals.
# Is your thesis project purely descriptive of a new phenomena?
# Is it empirically testing causal relationships between particular variables of interest?
# Are your providing a critical evaluation of a particular topic or framework?
# Are you providing a new perspective by presenting a new typology?
# Are you creating, implementing, or testing a new research tool?
# Any such missions of the thesis should be clearly stated in this section.

- [ ] Objectives
  - [ ] Were the aims of the project clearly expressed?
        Were they specific and measurable? Were they realistic? Were adequate timescales referred to?
  - [ ] What is going to be investigated?
  - [ ] What is going to be measured?

*** Significance of the project
# What is the social importance of this thesis.
# That is, how will this thesis aid our collective understanding of emerging media, in terms of theory and real-world application to a particular social domain (e.g., politics, health, entertainment, design).

- [ ] Expected outcomes
  - Was the anticipated result of the project clearly defined?
  - Were sensible interim milestones identified?
- [ ] Beneficiaries
  - Is it made clear who would benefit from the work carried out in the project?

** Literature Review
# This section is an initial (not the final) report of what others who have studied the same problem or topic have found or concluded. This review should be selective, and should be limited to information that is relevant to the thesis topic. This section should include formal statement of research questions and/or hypotheses derived from your review of the extant literature. A fuller review should come later as part of the thesis itself, including extensive consideration of prior studies or other writings that focus directly on the issue under investigation in order to show the state of knowledge that already exists.

- [ ] Context
      Has sufficient evidence been presented of the previous work on the subject?
- [ ] Significance
      Is the significance of the previous work clearly stated and critically evaluated in terms of its contribution to the subject and its wider impact?
- [ ] Relevance
      Are the cited sources and the discussion relating to these relevant to the project?
- [ ] Methodologies
      Have sufficient methodologies been explored in the review to place the proposed methodology in its context?
- [ ] Logical progression and argument
      Does the review clearly explain and justify the stated aims and objectives and the chosen methodology?
- [ ] Structure of the report
      Is the report's structure adequate to usefully convey the important information?
- [ ] Presentation Quality
      Does the report meet publication standards in terms of English usage, use of tables and figures to underpin the argument in the text, and general level of presentation and layout?
- [ ] Referencing and bibliography
      Are sources adequately and properly referenced in the text and figure/table captions? Is the bibliography adequately formatted following a generally recognized referencing convention?
- [ ] Length
      Is the length of the review within the range and appropriate to the material presented (not too many irrelevant words but enough relevant words)?
- [ ] Originality
      Is the content of the report the work of the student?
      Has the student avoided copying blocks of text or figures verbatim from other sources?
      (Marks should be deducted for excessive use of others' published work, even if the use is attributed.)
** Proposed method
# This section should provide a clear description of the methods you will implement for conducting your thesis project. In order to gather information, will you conduct an experiment, a survey, a content analysis, a focus group, or some other means of data collection? This section should specifically describe the following, as applicable to your intended method of inquiry:

*** Procedure
# What will be the general steps for completing data collection? Here you should describe any all general steps for recruiting participants, conducting an experiment, leading a focus group, distributing surveys, gathering publicly-available data, or otherwise completing your intended means of data collection.

*** Measures
# If examining the associative or causal relationships between variables, how exactly will you measure or operationalize these variables.

** Overall structure of the proposed thesis
# In this section you should provide a brief outline of the general structure of your intended thesis. If a typical empirical investigation, this may simply include an introduction, literature review, methods section, results section, and closing discussion. If another format or type of thesis, similarly provide a general outline of the overall structure of the future deliverable.


- Abstract
  Succinct abstract of less than one page.
- Table of content
  The table of content lists all chapters (headings/subheadings) including page number.
- Introduction
  Explain why this work is important giving a general introduction to the subject, list the basic knowledge needed and outline the purpose of the report.
- Background and results to date
  List relevant work by others, or preliminary results you have achieved with a detailed and accurate explanation and interpretation. Include relevant photographs, figures or tables to illustrate the text. This section should frame the research questions that your subsequent research will address.
- Goal
  List the main research question(s) you want to answer. Explain whether your research will provide a definitive answer or simply contribute towards an answer.
- Methodology
  Explain the methods and techniques which will be used for your project depending on the subject: field work, laboratory work, modeling technique, interdisciplinary collaboration, data type, data acquisition, infrastructure, software, etc.
- Time Plan 3 for Master’s Project Proposal and Master’s Thesis
  Give a detailed time plan. Show what work needs to be done and when it will be completed. Include other responsibilities or obligations.
- Discussion / Conclusion
  Explain what is striking/noteworthy about the results. Summarize the state of knowledge and understanding after the completion of your work. Discuss the results and interpretation in light of the validity and accuracy of the data, methods and theories as well as any connections to other people’s work. Explain where your research methodology could fail and what a negative result implies for your research question.
- Acknowledgements
  Thank the people who have helped to successfully complete your project, like project partners, tutors, etc.
- Reference & Literature (Bibliography)
  List papers and publication you have already cited in your proposal or which you have collected for further reading. The style of each reference follows that of international scientific journals.
- Appendix
  Add pictures, tables or other elements which are relevant, but that might distract from the main flow of the proposal.

** Project Management

# The students must use Microsoft’s MS Project or a similar application to illustrate how software packages can be used to support the successful planning and management of projects. MS Project Guidelines, Material, and Computer Lab exercises can be accessed on Canvas.
# This is a one-page diagrammatic work plan following the appropriate format of a “Microsoft Office Project Gantt chart view and supplement information in the text (” to present and include:

- [ ] Title & Headline Info
  - [ ] Project Name
  - [ ] Anticipated start /finish dates and durations
- [ ] Work-Packages
      Are work packages clearly expressed?
      Do the work packages in the work plan match those in the project proposal?
- [ ] Timescale
      Are the work packages in the right chronological order?
      Has sufficient time been allocated to each work package?
  - [ ] Activities for Course B81EZ background Research
        from January to the end of March
  - [ ] Activities for B51MD dissertation execution work
        from May to the end of August
  - [ ] Realistic break in activities
        A break for the Easter holidays and second-semester exams
  - [ ] Full push during summer
        Full project activities during the summer and final dissertation submission
- [ ] Task Dependencies
      Is it clear which work packages must be completed before others can begin?
      Have all the necessary dependencies been considered?
      Are these effectively illustrated by the plan?
- [ ] Project Milestones and Deliverables
  - [ ] Are milestones and deliverables clearly expressed?
  - [ ] Do they match those in the project proposal?
  - [ ] Are they indicated in a sensible chronological order?
- [ ] Health and Safety / Ethical aspects
  - [ ] Were the Health and Safety risks addressed?
  - [ ] Were measures suggested to mitigate these?
  - [ ] Were ethical considerations addressed if appropriate?

*** Health and Safety aspects

Research may generate risks during the exploration of new ideas and processes, especially if changes occur without a review of possible risks. This section is aimed at minimising the risks to the health and safety of the author and other University researchers when engaged in research activities in University premises.

**** Lone working guidance

For the purposes of this MSc thesis, lone working is defined as someone who works on their own with no close or direct supervision, especially if they do not have visual or audible communication with someone who can summon assistance in the event of an accident or illness.

Risk assessments need to be collaboratively discussed with supervisor for:
- low-risk environment such as lone working at an office desk
- high-risk environment such as operating equipment

Risk assessments need to be communicated to the lab manager for feedback.

- [ ] Appropriate working environmment
  HVAC & Ventilation
  Lighting
  Harmful chemicals?
- [ ] Welfare facilities and Medical concerns
  Are the welfare facilities adequate and accessible?
  Are first-aid facilities available?
  Is the student medically fit to undertake the work alone?
  Is there a requirement for on-going health checks, health monitoring?
- [ ] Contingency plans
  Are there contingency plans in place should an alert/alarm be raised by a lone worker and are these plans well known and rehearsed:
  - what to do
  - who to contact, etc?
  - means of communication? mobile phone, Safezone app

**** Control measures

- [ ] Elimination or substitution
  Can less hazardous materials, equipment or processes be used?
- [ ] Engineering controls
  Can risks be mitigated at source using engineering controls such as equipment guards and interlocks?
- [ ] Administrative controls
  Can suitable systems of work be designed, specifying what is required in terms of training, rules, procedures and supervision.
- [ ] Personal Protective Clothing and Equipment
  What individual protective measures are required, such as personal protective equipment or health surveillance/



* Standards - ASTM & ISO

** ISO 4499 - Metallographic determination of microstructure

ISO 4499-1:2020
Hardmetals — Metallographic determination of microstructure — Part 1: Photomicrographs and description
ISO 4499-2:2020
Hardmetals — Metallographic determination of microstructure — Part 2: Measurement of WC grain size

ISO 4499-3:2016
Hardmetals — Metallographic determination of microstructure — Part 3: Measurement of microstructural features in Ti (C, N) and WC/cubic carbide based hardmetals

ISO 4499-4:2016
Hardmetals — Metallographic determination of microstructure — Part 4: Characterisation of porosity, carbon defects and eta-phase content


** Vickers

id:Sangwal2003511 does great work in explaining the empirical relationships of Vickers hardness on cobalt-based alloys between different stuff. You know how to make this even cooler. Make a paper!

Would be even cooler if you did one with image measurement of Vickers


** NoAuthor2005 - Metallic Materials - Vickers Hardness Test - Part 1: Test Method
:PROPERTIES:
:ID: NoAuthor2005
:END:

#+BEGIN_SRC bibtex
@ARTICLE{NoAuthor2005,
title={Metallic Materials - Vickers Hardness Test - Part 1: Test Method},
journal={Metallic Materials - Vickers Hardness Test - Part 1: Test Method},
year={2005},
note={cited By 580},
}
#+END_SRC

** NoAuthor2009 - Method of Test at Ambient Temperature
:PROPERTIES:
:ID: NoAuthor2009
:END:

#+BEGIN_SRC bibtex
@ARTICLE{NoAuthor2009,
title={Method of Test at Ambient Temperature},
journal={Method of Test at Ambient Temperature},
year={2009},
note={cited By 5},
}
#+END_SRC

** NoAuthor0000 - ASTM G65-00: Standard Test Method for Measuring Abrasion Using the Dry Sand/rubber Wheel Apparatus
:PROPERTIES:
:ID: NoAuthor0000
:END:

#+BEGIN_SRC bibtex
@ARTICLE{NoAuthor0000,
journal={ASTM G65-00: Standard Test Method for Measuring Abrasion Using the Dry Sand/rubber Wheel Apparatus},
year={0000},
note={cited By 3},
}
#+END_SRC






** NoAuthor2010 - Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus
:PROPERTIES:
:ID: NoAuthor2010
:END:

#+BEGIN_SRC bibtex
@ARTICLE{NoAuthor2010,
title={Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus},
journal={Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus},
year={2010},
note={cited By 243},
}
#+END_SRC

** NoAuthor2016 - Standard Test Method for Linearly Reciprocating Ball-on-Flat Sliding Wear
:PROPERTIES:
:ID: NoAuthor2016
:END:

#+BEGIN_SRC bibtex
@ARTICLE{NoAuthor2016,
title={Standard Test Method for Linearly Reciprocating Ball-on-Flat Sliding Wear},
journal={Standard Test Method for Linearly Reciprocating Ball-on-Flat Sliding Wear},
year={2016},
note={cited By 282},
}
#+END_SRC



* Phase

Co3W
Co3W3C
Co6W3C
Co


Co-W (Cobalt-Tungsten)


Blend A
- α-cobalt (FCC)
- Cr7C3
- Cr23C6
- Co7W6
- Co6W6C
- Co3W

Blend B
- α-cobalt (FCC)
- Cr7C3
- Cr23C6
- Co7W6
- Co6W6C
- Co3W3C
- Co3W

Blend C
- α-cobalt (FCC)
- Cr7C3
- Cr23C6
- Co7W6
- Co6W6C
- Co3W


α-cobalt (FCC)
Cr7C3
Cr23C6
Co7W6
Co6W6C
Co3W3C
Co3W

id:Gui20171271
|               | Cr | Mo | Co |
| $M_{7}C_{3}$  |    |    |    |
| $MC$          |    |    |    |
| $M_{23}C_{3}$ |    |    |    |
| $M_{6}C_{3}$  |    |    |    |




* Effects of Indentation Loading Force and Number of Indentations on the MicroHardness Variation for Stellite
* Simulations

https://github.com/stromatolith/RP_Bubble?tab=readme-ov-file