2019 Fiscal Year Research-status Report
Corrosion-wear mitigation: are metallic glass coating deposited by cold spray good candidates?
| Project/Area Number |
19K05092
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| Research Institution | Tohoku University |
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Principal Investigator |
MARY Nicolas 東北大学, 高等研究機構等, 客員准教授 (90794397)
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| Co-Investigator(Kenkyū-buntansha) |
小川 和洋 東北大学, 工学研究科, 教授 (50312616)
加藤 秀実 東北大学, 金属材料研究所, 教授 (80323096)
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| Project Period (FY) |
2019-04-01 – 2021-03-31
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| Keywords | Metallic glass / cold spray / microstructure behaviour / corrosion resistance / Spark plasma sintering |
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| Outline of Annual Research Achievements |
FY2019 was dedicated to elaborate stainless steel metal glass powders. In order to use them for Cold spray, a large quantity (at about 3 kg) was made at the lab scale. The glassy state of ores was confirmed by X-ray diffraction. Atomisation of ores was contracted out a company. Size distribution at about 20-30 micronmeter was requested and confirmed by laser scattering granulometry. X-ray diffraction patterns were recorded to check the glassy state. SEM observations shown a mix of spherical and elongated particles suitable of cold spray.
First tests were carried out with High pressure cold spray. It was not able to deposite the raw powder with your setup since particles agglomeration (electrical static, etc.). Therefore a dispersent agent was added to the metal glass particles (Alumina nanometric-micrometric powder). Particles adhesion was partially achieved however the quantity of rebounded particles was qualitatively too high with those parameters. In order to save material and time, an alternative approach was selected.
Compacted samples were produced by Spark Plasma Sintering. The results show that the heating rate has a direct effect on the crystallinity but reduces the densification. Therefore, the final temperature of the sintering cycle has te be reduced to preserve the amorphous state and the pressure has to be increase to ensure the densification of the material.
Ceramic particles were also added to SPS samples. Higher density were achieved because the voids between metal glass particules was also filled by the ceramic.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
Production of stainless metal glass powder required the use of Yttrium to stabilize (among other element) the amorphous phase. The use of this element which has a low mixing properties in liquid phase with the other elements leads to crystallization. This effect is not well documented in the literature and induced delayed in the initial plan.
However, we achieved elaboration of powder and analyzed them. We also started to elaborate High pressure colds pray as well as amorphous bulk materials by SPS. In order to improve density, we are adding some ceramic particles with the metal glass powder. Alumina is one candidate since the literature reports that it should no modify the corrosion behaviour of the material.
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| Strategy for Future Research Activity |
In FY2020, we will finish to characterize and analyse Metal glass materials produced by SPS: corrosion tests and we will prepare a draft for a peer-review paper. We will also work on the parameter optimization of deposition by High pressure cold spray with and without addition of alumina particles in order to look on the adhesion of the coating. Micro-structural investigations are also plan as well confirmation of the glassy state of the coating after elaboration.
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| Causes of Carryover |
This FY, budget will be used to reach the optimized parameter of Cold spray deposition (including nozzle, gas carrier).
A part of the budget will be dedicated to operational actions as surface analysis (SEM, XPS, etc.). SEM will be used to characterize the coating morphology (porosity, thickness). XPS will deal with the oxide formation on surface according to the process. Both SPS and Cold spray sample will be analysed to discuss about the role of the material process on the passive film properties.
Corrosion tests will be carried out. For that we need to elaborate the electrochemical cell and provide the different electrode requiered (graphite counter electrode and reference electrodes) for the measurements
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