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5306 |
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Friday, June 09, 2017, Hall 26 2:00 PM Amorphous Coatings |
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Amorphous steel coatings deposited by HVOF and cold gas spray processes |
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Francesco Marra / University of Rome, Italy Mario Tului* / Centro Sviluppo Materiali S.p.A., Italy Alessia Bezzon/ Centro Sviluppo Materiali S.p.A., Italy Angelo Luigi Marino/ Centro Sviluppo Materiali S.p.A., Italy Susanna Matera/ Centro Sviluppo Materiali S.p.A., Italy Giovanni Pulci/ Sapienza - University of Rome / INSTM reference center, Italy |
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In this paper is considered the deposition of a commercial steel powder with a chemical composition that allow to obtain amorphous coatings using thermal spray techniques. In fact, these processes are characterized by high cooling speeds of the particles after the impact upon the substrate. The powders were sprayed with two different processes: Cold Gas Spray (CGS) and High Velocity Oxygen Fuel (HVOF). A comparison between the samples obtained reveals that only the CGS coatings are completely amorphous while the HVOF ones present nanocrystalline phases, detected with XRD analysis and SEM micrographs. Furthermore CGS coatings are more compact and show higher hardness (approx. 1050 HV50 for CGS vs. 950 HV50 for HVOF). An hypothesis is that amorphization phenomenon observed is related to the severe adhiabatic plastic deformation at the impact, due to the high particles kinetic energy. Additional tests are in progress to investigate mechanical properties. |