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Wednesday, June 04, 2008, Auditorium 2 4:40 PM Cold Spraying 4 Everything around this young thermal spraying technique, possible applications and latest developments for equipment of high pressure and low pressure cold spraying, models and simulations for a deeper process knowledge |
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Microstructure and mechanical properties of low-pressure cold sprayed (LPCS) coatings |
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Heli Koivuluoto* / Tampere University of Technology, Finland Juha Lagerbom / Tampere University of Technology, Institute of Materials Science, Finland Mikko Kylmälahti/ Tampere University of Technology, Institute of Materials Science, Finland Petri Vuoristo/ Tampere University of Technology, Institute of Materials Science, Finland |
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In low-pressure cold spray (LPCS) process, compressed air is used as a process gas and the most important process parameters are gas (air) preheating temperature and gas pressure. Maximum preheating temperature of air is 650ºC and pressure is 9 bar in the LPCS system used in the present study. Powders used in LPCS process contain hard particles (AL2O3) with metallic powders. LPCS is the method to spray soft metallic coatings with ceramic hard phase for different application areas. For example LPCS opens a way to produce thick coatings for electrical and thermal conductive applications and for corrosion protection. Aim of this study was to investigate microstructural properties such as microstructure and denseness of LPCS coatings. Also mechanical properties (hardness and adhesion strength) were studied. One interest of this study was to clarify effect of hard phase on different coating properties. Coating materials are Cu, Ni, and Zn. Substrate material is carbon steel. LPCS coatings seemed to be dense according to SEM studies but corrosion tests were needed to identify existence of open porosity. Furthermore, reinforcement effect of hard phase was investigated with hardness and adhesion strength measurements. |