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2076 |
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Monday, May 03, 2010, Moor Room 5:00 PM Biomedical Coatings |
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Deposition of TiO2 ceramic particles on cold spray process |
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Motohiro Yamada* / Toyohashi University of Technology, Japan Hiroaki Isago / Toyohashi University of Technology, Japan Koichiro Shima/ Toyohashi University of Technology, Japan Hiromi Nakano/ Toyohashi University of Technology, Japan Masahiro Fukumoto/ Toyohashi University of Technology, Japan |
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Titanium dioxide (TiO2) is a promising material for photocatalyst coating. However, it was difficult to fabricate TiO2 coatings which have excellent photocatalyst property by thermal spray processes. Because anatase phase of TiO2 transforms into rutile phase under high temperature i.e. the photocatalytic property of TiO2 declines by heating. On the other hand, cold spray process, in which solid particles accelerated by ultrasonic gas flow and deposit onto the substrate surface has been developed. In this study, TiO2 ceramic coatings were fabricated by cold spray process and its deposition mechanisms were investigated. Agglomerated TiO2 powder with 100% anatase phase was injected into process gas stream and deposit onto steel substrate. It was possible to fabricate TiO2 ceramic coatings by cold spray process. The deposition efficiency was increased with both working gas temperature and pressure. It means that the increasing of gas velocity increase the particle velocity and the deposition efficiency. Therefore, it is considered that the sprayed TiO2 ceramic particles deposit with deformation like metallic particles on the substrate by the kinetic energy. TEM observation of the feedstock particle exhibited that the particle consists of nano-scaled fine primary particles. This structure of particle achieved fabrication of TiO2 ceramic coating by cold spray process. |