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2767 |
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The synthesis of titanium dioxide powders for cold spray |
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Noviana Tjitra Salim* / Toyohashi University of Technology, Japan Motohiro Yamada / Toyohashi University of Technology, Japan Hiromi Nakano/ Toyohashi University of Technology, Japan Koichiro Shima/ Toyohashi University of Technology, Japan Hiroaki Isago/ Toyohashi University of Technology, Japan Masahiro Fukumoto/ Toyohashi University of Technology, Japan |
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Titanium dioxide (TiO2) is unique material that has wide potential especially in the area of photocatalysis. It can be coated on large surfaces such as building or housing walls for air purification. Thermal spray process is well known to be suitable for large area coating deposition. However, the photocatalytic property of thermal sprayed TiO2 coating is relatively low due to the anatase-rutile phase transformation that occurs well below the melting temperature of TiO2. Due to this reason, cold spray process is considered to be more suitable for the deposition of TiO2 coating for photocatalysis as it is a solid phase deposition method that will not cause high temperature phase transformation. However, cold spraying of ceramic materials, including TiO2 is difficult due to its hardness and brittleness. We have developed several TiO2 powders with unique structures and they can be cold sprayed. The synthesis method involved the hydrolysis of titanyl sulphate in water. By addition of ammonium sulphate during hydrolysis and post-treatments, the structure of TiO2 powders can be altered. These special structures are important for the cold sprayability of the TiO2 powders. |