F. X. Ye, Tianjin University, Tianjin, China; T. Tsumura, K. Nakata, Osaka University, Osaka, Japan; A. Ohmori, Tocalo Co., Ltd., Akashi, Japan; C. J. Li, School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, China
Hydroxyapatite (HAp Ca10(PO4)6(OH)2) is very known to be a practical biomaterial and an absorbent for chromatography. It also exhibits thermal catalytic activities in many chemical reactions. In this study, HAp was agglomerated with anatase TiO2 to manufacture thermal spray powders to improve the absorption activity of TiO2 and then improve it photocatalytic activity. The microstructures and compositions of plasma sprayed TiO2, TiO2-10%HAp, TiO2-30%HAp and HAp coatings were investigated. For the lower thermal conductivity of HAp compound, the addition of HAp inhibited the phase transformation of anatase TiO2 to rutile. Although slightly decomposition of HAp to Ca3(PO4)2 was found under high plasma spray parameters, it did not decompose to CaO and P2O5 according to the XRD analysis. With the increasing of the spraying distance from 70 mm to 110 mm, the anatase content in the TiO2-30%HAp coatings deceased from 39% to 17% under arc current of 700 A and helium gas flow of 9 splm. With the increasing of arc current, the coatings became denser for the higher temperature and speed of plasma jet.
Summary: N/A
