Phase Formation during Deposition of TiO<SUB>2</SUB> Coatings through High Velocity Oxy-Fuel Spraying

Abstract

The crystalline structure of TiO 2 coating is of significant importance for controlling its property and performance, such as photocatalytic activity. The aim of this study is to examine the phase formation mechanisms during high velocity oxy-fuel (HVOF) spraying of TiO 2 coating. TiO 2 coatings were deposited under different spray conditions using both anatase powder and rutile powder as feedstocks. The results showed that the anatase content in the coatings was increased with the increase of fuel gas flow when using the rutile powder as feedstock. A TiO 2 coating of anatase content up to 35% can be obtained by well-melted particles. The high content of anatase phase possibly resulted from rapid solidification and cooling process of the particles. The anatase content in the TiO 2 coating deposited with an anatase powder in partially melted state reached 55-65%. The coating deposited by well-melted anatase powder contained the same anatase content as that by rutile powder. A model was proposed to explain the phase formation within the coatings deposited through HVOF spraying.

Development of a Fabrication Process Using Suspension Plasma Spray for Titanium Oxide Photovoltaic Device

“…can be deposited by various deposition techniques such as sputtering [1], metalorganic chemical vapour deposition (MOCVD) [2], spray pyrolysis [3], the sol-gel process [4], thermal spray [5][6][7][8], or by various other methods. However, there are several engineering problems associated with these deposition processes, such as the necessity of vacuum equipment, low deposition rates, deposition time, the requirement of special and costly equipment, as well as feedstock powder [9].…”

Fabrication of Titanium Dioxide Photocatalyst Coatings by Cold Spray

“…For fabrication of large scale thick coatings, thermal spray process is well known as the atmospheric high deposition rate process. Therefore, there are many researches about fabrication of TiO 2 photocatalyst coatings by thermal spray processes [6][7][8][9][10] . Fabrication of TiO 2 coatings is not difficult by thermal spray process, though it has been difficult to obtain high photocatalytic property.…”