Phase Composition and Photocatalytic Activity of TiO_2-Fe_3O_4 Coatings Prepared by Plasma Spraying Technique(Materials, Metallurgy & Weldability, INTERNATIONAL SYMPOSIUM OF JWRI 30TH ANNIVERSARY)
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Owing to the much concern with global environmental problem, photocatalytic TiO_2 coatings were obtained using plasma spraying technique. The influence of the content of Fe_3O_4 additive to the TiO_2 powder on the phase composition, microstructure and photo-absorption of plasma sprayed TiO_2 coatings was systematically studied. The photocatalytic efficiency of the sprayed coatings was evaluated through the photo degradation of acetaldehyde. The UV-VIS-NIR absorption spectra of the deposited coatings were obtained by using Shimadzu UV-3100PC scanning spectrophotometer. The results showed that the TiO_2-Fe_3O_4 coatings consist of anatase TiO_2, rutile TiO_2, and Fe_2TiO_5 pseudobrookite phase which appears when the content of Fe_3O_4 additive is equal to or over 10%. The content of FeTiO_3 is highest in the sprayed TiO_2-10%Fe_3O_4 coatings. The content of anatase TiO_2 in the sprayed coatings decreases with the increasing of Fe_3O_4 content. The addition of Fe_3O_4 decreases the anatase-rutile transformation temperature according to the heat treatment results of feedstock powders. It was found that TiO_2 coatings can decompose acetaldehyde under the illumination of ultraviolet rays, and the degrading efficiency is improved with an increase in the content of FeTiO_3 in the coatings. However, presence of large amount of Fe_2TiO_5 compound substantially lowers the photocatalytic efficiency of the sprayed TiO_2-Fe_3O_4 coatings for its unfavorable photo-excited electron-hole transfer process.
- Transactions of JWRI
Transactions of JWRI 32(1), 167-174, 2003-07