Formation and Characterization of Plasma Sprayed Photocatalytic TiO_2-ZnO Nano-Compounded Coatings

摘要

Two kinds of TiO_2-ZnO nano-compounded powders aggregated by spray-drying process and evaporation method were used to deposit photocatalytic coatings by atmospheric plasma spraying technique. The phase compositions, morphologies of the agglomerated TiO_2-ZnO powders and the as-sprayed coating were characterized using X-ray diffraction (XRD) and field emission scanning electron microscope(FESEM) respectively. Furthermore, roughness measurements were carried out on their surfaces of the plasma sprayed TiO_2-ZnO nano-compounded coatings. Compared with the TiO_2-ZnO nano-compounded coating deposited from the spray-dried powder, it was found that the TiO_2-ZnO nano-compounded coating deposited from the evaporated powder possesses higher anatase phase. It is ascribed to the existing of partially-melted or non-melted microstructure in the TiO_2-ZnO coating deposited from the evaporated powder. The partially-melted or non-melted microstructure was retained from the starting agglomerated powder. This microstructure is beneficial to improve the photocatalytic properties of plasma sprayed TiO_2-ZnO nano-compounded coatings.