Influence of Spraying Power and Distance on Porosity and Microhardness of Plasma Sprayed TiO₂ Coatings

The influence of the two deposition parameters on microstructure, and microhardness of plasma sprayed TiO2 coatings were investigated. It was found that a higher spraying power and a shorter distance resulted in a lower porosity and a higher microhardness for the coatings. The anisotropy on the microstructure and microhardness of TiO2 coatings was also found. The denser microstructure is attributed to the higher degree of melting and higher velocity of the TiO2 powders during spraying. The improvement of microhardness is associated with the lower porosity. The difference of porosity and microhardness between surface and cross section resulted from their different microstructures.