Influence of Spraying Angle on the Properties of Plasma Sprayed AT13 Ceramic Coatings

Micro-and nano-Al₂O₃-13%TiO₂ coatings are sprayed by using the APS system. The influences of the spray angle on the increased thickness of a single pass, coating microstructure, hardness and bonding strength are studied. The results show that with the decrease of the spraying angle, the increased thickness of a single pass and binding strength decrease, that the porosities of the two coatings increase, and that the hardness does not change significantly. When the spray angle is 90°, the two coatings are in good condition, and the increased thickness of a single pass of the nano-Al₂O₃-13%TiO₂ coating is 21.5% higher than that of the micro-Al₂O₃-13%TiO₂ coating. When the spray angle is 45°, the increased thickness of a single pass and bonding strength of the former are 47% and 42.1% higher than those of the latter. When the spray angle is 30°, the microAl₂O₃-13%TiO₂ coating has serious defects, and the nano-Al₂O₃-13%TiO₂ coating also has large pores. The hardness of the micro-Al₂O₃-13%TiO₂ coating is slightly higher than that of nano-Al₂O₃-13%TiO₂.