Y. Kobayashi, Tocalo Co., Ltd., Akashi, Japan; E. Ohmura, Graduate School of Engineering, Osaka University, Suita, Japan; S. Ueki, Osaka University, Osaka, Japan
In order to clarify the effects of CO2 laser irradiation on densification of plasma sprayed Al2O3 coatings, microstructure, crystallization and mechanical properties of the spacemen were examined and heat conduction in the laser irradiation processes were also analyzed by the finite element method. Especially, Al2O3 coatings were irradiated with low power density condition, fine structure formation composed of α-Al2O3 was confirmed and the surface roughness was modified although the hardness decreased a little. It was concluded to that the modified layer correspond to the heated area over about 1000 to 1100 degrees centigrade in the calculated maximum temperature distribution.
Summary: Plasma sprayed Al2O3 coatings were irradiated by laser with low power density. Microstructure, crystallization and mechanical properties correspond to the heat conduction in the processes were investigated. As a result, fine structure formation was confirmed and the surface roughness was modified although the hardness decreased a little.It was concluded to that the modified layer correspond to the heated area over about 1000 to 1100 degrees centigrade.
