Thermal Shock Resistance of Plasma-Sprayed ZrO_2 Thermal Barrier Coatings
摘要
The thermal shock resistance of plasma-sprayed ZrO2 thermal barrier coatings under the conditions of water quenching and flame jet was studied.It was found that under the condition of water quenching,the vertical cracks were mainly generated and distributed in the zones about 12 mm within the center of the coating;the vertical cracks were developed into the subsurface with increasing cycle of thermal shock,and the cracks near to the center of the coating were propagated at a faster rate.Under the condition of flame jet,the vertical cracks were mainly generated and distributed in the zones about 10 mm within the center of the coating;the vertical cracks propagating faster near the center of the coating assumed a deflexion at the interface between the top-coating and the subsurface-coating with increasing cycle of thermal shock;and the cracks near to the center of the coating were propagated as well at a faster rate under this condition.Moreover,the plasma-sprayed ZrO2 thermal barrier coating showed better thermal shock resistance under the condition of flame jet than under that of water quenching,and the pores in coating accelerated the propagation of the cracks under two conditions.