等离子喷涂纳米ZrO_2功能梯度热障涂层的孔隙结构

Pore Structure of the Plasma Sprayed Nanostructured ZrO_2 Gradient Thermal Barrier Coating

采用大气等离子喷涂技术制备了纳米ZrO2功能梯度热障涂层，采用定量金相分析技术分别研究了表面陶瓷层、中间层及界面处的孔隙率、孔隙尺寸和孔隙形状。结果表明：各区域的孔隙率、孔隙尺寸和孔隙形状系数服从各自相似的概率分布；界面处孔隙率最高为6．87％，表面陶瓷层和中间层孔隙率略低；涂层中尺寸在1μm以下的孔隙数量最多，约占65％；孔隙大多呈等轴状，所占比例在70％～73％之间。

Nanostructured ZrO2 functional gradient thermal barrier coating was prepared by air plasma spraying technology. The porosity, size and shape of the pores in the ceramic layer, intermediate layer and interface between ceramic layer and intermediate layer were analyzed by quantitative analysis technology. The results show that the pores possessed the same microstructure characteristics in the ceramic layer, intermediate layer and interface. The cumulative probability of the porosity, the pore size and the pore shape showed similar distribution in different layers. The greatest porosity appeared in the interface between ceramic layer and intermediate layer, being about 6.87%. Most of the pores size in the coating was smaller than 1 tan（about 65%）, and showed equiaxial shape （with the content of 70%--73%）.