大气等离子喷涂的YSZ纳米热障涂层的微观结构

采用YSZ(8％Y2O3-Zr02，质量分数)纳米粉末，经大气等离子喷涂(APS)方法制备得YSZ纳米热降涂层(TBC)．喷涂前的粉末额粒直径为30—50nm，晶粒尺寸约12nm．对涂层的分析结果表明：YSZ纳米涂层平均晶粒尺寸在20—30nm，有个别粗晶直径达200—300nm．涂层由立方相c—ZrO2和四方相t′—ZrO2组成，t′相内存在畴结构．涂层内孔洞细小弥散，多呈闭合式．TEM下可见位错缠结和富层错的板条带结构．

MICROSTRUCTURE OF AIR PLASMA SPRAYED YSZ NANOSTRUCTURED THERMAL BARRIER COATING

Nanostructured thermal barrier coating was prepared by air plasma spraying with the YSZ (8%Y2O3-ZrO2, mass fraction)nanopowder with particle size range of 30-50 nm and grain size of about 12 nm. The microstructure of the nanocoatings was analyzed. The results show that the average grain size of the coating is about 20-30 nm, while exit some abnormal coarse grains of about 200-300 nm. The coating composes of c-ZrO2 and t'-ZrO2 phase. The domain structure is found in the t' phase. Pores in the coating are small, disperse and in closed shape. Lath-shape structure and dislocation tangles appear as well.