中文摘要：

本试验采用大气等离子喷涂（APS）在含有NiCoCrAlYTa粘结层的镍基高温合金基体表面沉积氧化钇部分稳定氧化锆（YSZ）热障涂层,然后采用Nd：YAG的脉冲激光对热障涂层表面进行选择性激光表面改性处理,最后对喷涂态和＂桩钉结构＂激光改性YSZ涂层的组织与性能进行分析研究。结果表明：选择性激光表面改性形成的单元体表面粗糙度明显降低,表面的孔隙基本消除,同时形成了垂直于表面的分割网状裂纹,激光改性的＂桩钉结构＂单元体中还包含有柱状晶和等轴晶组织。XRD分析发现,喷涂态与＂桩钉结构＂单元体中都包含有非平衡四方相T＇,然而经过激光改性后,喷涂态中的单斜相M消失,72°~76°范围中T＇峰明显增大。结果还发现,＂桩钉结构＂激光表面改性后,喷涂态YSZ热障涂层的平均结合性能由7.3 MPa增大到13.3 MPa;＂桩钉结构＂YSZ涂层的隔热性能比喷涂态的隔热性能有所下降,这是由于激光表面改性导致陶瓷层组织结构改变所造成的。

英文摘要：

Yttria partially stabilized zirconia（YSZ） thermal barrier coatings（TBCs） were deposited by an air plasma spraying（APS） method on nickel-based superalloy with initially sprayed NiC o CrA lY Ta bond coat. After that, the surface of the plasma sprayed TBCs was subjected to selective laser modification using a Nd：YAG pulsed laser. The microstructure and performance of the plasma sprayed and peg-nail structured YSZ coatings by selective laser modification were investigated. The results reveal that selective laser modification helps to reduce the surface roughness considerably, eliminate surface porosities and produce a network of continuous cracks perpendicular to the surface. The microstructure of peg-nail structured units consists of columnar grains in the cross-section and equiaxed grains on the surface. XRD patterns show that both as-sprayed and the peg-nail structured coatings by selective laser modification consist of nonequilibrium tetragonal（T＇） phase; however, monoclinic（M） phase disappeared and intensity of T＇ phase slightly increases in the range of 72°~76°（2θ） after selective laser modification. It has been found that the average bonding strength YSZ coatings is enhanced from 7.3 MPa to 13.3 MPa after selective laser modification. Thermal insulation capability of the peg-nail structured YSZ coating by selective laser modification, as compared to the as-sprayed YSZ coating, is decreased due to microstructure change in the ceramic top coat.