等离子喷涂-物理气相沉积涡轮叶片7YSZ热障涂层

Preparation of 7YSZ thermal barrier coatings for turbine blades by plasma spraying-physical vapor deposition

以纳米团聚的氧化钇稳定氧化锆(7YSZ)粉末为原料,通过等离子喷涂-物理气相沉积(PS-PVD)技术在涂覆有NiCoCrAlY粘结层涡轮叶片表面制备了羽毛柱状热障涂层,对不同部位涂层的微观结构进行表征.结果表明:PS-PVD技术在涡轮叶片上不同部位制备的热障涂层结构相同,能够在非视线沉积区域的叶缘板表面获得典型的PS-PVD热障涂层结构.涂层沉积过程中,涡轮叶片构型对涂层沉积效率有明显影响,当喷枪垂直叶片旋转轴时,涂层在远离叶片旋转轴区域的厚度较低,原因在于凹型曲面对反射粒子具有汇聚作用而凸型曲面对粒子具有分散作用,两种因素结合可预测复杂构型叶片表面的涂层厚度分布规律.PS-PVD技术制备的热障涂层具有良好的抗热震性能,采用涂层表面镀铝改性工艺能减缓循环热应力造成的涂层失效.

With nano-agglomerated yttrium stabilized zirconia(7 YSZ) powder as raw material, feather-like columnar thermal barrier coatings were obtained on turbine blade surface by plasma spraying-physical vapor deposition(PS-PVD) technology. The microstructure of 7 YSZ coating at different region was investigated. The results show similar structure of 7 YSZ coating was deposited on different regions of the turbine blade. This means 7 YSZ coatings with the same structure in PS-PVD were obtained on the edge plate surface of non-line-sight surface. Turbine blade configuration has a significant influence on coating deposition efficiency. When the spray gun axis is vertical to the rotating axis of the blade, the thickness of the coating is lower in the area far from the rotating axis. Concave surface has convergence effect on particles and convex surface have dispersion effect on particles. The coating thickness distribution on the blade surface with complex configuration can be qualitatively determined by combining those two factors. The thermal barrier coatings prepared by PS-PVD technology have good thermal shock resistance. Al-modification on the coating’s surface can slow down the failure caused by cyclic thermal stress.