等离子喷涂-物理气相沉积用YSZ粉末制备及涂层表征

Preparation of YSZ Powder for Plasma Spraying-Physical Vapor Deposition and Its Coating Characterization

热障涂层与高温合金、气膜冷却技术并称为航空发动机涡轮叶片的三大关键技术.等离子喷涂-物理气相沉积(PS-PVD)工艺是最具潜力的未来航空发动机热障涂层制备方法之一,其制备的羽-柱状结构热障涂层兼具APS和EB-PVD热障涂层的优点.为了进一步提高热障涂层性能,需要开发与PS-PVD工艺相匹配的新型YSZ粉末.该文先采用喷雾干燥法制备出3种不同纳米团聚YSZ粉末,再使用相同PS-PVD工艺制备成涂层,最后对粉末特性和涂层性能进行评价,以研究制粉工艺-粉末特性-涂层性能之间的联系.实验结果表明:悬浮液固含量越高,制备出的粉末呈现球形越规则,粒径也越大,喷涂的气化率和沉积率越高;制备的YSZ涂层由致密初始生长层和羽-柱状结构两部分构成;使用固含量45%的悬浮液制备的粉末喷涂所获得的涂层具有良好的结合强度和抗热震性能.

Thermal barrier coatings(TBCs),super-alloys,and air-cooling technique are known as the three key technologies of the aero-engine turbine blades.The plasma spraying-physical vapor deposition(PS-PVD)process is one of the most potential technologies for preparing future TBCs.The prepared columnar TBCs using the PS-PVD has the advantages of APS and EB-PVD TBCs.In order to further improve the performance of the TBCs,new YSZ powders matching the PS-PVD process needs to be developed.In this paper,three different nano-agglomerated YSZ powders were prepared by spray drying method,and then fabricated the coatings through the same PS-PVD process.With the evaluation of powder characteristics and coating performance,the relationship between the powder preparation,powder characteristics,and coating properties was studied.The results showed that as the solid content of the YSZ suspension increased,the sphericity of obtained powder became better with larger particle size.Meanwhile,the vaporization rate and deposition efficiency of the YSZ powder was improved.The prepared YSZ coatings were composed of a dense bottom layer and a columnar surface layer.The thickness of the dense layer was related to the initial particle size of the original powder.The coating corresponding to the powder adopting the suspension with a solid content of 45%had excellent adhesive strength and thermal shock resistance.