热障涂层的激光表面改性参数优化和结构设计  

Laser modification parameters optimization and structural design of thermal barrier coatings

作　　者：郭磊[1,2] 高远[1] 辛会 GUO Lei;GAO Yuan;XIN Hui(School of Materials Science and Engineering,Tianjin University,Tianjin 300072,China;Tianjin Key Laboratory of Advanced Joining Technology,Key Lab of Advanced Ceramics and Machining Technology of Ministry of Education,Tianjin 300072,China)

机构地区：[1]天津大学材料科学与工程学院,天津300072 [2]天津市现代连接技术重点实验室先进陶瓷与加工技术教育部重点实验室,天津300072

出　　处：《航空学报》2021年第7期562-571,共10页Acta Aeronautica et Astronautica Sinica

基　　金：国家自然科学基金(51971156)。

摘　　要：热障涂层是航空发动机涡轮叶片关键核心技术之一,但在服役条件下常受环境沉积物、熔盐等的腐蚀而过早失效。激光表面改性是一种提高涂层抗腐蚀性能的有效办法,但改性涂层的激光工艺优化和结构设计亟待研究。本文采用脉冲Nd:YAG激光系统对Y2O3部分稳定ZrO2(YSZ)热障涂层进行表面改性,研究了激光功率、扫描速度以及光束长度对改性层厚度、微观结构的影响。结果表明,激光改性层呈致密的柱状晶结构,并有纵向裂纹贯穿其中。改性层的厚度与激光功率成正比,受扫描速度影响不大,与光束长度成反比。激光功率过高,则改性层裂纹增加明显;光束长度过大,则改性层与下方涂层的界面缺陷增多,不利于界面结合。优化的激光改性参数为:激光的功率为75~80 W,扫描速度8mm/s,光束长度为160mm。设计了双层激光改性层,每层中的纵向裂纹不连续,使得整个改性层中无贯穿的纵向裂纹,有助于抑制高温腐蚀熔体的内渗。Thermal Barrier Coating(TBC)is one of the key technologies of aero engine turbine blades,but it often fails prematurely due to the corrosion resulting from environmental deposits and molten salts under service conditions.Laser surface modification has been considered as an effective way to improve the corrosion resistance of TBCs,but the laser process optimization and structure design of the modified coating need to be studied urgently.In this study,the surfaces of Y2O3 partially stabilized ZrO2(YSZ)TBCs are modified by apulsed Nd:YAG laser system.The results showed that the laser modified layer had a dense columnar crystal microstructure,and longitudinal cracks ran through it.The thickness of the modified layer was directly proportional to the laser power,little affected by the scanning speed,and inversely proportional to the beam length.When the laser power is too high,more cracks formed in the modified layer;when the beam length increased,the interface defects between the modified layer and the underlying coating increased,harmful to the interface bonding.The optimized laser modification parameters are:the laser power was 75-80 W,the scanning speed is 8 mm/s,and the beam length is 160 mm.A double-layer laser modified layer is designed.The longitudinal cracks in each layer are discontinuous,which made the whole modified layer free of longitudinal cracks,helpful to suppress the infiltration of corrosion melt at high temperatures.

关 键 词：热障涂层 高温腐蚀 激光改性 参数优化 结构设计 

分 类 号：V259[一般工业技术—材料科学与工程]