热处理对热障涂层孔隙率及热导率的影响

热障涂层高温使用过程中不可避免发生烧结,引起涂层失效。为探索烧结过程对涂层可靠性的影响,采用等离子喷涂制备氧化钇稳定氧化锆(YSZ)涂层,并对其进行1 000,1 100,1 200,1 300℃高温烧结试验,研究其高温烧结过程中的微观结构及热导率演变规律。结果表明:高温热处理引起热障涂层组织结构和热导率均发生变化,稳定状态的孔隙率为12%~14%,在热障涂层服役温度范围内热导率增加到1.25~1.45 W/(m·K)。

Effect of Heat Treatment on Porosity and Thermal Conductivity of Thermal Barrier Coatings

Sintering healing of thermal barrier coating occurrs inevitably in the process of high temperature using,which will cause the failure of coating.In order to explore the influence of sintering process on the reliability of coating,the yttria-stabilized zirconia (YSZ) coating was prepared by plasma spraying,and the high temperature treatment test was carried out at 1 000 ℃,1 100 ℃,1 200 ℃ and 1 300 ℃ to study the effects on microstructure and thermal conductivity during the high-temperature sintering process.Results showed that both microstructure and thermal conductivity changed during high temperature treatment.Besides,the porosity of the plasma-sprayed YSZ coatings declined to 12％-14％,and the thermal conductivity of coatings at the service temperature was improved to 1.25-1.45 W/(m · K).