杂质对氧化锆热障涂层性能的影响

Effects of Impurities on Properties of YSZ Thermal Barrier Coatings

降低热障涂层面层中的低熔点杂质含量,可提高涂层的高温稳定性和延长服役寿命。SiO2、Al2O3和Fe2O3是氧化钇稳定氧化锆(Yttria-Stabilized Zirconia,YSZ)热障涂层中几种常见的低熔点氧化物杂质,均会对涂层的性能产生一定的影响。本研究采用大气等离子喷涂法,制备SiO2、Al2O3和Fe2O3的含量从小于0.01wt%增加至1.00wt%的YSZ热障涂层。采用扫描电镜(SEM)和透射电镜(TEM)研究了上述涂层的微观结构;采用激光热导仪测试了涂层的热扩散系数和抗热震次数。研究结果表明,低熔点氧化物杂质对YSZ涂层的导热性、热处理状态的孔隙率具有明显影响,且更容易引起涂层的热震失效。当杂质氧化物含量在小于0.2wt%范围内变化时,涂层的性能变化更为显著。

Reducing low-melting impurity content in thermal barrier coatings(TBCs)can improve the high temperature stability and service life of coatings.But there is rare quantitative study on the relationship between the low-melting impurity content and coating properties.In the present work,the effect of SiO2,Al2O3,and Fe2O3 impurities on the properties of Yttria-Stabilized Zirconia(YSZ)TBCs prepared by atmospheric plasma spraying was investigated.The samples were prepared with the contents of these impurities being increased gradually from less than 0.01wt% to 1.00wt%.The results demonstrated that those low-melting oxide impurities exhibit a significant effect on thermal conductivity and porosity of the coatings,playing a key role on thermal shock failure.The performance of coatings deteriorated especially significantly when the impurity oxide content is less than 0.2wt%.