激光熔覆-等离子喷涂热障涂层高温氧化结构及残余应力

发布时间：2018-05-11 00:11

  本文选题：热障涂层 + 激光熔覆　； 参考：《材料热处理学报》2017年01期

【摘要】：采用半导体激光熔覆与等离子喷涂相结合的方法制备了YSZ/CoCrAlY热障涂层,利用扫描电镜(SEM)、X-射线衍射仪(XRD)分析了其高温氧化后的结构特征,建立了其高温氧化后应力特征的计算模型,并与拉曼显微光谱仪测试的应力进行了对比。结果表明:高温氧化后,粘结层组织为垂直于基体表面的树枝晶结构,陶瓷层出现细小裂纹与部分脱落现象,ZrO_2发生单斜相向立方相或正方相转变时伴随有4%的体积收缩,陶瓷层产生拉应力;ZrO_2发生立方相或正方相向单斜相转变时伴随有6%的体积膨胀,陶瓷层产生压应力;热障涂层经过750℃高温氧化108 h后,通过模型计算陶瓷层残余应力为496.5 MPa的压应力,与拉曼光谱测量结果(434.8 MPa)吻合得较好。
[Abstract]:YSZ/CoCrAlY thermal barrier coatings were prepared by laser cladding and plasma spraying. The structural characteristics of the coatings after high temperature oxidation were analyzed by scanning electron microscopy (SEM), and the stress characteristics of the coatings were calculated. The stress measured by Raman microspectrometer is compared with that measured by Raman microspectrometer. The results show that the microstructure of the bonding layer is dendritic structure perpendicular to the surface of the substrate after oxidation at high temperature, and the fine cracks and partial shedding of ceramic layer occur during the monoclinic phase to cubic phase or square phase transition with 4% volume contraction. During the transition from cubic phase or square phase to monoclinic phase, there is 6% volume expansion and compressive stress in ceramic layer, and the thermal barrier coating is oxidized at 750 鈩，

本文编号：1871534