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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。
YSZ / CoCrAlY thermal barrier coatings were prepared by a combination of semiconductor laser cladding and plasma spraying. The structure of the YSZ / CoCrAlY thermal barrier coatings was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) The calculation model of stress characteristics after high temperature oxidation is compared with the stress measured by Raman microspectrometer. The results show that the microstructure of the adhesive layer is a dendritic structure perpendicular to the surface of the substrate after the high temperature oxidation. The cracks and partial detachment of the ceramic layer appear. The monoclinic phase or the tetragonal phase transition of ZrO 2 is accompanied by 4% volume shrinkage , Ceramic layer tensile stress; ZrO_2 cubic phase or cubic phase when the monoclinic phase transition accompanied by 6% of the volume expansion, ceramic layer compressive stress; thermal barrier coating after high temperature oxidation at 750 ℃ for 108 h, calculated by the model of ceramic The compressive stress of layer residual stress is 496.5 MPa, which agrees well with Raman spectrum measurement (434.8 MPa).