氧化锆陶瓷四方相以及晶界热导率的定量计算

氧化钇部分稳定的氧化锆(YSZ)涂层是应用广泛的热障涂层材料。为了更好地研究各种因素对热障涂层热导率的影响, 使用压制烧结的方法制备基本致密的氧化锆陶瓷, 研究相组成和晶粒大小对热导率的定量影响。在不同的烧成制度下制备出不同晶粒大小的氧化锆陶瓷。用电子背散射衍射(EBSD)图像研究氧化锆陶瓷材料的相组成以及晶界的分布情况。综合有限元模拟的方法以及傅立叶传导方程, 计算出四方相和晶界的热导率分别为2.65 W/(m·K)和1.54 W/(m·K)。研究表明, 四方相的热导率比氧化锆陶瓷的热导率高, 而晶界的热导率比氧化锆陶瓷的低。

Quantitative Calculation of Thermal Conductivity of Tetragonal Phase and Grain Boundary on Zirconia Ceramics

The yttria-stabilized zirconia (YSZ) coatings have been widely used as thermal barrier coatings (TBCs). In order to investigate the factors that influenced the thermal conductivity of TBCs, bulk YSZ ceramics with different grain sizes were prepared via hot-pressing sintering methods under different annealing conditions. The quantitative effects of the phase and the grain size on the thermal conductivity were analyzed. Based on electron backscatter diffraction images (EBSD) of YSZ ceramics, the distribution of grain boundaries and tetragonal phase were obtained. And thermal conductivities of grain boundaries and tetragonal phase were calculated by finite element models and Fourier’s equation. The thermal conductivities of grain boundaries and tetragonal phase are 2.65 W/(m·K) and 1.54 W/(m·K), respectively. The results reveal that the thermal conductivity of tetragonal phase is higher than that of the YSZ ceramic (2.31 W/(m·K)), while grain boundary’s is lower than that of the YSZ ceramic.