La_2Zr_2O_7陶瓷在高温及高温湿氧环境中的组成结构演化

Evolution of Composition and Structure of La_2Zr_2O_7 in High Temperature and Water Vapor Environment

采用溶胶-凝胶法制备了锆酸镧（LZO）陶瓷,对比研究了LZO陶瓷在1300-1500℃空气环境及水汽环境中的组成、结构演变。采用电感耦合等离子体原子发射光谱（ICP-AES）仪,X射线衍射（XRD）仪、场发射扫描电子显微镜（SEM）、透射电子显微镜（TEM）对LZO陶瓷及经不同环境处理后的组成、物相与形貌进行了研究。结果表明：溶胶-凝胶法制备所得LZO陶瓷为烧绿石结构,平均晶粒尺寸为44 nm,陶瓷中的La和Zr摩尔比为0.94∶1;LZO陶瓷在高温空气环境中的组成与结构基本稳定,1500℃下出现了较为明显的高温烧结和晶粒生长;LZO陶瓷在高温水汽环境中失重明显,且发生了严重的分相和高温烧结,生成了m相Zr O2和c相La2O3,平均晶粒尺寸达到2μm。

La2Zr2O7 （ LZO） ceramic was prepared by sol-gel method. The chemical compositions and phases evolvement of LZO ceramic in the air and water vapor was studied from 1300 ℃to 1500 ℃ . The chemical compositions, phases and microstructures of LZO ceramic and LZO ceramic treated in different environment were characterized by inductively coupled plasmaatomic emission spectrometer（ICP-AES）, X-ray diffraction （ XRD ） , scanning electron microscope （ SEM ） , transmission electron microscope （TEM） . The results show that the LZO ceramic powder is pyrochlore structure, the molar rate of La to Zr in the LZO ceramic is 0. 94 to 1, the grain of LZO is 44 nm. The chemical compositions and phases of LZO ceramic are almost stable in the air, but sintering and grain growth happens at 1500 Tl . The loss of components, phase separation and sintering of LZO ceramic happens, the m-ZrO2 and c-La2O3 were produced and the grain of LZO can reach 2 μm in water vapor environment.