热障涂层用新型复合氧化物的制备及其热物理性能  

Preparation and Thermophysical Properties of New Composite Oxides for Thermal Barrier Coating

作　　者：冉书明[1] RAN Shuming(School of Intelligent Manufacturing,Chongqing Water Resources and Electrical Engineering College,Chongqing 402160,China)

机构地区：[1]重庆水利电力职业技术学院智能制造学院,重庆402160

出　　处：《机械工程材料》2022年第7期27-31,37,共6页Materials For Mechanical Engineering

基　　金：重庆市教科委科学技术研究项目(KJZD-K201903801)。

摘　　要：以高纯度La_(2)O_(3)、MgO、SrCO_(3)、CeO_(2)和Ta_(2)O_(5)为原材料,采用多步高温固相烧结法制备了Sr_(3)La_(3)Ce_(7)Ta_(2)O_(26.5)和Mg_(3)La_(3)Ce_(7)Ta_(2)O_(26.5)氧化物,研究了其晶体结构、微观形貌和热物理性能。结果表明:所合成的氧化物具有单一焦绿石结构,其显微组织致密,晶界清晰,元素种类和原子比与化学式基本一致;Sr_(3)La_(3)Ce_(7)Ta_(2)O_(26.5)的热膨胀系数大于Mg_(3)La_(3)Ce_(7)Ta_(2)O_(26.5),二者在1000℃时的热膨胀系数分别是11.6×10^(-6),11.37×10^(-6) K^(-1),明显大于7YSZ的9×10^(-6) K,并且二者在高温下均具有良好的晶体结构稳定性;Sr_(3)La_(3)Ce_(7)Ta_(2)O_(26.5)和Mg_(3)La_(3)Ce_(7)Ta_(2)O_(26.5)在1200℃时的热导率分别为1.68,1.87 W·m^(-1)·K^(-1),均低于7YSZ的2 W·m^(-1)·K^(-1);Sr^(2+)较大的离子半径和原子质量导致Sr_(3)La_(3)Ce7Ta_(2)O_(26.5)的热导率低于Mg_(3)La_(3)Ce_(7)Ta_(2)O_(26.5);合成氧化物的热导率和热膨胀系数均满足热障涂层的要求。Taking La_(2)O_(3),MgO,SrCO_(3),CeO_(2) and Ta_(2)O_(5) with high purity as raw reactants,the Sr_(3)La_(3)Ce_(7)Ta_(2)O_(26.5) and Mg_(3)La_(3)Ce_(7)Ta_(2)O_(26.5) oxides were synthesized by multi-step high temperature sintering,and the crystal structure,microstructure and thermophysical properties were investigated.The results show that the obtained oxides exhibited a single pyroxhlore crystal structure;the microstructure was very dense,and the grain boundaries were very clear;the element composition and the corresponding mole ratio were consistent with the corresponding chemical formula.The thermal expansion coefficient of Sr_(3)La_(3)Ce_(7)Ta_(2)O_(26.5) was larger than that of Mg_(3)La_(3)Ce_(7)Ta_(2)O_(26.5),and the thermal expansion coefficients at 1000℃were 11.6×10^(-6),11.37×10^(-6) K^(-1),respectively,which were obviously larger than 9×10^(-6) K of 7 YSZ;the two oxides had good crystal structure stability at high temperature.The thermal conductivity at 1200℃of Sr_(3)La_(3)Ce_(7)Ta_(2)O_(26.5) and Mg_(3)La_(3)Ce_(7)Ta_(2)O_(26.5) were 1.68,1.87 W·m^(-1)·K^(-1),respectively,which were smaller than 2 W·m^(-1)·K^(-1) of 7 YSZ;the large ionic radius and atomic mass of Sr^(2+)resulted in the lower thermal conductivity of Sr_(3)La_(3)Ce_(7)Ta_(2)O_(26.5) than Mg_(3)La_(3)Ce_(7)Ta_(2)O_(26.5).The thermal conductivity and expansion coefficient of the synthesized oxides both satisfied the requirements for thermal barrier coating.

关 键 词：复合氧化物 热障涂层 热导率 热膨胀系数 

分 类 号：TG174.4[金属学及工艺—金属表面处理]