摘要
研究了La2(Zr0.7Ce0.3)2O7(LZ7C3)的合成动力学及相结构,并根据合成过程中的损失对初始成分进行了设计,最终制备出符合原子比La∶Zr∶Ce为10∶7∶3的LZ7C3粉末.用X射线衍射仪和场发射扫描电镜研究了样品的相成分和微观组织,用激光脉冲法和推杆法测量了样品的热导率和热膨胀系数.结果表明:LZ7C3是由烧绿石结构的La2Zr2O7(LZ)固溶体和萤石结构的La2Ce2O7(LC)固溶体组成,其中LZ固溶体是主相;热导率随着温度的升高而逐渐降低,在1473 K时为0.79 W.m-1.K-1,较LZ降低了50%左右;热膨胀系数在1473 K时为11.6×10-6 K-1,比LZ提高了20%左右.这些优越的性能表明LZ7C3是一种具有较大应用前景的新型热障涂层陶瓷材料.
The synthesis kinetics and phase structure of L% （Zr0.7 Ce0.3 ）207 （LZ7C3） ceramic was investigated. The preparation composition was designed according to the mass loss in the synthesis process. LZTC3 powder was prepared successfully by a solid state reaction method and its atom ratio of La： Zr： Ce is close to the theory value of 10： 7： 3. The phase composition, microstructure, and thermophysical properties of the powder were studied by X-ray diffraction （XRD）, field emission scanning electron microscopy （FESEM） , the laser-flash method and the pushing-rod method. XRD results reveal that LZ7C3 is a mixture of L%Zr207 （LZ） with pyrochlore structure and L% C% 07 （LC） with fluorite structure, and its main phase is the LZ solid solution. The thermal conductivity of LZ7C3 decreases gradually with increasing temperature ; at 1473 K its value is 0. 79 W m - K - , which is almost 50% lower than that of LZ. The thermal expansion coefficient is 20% larger than that of LZ, and its value is 11.6 x 10-6 K - at 1 473 K. These results show that LZ7C3 ceramic can be explored as a novel prospective candidate material for use in new thermal barrier coating systems in the future.
出处
《北京科技大学学报》
EI
CAS
CSCD
北大核心
2012年第3期310-315,共6页
Journal of University of Science and Technology Beijing
基金
国家重点基础研究发展计划资助项目(613112)
关键词
陶瓷
热障涂层
热导率
热膨胀
ceramics
thermal barrier coatings
thermal conductivity
thermal expansion
