等离子喷涂La_2(Zr_(0.7)Ce_(0.3))_2O_7热障涂层的抗热震性能  

THERMAL SHOCK RESISTANCE OF La_2(Zr_(0.7)Ce_(0.3))_2O_7 THERMAL BARRIER COATING PREPARED BY ATMOSPHERIC PLASMA SPRAYING

作　　者：项建英[1] 陈树海[1] 黄继华[1] 赵兴科[1] 张华[1] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083

出　　处：《金属学报》2012年第8期965-970,共6页Acta Metallurgica Sinica

基　　金：国家重大基础研究发展计划资助项目61311203B~~

摘　　要：采用等离子喷涂制备了La_2(Zr_(0.7)Ce_(0.3))_2O_7(LZ7C3)热障涂层,并对涂层的微观组织、相结构、成分、相稳定性、涂层热导率以及抗热震性能进行了研究.结果表明,LZ7C3涂层由单相烧绿石结构物质组成,高温稳定性较好;涂层的热导率较块材下降约20%,这是由于涂层具有较高的孔隙率所致:涂层在不同温度范围的热震寿命和失效机制不同,在室温至约1000℃间的热震寿命为116 cyc,涂层失效方式以片状剥落为主:在室温至1100℃间的热震寿命为53 cyc,涂层失效方式为片状剥落和层状撕裂;在室温至1200℃间的热震寿命为3 cyc,涂层失效方式以层状撕裂为主.Thermal barrier coatings （TBCs） are widely used in turbine engines to protect hot-section metallic components from corrosion and oxidation. The typical material of TBCs is 8YSZ due to its low thermal conductivity （2.1 W.m-1.K-1） and relatively high thermal expansion coefficient （1.1x10^-5 K-l）. However, at temperature above 1200 °C, it could hardly be used for lon°term application for its low sintering resistance and low phase stability. So it is urgently needed to develop novel TBCs materials with higher phase stability and lower thermal conductivity than 8YSZ. Recently, some materials have been evaluated as the candidates for TBCs, such as LaMgAlnO17 （LMA）, La2Zr2OT（LZ）, La2Ce2OT（LC） and La2（Zr0.zCe0.3）2Oz （LZ7C3）. Among those interesting candidates, the LZTC3 ceramic shows the promising thermophysical properties for high-temperature TBCs. In this paper, the novel thermal barrier LZTC3 coating was prepared by atmospheric plasma spraying. The microstructure, phase structure, composition, phase stability, thermal conductivity and thermal shock behavior of LZ7C3 coating were studied. These results show that the coating had single pyrochlore structure with high phase stability in high temperature. The thermal conductivity of coating is 20% lower than the bulk material due to high porosity of coating. The thermal shock tests indicate that the lifetime and failure mechanism depend on the test temperature. The coatings are failed after 116 cyc thermal shock from 1000 °C to room temrature, which is attributed to the spallation of lamella. The failure mode of lamella spallation and layer fracture are found when the coating tested at 1100 °C, the thermal shock lifetime is 53 cyc. Whereas at 1200 °C, the coatings are spalled entirely after 3 cycthermal shock in the way of layer fractur at tile interface between LZ7C3 and bond coat.

关 键 词：热障涂层 La_2(Zr_0.7Ce_0.3)_2O_7 等离子喷涂 热导率 抗热震性能 

分 类 号：TB174.45[生物学—生物工程]