新型La_2Zr_2O_7环境障涂层的1300℃热冲击行为研究  

Investigation of new La_2Zr_2O_7 environmental barrier coatings on high temperature thermal shock behavior at 1300℃

作　　者：许振华[1] 何利民[1] 戴建伟[1] 王晋平[1] 王凯[1] 牟仁德[1] 

机构地区：[1]北京航空材料研究院金属腐蚀与防护研究室,北京100095

出　　处：《真空》2014年第3期20-25,共6页Vacuum

基　　金：航空科学基金项目(2011ZF21011)

摘　　要：采用化学气相沉积和原位合成工艺在Cf/SiC基体上制备了Si/3Al2O3·2SiO2/La2Zr2O7新型环境障涂层(Environmental Barrier Coatings,EBC),研究了EBC涂层在1300℃的抗热冲击性能。结果表明,涂覆Si/3Al2O3·2SiO2/La2Zr2O7涂层的Cf/SiC试样,在热冲击试验进行到121次时发生了过早剥落失效。试验过程中,3Al2O3·2SiO2中间层内的Al元素发生外扩散并在面层中发生反应生成LaAlO3,La2Zr2O7在1300℃高温热冲击环境下发生烧结和粉化,以及由于热膨胀系数差异造成的EBC涂层内残余应力的产生均是导致EBC涂层过早剥落失效的主要原因。A new environmental barrier coating （EBC）system including Si/3Al2O3·SiO2/La2Zr2O7 was investigated in this study. Si and mullite （3Al2O3·SiO2）bond coating was firstly deposited on top of Cf/SiC substrate by chemical vapor deposition（CVD）, and then La2Zr2O7 as one top coating was fabricated by in-situ synthesis.High temperature thermal shock behavior of EBC system was tested at 1300 ℃.The results indicate that the degradation of the coatings occurs after exposure of 121 cycles.The Al element contained in the middle layer diffuses outward to La2Zr2O7 top coating and then one new phase of LaAlO3 is formed,and the early sintering and increment of porosity within La2Zr2O7 at 1300℃,and the residual stresses induced by the mismatch of thermal expansion coefficients among Si,mullite and La2Zr2O7 are the primary factors leading to the spallation failure of EBC.

关 键 词：LA2ZR2O7 环境障涂层 热冲击 失效 

分 类 号：TQ174.15[化学工程—陶瓷工业]