Si/3Al2O3·2SiO2+BSAS/Yb2SiO5环境障涂层13000℃抗水蒸气性能研究

摘要

A Si bond coat had been deposited on a Cf/SiC specimen by electron beam physical vapor deposition(EB-PVD), and then a mixed layer of mullite and BSAS and a Yb2SiO5 top coat were sprayed by plasma spraying(PS). The water vapor corrosion behavior was tested under the conditions of 0.54m/s, 1. 013 × 105Pa and 1300℃. The results indicate that the loss of mass was observed after 175h exposure under experiment conditions. The formation and volatilization of Yb(OH)3 and Si (OH)4 can be accountable for mass loss of those specimens. The combination of outward diffusions of Ba,Sr and Al in middle coating and inward diffusions of Yb in Yb2SiO5 coating, and residual stresses existed in EBC lead to the failure of EBC.%采用电子束物理气相沉积和等离子喷涂工艺在Cf/SiC基体上制备了Si/3Al2O3·2SiO2+BSAS/Yb2SiO5环境障涂层(Environmental Barrier Coatings,EBC),研究了在1300℃、1.013×105Pa、气体流速为0.54m/s的水蒸气环境中Cf/SiC基体和EBC涂层的抗水蒸气性能.结果表明:涂覆Si/3Al2O3·2SiO2+BSAS/Yb2SiO5EBC的Cf/SiC试样,在实验进行到175h时开始出现失重,实验过程中生成的Yb(OH)3和Si(OH)4气体不断地挥发是造成Yb2SiO5面层变薄并导致试样失重的主要原因;同时,3Al2O3·2SiO2+BSAS中间层内Ba,Sr,Al元素的向外扩散、Yb2SiO5面层中的Yb元素向内扩散,以及EBC涂层内存在的残余应力是导致EBC发生失效的主要原因.