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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。
The Si / 3Al2O3.2SiO2 + BSAS / Yb2SiO5 environmental barrier coatings (EBC) were prepared on Cf / SiC substrates by electron beam physical vapor deposition and plasma spraying. The effects of gas at 1300 ℃, 1.013 × 105Pa, Water vapor resistance of Cf / SiC substrates and EBC coatings in water vapor at a flow rate of 0.54 m / s. The results show that the Cf / SiC samples coated with Si / 3Al2O3.2SiO2 + BSAS / Yb2SiO5EBC begin to lose weight when the experiment reaches 175h. The Yb (OH) 3 and Si (OH) 4 gases generated during the experiment continuously Volatilization is the main reason for the thinning of the Yb2SiO5 surface layer and the loss of weight of the sample; meanwhile, the outward diffusion of Ba, Sr and Al elements in the 3Al2O3.2SiO2 + BSAS interlayer and the inward diffusion of Yb elements in the Yb2SiO5 surface layer, Residual stresses in the EBC coating are the main causes of EBC failure.