Fabrication and Water-vapor Corrosion Resistance of Ba_(0.25)Sr_(0.75)Al_2Si_2O_8 Environmental Barrier Coating

Ba_(0.25)Sr_(0.75)Al_2Si_2O_8(BSAS) as environmental barrier coating(EBC) was coated on the 2D Cf/SiC substrate using slurry-brushing process.The water-vapor corrosion resistance of Cf/SiC and Cf/SiC-BSAS were studied in 50%H2O-50%O2 water vapor under atmospheric pressure and static atmosphere at 1250℃,respectively.The results show that the dense BSAS coating with free cracks can be prepared by slurry-brushing method followed by heat-treatment at 1350℃ in high purity argon.The coating thickness approximate to 15μm after pasted once,and can reach 50μm after pasted for three times.The weight and flexural strength of Cf/SiC-SiC decreases greatly,while the weight of Cf/SiC-BSAS has no obvious change and the flexural strength retention is over 90% after corroded for 100 h.