Fabrication and water-vapor corrosion resistance of Ba_0.25Sr_0.75 Al₂Si₂O₈ environmental barrier coating

Ba_0.25Sr_0.75 Al₂Si₂O₈ (BSAS) as environmental barrier coating (EBC) was coated on the 2D C_f/SiC substrate using slurry-brushing process. The water-vapor corrosion resistance of C_f/SiC and C_f/SiC-BSAS were studied in 50%H₂O-50%O₂ water vapor under atmospheric pressure and static atmosphere at 1250°C, 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°C 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 C_f/SiC-SiC decreases greatly, while the weight of C_f/SiC-BSAS has no obvious change and the flexural strength retention is over 90% after corroded for 100 h.