An Investigation of Environment Barrier Coating on 2D C/SiC Composites Prepared by Liquid Phase Process

Sc Si O -based environmental barrier coating (EBC) was prepared on 2D C/SiC composites by different liquid phase processes. Single Sc Si O coating was brushed with sol and slurry. The multi-layer coating, which consisted of BSAS (Ba Sr Al Si O , B) as bond coat, BSAS + Sc Si O (BS) as interlayer and Sc Si O (S) as top coat, was painted with slurry and modified slurry. The slurry process was modified using amorphous instead of crystallized powders as raw materials derived from the sol-gel method. Modification mechanisms were proposed and characterized by weight losses of BSAS and Sc Si O dry gel from thermogravimetric analysis and their sintering shrinkage ratios from coefficient of thermal expansion tests. The microstructure of the prepared coating was observed using scanning electron microscopy. The phase composition was detected by X-ray diffraction. The results showed that the S/BS/B coating with 30 μm thickness, which was prepared by the modified slurry, possessed excellent adhesion to the substrate and the best compactness among the above coatings. Higher activity, lower sintering energy barrier and tiny sintering shrinkage of S and B amorphous powders are mainly responsible for the performance enhancement. © 2012 Springer Science+Business Media, LLC.