Novel Chemical Method to Fabricate SiC/Al_2O_3 Ceramic Composite Coatings on Metallic Substrates

Ceramic coatings on metallic substrates have increasing application in industry due to enhanced mechanical properties and corrosion resistance of the ceramic coatings.In particular,the SiC/Al2O3 composite coating is desirable since it could offer both high wear resistance and chemical stability at both room and high temperature.In this work,polycarbosilane(PCS) as the SiC precursor polymer,SiC nano powder as the inert filler,Al powder as the reactive filler were mixed to produce the SiC/Al2O3 composite coating,where the SiC is produced from the PCS together with SiC nanoparticles,and Al2O3 is formed due to oxidation of the Al.The Al and SiC nanopowder are used here to reduce the volume shrinkage due to formation of SiC from PCS.With variation of the processing condition,the SiC/Al2O3 composite coatings with thickness up 50 μm were produced on the Fecralloy substrates.Such coatings show dense structure without apparent crack,which indicate a great potential of such simple and flexible method to fabricate ceramic coatings on metallic substrates.