Formation and characterization of uniform SiC coating on 3-D graphite substrate using halide activated pack cementation method

Protective coatings are required for enhanced performance of carbon base materials for application in an oxidizing environment. Studies were carried out to uniformly coat SiC over the graphite substrate, using halide activated pack cementation (HAPC) method. Experimental results revealed that the optimum pack composition for adherent and dense coating was 2.5 wt.%NH4F-15wt.%Si-82.5wt.%Al2O3. Uniform, homogeneous and dense SiC coating with an average coating thickness of 5 μm was obtained at the deposition temperature of 1400 °C. The coated samples were characterized with respect to coating thickness, phase and oxidation resistance. The SiC coating on a graphite substrate has enhanced its life as compared to the uncoated substrate in the oxidative environment.