Preparation and properties of alumina-carbon castables using SiC nanofiber coated graphite flake

Abstract

SiC nanofiber coated graphite flakes were fabricated at a relatively low temperature of 1623 K via an in-situ catalytic reaction approach employing Co(NO3)(2)center dot 6H(2)O as a catalyst precursor. The effects of catalyst amount and firing temperature on phase composition, morphology and water wettability of the as-prepared SiC nanofiber coated graphite flakes were studied. The Co catalyst promoted the growth of SiC nanofibers, which according to the density functional theory calculations, can be attributed to the increased bond length and weakened bonding of CO(g) and SiO(g) molecules upon their adsorption onto the Co catalyst. The water contact angle of SiC nanofiber coated graphite was reduced to 25 degrees from that 111 degrees in the case of its uncoated counterpart. Further-more, Al2O3-C castables using SiC nanofiber coated graphite flakes exhibited 73.1 % higher residual CMOR ratio after thermal shock test, 20.0 % lower in oxidation, and 43.5 % less in slag corrosion, than their counterparts using uncoated graphite flakes.