Laser Surface Alloying Grey Iron with Cr, Ni, Co, and Co–Cr Coatings

AbstractA flake graphite grey cast iron has been laser surface alloyed with coatings containing 13-40% Cr, 9-52%Ni, and 26-45% Co. The Ni coatings contained up to 11%Al and the Co coatings contained up to either 2%Al or 25%Cr. The coatings were of high integrity, low porosity, and uniform in composition, microstructures, and hardness. Coatings containing more than 20% Cr reduced considerably the amount of corrosion in 10% nitric acid solution and 3%NaCl solution. A coating containing 20%Cr suppressed completely the substantial corrosion component of wear against a SiC pin in distilled and 3%NaCI waters. The cavitation erosion resistance of the coatings in distilled and salt waters was greatly increased.