Enhancement of wear resistance of ductile cast iron by Ni–SiC composite coating

Wear resistance of unalloyed ductile iron (Dl) can be enhanced either by heat treatment or by deposition of hard coating. The electrodeposition of Ni–SiC composite on unalloyed Dl (GGG 40) has been applied. The effect of operating conditions including current density and SiC content in the plating solution on the SiC incorporation in the deposited layer were studied. It was found that the volume percent of SiC particles in the composite layer increases with increasing current density and SiC content in the bath. The maximum SiC incorporation could be attained at optimum conditions; 60 g/1 of SiC particles in suspension, 5 A/dm2, pH 5 and 50 °C. Also the results reveal that the particle inclusion in the coating layer depends mainly on the treatment process (activation with PdCI2). The mechanical properties of the composite such as hardness and wear resistance were examined comparing with the uncoated substrate. The reinforced particles incorporated with Ni-matrix improve the hardness and wear resistance of coated Dl comparing with uncoated substrate.