Microstructure and Tribological Behavior of SiC and BN(h) Reinforced Electrodeposited Ni Matrix Composite Coatings

Ni-SiC/BN(h) composite coatings were fabricated by electrodeposition to improve the surface performances of parts manufactured by H13 steel. The effects of SiC and BN(h) concentration on the microstructure and tribological behavior of the composite coatings were investigated. It was found that the cellular bulges on the composite coating caused by a tip discharge were increased with the particles concentration, resulting an increased surface roughness. While the grains in the composite coating were refined until the particles concentration reached 37.5 g/L. These dispersed particles embedded in the composite coating can prevent friction pair from cutting into the coating. And the generated wear debris during friction acted as a secondary solid lubricant was responsible for the reduction of friction coefficient. Ni-SiC/BN(h) composite coating with the compact and uniform microstructure, proper distribution of the particles was obtained at the particles concentration of 37.5 g/L, showing the highest wear resistance. It was characterized by the smallest weight loss and width of wear scar. Worn surface analysis showed that the incorporation of the SiC and BN(h) particles led to the composite coatings changing from a ductile to brittle nature. The wear mechanism was dominated by abrasive wear and oxidation wear.