Influence of SiC, Si 3N 4 and Al 2O 3 particles on the structure and properties of electrodeposited Ni

Abstract

The structure and properties of electrodeposited nickel composites reinforced with inert particles like SiC, Si 3N 4 and Al 2O 3 were compared. A comparison was made with respect to structure, morphology, microhardness and tribological behaviour. The coatings were characterized with optical microscopy, Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) technique. The cross-sectional microscopy studies revealed that the particles were uniformly distributed in all the composites. However, a difference in the surface morphology was revealed from SEM studies. The microhardness studies revealed that Si 3N 4 reinforced composite showed higher hardness compared to SiC and Al 2O 3 composite. This was attributed to the reduced crystallite size of Ni — 12 nm compared to 16 nm (SiC) and 23 nm (Al 2O 3) in the composite coating. The tribological performance of these coatings studied using a Pin-on-disk wear tester, revealed that Si 3N 4 reinforced composite exhibited better wear resistance compared to SiC and Al 2O 3 composites. However, no significant variation in the coefficient of friction was observed for all the three composites.