Synthesis and characterization of novel Cu, Cu-SiC functionally graded coating by pulse reverse electrodeposition

Abstract

Abstract A Cu based functionally graded coating (FGC) has been deposited on an annealed Cu substrate by galvanostatic pulse reverse electrodeposition (PRED) route. The objective is to develop a hard surface with highly ductile and conductive interior. The cathodic current density (CCD) has been increased stepwise (from 50 to 200\u202fmA/cm2) to synthesize Cu FGC on an annealed Cu substrate. It has three layers of Cu coating (20\u202fμm each) with a gradual reduction in crystallite size along the thickness. Two layers of Cu-SiC nanocomposite coating with an increment in the amount of incorporated SiC nanoparticles (from 2 to 7\u202fvol%) are electrodeposited on Cu FGC. This is done by introducing bath agitation (350 and 450\u202frpm) during deposition at CCD of 200\u202fmA/cm2, which has resulted in Cu, Cu-SiC FGC with five layers (12\u202fμm each). SiC nanoparticles are used to impart hardness to the coating through dispersion strengthening. The Cu, Cu-SiC FGC possesses higher hardness (∼3.8\u202fGPa), lower residual compressive stress (∼291\u202fMPa), and lower surface roughness (∼0.9\u202fμm) as compared to electrodeposited single layer Cu-SiC nanocomposite coating. With such properties Cu, Cu-SiC FGC on annealed Cu substrate can serve as a novel prospective electrical contact material.