Nickel–carbon composite plating using a Watts nickel electroplating bath

Abstract

Metal–carbon composite platings have potential applications in various fields. We previously reported the preparation of nickel–nanocarbon composite platings using a Wood’s bath. The maximum carbon content was 1.2 mass%, but the maximum current efficiency of plating was 12%. The present study focuses on improving the current efficiency of the electroplating process used to prepare nickel–carbon black composites in a Watts bath contained carbon black. The microstructure and carbon content in the nickel plating were evaluated. The current efficiency was greater than 90%, but the carbon content of the composite plating layer was approximately 0.6 mass%. The incorporation of carbon black particles into the plating layer was influenced by the adsorption of particles onto the cathode surface, the supply of particles to the surface, and the electrodeposition rate. The carbon content in the plating layer was highest near the cathode surface and decreased with increasing thickness of the plating layer. The grain size of electrodeposits with carbon black was larger than that of deposits without carbon black. The space between grains was increased with increasing grain size. The corrosion resistance was diminished, indicating that the boundary was the originating point of corrosion.