Effects of direct current and pulse-plating on the co-deposition of nickel and nanometer diamond powder

Nickel and nanometer-diamond powder have been successfully co-deposited on Cu alloy by the direct current and pulse plating methods. The variables investigated within this research work include the concentration of diamond powder in the plating solution, current density (d.c.), current frequency (pulse plating), plating temperature, plating time, and stirring speed during plating processes. The microhardness of the co-deposited layer is increased with increasing concentration of diamond powder in the plating solution. The surface roughness is increased as well. The microhardness value of the specimen treated with 40 g/l diamond powder concentration can reach 611 HV using the method of pulse plating. The stirring speed below 300 rpm and plating temperature ranging from 30 to 50 degrees C are found to be suitable for Ni-diamond composite plating. The friction coefficient, mu, of the Ni-20 g/l diamond co-deposition specimen is about 0.16, which is much lower than that of pure Ni-plated layer (mu=0.44). (C) 1999 Elsevier Science S.A. All rights reserved.