Simulation and Test Analysis on Effect of Current Density on Electrodepositing Minuteness Structure under Supercritical Fluids

Abstract

This study simulates the electric field of the supercritical electrodepositing system using Comsol software. The effects of the current density on the Ni 2+ concentration distribution and the electrodepositing film growth on the cathodic surface are analyzed. The surface morphology and micro-hardness were discussed first. The results show that the electric field is uniformly distributed inside the minuteness groove. The average Ni 2+ concentration on the cathodic surface decreases at first, but then increases with the proceeding electrodepositing process; the growth of the electrodepositing films is similar to the distribution of the cathodic current density. The grain size and organization of the Ni-diamond composite electrodepositing minuteness films under supercritical fluid are fine and compact. Moreover, the micro-hardness of the sample reaches 900.75 HV (200 g), a figure that is 70 % higher than that of traditional electrodepositing when the current density is 700 A/m 2 , the electrodepositing temperature is 323 K, the supercritical pressure is 12 MPa, and the nano-diamond particles content is 30 g/L.