Ni-SiC composite coating plant

Abstract

This paper discusses the features of the process of forming a composite coating based on Ni-SiC by the electrodeposition method. A model of the action of electrostatic, gravitational and centrifugal forces on SiC particles in an electrolyte solution for electrodeposition is presented. Based on the proposed model, an installation was designed on which the technological process of applying a composite Ni-SiC coating to flat samples of aluminum alloy AK7, simulating a sector of an axisymmetric part, was successfully tested. Due to the fact that the cylindrical bath with the processed sample fixed on it takes both a vertical and horizontal position, coatings with different structures were obtained. With a vertical arrangement of the cylindrical bath of the installation, a nickel-based coating with a thickness of 25±3 μm is formed during the electrodeposition process. With a horizontal arrangement of the cylindrical bath of the installation, a composite nickel coating with a uniform distribution of reinforcing SiC particles with a volume fraction of 30% and a thickness of 32±3 μm is formed during the electrodeposition process. The nickel coating with a uniform distribution of SiC particles is characterized by a maximum microhardness value of 690±8HV, increased roughness Ra=6.80±0.50 and a low groove width b=67±3 μm after the scratch test, which indicates good adhesion to the substrate material.