INFLUENCE OF SURFACE ROUGHNESS OF SUBSTRATE ON THE PROPERTIES OF Ni–Co–Fe ELECTRODEPOSITION COATING ON COPPER
Abstract
Effects of copper surface roughness Ra on the properties of Ni–Co–Fe alloy coatings were studied by the measurement of coating roughness, thickness, hardness, substrate/coating bonding force and the potentiodynamic polarization curve. Results showed that at the current density of 4A/dm2, the coating roughness increased with the increase of the value of substrate Ra in the range 0.1–1.1μm. The coating thickness and hardness increased with the decrease of substrate Ra. When substrate Ra was 0.4μm, the substrate/coating bonding force reached the maximum level. When substrate Ra was 0.1μm, the coating exhibited the best corrosion resistance. The comprehensive properties of the Ni–Co–Fe coatings can be effectively improved by controlling the surface roughness of copper substrate properly.