INFLUENCE OF SURFACE ROUGHNESS OF SUBSTRATE ON THE PROPERTIES OF Ni-Co-Fe ELECTRODEPOSITION COATING ON COPPER

Effects of copper surface roughness R-a 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 4 A/dm(2), the coating roughness increased with the increase of the value of substrate R-a in the range 0.1-1.1 mu m. The coating thickness and hardness increased with the decrease of substrate R-a. When substrate R-a was 0.4 mu m, the substrate/coating bonding force reached the maximum level. When substrate R-a was 0.1 mu m, 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.