Narrow Results

Effects of copper surface roughness $R_{\mathrm{\text{a}}}$ 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 4A/dm², the coating roughness increased with the increase of the value of substrate $R_{\mathrm{\text{a}}}$ in the range 0.1–1.1$\mu$m. The coating thickness and hardness increased with the decrease of substrate $R_{\mathrm{\text{a}}}$. When substrate $R_{\mathrm{\text{a}}}$ was 0.4$\mu$m, the substrate/coating bonding force reached the maximum level. When substrate $R_{\mathrm{\text{a}}}$ 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.