Improvement in Current Efficiency of Gel-plating Process for Soft Magnetic Ni and Co Films

Recently, we reported Ni films prepared from gel electrolytes and showed the potential of the gel-plating process. Our previous study confirmed that the saturation magnetization of the Ni films was smaller than that of bulk Ni, indicating that we need to improve the saturation magnetization for gel-plating. The present study focuses on improving the current efficiency of the gel-plating process and investigates the effects of the current density during the electroplating and the metal reagent's concentration in the baths on the efficiency and the saturation magnetization of Ni and Co films. From the results of the investigations for the current density, we confirmed that low current density improves the current efficiency of the process and increases the saturation magnetizations of Ni and Co films. Increasing the concentration of metal reagents also improves current efficiency and increases saturation magnetizations. From these results, we found that improvement in the diffusion limitation of metal ions, such as reduction in the current density and increase in the metal ion concentration, can enhance the current efficiency of the gel-plating process. The improvement in the efficiency increased the saturation magnetization, and we also found that an improvement in efficiency leads to an improvement in the magnetic properties.