Preparation of Ni Films using Solid/Liquid Hybrid Electroplating Method

Electroplating is one of the important fabrication methods to obtain magnetic films commercially, and we have reported many soft magnetic films electroplated from water-based plating baths (liquid baths). Recently, we reported Ni films using gel-based plating baths (solid baths) to reduce waste after electroplating, considering the recent trend of raising environmental awareness. Expecting the spread of the application possibilities of the gel plating method, the present study focuses on solid/liquid hybrid plating, a combination of solid and liquid plating, and investigates the film's qualities and magnetic properties. In the investigations for single baths, the plating rates of both baths (liquid and solid baths) showed almost the same value, up to 10 min of plating time. The saturation magnetizations for both baths are also nearly the same. In the case of the hybrid baths, although no interaction was observed with the film's appearance, the saturation magnetization for the solid bath is slightly lower than that for the liquid bath. The decrease in the saturation magnetization is often observed when water decomposition becomes the dominant reaction on the cathode surface instead of metal ions' reduction; these results indicate that the hybrid bath process differs from the single bath process in Ni reduction. Although further study is required for the reduction process, the present study finds that ferromagnetic Ni films can be prepared by hybrid plating.