Novel Electroplating Method Using Foam of an Electrolyte Solution

Abstract

A novel electroplating method in which the foam of an electrolyte solution was used instead of liquid electroplating solutions was developed. The foam of the electrolyte solution was generated by bubbling nitrogen gas at a rate of 50–100 mL/min through 20 mL of modified Watt bath in which 2–6 × 10−3 wt% of sulfuric acid monododecyl ester sodium salt (SDS) was added as a surfactant. The nitrogen gas was introduced through a glass filter. The foam of the electrolyte solution drew electric current sufficient to cause electrochemical deposition. Nickel films deposited on brass substrates by this method had a considerably smaller number of pits and pinholes when compared to films deposited using a liquid electrolyte solution. It is suggested that the reduction in the number of pits and pinholes was a result of the prompt removal of hydrogen bubbles from cathode surface as a result of interaction of the hydrogen bubbles with the bubbles in the foam of the electrolyte solution. Uniform films were obtained by using a foam with an average bubble diameter of the submillimeter scale. The use of the foam of the electrolyte solution also required the use of a lesser amount of electroplating solution.