Electroless pure nickel plating process with continuous electrolytic regeneration system

We have developed an electroless nickel plating solution in which titanium ion redox system, Ti3+→Ti4++e−, was used as a reducing agent. The stability of the solution has been improved by the selection of chelating agents and their ratio to nickel and titanium ion, and by the addition of an amino acid and a sulfur-containing compound. A pure nickel film containing no phosphorus was obtained from the new electroless plating solution. Any other elements except nickel were not detected by inductively coupled plasma analysis. Electrolytic regeneration system of the solution has been also developed. Continuous running test for more than 100 h has been achieved in a pilot plant and the bath is believed to be stable enough to apply to a commercial production line.