An electrodeless nickel bath uses a chemical reducing agent to deposit nickel coatings uniformly on a receptive surface without the use of applied current. Typical systems use hypophosphites, aminoboranes or borohydrides as reducing agents. The plating reaction depletes the bath of nickel, reducing agent and stabilizing ingredients and also forms H+ that lowers the bath pH. In order to keep the bath components within the appropriate ranges, replenishing concentrates are added based on an analysis of bath concentration.

Control Strategy

The consumption of critical components in the bath occurs in direct proportion to the consumption of nickel. Typically, two proprietary concentrations containing nickel, reducer and trace ingredients are added in equal volumes. Alkaline ingredients (ammonium hydroxide or potassium carbonate) may need to be separately added or may be formulated to automatically adjust pH as a function of the concentrate addition.

Apparatus