Patent ID: 7833583

Claim:
A method of operating and regenerating an electroless nickel plating bath, the method comprising the steps of: a) depositing electroless nickel from the electroless nickel plating bath onto a substrate, wherein the electroless nickel plating bath comprises a source of nickel ions and a source of hypophosphite ions; b) maintaining a concentration of nickel ions and hypophosphite ions in the plating bath such that plating can continue; c) operating the plating bath until a desired number of metal turnovers is reached; d) processing a portion of the electroless nickel plating bath through a cation exchange resin to separate nickel, wherein after the nickel is removed, a phosphite solution comprising ammonium phosphite, ammonium hypophosphite, and organic acid remains and wherein the phosphite solution comprises less than 10 g/l of sodium ions and less than 10 g/l of sulfate ions; e) regenerating the cation exchange resin with hypophosphorous acid thereby creating a dilute nickel hypophosphorous acid solution; f) increasing the concentration of nickel in the dilute nickel hypophosphorous acid solution of step e) by adding a source of nickel ions selected from the group consisting of nickel carbonate, nickel hydroxide, nickel oxide, and combinations thereof to the solution to form a concentrated nickel solution; and g) adding the concentrated nickel solution of step f) to the plating bath of step b) to maintain the concentration of nickel ions in the plating bath.