Plating process for electroless nickel on zinc die castings

Abstract

A process is provided for plating zinc die cast substrates with an electroless nickel coating comprising depositing an electrolytic zinc layer on the substrate followed by depositing a first electroless nickel layer on the electrolytic zinc layer using a first alkaline electroless nickel bath and then depositing a finish electroless nickel layer on the first electroless nickel layer using an acidic electroless nickel bath. In a preferred embodiment, a second electroless nickel layer is deposited on the first electroless nickel layer using a second alkaline electroless nickel bath. It is preferred that at least one and preferably all of the electroless nickel baths contain an effective amount of antimony ions to enhance bath stability and metal to metal adhesion. Mechanical cleaning of the zinc die casting before plating is preferred.

Dependencies are inferred from the claim text.