Selected stripping of nickel-iron alloys from ferrous substrates

Abstract

A composition and process for selectively removing nickel and nickel alloys with iron and/or cobalt from a surface of a metal substrate which comprises contacting said metal surface with an aqueous bath containing: A. at least one nitro substituted organic compound: B. at least one organic amine or polyamine or substituted amine or polyamine; and C. at least one phosphorus oxo acid or organic phosphorus oxo acid or salts thereof or alkyl phosphonate substituted amines. By nickel-iron alloy deposit is meant a deposit containing from about 5 to 90 percent by weight iron with that portion which is not iron being primarily nickel or nickel and cobalt. Although small amounts of impurities such as copper, zinc, cadmium, lead, etc. may also be present, the major constituents of the alloy are nickel and iron.

Dependencies are inferred from the claim text.