Finishing agent for trivalent chromium conversion coating and finishing method of black trivalent chromium conversion coating

摘要

The present invention provides a trivalent chromium chemical conversion film, in particular, a black trivalent chromium chemical conversion film having low insulation, no problem in tightening, excellent gloss and high corrosion resistance, and few scratches and spots. An object of the present invention is to provide a water-soluble finish for a trivalent chromium chemical conversion film. The present invention relates to a trivalent chromium source, a phosphate ion source, a zinc ion source, a chelating agent capable of forming a complex with trivalent chromium, and polyvinyl alcohol and derivatives thereof, polyvinylpyrrolidone and derivatives thereof, polyalkylene glycol and derivatives thereof Provided is a trivalent chromium chemical conversion coating finish characterized by containing a derivative and a nonionic water-soluble polymer compound selected from the group consisting of cellulose ethers and derivatives thereof.