PROCESS FOR IMPROVING THE CORROSION RESISTANCE OF METAL SURFACES AND METAL PIECES HAVING IMPROVED CORRSION RESISTANCE

摘要

A metal piece having an organic coating with improved corrosion resistance and adhesion is described which comprises a zinc or zinc alloy plated metal piece having on its surface, a chromate film deposited from an aqueous acidic chromium solution comprising trivalent chromium as substantially the only chromium ion present, and a cathodic electrocoated siccative organic coating on the chromate film. In one embodiment, the zinc alloy includes a substantial gamma crystallographic phase. A process for obtaining such coated metal pieces also is described.