Patent ID: 7811391
Filing Date: 2010-10-12
Classification: C23C

Abstract:
1. Compositions for coating metal substrates to improve the corrosion protection and adhesion bonding strength of said metal which comprise an acidic aqueous solution having a pH ranging from about 1.0 to 5.5 and per liter of said solution from about 0.01 to 100 grams of at least one trivalent chromium compound, from about 0.01 to 24 grams of at least one fluorozirconate, an effective amount of at least one water-soluble corrosion inhibitor selected from the group consisting of triazoles, benzimidazoles, benzazoles, benzoxazoles and mixtures of said inhibitors, from about 0.0 to 20 grams of divalent zinc compounds, from about 0.0 to 20 grams of surfactants, from about 0.0 to 20 grams of thickeners, and effective amount of a stabilizing compound selected from the group consisting of polyhydroxy compounds, carboxylic compounds and mixtures of polyhydroxy and carboxylic compounds, wherein the carboxylic compound is a hydroxyl-carboxylic acid and the water soluble salts thereof, wherein the hydroxyl-carboxylic acid compound is glycolic acid and the water soluble salts thereof.