Patent ID: 6485580
Filing Date: 2002-11-26
Classification: C23C

Abstract:
An aqueous liquid composition for treating the surfaces of light metals and light metal alloys, said liquid composition having a pH value within a range from 1.0 to 7.0 and consisting essentially of water and the following components:(A) from 0.01 to 50 g/L of a component selected from the group consisting of permanganic acid, water soluble salts thereof, and mixtures of any two or more of permanganic acid and any of its water soluble salts; (B) from 0.01 to 20 g/L of a component selected from the group consisting of water soluble compounds of titanium, water soluble compounds of zirconium, and mixtures of any two or more of said water soluble compounds of titanium and zirconium; and, optionally, one or more components selected from (i) one or more water soluble manganese compounds other than permanganic acid or its salts, (ii) one or more pH adjustment agents other than phosphoric acid, (iii) one or more sequestering agents, or (iv) one or more supplemental oxidizing agents, wherein said aqueous liquid composition is free from phosphate ions.