Paint pretreatment processes with low environmental impact, as an alternative to conventional phosphating treatments

摘要

A substitution process of zinc phosphating comprising: a. alkaline degreasing article to be phosphated; b. first washing with running water; c. second washing with demineralized water; d. conversion treatment in a bath comprising zirconium salts, phosphates, fluoride complexes, ammonia, at least one corrosion inhibitor, at least one accelerating agent process, at least a sequestering agent, a thickening system slush reaction and vanadium, and optionally titanium compounds; and. washed finish before treating the article in the furnace; wherein the corrosion inhibitor is a branched amine or alkyne derivative, a thiourea derivative or vanadium salts, molybdenum or antimony; in which the sludge thickening system reaction is a suitably balanced combination of a polysaccharide and a glycol.