Abstract: A composition and method is disclosed for inhibiting the corrosion of metals in contact with an aqueous system capable of corroding the metal. The inventive composition contains a substantially water-soluble polymer of an acidic amino acid and at least one water-soluble salt of molybdenum or zinc. The composition is substantially non-toxic and environmentally acceptable and is supplied in a corrosion-inhibition amount to the otherwise metal-corrosive aqueous system.

Abstract: A combination of sulfur-free azoles, preferably benzotriazole and tolyltriazole, with sulfur-containing azoles, preferably 2-mercaptobenzothiazole or mercaptobenzimidazole, prevents discoloration, staining, or corrosion of metal surfaces being coated with an organic protective coating from aqueous dispersion or solution.

Abstract: Water-circulating systems are treated with an aqueous, alkaline composition comprising I) an organo-phosphorus chelating agent, II) an acrylate homopolymer, III) a salt of an acrylic copolymer, a portion of the repeating units of which contain sulfonate groups, IV) a molybdate salt, and V) a salt of a fused-ring aromatic triazole. This composition (which is formulated in accordance with a specific order of addition of the ingredients) is effective against white rust (corrosion of galvanized metal parts). When the water-circulating system is also fouled with a biofilm, it is preferred to introduce a biofilm remover having biocidal, surfactant, and chelating properties into the system, but the biofilm remover is introduced separately from the above-described composition.