Patent ID: 6585933
Filing Date: 2003-07-01
Classification: C23F

Abstract:
A method for controlling the corrosion of metals in contact with an aqueous system at a pH of about 5 to about 12 which comprises introducing into said system a combination of:(a) a tetrazolium compound of the formula: â€ƒwherein R1, R2 and R3 are selected from the group consisting of lower alkyl, branched lower alkyl, aryl, substituted aryl, alkylaryl, substituted alkyaryl and heterocyclic substituted aryl, with the proviso that neither R1, R2, or R3 contain more than 14 carbon atoms; and n is 1 or 2, such tetrazolium compound optionally having associated water soluble ionic species if needed to obtain a neutral charge, and (b) at least one other aqueous system treatment material chosen so that the material does not substantially reduce the tetrazolium compound selected from the group consisting of inorganic phosphates; nitrites; compounds that release a metal anion in water; 2,3-dihydroxybenzoic acid; 1,10-phenanthroline; polycarboxylates; alkyl hydroxylcarboxylate acids; aminohydroxysuccinic acids; carboxyamines; polyepoxysuccinic acids; modified polyepoxysuccinic acids; monophosphonic acids; diphosphonic acids; phosphonocarboxylic acids; hydroxyphosphonocarboxylic acids; aminophosphonic acids; phosphonomethylamine oxides; polymeric amine oxides; polyetherpolyaminomethylene phosphonates; polyetherpolyamino-methylene phosphonate N-oxides; long chain fatty acids derivatives of sarcosine; telomeric, co-telomeric, polymeric or copolymeric phosphorus-containing carboxylates; amines; diamines; alkanolamines; fatty amines and diamines; quaternized amines; oxyalkylated amines; alkyl pyridines; benzoates; substituted benzoates; straight chain C5-C11 monocarboxylates; C4-C15&agr;,&ohgr;-dicarboxylates; amine salts of carboxylic acids; mercaptocarboxylic acids; amino acids; polyamino acids; dicarboxylic acids; tricarboxylic acids; phosphoesters; phosphate esters; water soluble salts thereof and mixtures thereof, wherein the weight ratio of component (b) to component (a) is from about 100:1 to about 1:20.