| 摘要 |
PCT No. PCT/EP81/00128 Sec. 371 Date Apr. 5, 1982 Sec. 102(e) Date Apr. 5, 1982 PCT Filed Aug. 19, 1981 PCT Pub. No. WO82/00665 PCT Pub. Date Mar. 4, 1982.The metal surfaces are treated with 0.5 to 5 wt. % aqueous solutions (pH value 7.5 to 10.5), in which is contained a synergistic combination-giving a clear solution in water-of corrosion-inhibiting substances. The combination consists of: a. one or more maleic acid mono-n- or -iso-alkylamides with 6 to 14, preferably 8 to 10 C atoms, b. one or more alkalolamines, preferably mono-, di- and/or tri-ethanolamine, and c. complexing phosphonic acids, preferably 1-hydroxy-alkyl-1,1-diphosphonic acid, 1-aminoalkyl-1,1-diphosphonic acid, phosphonocarboxylic acid and/or a phosphonic acid of the formula: <IMAGE> <IMAGE> Preferred phosphonic acids are 1-hydroxyethane-1,1-diphosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid and/or nitrilotrimethylene-phosphonic acid. The weight ratio of a:b should be in the solutions 1:0.3 to 1:10, that of a:c, 1:0.01 to 1:0.5. The solutions can contain additionally surfactants, preferably non-ionogenic surfactants in small quantities, also builders, preferably phosphates and/or borates. |
