Excor Korrosionsforschung Gmbh

Urte Ludwig

Gerhard Hahn

Georg Reinhard

George Reinhard

Signe Lautner

The present invention relates to new substance combinations as vapor phase corrosion inhibitors for protecting a broad range of customary utility metals, including iron, chromium, nickel, tin, zinc, aluminum, copper, magnesium and their alloys, against corrosion in humid climates. Said substance combinations comprise (1) at least one Cto Caliphatic monocarboxylic acid, (2) at least one Cto Caliphatic dicarboxylic acid, and (3) a primary aromatic amide. Preferably they further comprise (4) an aliphatic ester of hydroxybenzoic acid, in particular of 4-hydroxybenzoic acid, and/or (5) a bemzimidazole, in particular a benzimidazole substituted on the benzene ring.

Vapor phase corrosion inhibitors and method for their production

Substance combinations which contain (1) an inorganic salt of nitrous acid, (2) a water-insoluble polysubstituted phenol, (3) an aliphatic ester of a dihydroxybenzoic acid, and (4) a tocopherol plus optionally (5) a suitable water vapor-volatile bicyclic terpene or an aliphatically substituted naphthalene which promotes sublimation of the components present in the respective substance combination, especially in air at a relatively high atmospheric humidity, and the use of such substance combinations as vapor phase corrosion inhibitors in packaging or in storage in closed spaces for protection of the conventional metals for use such as iron, chromium, nickel, tin, zinc, aluminum, copper and their alloys against atmospheric corrosion are described.

Vapor-phase corrosion inhibitors and method of preparing same

The invention concerns combinations of substances with (1) an aromatic mercaptothiazole or triazole, (2) a multiple substituted phenol insoluble in water, (3) L ascorbic acid or one of its salts and possibly (4) a suitable carboxylic acid/salt pair that after sublimation and condensation on metal surfaces can stabilize the pH value of a condensed water film in the range 4.8&lE;pH&lE;6.5 (referred to 25&deg; C.), and use of the combinations of substances as vapor-phase corrosion inhibitors in packaging or for storage in closed spaces for protecting preferably metals that cannot be passivated, like copper, silver, manganese, magnesium and their alloys, against atmospheric corrosion.

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Dresden, Germany

Urte Ludwig