Dipsol Chemicals Co., Ltd.

Shigemi Tanaka

Katsuhide Oshima

Manabu Inoue

Tomitaka Yamamoto

Akira Hashimoto

Masaru Kawai

Toshio Igari

Yukihisa Toyoda

A processing solution for forming a hexavalent chromium free, corrosion resistant trivalent chromate conversion film on zinc or zinc alloy plating layers comprises: trivalent chromium and oxalic acid in a molar ratio ranging from 0.5/1 to 1.5/1, wherein the trivalent chromium is present in the form of water-soluble complex with oxalic acid; and cobalt ions, which do not form a hardly soluble metal salt with oxalic acid and are stably present in the processing solution without causing any precipitation; wherein the solution reacts with zinc when bringing it into contact with the zinc or zinc alloy plating to form a hexavalent chromium free, corrosion resistant, trivalent chromate conversion film containing zinc, chromium, cobalt, oxalic acid and silicon on the plating. The film is quite thin, free of any hexavalent chromium, has corrosion resistance identical to or higher than that achieved by the conventional hexavalent chromium-containing film and can be formed using a processing solution having a quite low concentration.

Processing solution for forming hexavalent chromium free and corrosion resistant conversion film on zinc or zinc alloy plating layers, hexavalent chromium free and corrosion resistant conversion film, method for forming the same

A processing solution for forming a hexavalent chromium free, corrosion resistant trivalent chromate conversion film on zinc or zinc alloy plating layers comprises: trivalent chromium and oxalic acid in a molar ratio ranging from 0.5/1 to 1.5/1, wherein the trivalent chromium is present in the form of a water-soluble complex with oxalic acid; and cobalt ions, which do not form a hardly soluble metal salt with oxalic acid and are stably present in the processing solution without causing any precipitation; wherein the solution reacts with zinc when bringing it into contact with the zinc or zinc alloy plating to form a hexavalent chromium free, corrosion resistant, trivalent chromate conversion film containing zinc, chromium, cobalt, oxalic acid and silicon on the plating. The film is quite thin, free of any hexavalent chromium, has corrosion resistance identical to or higher than that achieved by the conventional hexavalent chromium-containing film and can be formed using a processing solution having a quite low concentration.

PROCESSING SOLUTION FOR FORMING HEXAVALENT CHROMIUM FREE AND CORROSION RESISTANT CONVERSION FILM ON ZINC OR ZINC ALLOY PLATING LAYERS, HEXAVALENT CHROMIUM FREE AND CORROSION RESISTANT CONVERSION FILM, METHOD FOR FORMING THE SAME

A processing solution for forming a hexavalent chromium free, corrosion resistant trivalent chromate conversion film on zinc or zinc alloy plating layers comprises a silicon compound; trivalent chromium and oxalic acid in a molar ratio ranging from 0.5 to 1.5, wherein the trivalent chromium is present in the form of a water-soluble complex with oxalic acid; and cobalt ions, which form a hardly soluble metal salt with oxalic acid and are stably present in the processing solution without causing any precipitation, wherein the solution reacts with zinc when bringing it into contact with the zinc or zinc alloy plating to form a hexavalent chromium free, corrosion resistant, trivalent chromate conversion film containing zinc, chromium, cobalt, oxalic acid and silicon on the plating. This solution can provide a corrosion resistant trivalent chromate conversion film excellent in the corrosion resistance after heating.

PROCESSING SOLUTION FOR FORMING HEXAVALENT CHROMIUM FREE AND CORROSION RESISTANT CONVERSION FILM ON ZINC OR ZINC ALLOY PLATING LAYERS, HEXAVALENT CHROMIUM FREE AND CORROSION RESISTANT CONVERSION FILM AND METHOD FOR FORMING THE SAME

An electrolytic conversion solution for metal surface treatment comprises (A) a vanadate or a vanadium salt of an inorganic acid and (B) an organic acid having a reducing ability, and has a pH of not less than 7. The electrolytic conversion solution can be employed in a method for electrolytic conversion treatment which comprises the steps of immersing a subject to be treated in the treating solution and then cathodically electrolyzing the subject in the solution. The electrolytic conversion solution is free of any chromate compound and permits the formation of uniform corrosion-resistant film on the surfaces of various kinds of metallic materials without impairing the working environment and causing any environmental pollution.

Electrolytic conversion solution for treating metal surface and method

A deterring solvent essentially consists of (A) a brominated hydrocarbon of the formula: C.sub.n H.sub.2n+1 Br wherein n represents a number of 3 or above and/or a brominated hydrocarbon of the formula: C.sub.m H.sub.2m-1 Br wherein m represents a number of 2 or above. A deterging solvent composition comprises the above-described solvent (A) and a stabilizer selected from the group consisting of nitroalkanes, ethers, epoxides and amines. These solvent and solvent composition have an excellent deterging effect and usable as a substitute for the flon and chlorine solvents. Furthermore, the deterging solvent composition has a high stability.

Method for washing an article with composition having a brominated

A zinc-cobalt alloy-plating alkaline bath comprises a zinc compound, a cobalt compound, an alkali hydroxide and a reaction product of an alkyleneamine with an alkylene oxide and having a pH of not less than 13 and a method for forming a zinc-cobalt alloy plating film comprises the step of forming, on a substrate, a zinc-cobalt alloy plating film having a cobalt content ranging from 0.05 to 20% by weight and a zinc content ranging from 80 to 99.95 % by weight, while using the foregoing alkaline plating bath. The Zn-Co alloy-plating bath permits the achievement of a desired rate of Co-eutectoid even when a small amount of a chelating agent is incorporated into the bath and therefore, the bath is excellent in the disposability of waste water.

Zinc-cobalt alloy-plating alkaline bath and plating method using the same

A deterging solvent essentially consists of (A) a brominated hydrocarbon of the formula: C.sub.n H.sub.2n+1 Br wherein n represents a number of 3 or above and/or a brominated hydrocarbon of the formula: C.sub.m H.sub.2m-1 Br wherein m represents a number of 2 or above. A deterging solvent composition comprises the above-described solvent (A) and a stabilizer selected from the group consisting of nitroalkanes, ethers, epoxides and amines. These solvent and solvent composition have an excellent deterging effect and usable as a substitute for the flon and chlorine solvents. Furthermore, the deterging solvent composition has a high stability.

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Katsushika-ku, Japan

Shigemi Tanaka