Yoshida Kogyo K.k.

Yoshida Kogyo Kabushiki Kaisha

Shin-etsu Chemical Co., Ltd.

Toa Paint Co. Ltd.

Mutsuo Hasegawa

Kazuo Aikawa

Katsuyuki Nagata

Yoshiaki Kudo

Hiroshi Yamagata

Hatsuo Hirono

Shiro Gomyo

Hisao Okada

Toshikazu Imaoka

Yuji Koise

Sunichi Segawa

Shinji Hayashi

The corrosion resistance of an anodically oxidized surface film on aluminum articles is improved by sealing micropores and the like in such surface film with an aqueous sealing solution or dispersion containing siliceous material, such as silicic acid or a silicate, therein and thereafter overcoating the so-sealed surface with a select coating composition. The aqueous sealing solution is brought into contact with the aluminum article, such as by dipping the article into the solution and drying the so-coated article. Optionally, an electrical voltage may be applied through the sealing liquid and through the aluminum article during the sealing process. Further, in certain embodiments an electrical voltage may be applied through the sealing liquid before the liquid contacts the aluminum article. If desired, the surface of the aluminum article may be colored prior to sealing.

Method of improving the corrosion resistance of an anodically oxidized

Shaped aluminum bars fresh from an extruder machine are coated with a specific organopolysiloxane composition while remaining uncooled and staying at temperatures not lower than about 250.degree. C, or at a temperature between about 550.degree. and 250.degree. C. The thus coated aluminum bars are then, preferably, subjected to annealing. The coatings formed on the surfaces of the aluminum materials have a superior resistance to attack by chemicals, weather, stains and heat as well as excellent adhesion and mechanical properties.

Process of coating aluminum materials molded by extrusion with

Aluminum or aluminum alloy is first anodized to form an oxide film thereon. With the pores in this oxide film unsealed, the basis metal is then electrolyzed by use of alternating current at a preselected starting voltage, and this voltage is lowered at least once before completion of the electrolytic coloring of the basis metal. The electrolytic solution in which the electrolysis is effected contains either at least three metallic salts or at least two metallic salts and a strong reducing compound.

Process for electrolytically coloring aluminum and aluminum alloys

Aluminum or aluminum alloy is first anodized to form an oxide film thereon. Before being colored electrolytically in an electrolytic solution, the anodized basis metal is made anodic in this solution, and direct current is passed therethrough. The basis metal is then electrolyzed in the same solution by use of alternating current for actual coloring operation. The electrolytic solution in use contains at least two metallic salts, together with or without a strongly reducing compound.

Aluminum or aluminum alloy is first anodized to form an oxide film thereon. With the pores in this oxide film unsealed, the basis metal is then electrolyzed in an electrolytic solution containing at least two metallic salts and a strongly reducing compound, by use of alternating current at potentials not more than about 15 volts.

Aluminum or aluminum alloy is first anodized to form an oxide film thereon. The anodized basis metal is electrolyzed by use of alternating current in an electrolytic solution which is prepared by adding formaldehyde, usually as formalin, and a thiosulfate to an acid solution of stannous sulfate. The acid solution of stannous sulfate can be prepared by dissolving stannous sulfate in an aqueous solution of sulfuric acid, sulfamic acid, tartaric acid or the like.

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Uozu, Japan

Mutsuo Hasegawa