Nippon Paint Compnay, Ltd.

Masayuki Kamimura

Satoshi Ikeda

Toshiaki Shimakura

Satoshi Miyamoto

Yuichi Yoshida

Takeyasu Ito

Miyuki Shimada

Yasuo Matsuura

A surface treatment aqueous solution is provided which is superior in corrosion resistance and coating adhesiveness as well as in ability of inhibiting the production of precipitate. A tinned DI can, which has been degreased, is conversion coating processed in a treatment bath filled with a surface treatment aqueous solution containing at least phosphate ions, organophosphonate compound and tin ions with a pH value of 5 or less. After the conversion coating, the DI can is washed with water and dried. A preferable organophosphonate compound is one in which a phosphorus atom constituting a phosphonate group is bonded to a carbon atom.

Surface treatment aqueous solution for metal

A highly uniform thin protective coating, with good appearance, anti-corrosion properties and adhesion properties, is provided by a surface treatment method wherein a surface treatment solution for aluminum and its alloys is prepared using a surface treatment composition for aluminum and its alloys comprising at least one type of phosphoric acid, condensed phosphoric acid or salt of these acids, at least one type of zirconium salt or titanium salt and effective fluoride, further comprising at least one type of phosphorous acid, hypophosphorous acid or salts of these acids, and this solution is brought in contact with the surface of an aluminum type metal.

Surface treatment composition, surface treatment solution and surface

An acidic cleaning aqueous solution for carrying out a low temperature acidic cleaning of aluminum and aluminum alloy and a cleaning method for the same free from harmful fluorine and chromium ions. The acidic cleaning aqueous solution includes oxidized metal ions as an etching promoter, an inorganic acid, a surfactant and a certain amount of polyhydric alcohols having at least two hydroxyl groups directly coupled with two adjacent carbon atoms of a principal chain within one molecule and further includes an oxidizing agent for oxidizing the oxidized metal ions reduced in the cleaning. Certain alcohols in the acidic cleaning aqueous solution can control the oxidative decomposition reaction of the surfactant to obtain a long life acidic cleaning aqueous solution.

Acidic cleaning aqueous solution for aluminum and aluminum alloy and

Disclosed is an acidic cleaning aqueous solution for aluminum and aluminum alloy and a process for cleaning the same, intended to execute acidic cleaning without using harmful fluoride and chloride ions. The oxidation-reduction potential of a cleaning bath is controlled to be at 0.5 to 0.8 V (vs. Ag-AgCl). The cleaning bath is obtained by diluting an acidic cleaning aqueous solution for aluminum and aluminum alloy to a predetermined volume. The acidic cleaning aqueous solution contains specified amounts of at least one of inorganic acids, Br.sup.- ions and oxidized metal ions, with the addition of a surfactant and oxidizing agent if necessary. It is thus possible to present a uniform etching effect irrespective of low temperature (below 60.degree. C.) without containing fluoride ions and chromic ions within the acidic cleaning aqueous solution. Br.sup.- also has an effect of inhibiting the oxidation-decomposition reaction of the surfactant arising from the oxidizing agent and oxidized metal ions, thereby obtaining a long-life acidic cleaning aqueous solution.

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Ichikawa, Japan

Masayuki Kamimura