Nippon Light Metal Company, Ltd.

Masashi Isobe

Masahiko Katano

Toru Ishii

Shinichi Arai

Yuya Yoshida

Tooru Ishii

Mariko Endo

This invention provides an aluminum electrode plate for an electrolytic capacitor, which, even when the thickness of an etching layer is large, can realize a high level of impregnation of a solid electrolyte and can reduce ESR of a capacitor. An aluminum plate having an aluminum purity of not less than 99.98% by mass is etched to form an etching layer having a depth of 70 &#x3bc;m or above. When a plane cross section of a position deeper than 20 &#x3bc;m from the surface in the etching layer is measured with an image analyzer, for each measured face, not less than 70% of the total number of pits within the measured face is accounted for by pits having a diameter of 0.01 to 1 &#x3bc;m &#x3c6;; in terms of equivalent circle diameter. The aluminum plate has an aluminum purity of not less than 99.98% by mass and comprises 5 to 50 ppm of Fe and 5 to 40 ppm of Cu with the balance consisting of inevitable impurities. The aluminum plate further contains 1&#xd7;10to 10/cmiron-containing intermetallic compound having a particle diameter of 0.1 to 1.0 &#x3bc;m &#x3c6; in terms of spheres.

Aluminum electrode plate for electrolytic capacitor

An aluminum plate having an aluminum purity of not less than 99.98% by mass and an Fe content of 5 to 50 ppm with the balance consisting of unavoidable impurities is used to realize increased capacitance of an aluminum electrolytic capacitor, reduced height, and improved high frequency characteristics. In this aluminum plate, the total content of Fe in crystal/precipitate is 1 to 50% based on the original content, and the thickness of the aluminum plate 0.2 to 1 mm. In the formation of a capacitor anode, the aluminum plate is subjected to alternate current etching so as to leave a core part having an average thickness of 50 to 150 &#x3bc;m in the center part in the thickness-wise direction to increase the surface area, followed by anodic oxidation.

Aluminum plate for aluminum electrolytic capacitor electrode, aluminum electrolytic capacitor, and method for manufacturing aluminum electrolytic capacitor

A hydrophilic corrosion-resistant coat is formed on the surface of a metallic material, e.g., aluminum and its alloys, by a method which comprises preparatorily cleaning the surface of the metallic material, applying on the cleaned surface of the metallic material an aqueous treating liquid produced by adding a water-soluble acrylic acid polymer and colloidal silica and effective amounts of a polyhydric alcohol and/or saccharide to an aqueous solution containing hexavalent chromium compound or trivalent and hexavalent chromium compounds, phosphoric acid, and a fluorine compound. The applied layer of the treating liquids is dried and baked, the baking being at a temperature in the range of 100.degree. to 250.degree. C.

Method for formation of hydrophilic corrosion-resistant coating on the

The invention involves a nonrinse type hydrophilic surface-treating process capable of imparting hydrophilicity to the surface of a metal material, e.g., aluminum, and, at the same time, forming thereon a coating excelling in resistance to corrosion. In the process there is applied an aqueous solution which contains selected amounts of Cr ions (III, VI), F.sup.-, SiO.sub.2 and a water-soluble acrylic acid polymer, and optionally PO.sub.4.sup.-3, if necessary. An aluminum article treated by this process is suitable for the fins of a heat exchanger.

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Shizuoka, Japan

Masashi Isobe