Showa Aluminum Corporation

Showa Aluminium Kabushiki Kaisha

Showa Aluminum Kabushiki Kaisha

Kozo Arai

Takao Suzuki

Hideo Shingu

Syozo Umetsu

Ryotatsu Otsuka

Masashi Sakaguchi

Kenji Tsukamoto

Ryotatsu Ootsuka

Yasushi Tashiro

Osamu Watanabe

Toshio Nishide

Tatsuhiko Ejima

Eizo Isoyama

Tadao Fujihira

An aluminum alloy foil for the cathode of an electrolytic capacitor is produced from a continuously cast aluminum alloy plate containing 0.03 to 0.5% of copper.

Aluminum alloy foil for cathode of electrolytic capacitors

A process for treating the surface of aluminum foil for use as an electrode of electrolytic capacitors to increase the surface area of the foil to the greatest possible extent includes the three steps of pre-etching treatment, intermediate nitric acid treatment and post-etching treatment. The pre-etching treatment is conducted electrolytically in an aqueous solution of chromic acid and at least one of chromic acid and chromates. The intermediate nitric acid treatment is carried out by immersing the pre-etched foil in an aqueous solution of nitric acid to remove a chromate film formed by the pre-etching from the foil surface, especially from the interior of the resulting pits. The post-etching treatment is conducted electrolytically in an aqueous solution of hydrochloric acid, or hydrochloric acid and an oxidizing acid.

Process for treating surface of aluminum foil for use as electrode of

To obtain a high-purity aluminum fraction from aluminum containing both eutectic impurities and peritectic impurities, the contents of these impurities in the original aluminum are reduced by melting the original aluminum to obtain molten aluminum, adding boron to the molten aluminum, and rotating a cooling body as immersed in the boron-containing molten aluminum while introducing a cooling fluid to the interior of the body to crystallize high-purity aluminum on the surface of the body. The peritectic impurities react with the boron to form metallic borides, which are centrifugally forced away from the cooling body by the rotation of the body without being incorporated into the aluminum crystallized on the surface of the body. The eutectic impurities are removed from the crystallized aluminum on the surface based on the principle of segregation.

Process for producing high-purity aluminum

An aluminum alloy foil useful for the cathodes of electrolytic capacitors is prepared from an aluminum alloy comprising 0.03 to 0.5% of copper and 0.002 to 0.05% of titanium.

Aluminum alloy foils for cathodes of electrolytic capacitors

In melting aluminum containing impurities which form a eutectic with the aluminum and solidifying the molten aluminum by cooling, the aluminum is purified by breaking down dendrites extending from the liquid-solid interface into the liquid phase to release impurities from between the dendrites or between the branches of the dendrites, and dispersing the released impurities in the entire body of the liquid phase.

Process of preparing aluminum of high purity

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Osaka, Japan

Kozo Arai