Mitsubishi Chemical Corporation

Hiroshi Takaha

Fumikazu Mizutani

Makoto Ue

Yasuhiro Kawase

Makoto Ishikawa

Sachie Takeuchi

A gold plating solution comprising iodide ions, gold iodide complex ions and a non-aqueous solvent, which is less toxic and stable, while having a performance comparable to a cyanide type gold plating solution. The present invention further provides a gold plating solution comprising iodide ions, gold iodide complex ions, a non-aqueous solvent and a water-soluble polymer, which is less toxic and stable, while having a performance comparable to a cyanide type gold plating solution and which is capable of forming a gold plating film in which gold crystal particle sizes are very fine and grain boundaries are dense. The present invention further provides a gold plating method employing such a gold plating solution.

Gold plating solution and gold plating method

Disclosed is a forming electrolyte for forming metal oxide coating films which comprises one or more kinds of solutes selected from the group consisting a salt of inorganic acid and salt of organic carboxylic acid dissolved in a solvent having analcoholic hydroxyl group or aprotic organic solvent, provided that, when the solvent having an alcoholic hydroxyl group is selected, the salt of organic carboxylic acid is selected from salts of aromatic carboxylic acids, salts of aliphatic polycarboxylic acid having 3-5 carbon atoms with no hydroxyl groups, salts of monohydroxy carboxylic acid having 2-5 carbon atoms, and salts of amino acid. By anodically oxidizing metal using the forming electrolyte, there can be formed an oxide coating film of high insulation property with a high throughput, in which hillocks are effectively suppressed.

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Kanagawa, Japan

Hiroshi Takaha