Dowa Mining Co., Ltd.

Kentaro Asai

Hirofumi Takei

Hiroshi Miyazawa

There is provided a tin-plated product which has a small deterioration of contact resistance with age, an excellent wear resistance and a low coefficient of friction. A coating of a composite material, which contains 0.1 to 1.0 wt % of carbon particles dispersed in a tin layer and which has a thickness of 0.5 to 10.0 &#x3bc;m, preferably 1.0 to 5.0 &#x3bc;m, is formed as the outermost layer of a substrate. Thus, the coefficient of dynamic friction between the tin-plated products of the same kind is 0.20 or less, and the coefficient of dynamic friction between the tin-plated product and a reflow tin-plated product is 0.20 or less, while the contact resistance is 1 m&#x3a9; or less.

Tin-plated product

There are provided a method for producing a fine zirconium oxide powder which has a narrower particle size distribution than that of conventional zirconium oxide powders and which is capable of lowering the starting temperature in the sintering reaction of a reactant to which the fine zirconium oxide powder is added. When a hydrated zirconium is calcined to be dispersed in a solvent with a dispersing agent, an alcohol (e.g., IPA or t-butanol) having a branched chain structure, not a straight chain structure, is used as the solvent, and a dicarboxylic acid (e.g., maleic acid or oxalic acid) having two carboxyl groups in its molecule is used as the dispersing agent. Thus, a fine zirconium oxide powder having a narrow particle size distribution and a small particle size at 90 vol % is obtained.

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Honjo, Japan

Kentaro Asai