Yazaki Corporation

Dowa Metaltech Co., Ltd.

Jyun Toyoizumi

Hideki Endo

Akira Sugawara

Hirotaka Kotani

Yuta Sonoda

Hiroto Narieda

Yuya Kishibata

Takaya Kondo

Hideki Ohsumi

Tetsuo Kato

Tatsunori Murata

A tin-plated product contains: a substrateof copper or a copper alloy; an underlying layerof nickel which is formed on the surface of the substrate; and an outermost layercontaining tin, the outermost layerbeing formed on the surface of the underlying layer, the outermost layerbeing composed of a copper-tin alloy layerof a large number of crystal grains of a copper-tin alloy, tin layersof tin having an average thickness of 0.01 to 0.20 micrometers, and a plurality of copper-nickel-tin alloy layersof a copper-nickel-tin alloy, each of the tin layersbeing formed in a corresponding one of recessed portions between adjacent two of the crystal grains of the copper-tin alloy on the outermost surface of the copper-tin alloy layer, the copper-nickel-tin alloy layersbeing arranged on the side of the underlying layerin the copper-tin alloy layerso as to be apart from each other.

Tin-plated product and method for producing same

In a tin-plated product wherein a surface of a substrateof copper or a copper alloy is plated with tin, an underlying layerof at least one of nickel and a copper-nickel alloy is formed on the surface of the substrate, and an outermost layer formed on the surface of the underlying layeris composed of a copper-tin alloy layerand tin layers, the copper-tin alloybeing formed of a large number of crystal grains of a copper-tin alloy, each of the tin layersbeing arranged in a corresponding one of recessed portions, each of which is formed between adjacent crystal grains of the large number of crystal grains of the copper-tin alloy, the adjacent crystal grains being adjacent to each other on the outermost surface of the outer most layer, the area ratio occupied by the tin layerson the outermost surface being 20 to 80%, and the maximum thickness of the tin layersbeing smaller than the average particle diameter of the crystal grains of the copper-tin alloy.

There is provided a tin-plated product having an excellent minute sliding abrasion resistance property when it is used as the material of insertable and extractable connecting terminals, and a method for producing the same. After a nickel layeris formed on a substrateof copper or a copper alloy so as to have a thickness of 0.1 to 1.5 &#x3bc;m by electroplating, a tin-copper plating layercontaining tinmixed with a copper-tin alloyis formed thereon so as to have a thickness of 0.6 to 10 &#x3bc;m by electroplating using a tin-copper plating bath which contains 5 to 35% by weight of copper with respect to the total amount of tin and copper, and then, a tin layeris formed thereon so as to have a thickness of 1 &#x3bc;m or less by electroplating if necessary.

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Shizuoka, Japan

Jyun Toyoizumi