Dowa Metaltech Co., Ltd.

Yazaki Corporation

Yuta Sonoda

Hiroto Narieda

Akira Sugawara

Hirotaka Kotani

Hideki Endo

Jyun Toyoizumi

Yuya Kishibata

Yukiya Kato

Takaya Kondo

Hideki Ohsumi

Tsuyoshi Ito

Tetsuo Kato

Tatsunori Murata

Yoshitaka Ito

Tatsuhiro Doi

Takao Tomiya

Masaaki Izaki

There are provided a composite plated product, which has little uneven appearance, a low contact resistance and good wear resistance, and a method for producing the same without the need of any silver-plating solutions containing cyanides and any silver-plating solutions containing silver nitrate as a silver salt. After carbon particles are caused to be suspended in water, an oxidizing agent is added thereto for carrying out a wet oxidation treatment of the carbon particles, and a silver-plating solution, which contains at least one sulfonic acid and the carbon particles treated by the wet oxidation treatment, is used for electroplating a base material to form a coating film of a composite material, which contains the carbon particles in a silver layer, on the base material to produce a composite plated product.

Composite plated product and method for producing same

There are provided a composite plated product, which has little uneven appearance and good wear resistance, and a method for producing the same without the need of any cyanide-containing silver-plating solutions and any silver-plating solutions containing silver nitrate as a silver salt. A sulfonic-acid-containing silver-plating solution, to which a carbon particle dispersing solution (preferably containing a silicate) is added, is used for electroplating a base material (preferably made of copper or a copper alloy) to form a composite plating film of a composite material, which contains the carbon particles in a silver layer, on the base material to produce a composite plated product.

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

After drying the surface of a tin plating layer having a thickness of 0.4 to 3 &#x3bc;m which is formed on a base material of copper or a copper alloy by electroplating at a current density of 5 to 13 A/dmin a tin plating solution consisting of water, tin sulfate, sulfuric acid and a surfactant, the surface of the tin plating layer is heated to melt tin, and then, cooled to cause a layer of the tin plating layer on the side of the outermost surface to be a tin layer, which has a structure obtained by solidification after melting, while causing a layer of the tin plating layer between the tin layer and the base material to be a copper-tin alloy layer, to produce a tin-plated product wherein a tin layer, which has a structure obtained by solidification after melting, is formed on a copper-tin alloy layer formed on a base material of copper or a copper alloy and wherein the tin-plated product has a glossiness of 0.3 to 0.7.

There are provided a tin-plated product which has a zinc plating layer on the surface thereof and which has good corrosion resistance and good adhesion of the zinc plating even if the connecting portion of a terminal of the tin-plated product to an electric wire of aluminum or an aluminum alloy is not processed during press fitting such as swaging (or caulking) when the tin-plated product is used as the material of the terminal which is to be connected to the electric wire by press fitting, and a method for producing the 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.

A Cu-based materialis immersed into an alkali hydroxide solution with a concentration of 3.0 to 37.5 mass % and a HOsolution with a concentration of 3.0 to 50.0 mass % is added in the alkali hydroxide solution, a temperature of the alkali hydroxide solution when the Cu-based material is immersed ranges from 60 to 105&#xb0; C., a ratio A/B between a mol number A of alkali hydroxide in the alkali hydroxide solution and a mol number B of HOin the HOsolution is 10 or more, and where a mol number of Sn in the Sn layer is C and a mol number of Sn in the CuSn layer is D, B&#x2267;C&#xd7;2+D&#xd7;6.

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Tokyo, Japan

Yuta Sonoda