Tin-plated product and method for producing same

Patent metadata

Field	Value
Publication number	US-2018245230-A1
Application number	US-201615752996-A
Country	US
Kind code	A1
Filing date	Aug 23, 2016
Priority date	Sep 1, 2015
Publication date	Aug 30, 2018
Grant date	—

Abstract

A tin-plated product contains: a substrate 10 of copper or a copper alloy; an underlying layer 12 of nickel which is formed on the surface of the substrate 10; and an outermost layer 14 containing tin, the outermost layer 14 being formed on the surface of the underlying layer 12, the outermost layer 14 being composed of a copper-tin alloy layer 14a of a large number of crystal grains of a copper-tin alloy, tin layers 14b of tin having an average thickness of 0.01 to 0.20 micrometers, and a plurality of copper-nickel-tin alloy layers 14c of a copper-nickel-tin alloy, each of the tin layers 14b being 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 layers 14c being arranged on the side of the underlying layer 12 in the copper-tin alloy layer 14a so as to be apart from each other.

First claim

1 . A tin-plated product comprising:
a substrate of copper or a copper alloy; an underlying layer of nickel or a copper-nickel alloy which is formed on a surface of the substrate; and an outermost layer containing tin, the outermost layer being formed on a surface of the underlying layer, wherein the outermost layer is composed of a copper-tin alloy layer of a copper-tin alloy, tin layers of tin, and copper-nickel-tin alloy layers of a copper-nickel-tin alloy, each of the tin layers being formed in a corresponding one of recessed portions on an outermost surface of the copper-tin alloy layer, the copper-nickel-tin alloy layers being arranged on the side of the underlying layer in the copper-tin alloy layer, the tin layers having an average thickness of 0.01 to 0.20 micrometers.

2 . A tin-plated product as set forth in claim 1 , wherein said copper-tin alloy layer is formed of crystal grains of the copper-tin alloy, and each of said recessed portions is formed between adjacent two of said crystal grains of the copper-tin alloy on said outermost surface.

3 . A tin-plated product as set forth in claim 1 , wherein said copper-nickel-tin alloy layers are composed of a plurality of layers which are arranged so as to be apart from each other.

4 . A tin-plated product as set forth in claim 1 , wherein an area ratio occupied by said tin layers on the outermost surface of the tin-plated product is 10 to 80%.

5 . A tin-plated product as set forth in claim 1 , wherein said tin layers have a maximum thickness of 1.5 micrometers or less.

6 . A tin-plated product as set forth in claim 1 , wherein said copper-tin alloy layer has an average thickness of 0.5 to 1.5 micrometers.

7 . A tin-plated product as set forth in claim 1 , wherein said underlying layer has an average thickness of 0.05 to 0.5 micrometers.

8 . A tin-plated product as set forth in claim 1 , wherein said outermost surface has an arithmetic mean waviness Wa of 0.06 micrometers or less in such a state that said tin layers are removed.

9 . A method for producing a tin-plated product, the method comprising the steps of:
treating a surface of a substrate of copper or a copper alloy; forming a nickel plating layer having a thickness of not less than 0.05 micrometers, a copper plating layer having a thickness of not less than 0.05 micrometers, and a tin plating layer having a thickness of 0.2 to 0.9 micrometers, on the treated surface of the substrate in this order; and thereafter, carrying out a heat treatment to form an outermost layer being composed of a copper-tin alloy layer of a copper-tin alloy, tin layers of tin, and copper-nickel-tin layers of a copper-nickel-tin alloy, each of the tin layers being formed in a corresponding one of recessed portions on an outermost surface of the copper-tin alloy layer, and the copper-nickel-tin alloy layers being arranged on the side of an underlying layer in the copper-tin alloy layer.

10 . A method for producing a tin-plated product as set forth in claim 9 , wherein said treatment of the surface of the substrate causes the surface of the substrate to have an arithmetic mean roughness Ra of 0.05 to 0.1 micrometers, a maximum height Rz of 0.4 to 1.0 micrometers and an arithmetic mean waviness Wa of 0.05 micrometers or less.

11 . A method for producing a tin-plated product as set forth in claim 9 , wherein a ratio of the thickness of said tin plating layer to the thickness of said copper plating layer is 1.2 to 3.5, and a ratio of the thickness of said tin plating layer to the sum of the thickness of said copper plating layer and the thickness of said nickel plating layer is 0.5 to 3.0.

12 . A method for producing a tin-plated product as set forth in claim 9 , wherein said heat treatment is a heat treatment for holding in a temperature range of 500 to 800° C. for 20 seconds or less, said heat treatment being carried out by setting temperature and time so as to form the outermost layer composed of the copper-tin alloy layer of the copper-tin alloy, the tin layers of tin formed in the corresponding one of the recessed portions on the outermost surface of the copper-tin alloy layer, and the copper-nickel-tin alloy layers of the copper-nickel-tin alloy arranged on the side of the underlying layer in the copper-tin alloy layer.

13 . An electrical element which uses a tin-plated product as set forth in claim 1 , as a material thereof.

Assignees

• Dowa Metaltech Co Ltd
• Yazaki Corp

Inventors

• Sonoda Yuta
• Narieda Hiroto
• Endo Hideki
• Sugawara Akira
• Kotani Hirotaka
• Toyoizumi Jyun
• Kando Takaya
• KISHIBATA Yuya

Classifications

• C25D5/50

  by heat-treatment · CPC title

• B32B2311/22

  Nickel or cobalt · CPC title

• H01R43/16

  for manufacturing contact members, e.g. by punching and by bending · CPC title

• H01R13/03

  characterised by the material, e.g. plating, or coating materials · CPC title

• B32B15/01 Primary

  all layers being exclusively metallic {(making layered metal workpieces by pressure cladding B23K20/22; making coatings with a metallic material characterised by its composition C23C30/00)} · CPC title