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JP-2026075868-A - Connector terminal material and method for manufacturing the same

JP2026075868AJP 2026075868 AJP2026075868 AJP 2026075868AJP-2026075868-A

Abstract

[Challenge] To not only maintain a low coefficient of friction, but also to improve resistance to micro-sliding wear. [Solution] A film is formed on the surface of a substrate made of copper or a copper alloy. The film comprises a nickel layer made of nickel or a nickel alloy formed on the surface of the substrate, a copper-tin alloy layer made of a copper and tin alloy formed on the nickel layer, and a tin layer made of tin or a tin alloy formed on the copper-tin alloy layer. The average thickness of the nickel layer is 0.30 μm or more and 3.00 μm or less, the average thickness of the copper-tin alloy layer is 0.30 μm or more and 1.20 μm or less, and the average thickness of the tin layer is 0.15 μm or more and 0.80 μm or less. The copper-tin alloy layer contains a Cu 6 Sn 5 alloy whose interface with the tin layer has an uneven shape. The average thickness of the protrusions of the Cu 6 Sn 5 alloy in a cross section parallel to the rolling direction of the substrate is 0.80 μm or more and 3.00 μm or less. The average KAM of the Cu 6 Sn 5 alloy in a cross section parallel to the rolling direction is 0.55° or more and 0.80° or less. [Selection Diagram] Figure 2

Inventors

  • 北野 麻奈
  • 樽谷 圭栄
  • 前田 晃弥
  • 匝瑳 宏信

Assignees

  • 三菱マテリアル株式会社

Dates

Publication Date
20260511
Application Date
20241023

Claims (6)

  1. A film is formed on the surface of a substrate made of copper or a copper alloy, and the film comprises a nickel layer made of nickel or a nickel alloy formed on the surface of the substrate, a copper-tin alloy layer made of a copper-tin alloy formed on the nickel layer, and a tin layer made of tin or a tin alloy formed on the copper-tin alloy layer, wherein the average thickness of the nickel layer is 0.30 μm or more and 3.00 μm or less, the average thickness of the copper-tin alloy layer is 0.30 μm or more and 1.20 μm or less, and the average thickness of the tin layer is 0.15 μm or more and 0.80 μm or less, and the copper-tin alloy layer contains a Cu 6 Sn 5 alloy whose interface with the tin layer has an uneven shape, the average thickness of the protrusions of the Cu 6 Sn 5 alloy in a cross section parallel to the rolling direction of the substrate is 0.80 μm or more and 3.00 μm or less, and the Cu 6 Sn in a cross section parallel to the rolling direction A terminal material for connectors characterized in that the average KAM value of the 5 alloy is 0.55° or more and 0.80° or less.
  2. The connector terminal material according to claim 1, characterized in that the radius of curvature of the convex surface of the Cu6Sn5 alloy in a cross section parallel to the rolling direction of the substrate is 0.40 μm or more and 2.00 μm or less.
  3. A connector terminal material according to claim 1 or 2, characterized in that it has a connecting portion that is connected to the other side and a substrate fixing portion that is fixed to the substrate, and at least the connecting portion has the coating formed on it.
  4. The connector terminal material according to claim 3, characterized in that the substrate fixing portion has a tin surface layer made of tin or a tin alloy formed on its entire surface, including the front, back, and both sides.
  5. The process includes a plating layer formation step of forming a plated substrate by laminating a nickel plating layer made of nickel or a nickel alloy, a copper plating layer made of copper or a copper alloy, and a tin plating layer made of tin or a tin alloy in this order onto the surface of a substrate made of copper or a copper alloy, and a reflow treatment step of heating the plated substrate and performing a reflow treatment. The reflow process comprises a first heat treatment in which the plated substrate is heated in a furnace at a temperature of 240°C to 380°C for a time of 5 seconds to 30 seconds to dissolve the tin plating layer, and a second heat treatment in which the plated substrate is heated in a furnace at a temperature of 150°C to 235°C for a time of 10 seconds to 60 seconds after the first heat treatment, and a coating is formed on the substrate by cooling after the second heat treatment, wherein a nickel layer made of nickel or a nickel alloy with an average thickness of 0.30 μm to 3.00 μm, a copper-tin alloy layer made of a copper-tin alloy with an average thickness of 0.30 μm to 1.20 μm, and a tin layer made of tin or a tin alloy with an average thickness of 0.15 μm to 0.80 μm are laminated in this order on the substrate.
  6. The method for manufacturing a connector terminal material according to claim 5, characterized in that, prior to the plating layer forming step, a punching step is taken to punch out a metal plate to form a terminal chain in which a plurality of terminal members are formed at intervals along the length of an elongated connecting member.

Description

This invention relates to a connector terminal material having resistance to micro-sliding abrasion and a method for manufacturing the same. Conventionally, connectors used for connecting electrical wiring in automobiles, consumer electronics, etc., have terminal pairs designed so that an electrical connection is made when a contact piece provided on the female terminal and a male terminal inserted into the female terminal make contact with a predetermined contact pressure. As such connectors (terminals), terminal materials are known in which copper plating and tin plating are applied to a base material made of copper or a copper alloy, and then a copper-tin alloy layer and a tin layer are formed on the base material by reflow treatment. For example, Patent Document 1 reduces insertion force by making the tin layer, or a tin alloy layer, on the copper-tin alloy layer very thin. However, this has the problem of increased contact resistance in high-temperature environments due to the thinness of the tin layer. Furthermore, in Patent Document 2, a portion of the copper-tin alloy is replaced with nickel, creating a steep, uneven surface. By leaving a tin layer, friction is reduced, preventing increased contact resistance during heating. However, due to the steepness of the copper-tin alloy layer, there are limitations to the reduction in frictional force. On the other hand, in Patent Document 3, a nickel-tin alloy layer made of Ni3Sn4 is formed instead of a copper-tin alloy layer. However, the alloy shape is elongated, and when the nickel-containing alloy oxidizes, the resistance increases significantly, resulting in insufficient connection reliability and resistance to micro-sliding wear. Japanese Patent Publication No. 2011-012320Japanese Patent Publication No. 2014-240520Japanese Patent Publication No. 2020-056056 This is a plan view of a connector terminal material according to an embodiment of the present invention.Figure 1 is a schematic cross-sectional view of a connector terminal material.Figure 1 is a flowchart showing a method for manufacturing terminal material for connectors.Figure 2 is a schematic cross-sectional view showing a plated substrate for connector terminal material before the reflow process.This is a backscattered electron (BSE) image of the cross-section of Example 7. The embodiments of the present invention will be described below with reference to the drawings. [Configuration of connector terminal materials] As shown in Figure 1, the connector terminal material 1 of this embodiment is a terminal chain formed by connecting multiple terminal members 10, each having the shape of a pin terminal, and is formed by punching out a long sheet of material using a press process. Specifically, a plurality of elongated terminal members 10 are provided in parallel at predetermined intervals on one side of an elongated connecting member 11 of a predetermined width, along a direction perpendicular to the longitudinal direction of the connecting member 11. Each terminal member 10 has a pin-shaped connecting portion 13 and a substrate fixing portion 14 that is narrower than the connecting portion 13, formed continuously from the tip, with the base end of the substrate fixing portion 15 connected to the connecting member 11 at a right angle. After being detached from the connecting member 11, the terminal member 10 is used in an electrically connected state to a substrate by press-fitting or soldering the substrate fixing portion 15 into a through-hole or the like of the substrate, and an electrical connection is made by inserting the connecting portion 13 into another female terminal. Note that the shape of the terminal member 10 is just an example and is not limited to the one shown in Figure 1; it can be any member that has a connecting portion for electrical connection with the mating terminal. As schematically shown in Figure 2, the connector terminal material 1 has a coating 22 formed on a base material 21 made of copper or a copper alloy. The coating 22 consists of a nickel layer 23 made of nickel or a nickel alloy, a copper-tin alloy layer 24 made of a copper-tin alloy, and a tin layer 25 made of tin or a tin alloy, in this order. Figure 2 shows a cross-section of the substrate 21 parallel to the rolling direction, and the coating 22 is formed on both the front and back surfaces and the entire surface of both sides of the substrate 21. The base material 21 is not particularly limited in composition, as long as it is made of copper or a copper alloy. For example, it can be made of a plate material made of copper or a copper alloy such as oxygen-free copper (C10200), Cu-Mg copper alloy (C18665), brass, or phosphor bronze. The nickel layer 23 has the function of suppressing the diffusion of copper and other components (substrate components) from the substrate 21 to the copper-tin alloy layer 24 and tin layer 25 formed thereon. The average thickness (film thickness) of the nickel layer 23 is 0.30 μm