JP-2026075869-A - Connector terminal material and method for manufacturing the same

Abstract

[Problem] To provide a coating that can be applied to various copper-based substrates, suppresses the generation of voids, reduces the coefficient of friction, and prevents peeling of the coating under high-temperature conditions for extended periods. [Solution] A film is formed on the surface of a substrate made of copper or a copper alloy, and the film has 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 0.15 μm or more and 3.00 μm or less, the average thickness of the copper-tin alloy layer is 0.2 μm or more and 1.0 μm or less, the average thickness of the tin layer is 0.1 μm or more and 2.0 μm or less, and the copper-tin alloy layer contains a Cu 6 Sn 5 alloy, and the average GOS value of the Cu 6 Sn 5 alloy in a cross section parallel to the rolling direction of the substrate is 0.48° or more and 0.70° or less. [Selection Diagram] Figure 2

Inventors

• 北野 麻奈
• 樽谷 圭栄
• 匝瑳 宏信
• 前田 晃弥

Assignees

• 三菱マテリアル株式会社

Dates

Publication Date

20260511

Application Date

20241023

Claims (6)

1. A terminal material for connectors, characterized in that a film is formed on the surface of a substrate made of copper or a copper alloy, the film comprising 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 0.15 μm or more and 3.00 μm or less, the average thickness of the copper-tin alloy layer is 0.2 μm or more and 1.0 μm or less, the average thickness of the tin layer is 0.1 μm or more and 2.0 μm or less, and the copper-tin alloy layer contains a Cu 6 Sn 5 alloy, and the average GOS value of the Cu 6 Sn 5 alloy in a cross section parallel to the rolling direction of the substrate is 0.48° or more and 0.70° or less.
2. The connector terminal material according to claim 1, characterized in that the average value of the aspect ratio Str of the surface properties of the copper-tin alloy layer is 0.3 or more and 0.7 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 is characterized by comprising: a first heat treatment in which the plated substrate is heated in a first heating furnace set to an internal temperature of 100°C to 200°C in an atmospheric environment for a period of 10 seconds to 25 seconds; a second heat treatment in which, after the first heat treatment, the plated substrate is heated in a second heating furnace set to an internal temperature of 235°C to 300°C for a period of 10 seconds to 40 seconds to melt the tin plating layer; and after the second heat treatment, the plated substrate is heated in a third heating furnace set to an internal temperature of 50°C to 200°C for a period of 10 seconds to 50 seconds, and then cooled, thereby forming a coating on the substrate in which a nickel layer with an average thickness of 0.15 μm to 3.00 μm, a copper-tin alloy layer with an average thickness of 0.2 μm to 1.0 μm, and a tin layer with an average thickness of 0.1 μm to 2.0 μm are laminated in this order.
6. The method for manufacturing a connector terminal material according to claim 5, characterized in that, prior to the plating layer formation step, a punching step is performed to punch out a metal plate to form a terminal chain in which multiple terminal members are formed at intervals along the length of an elongated connecting member.

Description

This invention relates to a heat-resistant, low-insertion-force terminal material for connectors 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. In terminal materials with such copper-tin alloy layers and tin layers, for example, Patent Document 1 reduces insertion force by controlling the roughness of the base material and controlling the degree to which the copper-tin alloy layer is exposed from the tin layer. However, this requires pre-processing of the base material to control its roughness. Therefore, it is difficult to apply this method to terminal materials with complex or small component shapes that are manufactured by punching out and then plating them. Furthermore, while Patent Document 2 reduces insertion force by making the tin layer, or a tin alloy layer, very thin on the copper-tin alloy layer, there is a problem that the contact resistance increases in high-temperature environments due to the small amount of tin layer. Furthermore, Patent Document 3 describes a method in which a portion of the copper-tin alloy is replaced with nickel (Ni), creating a steep, uneven surface while retaining a certain amount of the tin layer. This reduces the coefficient of friction and prevents an increase in contact resistance under high-temperature conditions. However, due to the steepness of the copper-tin alloy layer, there are limitations to the reduction in the coefficient of friction. On the other hand, when forming a film by applying plating in multiple layers, the components of each plating layer tend to diffuse due to heating, leading to the formation of voids. If many voids form, the film will peel off. Therefore, Patent Document 4 describes a method in which a specific copper alloy plate is used and a copper-tin alloy layer is formed on it to suppress metal diffusion due to heating between the alloy additive components of the copper alloy plate and the copper-tin alloy layer, thereby preventing the generation of numerous voids. However, the copper alloy plate is limited and cannot be used with brass alloys commonly used in pin terminals, and furthermore, it was not possible to completely suppress the peeling of the coating due to prolonged heating. Japanese Patent Publication No. 2007-100220Japanese Patent Publication No. 2011-012320Japanese Patent Publication No. 2014-240520Japanese Patent Publication No. 2005-226097 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. 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 14 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 14 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