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JP-2026075870-A - Terminal materials for connectors

JP2026075870AJP 2026075870 AJP2026075870 AJP 2026075870AJP-2026075870-A

Abstract

[Challenge] To achieve both a reduction in insertion force and improved solder wettability in high-temperature, high-humidity environments. [Solution] The average thickness of the nickel layer is 0.15 mm or more and 4.0 mm or less, and the average thickness of the copper-tin alloy layer is 0.15 μm or more and 0.8 μm or less. In a cross section parallel to the rolling direction of the substrate, if the area ratio of the tin layer to the total area of the copper-tin alloy layer and tin layer at the connection point is X%, and the area ratio of the tin layer to the total area of the copper-tin alloy layer and tin layer at the soldering point is Y%, then X% is 21% or more and 50% or less, Y% is 31% or more and 90% or less, Y > X, and the difference between them is 10% or more. [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 (3)

  1. A coating is formed on a base material made of copper or a copper alloy, comprising a nickel layer made of nickel or a nickel alloy formed on the surface of the base material, 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, and also having a connecting portion for connection to the mating side and a soldering portion for soldering to the substrate. The average thickness of the nickel layer is 0.15 μm or more and 4.0 μm or less, and the average thickness of the copper-tin alloy layer is 0.15 μm or more and 0.8 μm or less. In a cross-section of the substrate parallel to the rolling direction, if the ratio of the cross-sectional area of the tin layer to the total area of the copper-tin alloy layer and the tin layer in the connection portion is X%, and the ratio of the cross-sectional area of the tin layer to the total area of the copper-tin alloy layer and the tin layer in the soldering portion is Y%, then X% is 21% or more and 50% or less, and Y% is 31% or more and 90% or less. A terminal material for connectors characterized in that Y > X, and the difference between them is 10% or more.
  2. The connector terminal material according to claim 1, characterized in that the skewness Ssk of the nickel layer after the tin layer and the copper-tin alloy layer have been removed from the soldered portion.
  3. The connector terminal material according to claim 1 or 2, characterized in that the exposure area ratio of the copper-tin alloy layer exposed from the tin layer on the surface of the coating is 20% or more at the connection portion and less than 10% at the soldering portion.

Description

This invention relates to a connector terminal material that reduces the insertion force during connector mating and improves solder wettability during mounting. 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, high-humidity 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 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 insertion force. Incidentally, when these terminal materials are formed into terminals, fracture surfaces are created, which leads to a problem of reduced solder wettability. To prevent this, it is conceivable to perform plating and reflow treatment after forming the terminal shape. However, in all terminal materials, a thin tin layer is necessary to maintain low friction. Therefore, if there is a long time between the plating and reflow treatments, or if the material is exposed to a high-temperature, high-humidity environment, a problem arises where solder wettability decreases. Japanese Patent Publication No. 2007-100220Japanese Patent Publication No. 2011-012320Japanese Patent Publication No. 2014-240520 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 length of the connecting member 11. Each terminal member 10 has a pin-shaped connecting portion 13 and a soldering portion 14 narrower than the connecting portion 13, which are formed continuously from the tip, with the base end of the soldering 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 soldering the soldering portion 14 to a through-hole or the like on the substrate, and an electrical connection is made by inserting the connecting portion 13 into another female terminal. For example, the plate thickness is formed to be 0.06 mm or more and 1.00 mm, and the width of the connecting portion 13 is formed to be 0.1 mm or more and 2.0 mm or less. However, Figure 1 is just one example, including the shape of the terminal member 10, and is not limited to what is shown in Figure 1. Any device that has a connecting portion that makes an electrical connection with a mating terminal is acceptable. The connector terminal material 1 has a coating 22 for the connection part and a coating 23 for the soldering part formed on a base material 21 made of copper or a copper alloy. The