Connector Terminal Material Friction and Abrasion Control
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Solution Overview
Problem
Terminal materials for connectors face challenges in reducing friction coefficient while maintaining abrasion resistance and electrical connection reliability, as thinning the tin layer to expose copper-tin alloy increases contact resistance and uneven interfaces lead to inferior abrasion resistance.
Innovation Solution
A terminal material with a nickel or nickel alloy layer, a copper-tin alloy layer, and a tin layer, where the copper-tin alloy layer is formed to be steep and uneven, and the nickel layer has controlled crystal grain diameter and roughness to reduce friction and enhance abrasion resistance, with specific thickness and exposure area ratios to balance friction and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the tin layer is thinned to expose the copper-tin alloy layer, then the friction coefficient is reduced, but the contact resistance is increased
Solution Approach 1:
The invention applies local quality by creating a composite construction where only a part of the copper-tin alloy layer is exposed from the tin layer surface, rather than fully exposing it. This partial exposure (1-60% area ratio) provides local friction reduction benefits while maintaining sufficient tin coverage to preserve electrical conductivity and prevent excessive contact resistance.
2Ease of operation
If the interface between copper-tin alloy layer and tin layer is made steep and uneven, then the friction coefficient is reduced, but the abrasion resistance is deteriorated
Solution Approach 1:
The invention applies parameter changes by precisely controlling the crystal grain diameter of the nickel layer within a specific range (0.01-0.5 μm) and maintaining the copper-tin alloy layer thickness at 0.05-0.40 μm. These parameter optimizations enable the formation of a steep and uneven interface that reduces friction while the controlled grain structure prevents excessive material loss during abrasion, thereby maintaining abrasion resistance.
3Strength
If the copper-plating layer is made thick to improve abrasion resistance, then the abrasion resistance is improved, but it becomes difficult to form a steep and uneven copper-tin alloy layer
Solution Approach 1:
The invention applies parameter changes by optimizing the copper-plating layer thickness to a specific range (0.05-0.40 μm) rather than simply making it thick. This precise parameter control, combined with controlling the nickel layer crystal grain diameter, enables the formation of a steep and uneven copper-tin alloy layer interface while maintaining sufficient copper content for abrasion resistance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves a low coefficient of kinetic friction of 0.3 or less, improving insertion/removal properties and abrasion resistance, suitable for small terminals with stable contact resistance, especially in vehicles and consumer products.
Implementation Method 1
In order to prevent copper in the substrate from diffusing, a nickel or nickel alloy layer is formed on the substrate
Implementation Method 2
the copper-tin alloy layer is a compound alloy layer that is mainly composed of Cu6Sn5
Data Source
AI summary
A terminal material for connectors, which is obtained by sequentially laminating on a substrate that is formed of copper or a copper alloy, a nickel or nickel alloy layer, a copper-tin alloy layer and a tin layer in this order, and: the tin layer has an average thickness of from 0.2 μm to 1.2 μm (inclusive); the copper-tin alloy layer is a compound alloy layer that is mainly composed of Cu6Sn5, with some of the copper in the Cu6Sn5 being substituted by nickel, and has an average crystal grain diameter of from 0.2 μm to 1.5 μm (inclusive); a part of the copper-tin alloy layer is exposed from the surface of the tin layer, with the exposure area ratio being from 1% to 60% (inclusive); the nickel or nickel alloy layer has an average thickness of from 0.05 μm to 1.0 μm (inclusive) and an average crystal grain diameter of from 0.01 μm to 0.5 μm (inclusive).