Silver-Tin Alloy Connector Terminal Abrasion Resistance
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Solution Overview
Problem
Silver-plated connector terminals used in automobiles face issues with abrasion and reduced connection reliability due to softness, leading to surface wear and exposure of underlying layers, which affects frictional coefficient and reliability, especially under vibrations.
Innovation Solution
An electric contact configuration featuring a silver-tin alloy layer with high hardness and surface roughness on one contact and a smooth silver layer on the other, with a nickel primer layer to enhance adherence and prevent diffusion, achieving a high frictional coefficient and abrasion resistance while minimizing silver usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silver plating layer is provided on the terminal surface, then heat resistance, corrosion resistance, and electroconductivity are improved, but the terminal tends to undergo adhesion and surface abrasion due to the softness of silver
Solution Approach 1:
The patent applies composite materials by combining silver and tin to form a silver-tin alloy plating layer. This composite structure integrates the excellent electroconductivity and corrosion resistance of silver with the high hardness and abrasion resistance of tin, resolving the contradiction between softness-induced adhesion and required connection reliability. The alloy composition typically contains 5-20 mass% tin, creating a material that exhibits both electrical performance and mechanical strength.
Solution Approach 2:
The patent changes the material parameters by adjusting the tin content in the silver-tin alloy within specific ranges (5-20 mass%). By controlling the concentration of tin, the patent optimizes the balance between hardness, electroconductivity, and corrosion resistance. This parameter adjustment allows the plating layer to maintain sufficient electrical performance while achieving the required surface hardness to prevent adhesion and abrasion.
2Strength
If the frictional coefficient of the silver coating surface is reduced, then abrasion suppression is improved, but unintended sliding occurs due to vibration and connection reliability deteriorates
Solution Approach 1:
The silver-tin alloy composite material inherently provides optimized friction characteristics. The tin component increases surface hardness and reduces the frictional coefficient compared to pure silver, thereby suppressing abrasion during insertion and removal operations. Simultaneously, the reduced friction prevents excessive adhesion that would cause unintended sliding under vibration, maintaining connection stability.
Solution Approach 2:
By adjusting the tin content parameter in the silver-tin alloy, the patent controls the frictional coefficient within an optimal range. The tin content of 5-20 mass% provides sufficient hardness reduction in friction while maintaining adequate adhesion to prevent unintended sliding. This parameter optimization resolves the contradiction between abrasion resistance and connection stability.
Data Source
AI summary
An electric contact that includes a first contact and a second contact that are capable of forming electrical contact with each other, wherein: the first contact has a silver-tin alloy layer exposed at an outermost surface that comes into contact with the second contact, the second contact has a silver layer exposed at an outermost surface that comes into contact with the first contact, and a surface roughness of the silver-tin alloy layer of the first contact is larger than a surface roughness of the silver layer of the second contact.