Tin-Copper Plating Layer for Abrasion Resistance
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Solution Overview
Problem
Tin-plated products used in insertable and extractable connecting terminals suffer from poor minute sliding abrasion resistance due to wear and tear from vibrations, leading to increased contact resistance and potential exposure of the substrate.
Innovation Solution
A tin-copper plating layer containing Cu6Sn5 is formed on a copper or copper alloy substrate using a tin-copper plating bath with alkyl sulfonic acid, along with a nickel layer, to enhance abrasion resistance, and optionally a thin tin layer is added for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reflow treatment is applied to form a tin-copper alloy layer, then sliding abrasion resistance improves, but manufacturing complexity increases
Solution Approach 1:
The invention applies preliminary action by incorporating copper particles into the tin plating bath before the plating process. This allows the copper-tin composite layer to be formed directly during electroplating without requiring subsequent reflow treatment, thereby achieving sliding abrasion resistance while simplifying the manufacturing process
Solution Approach 2:
The invention replaces the thermal reflow process with an electrochemical plating process. Instead of applying heat to diffuse copper and tin atoms, the invention uses electroplating to directly deposit a composite tin-copper layer, substituting a complex thermal process with a more controlled and simpler electrochemical process
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 method results in a tin-plated product with excellent minute sliding abrasion resistance, preventing substrate exposure and maintaining low electrical resistance values even after repeated sliding tests.
Implementation Method 1
forming a tin-copper plating layer, which contains tin mixed with a copper-tin alloy, on a substrate of copper or a copper alloy by electroplating
Data Source
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AI summary
There is provided a tin-plated product having an excellent minute sliding abrasion resistance property when it is used as the material of insertable and extractable connecting terminals, and a method for producing the same. After a nickel layer 16 is formed on a substrate 10 of copper or a copper alloy so as to have a thickness of 0.1 to 1.5 µm by electroplating, a tin-copper plating layer 12 containing tin 12b mixed with a copper-tin alloy 12a is formed thereon so as to have a thickness of 0.6 to 10 µm by electroplating using a tin-copper plating bath which contains 5 to 35 % by weight of copper with respect to the total amount of tin and copper, and then, a tin layer 14 is formed thereon so as to have a thickness of 1 µm or less by electroplating if necessary.