Tin-Plated Copper Terminal Galvanic Corrosion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Galvanic corrosion occurs when copper or copper alloy terminals are crimped to aluminum wires, leading to increased electric resistance and reduced crimping force, and existing solutions either increase production costs or fail to provide effective corrosion protection.
Innovation Solution
A tin-plated copper terminal material with a zinc-nickel alloy layer and a tin layer, where the zinc-nickel alloy layer has a thickness of 0.1 μm to 5.0 μm and a nickel content of 5-50 mass%, and the tin layer has a zinc concentration of 0.6-15 mass%, with a metal zinc layer formed under the oxide layer to reduce corrosion potential and maintain high zinc concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a copper or copper alloy terminal is crimped to an aluminum wire, then electrical conductivity is improved, but galvanic corrosion occurs leading to increased electric resistance and reduced crimping force
Solution Approach 1:
The terminal employs a composite plating structure with multiple layers: a base metal part made of copper or copper alloy, an intermediate layer made of zinc-nickel alloy plating, and a surface layer made of tin plating. This composite structure combines the advantages of each material to achieve both electrical conductivity and corrosion resistance, preventing galvanic corrosion between copper terminals and aluminum wires
Solution Approach 2:
The zinc-nickel alloy intermediate layer acts as a mediator between the copper base metal and the tin surface layer, providing a transition zone that prevents direct contact between dissimilar metals. This intermediate layer with controlled thickness (0.1-5.0 μm) and composition (5-50 mass% nickel) serves as a barrier to galvanic corrosion while maintaining electrical conductivity
2Reliability
If an intermediate layer and surface layer are added to prevent corrosion, then corrosion resistance is improved, but production cost and device complexity increase
Solution Approach 1:
The invention optimizes specific parameters of the plating layers to balance performance and complexity: the zinc-nickel alloy intermediate layer has a nickel content of 5-50 mass% and thickness of 0.1-5.0 μm, while the tin surface layer has a zinc concentration of 0.6-15 mass%. These controlled parameter ranges ensure effective corrosion protection while maintaining manufacturing feasibility
3Reliability
If the zinc-nickel alloy layer thickness is increased, then corrosion protection is improved, but crimping workability and productivity deteriorate
Solution Approach 1:
The invention establishes an optimal thickness range of 0.1-5.0 μm for the zinc-nickel alloy intermediate layer. This controlled thickness provides sufficient corrosion protection through the alloy's inherent resistance while maintaining the terminal's overall dimensions and crimping characteristics, ensuring good workability during assembly
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
Prevents galvanic corrosion by matching the corrosion potential of aluminum, maintaining corrosion resistance over time, and preventing increases in electric resistance and crimping force deterioration.
Implementation Method 1
a zinc-nickel alloy layer including zinc and nickel and a tin layer made of tin alloy which are stacked on the base member in this order
Implementation Method 2
a metal zinc layer is further provided on the tin layer and under an outermost oxide layer
Data Source
AI summary
On a base member made of copper or a copper alloy, a zinc-nickel alloy layer including zinc and nickel, and a tin layer made of tin alloy are laminated in this order: the zinc-nickel alloy layer has a thickness of 0.1-5 μm inclusive and has a nickel content of 5-50 mass % inclusive, the tin layer has a zinc concentration of 0.6-15 mass % inclusive, and, under an oxide layer which is the outermost layer, a metal zinc layer, having a zinc concentration of 5-40 at % inclusive and a thickness of 1-10 nm inclusive in SiO2 conversion, is formed on the tin layer.