Copper-Coated Aluminum Wire Thin Film for Strong Adhesion
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Solution Overview
Problem
Existing copper-clad aluminum wires face issues with adhesion defects and difficulty in maximizing weight reduction due to high copper content and passive oxide films, leading to limited practical use in applications like vehicle wire harnesses.
Innovation Solution
A copper-coated aluminum wire material produced using an ion plating method with controlled copper thin film deposition, achieving a space factor of 0.2% to 4% and adhesiveness exceeding 10 mN, while removing passive oxide films, using an ion plating method with specific vacuum conditions and cross-rotating return rolls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pure copper is used to clad aluminum wire, then adhesion is improved, but weight increases and the advantage of aluminum's lightness is lost
Solution Approach 1:
The patent changes the parameter of copper layer thickness from conventional thick cladding to a thin film range (0.01-2.0 μm), optimizing the balance between adhesion strength and weight reduction. This parameter optimization allows the copper coating to provide sufficient adhesion while minimizing the weight penalty, preserving aluminum's lightness advantage.
Solution Approach 2:
The patent applies copper coating only as a thin surface layer rather than thick cladding, creating local quality enhancement at the surface for adhesion while maintaining the bulk aluminum's light weight. The non-uniform distribution of copper (thin film vs. bulk) resolves the contradiction between needing copper for adhesion and avoiding copper for weight reduction.
2Strength
If aluminum surface oxide film is removed to improve copper adhesion, then adhesion improves, but aluminum oxidizes quickly during water washing and causes adhesion defects
Solution Approach 1:
The patent performs preliminary copper ion implantation into the aluminum surface before final copper plating. This preliminary action creates a copper-rich interface layer that prevents rapid re-oxidation of aluminum during subsequent water washing, while still providing excellent adhesion. The preliminary copper layer acts as a barrier against oxidation.
Solution Approach 2:
The patent introduces copper ions as an intermediary substance between the aluminum substrate and the environment. These copper ions form a stable interface layer that mediates between the reactive aluminum surface and oxidizing conditions, preventing direct oxidation of aluminum while maintaining strong adhesion to subsequent copper plating.
3Weight of moving object
If ion plating is used to deposit copper thin film, then weight is reduced and adhesion is improved, but production time increases for long wires
Solution Approach 1:
The patent replaces conventional mechanical plating or electroplating methods with ion plating technology. Ion plating allows for faster deposition rates and more uniform thin film formation, reducing the time required to achieve the desired copper coating thickness on long wires while maintaining excellent adhesion and minimizing weight.
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 enables a lightweight, adhesive, and high-purity copper-coated aluminum wire with improved proof stress, suitable for ultra-thin wire drawing, reducing the risk of adhesion defects and enhancing the wire's mechanical properties.
Implementation Method 1
evaporating copper from the copper evaporation source by electron-beam heating
Implementation Method 2
ionizing the evaporated copper
Implementation Method 3
evaporating copper from the copper evaporation source by electron-beam heating
Implementation Method 4
forming the copper thin film on the aluminum wire material by bringing copper ions formed by ionizing the evaporated copper into collision with the aluminum wire material
Data Source
AI summary
The present disclosure provides a copper-coated aluminum wire material including an aluminum wire material and a copper thin film coating the aluminum wire material that a space factor of the thin copper film is in the range of 0.2% to 4%.