1. What Copper-Clad Aluminium Wire Is
Copper-clad aluminium (CCA) wire is a composite conductor with an aluminium core and a copper cladding, combining the low weight and low cost of aluminium with the surface conductivity and corrosion behavior of copper. The wire is used in cables, coils, antennas and electronic applications where weight and cost matter. The bond between the core and the cladding is critical to the performance of the wire.
2. Raw Materials
The process starts with aluminium rod for the core and copper strip for the cladding. The purity and surface condition of both materials determine the quality of the bond: oxide films and contamination on either surface prevent a metallurgical bond. The aluminium is typically 99.7% or higher purity, and the copper is oxygen-free or low-oxygen grade for demanding applications.
3. Bonding the Composite
The core and cladding are combined by forming the copper strip around the aluminium rod and welding the seam with high-frequency or laser welding in an inert atmosphere. The welded tube is then drawn, and the drawing pressure forms a metallurgical bond between the copper and the aluminium. The bond quality is checked by torsion and peeling tests, because a poor bond separates during subsequent processing.
4. Drawing and Annealing
The composite is drawn through successive dies to reduce the diameter to the target size, with intermediate annealing to restore ductility. The drawing schedule controls the final copper volume ratio, typically 10 to 15%, the diameter tolerance and the surface quality. Final annealing softens the wire to the required mechanical condition and stabilizes the electrical properties.
5. Quality Control
Bond integrity: torsion, peeling and bending tests.
Dimensions: diameter, ovality and concentricity of the cladding.
Electrical: DC resistance and conductivity measurements.
Mechanical: tensile strength and elongation.
Surface: cleanliness and absence of scratches and pinholes.
6. Applications
CCA wire is used in coaxial cables, magnet wires, automotive wiring, antennas and other applications where the weight and cost advantage over solid copper is valuable. The copper cladding provides the solderability and corrosion resistance of copper, while the aluminium core reduces the weight and material cost.
7. FAQ
Q1: What is copper-clad aluminium wire? A composite conductor with an aluminium core and a copper cladding, combining light weight with copper-like surface behavior.
Q2: How is the copper bonded to the aluminium? The copper strip is formed around the aluminium rod, welded, and drawn so that the pressure forms a metallurgical bond.
Q3: What is the typical copper ratio? The copper volume ratio is typically 10 to 15%.
Q4: How is the bond quality checked? By torsion, peeling and bending tests that reveal separation of the core and cladding.
Q5: What is CCA wire used for? Coaxial cables, magnet wires, automotive wiring, antennas and other weight-sensitive conductors.
Q6: Why choose CCA over solid copper? Lower weight and cost, with copper-like surface conductivity, solderability and corrosion behavior.
