Manufacturing process and microstructure of copper-coated aluminum wires

Abstract

Copper-coated aluminum wires exhibit good electrical conductivity, high thermal conductivity, low contact resistance of copper and low density, and provide economic advantages over aluminum. However, there are some problems in the manufacturing processes of hot-dip copper-coated aluminum wires, such as the difficulties in controlling coating process. In this work, the hot-dip copper-coating method of aluminum wires was investigated for producing copper-coated aluminum wire composites. The interface microstructure between the aluminum wire and the copper coating layer was analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS). Five different fluxing agents were tested. Experimental results show that appropriate conditions for the hot-dip process are determined as the liquid copper temperature of 1085°C and the treatment time less than 1 s. A success in hot-dip copper-coated aluminum wires is achieved by hot-dipping a low-melting-point metal into a high-melting-point metal liquid, which is significant for the further development and application of copper-coated aluminum wire composites.

Keywords

bimetallic / composites / copper / aluminum / hot dip coating / interfaces

References

[1] Sasaki TT, Barkey M, Thompson GB, Syarif Y, Fox D. Microstructural evolution of copper clad steel bimetallic wire. Mater. Sci. Eng. A, 2011, 58(6): 2974.

[2] Grünberger W, Heilmaier M, Schultz L. High-strength pearlitic steel-copper composite wires for conductors in pulsed high-field magnets. Mater. Sci. Eng. A, 2001, 303(1–2): 127.

[3] Rhee KY, Han WY, Park HJ, Kim SS. Fabrication of aluminum/copper clad composite using hot hydrostatic extrusion process and its material characteristics. Mater. Sci. Eng. A, 2004, 384(1–2): 70.

[4] Bokshitskii VI, Glezer AM, Zakharov EK, Sveshnikova GA. Structure and electrical properties of heat-resistant bimetallic conductors. Met. Sci. Heat Treat., 1997, 39(1): 38.

[5] Ahmed N. Extrusion of copper clad aluminum wire. J Mech. Work. Technol., 1978, 2(1): 19.

[6] Eslami P, Karimi Taheri A. An investigation on diffusion bonding of aluminum to copper using equal channel angular extrusion process. Mater. Lett., 2011, 65(12): 1862.

[7] Hug E, Bellido N. Brittleness study of intermetallic (Cu, Al) layers in copper-clad aluminium thin wires. Mater. Sci. Eng. A, 2011, 528(22–23): 7103.

[8] Wąsek S, Mróz S, Stradomski G, Laber K. The analysis of Al-Cu bimetallic bars bond layers joined by the explosive method. Solid State Phenom., 2013, 199, 514.

[9] Bouché S, Barbier F, Coulet A. Intermetallic compound layer growth between solid iron and molten aluminium. Mater. Sci. Eng. A, 1998, 249(1–2): 167.

[10] Xie JX, Sun DQ, Wu CJ, Wang ZD. Fabrication of bimetallic composite materials with dual-mold continuous casting technique. J. Mater. Eng., 2000, 4, 38.

[11] Wu CJ, Yu ZM, Xie JX, Wu Y. Fabrication of bimetal composites of copper cladding aluminum with process of continuous core-filling casting. Foundry, 2004, 53(5): 432.

[12] Su YJ, Liu XH, Wu YF, Huang HY, Xie JX. Numerical simulation of temperature field in horizontal core-filling continuous casting for copper cladding aluminum rods. Int. J. Miner. Metall. Mater., 2013, 20(7): 684.

[13] Bindumadhavan PN, Makesh S, Gowrishankar N, Wah HK, Prabhakar O. Aluminizing and subsequent nitriding of plain carbon low alloy steels for piston ring applications. Surf. Coat. Technol., 2000, 127(2–3): 251.

[14] Kerney U. Treatment of spent pickling acids from hot dip galvanizing. Resour. Conserv. Recycl., 1994, 10(1–2): 145.

[15] Marder AR. The metallurgy of zinc-coated steel. Prog. Mater Sci., 2000, 45, 191.

[16] Bouché K, Barbier F, Coulet A. Intermetallic compound layer growth between solid iron and molten aluminium. Mater. Sci. Eng. A, 1998, 249(1–2): 167.

[17] Gong LH, Tang RR, Zhu YQ, Chen DL. Influence of silane coupling agent on the conversion film forming of galvanized steel treated with cerium salt. Int. J. Miner. Metall. Mater., 2012, 19(9): 800.

[18] Li GX, Zheng YR. Review of solving difficult problems in hot-dip aluminum technology using different ways of thinking. J. Mater. Metall., 2011, 10(4): 329.

[19] Awan GH, ul Hasan F. The morphology of coating/substrate interface in hot-dip-aluminized steels. Mater. Sci. Eng. A, 2008, 472(1–2): 157.