Title: The effect of laser treatment on the mechanical and electrical properties of busbar joints

Authors: T.T. Wong, J.M.K. MacAlpine, G. An, G.Y. Liang

Addresses: Department of Mechanical Engineering, Hong Kong Polytechnic University, Hong Kong, China. ' Department of Electrical Engineering, Hong Kong Polytechnic University, Hong Kong, China. ' Department of Materials Physics, Science School, Xi'an Jiaotong University, Xi'an, China. ' Department of Materials Physics, Science School, Xi'an Jiaotong University, Xi'an, China

Abstract: A high proportion of the faults in electrical substations are due to the overheating of busbar joints. Surface contamination due to atmospheric corrosion is a main cause. Laser surface treatments have previously been applied by the authors to improve the surface hardness and corrosion resistance of aluminium alloys. Similarly, a chromium protective coating can be produced on copper by laser-alloying. This should allow more reliable bolt-together busbar joints to be made up on site with less attention to surface cleanliness. In this study, experimental investigations were made into the mechanical and electrical properties of laser-treated copper busbar joints under various conditions of applied torque and current flow. It was found that the maximum hardness of the laser-alloyed layer could reach HV95, which is almost 50% higher than that of the original sample. There were insignificant differences between the temperature distribution associated with the laser-alloyed and the untreated samples. The corrosion resistance of the laser-alloyed sample is slightly better than that of the original sample in the salt spray corrosion test. The electric conductivity of the uncorroded laser-alloyed joints was only slightly lower than that of the uncorroded untreated joints.

Keywords: copper busbars; electric conductivity; laser alloying; salt spray corrosion; busbar joints; overheating; surface contamination; atmospheric corrosion; laser surface treatment.

DOI: 10.1504/IJMPT.2004.005623

International Journal of Materials and Product Technology, 2004 Vol.21 No.6, pp.473 - 486

Published online: 31 Oct 2004 *

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