Wear and corrosion characteristics of copper-based composite coatings

Abstract

Purpose The purpose of this paper is to investigate the effects of reinforcing particles (B4C, TiB2 and TiC) on the physical, corrosion and wear behaviour of copper matrix composite coatings. Design/methodology/approach Coatings were produced by cold gas dynamic spraying process, and the contribution of reinforcements (B4C, TiB2 and TiC) to the coating characteristics was detected through microstructural examinations (scanning electron microscope examinations and X-ray diffraction analyses), hardness and electrical conductivity measurements, corrosion tests in Cl− environment with potentiostat/galvonostat apparatus and wear tests which were performed under dry conditions by reciprocating wear tester. Findings Coatings with high density, good bonding at the coating and substrate interface were obtained by cold gas dynamic spray process. The electrochemical polarisation test in a Cl− environment clearly indicated that the type of reinforcing particles did not significantly affect the corrosion performances of pure copper coating. In terms of the wear performances of the coatings, the best wear performance has been obtained for pure copper coating. Wear performance reduction of the composite coatings was related to the inhibition of continuous oxide layer formation on the worn surfaces due to third-body abrasion mechanism and delamination of oxide layer during wear tests. Originality/value Contrary to expectations, wear tests results of the study revealed the inverse effect of ceramic particle addition to the copper matrix in cold spray coating applications due to poor bonding between matrix and reinforcing particles.