Friction and wear properties of copper-based composites reinforced with micro- and nano-sized Al2O3 particles

Abstract

Copper-based composites with hard particles are widely applied in electrical sliding contacts such as those in railway overhead current collection system, lead frame in large scale integrated-circuit, welding electrodes, transfer switches and electrical contact material. Powder metallurgy is the most applicable technology way of producing the copper-based composites, especially when the matrix material is reinforced with second phase particles. Two copper-based composites reinforced with micro-sized Al2O3 particles (app. 750 nm in size) and nano-sized Al2O3 particles (less than 100 nm in size), and produced by powder metallurgy technology, were compared with a Cu-Cr-Zr alloy produced by casting technique. The tribological tests were carried-out on ball-on-disc nanotribometer, under the high-load (1 N), low-speed (8 mm/s) dry sliding condition. The addition of micro-sized Al2O3 particles did not showed so beneficiary effect, since this composite had the lowest hardness and wear resistance, and at the same time, the highest coefficient of friction. On the other hand the addition of nano-sized Al2O3 particles increased considerably hardness of composite and improved the wear resistance to a significant extent, and also reduces the coefficient of friction.