Tribological behavior of self lubricating Cu/MoS2 composites fabricated by powder metallurgy
(Department of Materials Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran)
Abstract: The effects of MoS2 content on microstructure, density, hardness and wear resistance of pure copper were studied. Copper-based composites containing 0-10% (mass fraction) MoS2 particles were fabricated by mechanical milling and hot pressing from pure copper and MoS2 powders. Wear resistance was evaluated in dry sliding condition using a pin on disk configuration at a constant sliding speed of 0.2 m/s. Hardness measurements showed a critical MoS2 content of 2.5% at which a hardness peak was attained. Regardless of the applied normal load, the lowest coefficient of friction and wear loss were attained for Cu/2.5MoS2 composite. While coefficient of friction decreased when the applied normal load was raised from 1 to 4 N at any reinforcement content, the wear volume increased with increasing normal load. SEM micrographs from the worn surfaces and debris revealed that the wear mechanism was changed from mainly adhesion in pure copper to a combination of abrasion and delamination in Cu/MoS2 composites.
Key words: copper matrix composite; microstructure; coefficient of friction; wear mechanism