Effect of exfoliated MoS2 on the Microstructure, Hardness, and Tribological Properties of Copper Matrix Nanocomposite Fabricated via the Hot Pressing Method

Abstract

In this study, copper matrix composites were prepared using the cold and hot pressing technique and then investigated to select the suitable one for the self-lubricating applications. A hybrid of alumina and molybdenum disulfide with a 1:1 ratio by the mechanical milling for 40 h was proceeded to peel the molybdenum disulfide and cover the alumina particles with their layers. Three different samples like Cu, Cu/10 Al2O3, and Cu/hybrid 20(Al2O3–MoS2) were mixed for 15 h. The ball-to-powder ratio in the two mentioned steps was 10:1. The X-ray analysis, HRTEM, Raman spectra, and scanning electron miscopy were used to study the crystal structure, chemical composition, and morphology of the new hybrid and prepared samples. The density was evaluated by the Archimedes method. Mechanical properties, including hardness, wear rate, and coefficient of friction, were investigated. The mixing for 15 h improves the exfoliation of MoS2 flakes inside the copper matrix. A clear hardness improvement was achieved by adding alumina and the mixture of (Al2O3–MoS2). The copper sample reinforced with the hybrid of alumina/MoS2 gave the lowest mechanical wear rate and the lowest average friction coefficient of 0.17.