Dry Sliding Wear and Friction Behavior of Graphene/ZrO2 Binary Nanoparticles Reinforced Aluminum Hybrid Composites

Abstract

Recently, aluminum matrix composites have been fabricated by pure zirconia (ZrO2) or pure graphene in the aluminum matrix because of good solid lubricant property of graphene and high compressive strength of ZrO2. Nevertheless, there is no study on the effect of both ZrO2 and graphene reinforced aluminum composite. In this current work, the tribological behaviors of Al-ZrO2 and Al-ZrO2-graphene composites with various contents (ZrO2: 1-12wt.%; graphene: 0.15-0.45wt.%) were investigated under different loads (5 and 10 N) via the pin-on-disk wear test unit. The density, porosity, hardness, and compressive strength were investigated by the Archimedes' principle kit, Vickers hardness test unit, and universal test machine, respectively. According to the test results, the micro-Vickers hardness, porosity, and compressive strength enhanced from 30 +/- 1.2 HV, 7%, 186 +/- 4 MPa (pure Al) to 75 +/- 2 HV, 3.7%, 490 +/- 4 MPa (Al-9%ZrO2-0.15%graphene), respectively. Similarly, the lowest friction coefficient (0.18 under a 10 N load), the mass loss (0.011 g under a 5 N load), and wear rate (0.0031 mm(3)/(Nm) under a 5 N load) were obtained at the Al-9%ZrO2-0.15%graphene composite. The mechanical strength and tribological behaviors of Al hybrid composites deteriorated in the case of over 9wt.%ZrO2 and 0.15wt.%graphene contents due to the agglomerations of graphene and ZrO2 nanoparticles. Therefore, it may be concluded that graphene is an excellent solid lubricator, and ZrO2 has a remarkable wear resistance for Al hybrid composites.