title: Tribological performance of Graphene/Carbon nanotube hybrid reinforced Al2O3 composites.
abstract: Tribological performance of the hot-pressed pure Al2O3 and its composites containing various hybrid contents of graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) were investigated under different loading conditions using the ball-on-disc method. Benchmarked against the pure Al2O3, the composite reinforced with a 0.5 wt% GNP exhibited a 23% reduction in the friction coefficient along with a promising 70% wear rate reduction, and a hybrid reinforcement consisting of 0.3 wt.% GNPs + 1 wt.% CNTs resulted in even better performance, with a 86% reduction in the wear rate. The extent of damage to the reinforcement phases caused during wear was studied using Raman spectroscopy. The wear mechanisms for the composites were analysed based on the mechanical properties, brittleness index and microstructural characterizations. The excellent coordination between GNPs and CNTs contributed to the excellent wear resistance property in the hybrid GNT-reinforced composites. GNPs played the important role in the formation of a tribofilm on the worn surface by exfoliation; whereas CNTs contributed to the improvement in fracture toughness and prevented the grains from being pulled out during the tribological test.
authors.affiliation: College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK.
authors.forename: Bahareh
authors.initials: B
authors.lastname: Yazdani
authors.affiliation: Department of Mechanical, Materials and Manufacturing Engineering, The University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: Fang
authors.initials: F
authors.lastname: Xu
authors.affiliation: Center of Excellence for Research in Engineering Materials, Advanced Manufacturing Institute, King Saud University-Riyadh 11421 - P.O. Box 800 - Kingdom of Saudi Arabia.
authors.forename: Iftikhar
authors.initials: I
authors.lastname: Ahmad
authors.affiliation: Department of Mechanical, Materials and Manufacturing Engineering, The University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: Xianghui
authors.initials: X
authors.lastname: Hou
authors.affiliation: College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK.
authors.forename: Yongde
authors.initials: Y
authors.lastname: Xia
authors.affiliation: College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK.
authors.forename: Yanqiu
authors.initials: Y
authors.lastname: Zhu