Tribological Behaviors of Graphene and Graphene Oxide as Water-Based Lubricant Additives for Magnesium Alloy/Steel Contacts.

Hongmei Xie,Jiahong Dai,Quan Li,Bin Jiang,Chunxia Li,Fusheng Pan,Cheng Peng

doi:10.3390/ma11020206

Abstract

The tribological behaviors of graphene and graphene oxide (GO) as water-based lubricant additives were evaluated by use of a reciprocating ball-on-plate tribometer for magnesium alloy-steel contacts. Three sets of test conditions were examined to investigate the effect of concentration, the capacity of carrying load and the endurance of the lubrication film, respectively. The results showed that the tribological behaviors of water can be improved by adding the appropriate graphene or GO. Compared with pure deionized water, 0.5 wt.% graphene nanofluids can offer reduction of friction coefficient by 21.9% and reduction of wear rate by 13.5%. Meanwhile, 0.5 wt.% GO nanofluids were found to reduce the friction coefficient and wear rate up to 77.5% and 90%, respectively. Besides this, the positive effect of the GO nanofluids was also more pronounced in terms of the load-carrying capacity and the lubrication film endurance. The wear mechanisms have been tentatively proposed according to the observation of the worn surfaces by field emission scanning electron microscope-energy dispersive spectrometer (FESEM-EDS) and Raman spectrum as well as the wettability of the nanofluids on the magnesium alloy surface by goniometer.

Highlights

Magnesium and its alloys are attractive materials for a wide range of applications in such demanding fields as transportation, electronics or aerospace [1,2]
The aim of this study was to evaluate the tribological performances of graphene and graphene oxide (GO) as water-based lubricant additives for the magnesium alloy/steel contacts using a ball-on-plate tribotester
The effect of graphene and GO concentrations in the water ranging from 0.2 to 1.0 wt.% on the tribological properties was performed for magnesium alloy/steel contacts under 0.08 m/s at the load of 3 N for 30 min test duration

Summary

Introduction

Magnesium and its alloys are attractive materials for a wide range of applications in such demanding fields as transportation, electronics or aerospace [1,2]. This is due to superior attributes such as low density, high thermal conductivity, and ease of manufacturing by conventional processes. The increasing demand for large-scale applications of wrought Mg alloy products, such as extruded profiles, rolled sheets and forgings, will determine the development of Mg alloys. The wrought Mg alloys offer better mechanical properties in comparison to cast Mg alloys because of the pronounced grain refinement without pores and uniform composition distribution after the deformation process [4]. The high friction between the workpiece and tool steel during the forming process cannot be avoided, resulting in relatively short tool life, high energy consumption and poor-quality products [5,6]

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