Tribological properties of graphene oxide and oxidized wood-derived nanocarbons as water-based lubricating additives

摘要

Graphene oxides (GOs) have graphitic single-layered sheets with a thickness of 1 nm and a size of more than 1 μm, and is fully oxidized. An oxygen ratio is very high (O:C = 1:2). GOs are well dispersed in water. We found that a friction coefficient under lubrication in a dispersion of GOs in water is below 0.04 with only slight plate surface wear using a steel plate (JIS SUS304) and tungsten carbide (WC) ball[l,2]. Recently, we investigate tribological properties of oxidized wood-based nanocarbons (oWNCs), which is composed of graphitic nanoshells. A friction coefficient of a water dispersion of oWNC shows very low friction using a steel plate and tungsten carbide ball [3]. In this study, in order to investigate such low friction coefficients of both of GO and oWNC water dispersions, we have carried out tribological tests and analyzed the friction surfaces using confocal laser scanning microscopy (CLSM) with an optical data storage system, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM).