Influence of Oxidation Treatment on Solid Lubrication Property of Carbon Onion

Abstract

Carbon onion was oxidized by hydrogen peroxide to modify its tribological properties. The microstructure of carbon onion oxidized was characterized with electron high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy and thermo gravimetric analysis. HRTEM and Raman studies showed that internal constitution of the carbon onions hardly change. Thermo gravimetric analysis showed that oxidation reduced the combustion temperature of carbon onion. Solid lubricant properties of the carbon onion oxidized were measured by ball-on-disk type friction testing using silicon wafers and steel balls in air, vacuum and dry nitrogen. By oxidation, friction coefficient of carbon onion became slightly higher and the lubrication life became longer, especially in vacuum. These results suggested that surface defects of carbon onion increase and its surface becomes active.