Abstract
Carbon nanotubes (CNTs) have extremely high tensile strength and elastic modulus, good flexibility and low density. In addition, CNTs are expected to have lubrication properties like other carbon-derived materials including graphite and diamond-like carbon. In this study, alumina ceramics reinforced with multi-walled CNTs (MWCNTs) were prepared by a flocculation method and the effects of the MWCNT content on mechanical and tribological properties of the composites were investigated. The results showed that the bending strength and fracture toughness simultaneously increased for the composite containing 10.0 vol.% MWCNTs. The friction coefficient of the composites containing 5.5 vol.% MWCNTs was about 0.15, measured by the ball-on-disk wear tests using alumina balls as a counterpart in air. Microstructural observations of the fractured and polished surfaces of the composites implied that the size of a MWCNTs agglomerate is one of the important factors for improving friction properties of the composite. It is suspected that there may be an optimal MWCNTs content for improving the mechanical and friction properties of the composites.
