Damage and wear resistance of Al2O3–CNT nanocomposites fabricated by spark plasma sintering

In this study, we prepare Al2O3–CNT (carbon nanotube) composites with different contents of CNT, 1–20 vol % into the Al2O3 ceramics, for the purpose of improving damage and wear resistance. Al2O3–CNT composites are obtained by spark plasma sintering in conditions of 1400–1600°C in vacuum and 30–80 MPa. Hardness evaluated by Vickers indentation shows that the hardness of Al2O3–CNT composites can be enhanced when the CNT addition is less than 5 vol %. Toughness evaluated by Vickers indentation indicates that the toughness of the composites is comparable with that of an Al2O3 monolith. Hertzian indentations using a spherical indenter indicate the hard and elastic behavior of the composites by the addition of CNT. The wear rate and friction coefficients of the composites evaluated by the ball-on-disk method show that the composites represent low friction and reduced wear loss under constant contact load. The results indicate that the damage and wear resistance of Al2O3 ceramics can be enhanced by the addition of carbon nanotubes in optimum conditions.