Unlubricated friction and wear behaviors of Al2O3/TiC ceramic cutting tool materials from high temperature tribological tests

The unlubricated friction and wear behaviors of Al2O3/TiC ceramic tool materials were evaluated in ambient air at temperature up to 800 degrees C by high temperature tribological tests. The friction coefficient and wear rates were measured. The microstructural changes and the wear surface features of the ceramics were examined by scanning electron microscopy. Results showed that the temperature had an important effect on the friction and wear behaviors of this Al2O3 based ceramic. The friction coefficient decreased with the increase of temperature, and the Al2O3/TiC ceramics exhibited the lowest friction coefficient in the case of 800 degrees C sliding operation. The wear rates increased with the increase of temperature. During sliding at temperature above 600 degrees C, oxidation of the TiC is to be expected, and the formation of lubricious oxide film on the wear track is beneficial to the reduction of friction coefficient. The wear mechanism of the composites at temperature less than 400 degrees C was primary abrasive wear, and the mechanisms of oxidative wear dominated in the case of 800 degrees C sliding operation. (C) 2012 Elsevier Ltd. All rights reserved.