| abstract |
Improved formulations for ceramic materials for use as cutting tools are provided. The cutting tool includes a substrate of a ceramic matrix reinforced by ceramic whiskers, which substrate is coated with an adherent outer layer. The ceramic matrix is preferably formed from alumina and may contain toughening agents. The ceramic whiskers are preferably formed from silicon carbide and consist of 2-40% of the substrate. The cuter adherent coating is preferably alumina applied by a CVD process and provides an unexpected improvement in cutting tool longevity. |