Influence of surface modification on the cutting performance of reaction-sintered Al2O3-TiOC ceramics

Abstract

Al2O3-TiC mixed ceramics are popular for dry cutting of hardened steel. In this work, the cutting performance of surface-modified mixed ceramic cutting tools has been studied. A 1-μm-thick modified surface has been obtained by CO2 posttreatment of the Al2O 3-TiOC mixed ceramics. The cutting performance of the modified tools has been found to be much better than the precursor-mixed ceramics. The density of the modified layer also has an influence on the cutting performance. Modified ceramics with a dense surface layer show considerably improved wear resistance compared with that of ceramics with a porous layer. While plastic deformation of the TiC layer in the flank surface, followed by abrasive wear of the exposed substrate is responsible for flank wear, crater wear is caused mainly by diffusion reaction as well as by abrasion. In our system, it is mainly the flank wear that controls the cutting performance of the inserts. © 2008 The American Ceramic Society.