Process for producing cermet cutting tools having both longitudinal and granular crystal structures

摘要

A cermet cutting tool, and process for producing the same, comprising a substrate formed from titanium carbo-nitride based cermet, and a hard coating layer of average thickness 0.5 DIFFERENCE 20 mu m, formed onto the surface of the cermet substrate comprising a lower layer formed from at least one layer of a compound selected from the group consisting of titanium carbide (TiC), titanium nitride (TiN), titanium carbo-nitride (TiCN), titanium carbo-oxide (TiCO) and titanium carbo-oxi-nitride (TiCNO), and aluminum oxide (Al2O3). Additionally, at least one of the layers comprising the hard coating layer is a titanium carbo-nitride layer, and at least one layer of this titanium carbo-nitride layer comprises a longitudinal growth crystal structure, and a further layer comprises a granular crystal structure. In the method of fabrication, chemical vapor deposition is performed using a reaction gas composed of 1 DIFFERENCE 5% of TiCl4, 0.1 DIFFERENCE 1% of CH3CN, 0 DIFFERENCE 25% of N2 with the remaining portion being composed of H2, under a reaction temperature of 800 DEG DIFFERENCE 900 DEG C. and a reaction pressure of 30 DIFFERENCE 200 Torr.