Mitsubishi Materials Corporation

Seiichirou Nakamura

Hironori Yoshimura

Niro Odani

Tetsuya Tanaka

Akira Osada

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.about.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 (Al.sub.2 O.sub.3). 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.about.5% of TiCl.sub.4, 0.1.about.1% of CH.sub.3 CN, 0.about.25% of N.sub.2 with the remaining portion being composed of H.sub.2, under a reaction temperature of 800.degree..about.900.degree. C. and a reaction pressure of 30.about.200 Torr.

Process for producing cermet cutting tools having both longitudinal and

The present invention discloses 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.about.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 (Al.sub.2 O.sub.3). 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. The process for producing a cermet cutting tool according to the present invention comprises a step for preparing a substrate from titanium carbo-nitride based cermet, and a step for forming a hard coating layer onto the surface of said substrate using a chemical vapor deposition method wherein in at least one part of this step, chemical vapor deposition is performed using a reaction gas composed of 1.about.5% of TiCl.sub.4, 0.1.about.1% of CH.sub.3 CN, 0.about.25% of N.sub.2 with the remaining portion being composed of H.sub.2, under a reaction temperature of 800.degree..about.900.degree. C. and a reaction pressure of 30.about.200 Torr.

Cermet cutting tool and process for producing the same

There is disclosed a surface coated cermet blade member which includes a cermet substrate and a hard coating of an average thickness of 0.5 to 20 .mu.m formed thereon. The substrate contains, apart from unavoidable impurities, a binder phase of 5 to 30% by weight of at least one of cobalt, nickel, iron and aluminum, and a hard dispersed phase of a balance carbo-nitride of metals. The metals are titanium, tungsten and at least one of tantalum, niobium, vanadium, zirconium, molybdenum and chromium. The substrate includes a surface portion having a hardness greater than an interior portion. The hard coating may be composed of one or more coating layers. Each coating layer is formed of TiX or Al.sub.2 O.sub.3, where X denotes at least one element of carbon, nitrogen, oxygen and boron.

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Ishige, Japan

Seiichirou Nakamura