Sumitomo Electric Industries, Limited

Michiko Ota

Haruyo Fukui

Hisanori Ohara

Satoru Kukino

Tetsuo Nakai

Tomohiro Fukaya

Junichi Shiraishi

A coated sintered body can be used for a cutting tool for precision machining of hardened steel. The coated PCBN cutting tool includes a substrate which contains not less than 35 volume % and not more than 85 volume % of CBN, and a hard coated layer formed on the substrate. The hard coated layer comprises at least one compound layer consisting of at least one element selected from the group 4a, 5a, and 6a elements of the periodic table and Al, and at least one element selected from C, N and O. The thickness of the layer is not less than 0.3 &mgr;m and not more than 10 &mgr;m. The center-line mean roughness of the hard coated layer is not more than 0.1 &mgr;m.

Coated PCBN cutting tools

In a surface-coated boron nitride sintered compact tool, at least a part of the tool edge related with cutting is based on a substrate of a high pressure phase type boron nitride, and a surface-coated layer is provided on the surface thereof. The surface-coated layer includes an intermediate layer present in a continuous manner at the interface of the high pressure phase boron nitride sintered compact substrate, and further includes a hard coated layer formed thereon. The intermediate layer consists of at least one element selected from the Groups 4a, 5a and 6a of the Periodic Table, and has a mean thickness of 0.005 to 0.05 &mgr;m. Thereby, a markedly improved adhesive strength of the hard coated layer on the substrate is achieved.

Tool of a surface-coated boron nitride sintered compact

In a surface-coated boron nitride sintered compact tool, at least a part of the tool edge related with cutting is based on a substrate of a high pressure phase type boron nitride, and a surface-coated layer is provided on the surface thereof. The surface-coated layer includes an intermediate layer present in a discontinuous manner or in the form of dispersed particles at the interface of the high pressure phase boron nitride sintered compact substrate, and further includes a hard coated layer formed thereon. The intermediate layer consists of at least one element selected from the Groups 4a, 5a and 6a of the Periodic Table, and has a thickness of at most 1 &mgr;m, or has a proportion of 1 to 20 vol % of particles with a particle diameter of 0.1 to less than 0.5 &mgr;m and at most 5 vol. % of particles with a particle diameter of at least 0.5 &mgr;m. Thereby, a markedly improved adhesive strength of the hard coated layer on the substrate is achieved.

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Itami, Japan

Michiko Ota