A TOOL OF A SURFACE-COATED BORON NITRIDE SINTERED COMPACT

摘要

The object of the present invention is to provide a cutting tool con-sisting of a suface-coated high pressure phase type boron nitride sinter ed compact, having a markedly improved adhesive strength of a hard coated layer to a cBN sintered compact substrate. The feature consists in a surface-coated boron nitride sintered compact tool, in which at least a part of the tool edge related with cutting is base d on a substrate of a high pressure phase type boron nitride, and a surface- coated layer is allowed to be present on the surface thereof, the said surface-coat ed layer comprising an intermediate layer present in continuous manner to the interface of the said high pressure phase boron nitride sintered compact sub-strate and a hard coated layer formed further thereon, the said intermediate layer consisting of at least one element selected from the Group 4a, 5a and 6a of Periodic Table having a mean thickness of 0.005 to 0.05 .mu. m.