| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a cutting tool made of a surface-coated cubic boron nitride-based ultrahigh pressure sintered material exhibiting excellent finished surface accuracy in a high-speed machining of a high hard steel over a long period of time. <P>SOLUTION: The cutting tool made of the surface-coated cubic boron nitride-based ultrahigh pressure sintered material comprises a pressed powder body composed of titanium nitride, aluminum and/or aluminum oxide and boron nitride in the remaining portion, and a hard coating layer is vapor-deposited on the surface of a main body wherein an ultrahigh pressure sintered reaction product is interposed on an interface between a cubic crystal boron nitride phase forming a dispersed phase and a titanium nitride phase forming a continuous phase. In the cutting tool, (a) the hard coating layer is composed of a lower layer having an average layer thickness of 1.5 to 3 μm and an upper layer having the average layer thickness of 0.3 to 3 μm, (b) the lower layer is composed of a composite nitride layer of Ti and Al, and (c) the upper layer has an alternatingly-layered structure of a thin layer A and a thin layer B of which one layer average layer thickness is 0.05 to 0.3 μm respectively, the thin layer A is composed of a composite nitride layer of Ti and Al which satisfies a specified composition formula and the thin layer B is composed of Ti nitride (TiN) layer. <P>COPYRIGHT: (C)2007,JPO&INPIT |
