| 摘要 |
A polycrystalline diamond cutting tool comprises a tool material of polycrystalline diamond formed by low-pressure vapor deposition, which is bonded to a shank of cemented carbide through a brazing layer. The thickness of the polycrystalline diamond layer is set at 0.1 to 1.0 mm, while that of the brazing layer is set at 10 to 50 mu m. The brazing layer is made of a material having a melting point of 950 DEG to 1300 DEG C., which is in the form of an alloy layer containing at least one material selected from metals belonging to the groups IVa, Va, VIa and VIIa of the periodic table and carbides thereof and at least one material selected from Au, Ag, Cu, Pt, Pd and Ni. The polycrystalline diamond cutting tool is improved in heat resistance and tool strength. In order to improve deposition resistance of the cutting tool, the surface roughness of a tool rake face is set to be not more than 0.2 mu m in Rmax. A portion of the polycrystalline diamond layer up to a depth of 10 mu m from the rake face contains 99 to 100 atomic percent of carbon elements, and 99 to 100% of carbon atoms are diamond-bonded. A surface of the polycrystalline diamond layer which has been in contact with the substrate during formation of the polycrystalline diamond layer defines the rake face, whose surface is subjected to ion beam machining and thereafter treated in the atmosphere at a temperature of 300 DEG to 500 DEG C.
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