| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a binderless cBN sintered compact which has sufficient strength even when made into a cutting tool, and to provide a production method therefor. <P>SOLUTION: A cBN sintered compact produced by directly converting a normally sintered boron nitride as a starting material into cBN under high pressure-high temperature, and simultaneously sintering the cBN is subjected to heat treatment at 800 to <1,400°C in a vacuum or in an inert gas. Thus, the particles of cBN are mutually bonded without using a binder, and a sintered compact in which a Raman spectrum by a TO (transverse-optical) mode of cBN lies in a wave number of 1,052 cm<SP>-1</SP>to 1,055 cm<SP>-1</SP>can be obtained. In this sintered compact, strain caused by crystal defects introduced into the cBN crystals on conversion sintering, and stress introduced into the sintered compact on its discharge from an ultrahigh pressure-high temperature state are reduced, and high strength suitable for a cutting tool is imparted thereto. <P>COPYRIGHT: (C)2003,JPO |
