CUBIC BORON NITRIDE (CBN) SINTERED BODY AND CUBIC BORON NITRIDE (CBN) SINTERED BODY TOOL

摘要

The purpose of the present invention is to provide a cBN sintered body having excellent antifriction properties and defect resistance even in the machining of hard centrifugally cast iron, and to also provide a cBN sintered body tool. This cBN sintered body contains: between 20 and 65 volume % cBN; between 34 and 80 volume % Al₂O₃ as a bonding material; at least one type (hereinafter X) selected from Zr nitrides, carbides, carbonitrides, borides, boronitrides, and the solid solutions thereof; and ZrO₂. The total of X and ZrO₂ is between 1.0 and 6.0 volume %. The volume % ratio of ZrO₂ and Al₂O₃, ZrO₂/Al₂O₃, is at least 0.010 and less than 0.100. When, in the x-ray diffraction peak of the cBN sintered body, the intensity of a plane (101) of the tetragonal ZrO₂ is I_{tetragonal ZrO2} (101), and the intensity of a plane (110) of the αAl₂O₃ (110) is I_αAl2O3 (110), I_{tetragonal ZrO2} (101)/I_αAl2O3 (110) is between 0.1 and 3.