| 摘要 |
A cBN sintered body superior in chipping resistance. The cBN sintered body is a sintered body in which cBN particles are bonded through a bonding phase. The bonding phase has a two-dimensionally continuous structure. The bonding phase comprises at least one kind selected from the group consisting of (a) carbide, nitride, carbonitride, or boride of a 4a-, 5a-, or 6a-group transition metal in the periodic table; (b) nitride, boride, or oxide of Al; (c) at least one kind of carbide, nitride, carbonitride, and boride of Fe, Co, or Ni; and (d) a mutual solid solution of those. The percentage of cBN content is 45 to 70% in volume. The bonding phase has the thickness of which the average value is 1.5 mum or less and the standard deviation is 0.9 mum or less with the cBN particles having an average particle size of 2 to 6 mum inclusive. The bonding phase has the thickness of which the average value is 1.0 mum or less and the standard deviation is 0.7 mum or less with the cBN particles having an average particle size of not less than 0.01 mum and less than 2.0 mum.
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