CUBIC BORON NITRIDE POLYCRYSTALLINE BODY AND METHOD FOR PRODUCING SAME, AND CUTTING TOOL AND GRINDING TOOL

Title:

CUBIC BORON NITRIDE POLYCRYSTALLINE BODY AND METHOD FOR PRODUCING SAME, AND CUTTING TOOL AND GRINDING TOOL

Document Type and Number:

WIPO Patent Application WO/2018/088369

Kind Code:

A1

Abstract:

A cubic boron nitride (cBN) polycrystalline body according to the present invention is a non-orientation polycrystalline body composed of cBN single-phase crystal structures having an average grain diameter of 200 nm or less, and has a Knoop hardness of 50 GPa or more. The Knoop hardness can be adjusted to 53 GPa or more by adjusting the average grain diameter to 100 nm or less, and it makes it possible to use the polycrystalline body suitably as a sharp cutting tool cutting edge or the like by adjusting the average grain diameter to 50 nm or less. A Knoop hardness of 54.5 GPa or more can be achieved in a cBN polycrystalline body in which cBN coarse crystal grains having an average grain diameter of 120 to 165 nm are dispersed in cBN fine polycrystalline structures having an average grain diameter of 70 nm or less and the average grain diameter of the polycrystalline body including the fine polycrystalline structures and the coarse crystal grains is 100 nm or less. The cBN polycrystalline body according to the present invention can be produced by retaining a raw material, which is composed of pyrolytic boron nitride (pBN) and is oriented in the [001] direction, at a predetermined temperature for a predetermined time period under a pressure of 25 GPa or more to convert pBN to cBN directly.

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Inventors:

ICHIDA YOSHIO (JP)
IRIFUNE TETSUO (JP)
OHFUJI HIROAKI (JP)

Application Number:

PCT/JP2017/039979

Publication Date:

May 17, 2018

Filing Date:

November 06, 2017

Export Citation:

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Assignee:

UNIV NAT CORP EHIME UNIV (JP)

International Classes:

C04B35/5831; B01J3/00; B23B27/14; B23B27/20; B24D3/00; C01B21/064

Domestic Patent References:

WO2013031681A1

2013-03-07

Foreign References:

JP2015529611A	2015-10-08
JPS62108718A	1987-05-20
JP2014055078A	2014-03-27

Attorney, Agent or Firm:

KYOTO INTERNATIONAL PATENT LAW OFFICE (JP)

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