Surface-coated cubic boron nitride sintered material tool

Patent metadata

Field	Value
Publication number	US-10744569-B2
Application number	US-201716082490-A
Country	US
Kind code	B2
Filing date	Mar 2, 2017
Priority date	Mar 7, 2016
Publication date	Aug 18, 2020
Grant date	Aug 18, 2020

Abstract

The present invention is directed to a surface-coated cubic boron nitride sintered material tool including a cBN substrate and a hard coating layer formed on a surface of the cBN substrate and having an alternate laminated structure of A layer and B layer. A peak of the grain size distribution of cBN grains in the cBN sintered material is present within a range of a grain size from 0.50 to 1.00 μm. The A layer has a composition of (Ti1-xAlx)N (0.4≤x≤0.7 in an atomic ratio). The B layer has a composition of (Cr1-y-zAlyMz)N (0.03≤y≤0.6 and 0≤z≤0.05 in an atomic ratio). An X-ray diffraction peak of a (200) plane is present at a position of a diffraction angle of 43.6 plus or minus 0.1 degrees, and a plastic deformation work ratio of the B layer is 0.35 to 0.50.

First claim

The invention claimed is:

1. A surface-coated cubic boron nitride sintered material tool comprising:
a tool body which is made of a cubic boron nitride sintered material; and
a hard coating layer formed on a surface of the tool body, the hard coating layer being made of an alternate laminated structure, in which at least one A layer and at least one B layer are alternately laminated, and having a total layer thickness of 0.5 to 4.0 μm,
wherein (a) the cubic boron nitride sintered material has a composition including:
10 to 50 vol % of one or more of TiC, TiN, and TiCN;
0.1 to 2 vol % of WC;
0.3 to 5 vol % of AN;
2 to 10 vol % of TiB 2 ;
1.5 to 10 vol % of Al 2 O 3 ; and
30 to 80 vol % of cBN (cubic boron nitride),
(b) when a grain size distribution of cBN grains in the cubic boron nitride sintered material is measured, a graph of the grain size distribution contains a single peak of the grain size distribution, said single peak being within a range of a grain size from 0.50 to 1.00 μm, and a value of a full width at half maximum of the single peak satisfies a range from 0.33 to 0.73 μm,
(c) the A layer is a Ti and Al complex nitride layer, which has an average single layer thickness of 0.1 to 3.0 μm and has an average composition satisfying 0.4≤x≤0.7 (x represents a content ratio of Al in terms of atomic ratio) in a case where the A layer is represented by a composition formula (Ti 1-x Al x )N,
(d) the B layer is a Cr, Al and M complex nitride layer, which has an average single layer thickness of 0.1 to 3.0 μm and has an average composition satisfying 0.03 ≤y≤0.6 and 0≤z≤0.05(y represents a content ratio of Al in terms of atomic ratio, z represents a total content ratio of the component M in terms of atomic ratio, and the component M represents one or more elements selected from group 4a elements excluding Cr, group5a elements, group 6a elements, B and Si in the periodic table) in a case where the B layer is represented by a composition formula (Cr 1-y-z Al y M z )N, and
(e) when an X-ray diffraction measurement is performed for the entirety of the hard coating layer constituted of the A layer and the B layer, an X-ray diffraction peak of a (200) plane is present at a position of a diffraction angle of 43.6 plus or minus 0.1 degrees, and a full width at half maximum of the diffraction peak satisfies 0.25 plus or minus 0.05 degrees.

2. The surface-coated cubic boron nitride sintered material tool according to claim 1 ,
wherein a value of a plastic deformation work ratio W plast /(W plast +W elast ) of the B layer, which is obtained by performing a nanoindentation test for the B layer with a load set to achieve an indentation depth of 1/10 times or smaller than a layer thickness, is within a range from 0.35 to 0.50.

3. The surface-coated cubic boron nitride sintered material tool according to claim 1 ,
wherein the A layer is formed immediately on the surface of the tool body and the B layer is formed as an outermost surface of the hard coating layer.

4. The surface-coated cubic boron nitride sintered material tool according to claim 1 ,
wherein the surface of the tool body has been subjected to bombardment treatment with argon ion prior to depositing the hard coating layer on the surface of the tool body.

Assignees

• Mitsubishi Materials Corp

Inventors

• Maekawa Takuya
• Takahashi Masakuni
• Sato Shun
• Yumoto Kenji

Classifications

• C04B35/5831 Primary

  based on cubic boron nitrides {or Wurtzitic boron nitrides, including crystal structure transformation of powder} · CPC title

• C04B2235/3843

  Titanium carbides · CPC title

• C04B2235/3865

  Aluminium nitrides · CPC title

• C04B2235/3847

  Tungsten carbides · CPC title

• C04B2237/36

  Non-oxidic · CPC title