JPS60243273A - Hard covering member - Google Patents

Abstract

PURPOSE:To improve an adhesive property of a BN film to a base body by providing a layer of a specified boride or nitride between the base body surface and the BN film when the ultrahard BN film is formed at the base body surface from gaseous phase. CONSTITUTION:When the film of ultrahard cubic crystal boron nitride (C-BN) is formed from gaseous phase to the surface of the hard base body such as cutting tool without using ultrahigh pressure method, the film of 0.1-20mu thickness of TiN, TiB2, TiBN, Si3N4, AlN, BN, etc. which are compounds of elements of one or >=2 kinds selected from transition metals of the periodic table 4a, 5a, 6a, 7a groups, and Al, Si, B, and B or N is formed previously on the surface of the hard base body by CVD method, spattering method, etc. Next, the ultrahard film composed of Ti-Bn or C-BN is formed similarly by 0.1- 20mu thickness from gaseous phase. The adhesive property between the ultrahard BN film and the base body is improved remarkably by the existence of said middle film.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a hard, wear-resistant BN-coated part that has a hard coating and is used for cutting tools, wear-resistant parts, and the like.

(rl) Technical background It is more thermally stable than almond and has no reactivity with iron, so it is widely used in cutting tools, grinding tools, wear-resistant tools, etc. However, in order to generate C-BN, extremely high pressure and temperature are required, so it is necessary to use an expensive ultra-high pressure generator, and even if this equipment is used, the C-BN that can be produced is extremely small. There are similar limitations for the diamond itself.

Recently, various techniques have been developed to deposit diamond from the gas phase onto the surface of a substrate without using ultra-high pressure. Since it was proposed to coat the tool with hard BN, it was found that the above-mentioned tool could not be put to practical use.

(C) Disclosure of the invention As a result of various studies to improve the adhesive strength between the BN layer and the substrate, the inventors provided an intermediate layer of boride and/or nitride between the BN and the substrate. It has been found that the adhesive strength is significantly improved by this.

The reasons for this limitation will be explained below. '■ The intermediate layer is made of one or more elements selected from the group consisting of Na, Va, VIa, and ■a group transition metals of the periodic table and #, Si, and B, and B and/or N. One or more thin layers made of one or more compounds and having a thickness of 0.1 to 20μ.

By providing the above-mentioned intermediate layer between the substrate and the surface BN layer, the adhesive strength is significantly improved.

In particular, TiN, TiBz, TiBN, Siz Na, A
It has been found that IN, BN (hexagonal crystal), etc. are excellent as intermediate layers among these. When the film thickness is 0.1 μm or less, no effect of improving adhesive strength is observed, and when the film thickness is 20 μm or more, the effect is saturated.

Note that similar results can be obtained even if C and/or 0 are included in this intermediate layer. Furthermore, similar results were observed when a carbide and/or nitride was coated between the substrate and the intermediate layer -F.

■ Regarding the surface coating layer BN, the present invention uses BN, which is harder than the gas phase, without using an ultra-high pressure device.
The purpose of this is to precipitate a layer of 1-BN (corresponding to i-carbon, which is an amorphous diamond in diamond, and is not crystallized but has a structure between atoms). The bond state is C
- BN) or C-BN is an essential requirement.

Further, if the film thickness is less than 0.1 μm, the result as an ultra-hard film will not be observed, and if it is more than 20 μm, it will be easy to peel off even if there is an intermediate layer, which is not preferable.

CVD is a coating method for the intermediate layer for carrying out the present invention.
method, plasma CVD, ion blating, and sputtering method are preferred. In addition, IBD is a coating method for the BN layer.
The ion beam mixing method (I
BM) and the like are preferred, but are not limited to these methods.

This will be explained in detail below using examples.

Example l l5OK-10 grade cemented carbide (model number SNMN43
2) 2μ of TiC was applied using the CVD method.

2μ of T'iN and 2μ of Ti(BN) were sequentially coated.

This coated cemented carbide was placed in a reaction vessel, and H2 was heated at 100C.
C/sn, B2Ha as l CC/min, N H
3 at 0.5 CG/min.

After flowing at 0.5 Torr, plasma was generated using microwaves. The cemented carbide was placed in plasma and was heated to 800°C.

After processing in this state for 1 hour, it was cooled to room temperature. When this sample was examined using electron diffraction and scanning electron microscopy, we found that
The surface layer was coated with a thickness of 1 μm mainly composed of C-BN. This sample was designated as A, and for comparison, a sample in which a cemented carbide was directly coated with C-BN was designated as B, and both were subjected to a cutting test under the following conditions.

Work material: 30M415 (HR, = 60) Cutting speed
: 100m/min Depth of cut: Q, 2mm Feed: 0.1 iua /rev Holder: FNIIR-44A As a result, flank wear of A was 0.0 after cutting for 10 minutes.
8 M, but B's coating film peeled off and 2
It was possible to cut for only 8 seconds.

By the way, it takes 13 seconds for cemented carbide without C-BN coating.
However, with a C-BN sintered composite tip manufactured using a commercially available ultra-high pressure device, the flank wear was 0.04 ml after cutting for 10 minutes.

Example 2 The same cemented carbide as in Example 1 was used as the substrate, and TiC was used in the same manner.

・Borazine (B) was added to the sample coated with TiN and Ti(BN).

1μ of 1-BN was coated by the IBD method using N1H6). A cutting test was conducted on this sample under the same conditions as in Example 1, and the flank wear was 0.1 mm after cutting for 5 minutes.
Met.

Claims (1)

[Claims] (1) On the surface of the substrate, the periodic table IVa, Va, veil■
A thin layer consisting of one or more compounds of B and/or N and one or more elements selected from the group consisting of group a transition metals and #+Si+B. .The surface of the hard coated parts having a coating layer of 1 to 20 μm in thickness is further coated with 0, which is mainly composed of BN and has excellent wear resistance.
, a hard coated part comprising a coating layer having a thickness of 1 to 20 μm. (2. In the hard coated component according to claim 1, part or all of the BH of the surface coating layer is 1-BN(
Although not crystallized, the crystalline state between atoms is C-BN and R4
A hard coated part characterized by being BN). (3) The hard-coated component according to claim 1, wherein part or all of the BN in the surface coating layer is C-BN.