JPS60152677A - Method for manufacturing cubic boron nitride coated hard body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention is directed to the use of cubic boron nitride (Cubic BoronNit), which has excellent wear resistance and is suitable for use as a cutting tool.
ride is abbreviated as CBN below. ) and a method for producing the same.

[Conventional cutting tools]

Currently, Ti(j,
Tools coated with TiN or A/203 are used. This current coated tool has excellent both toughness and wear resistance by attaching the coating layer, which has higher hardness and excellent wear resistance, to a base having high toughness.

However, as the cutting speed increases, the temperature of the cutting edge increases, but the coating layer cannot 1) reduce the reaction with the rigid material due to its chemical stability, and 2) reduce the temperature of the cutting edge due to its high thermal conductivity. As a result, it has been impossible to extend the life of the cutting tool made of the coating layer.

The present inventors studied the above-mentioned types 1) and 2) of the coating layer, and as a result of repeated research to develop a tool material that exhibits excellent performance in high-speed cutting, the present invention was developed. It is completed.

[Object of the present invention]

That is, an object of the present invention is to provide a coated hard body that does not cause a large increase in the temperature of the cutting edge even when cutting at high speed, and also has less wear due to reaction with the rigid material, and a method for manufacturing the same. .

[Configuration of the present invention]

As a means for achieving the above object, the present invention selects CBN as a coating layer, and also forms this coating layer on the surface of a hard substrate or on the surface of a hard substrate on which an intermediate coating layer has been applied. First, amorphous boron distillate is coated, and then this is coated with CB l
(K conversion. That is, the present invention is based on (1)
A sintered hard substrate containing at least one carbide along with a binder metal is coated directly or through an intermediate layer with a thickness o
, a cubic boron nitride-coated hard body characterized by having a coating layer of 5 to 20 microns of cubic boron nitride, and (2) a sintered hard substrate containing at least one glaze carbide together with a binder metal. or 4a of the periodic table in advance,
Amorphous boron nitride with a thickness of 0.5 to 20 μm is applied by a vapor phase method to the surface of the hard substrate coated with one or more of group 5a metal carbides, nitrides, oxides, and borides. A/and/or AI! A cubic boron nitride-coated hard material characterized by converting all amorphous boron nitride into cubic boron nitride by keeping it in the thermodynamically stable region of cubic boron nitride in contact with a compound. It is a method of manufacturing the body.

Hereinafter, to explain the present invention in detail, the present inventors have discovered that OB
N is a substance with the highest hardness next to diamond, and
We found that OBN is a material with excellent thermal conductivity and low reactivity with iron group metals at high temperatures, and that OBN can be directly or Thickness 0.5 to 0.5 through one or more intermediate layers of one or more coatings of carbides, nitrides, oxides, and borides of metals from groups 4a and 5a of the periodic table.
It has been discovered that a hard body coated with 20μ has unprecedented performance.

Incidentally, although research on vapor phase synthesis of CBN has been widely conducted, no practical method has yet been found. However, it is relatively easy to form an amorphous film with a uniform porosity by means of plasma CVN, ion blating, ion beam evaporation, or the like. The present inventors focused on this point, and first coated with an amorphous boron nitride thin film (of course, it may partially contain OBN), and then coated it with A7 and/or AI. ! In contact with the compound, the high pressure that is the stable region of OBN,
By exposing it to high temperature, it is converted into a 38N film. By this means, a strong coating layer consisting only of CBN can be easily obtained, and the adhesion strength to the hard substrate is also high. .

As mentioned above, OBN has excellent properties such as hardness, thermal conductivity, and chemical stability at high temperatures.
Even when a hard body coated with N on its surface is cut at high speed, the temperature of the cutting edge does not rise significantly and there is little wear due to reaction with the rigid material.

In the present invention, a sintered hard substrate containing at least iai carbide together with a binder metal is used as the substrate, for example, a wa group (Mo, W), etc.
It can be arbitrarily selected from known materials such as G cemented carbide and Tie-based cermets.

In the present invention, the thickness of the OBN coating layer on the surface is 0.5 to
The range is 20μ, but if the buried peak is less than 0.5μ,
This is because properties such as hardness, thermal conductivity, and chemical stability for the rigid material are not sufficient, leading to large variations between products.If the thickness exceeds 20μ, distortion is likely to occur within the coating layer, causing the layer itself to deteriorate. This is because the strength of the coating layer decreases, and micro-defects occur in the coating layer during cutting, resulting in a decrease in tool performance.

In addition, in the present invention, when coating the CBN layer with No-based cemented carbide, if amorphous boron nitride is directly coated, only a weak adhesion will be obtained, and as a base material, the substrate may be prepared using One or more intermediate layers of one or more of group metal carbides, carbides, oxides, and borides may be applied, and then amorphous boron nitride may be applied thereon. However, for example, if the hard substrate is TiO
, TiN, it is possible to directly coat amorphous boron oxide with good adhesion.

The thickness of this intermediate layer can be varied within certain limits while retaining its advantageous properties. To obtain an intermediate layer suitable according to the invention, K has a thickness of at least 0.5 microns. Best results were found between 1 and 10μ. This intermediate layer is coated by well-known methods such as PVD and CVD.

In coating the CBN layer, according to the invention, for example, the rigid substrate is placed in a BC/4 and NH3-containing gas stream at a temperature of 6oo to 1000 tll' and a pressure of Oj to 10 w.
Amorphous boron 9ide is coated using a plasma CVD method under Hg conditions, and this coated hard substrate and AI! The thermodynamic stability of CBN shown in Fig. 1 is achieved by filling a metal container, such as Mo or W, in contact with the CBN and/or A77 layer material, and placing the container in a high temperature and high pressure generation chamber. Exposure for several minutes or more in a certain area, that is, area A. (In addition, the first
In the figure, 1 is the cubic-hexagonal densified boron equilibrium line, A is the highly positive phase boron nitride stability region, and B is the hexagonal densified boron stability region. ) During this period, the amorphous boron nitride was transformed into AI! and/or A/ OBNK is converted by the catalytic action of the compound, and a ClBN layer is formed on the surface of the hard substrate. After the holding is completed, only the heating is stopped while the pressure is held, and after the inside of the high temperature and high pressure generating chamber is cooled to around room temperature, the holding pressure is gradually released and the pressure is returned to normal pressure. A CBN-coated hard body is obtained by treating the recovered sample with an acid in a metal reaction vessel.

For coating a hard substrate with amorphous boron nitride, in addition to the plasma CVD method described above, methods such as ion beam evaporation or ion blating can also be applied in the present invention.

EXAMPLES The present invention will be described in more detail below with reference to Examples.

[Example 1] 9.5% Co, 12% T based on the weight of we-based cemented carbide
i0, 6% TaO and the remainder we) using 5
A cutting tip of NG452 was made. CVD on this in advance
B
C/', NH3, H2 15% and 40% by weight, respectively
, placed in a mixed gas stream containing 45% at a temperature aooc
, pressure 0.51IIIHg) under conditions of 15.56Mh
2001f) Amorphous boron nitride coating treatment was performed by plasma CVD method using high frequency. Processing time is 2
It was time. As a result of this treatment, amorphous boron nitride with a thickness of about 4 microns was obtained. These were heated so that the coating layer and A/powder were in contact with each other, and then filled into a Mo container, and the container was heated to a temperature of 1200.
C, pressure was maintained at 40 kb for 1 minute. As a result, all amorphous boron nitride was converted to 0BNK. A cutting test was conducted on these chips under the conditions shown in Table 1.

For comparison, AI! was applied directly to the substrate using the CVD method. 2o3
A chip coated with was used. The results are shown in Table 2.

Table 1 Table 2 [Example 2] Six types shown in Table 5 were used as hard substrates.

Table 5 Using the hard substrates shown in Table 5, 5NG452 chips were prepared and coated using the plasma OVD method under the same conditions as in Example 1. Treatment time was 3 hours. As a result of this process,
An amorphous silicon nitride with a thickness of 5.4 μm was obtained. These are the supported groups and AI! The mixture was heated to 5K until the N powder was in contact with the powder, and then filled into a Mo container, and the container was kept at a temperature of 1250 tZ'45 kb for 10 minutes. As a result, all amorphous boron nitride is C
These chips that had been converted to BN were converted to Condition 1 of Example 1.
A cutting test was conducted under the same conditions. For comparison, chips were used in which substrates ig and c shown in Table 6 were directly coated with Al2O3 by the OVD method.

The results are shown in Table 4 (comparative materials -1 and -2, respectively).

Table 4 [Example 5] Using the hard substrate mA of Example 2, a CBN-coated chip (SNG 452) was produced in the same manner as in Example 1. Table 5 shows the thickness and processing time of these CBN layers. Table 5 shows the results of a cutting test conducted on these under the conditions of 2°3 of Example 1. Base material A K AI as a soft material
! A chip containing 5μ of 203 was used.

Table 5 [Effects of the present invention] As described in detail above, the present invention has excellent performance when used as a cutting tool, that is, even during high-speed cutting.
This has the effect that the temperature of the cutting edge does not rise significantly and there is less wear due to reaction with the rigid material.

[Brief explanation of drawings]

FIG. 1 shows the thermodynamically stable region on the pressure-temperature phase diagram of high-pressure phase type boron nitride.・ 1: Standing crystal - hexagonal boron nitride equilibrium line A: High pressure phase boron nitride stability region B: Hexagonal densified boron stability region Representative 1) Akira representative Ryo Hagiwara - Figure 1 Humidity ( 0C)

Claims (1)

[Scope of Claims] 0) A coating layer of cubic boron nitride with a thickness of 0.5 to 20 μm directly or via an intermediate layer on a sintered hard substrate containing at least one carbide together with a binder metal. A cubic boron nitride-coated hard body characterized by having the following characteristics: (2) The intermediate layer is one or more layers of one or more coatings of carbides, nitrides, oxides, and borides of metals from groups 4a and 5a of the periodic table. The cubic boron nitride-coated hard body according to item 1. (3) A sintered hard substrate containing at least 1wi carbide or preliminarily 4a of the periodic table along with a binder metal.
, carbides, nitrides, oxides and borides of Group 5a metals 1
The surface of the hard substrate is coated with a seed or more,
Amorphous boron nitride with a thickness of 0.5 to 20μ is coated by a vapor phase method, and the coated hard body is coated with A/ and/
Or, by maintaining the cubic boron nitride in the thermodynamically stable region in contact with the compound, all of the amorphous boron 9ide is converted to one element on the cubic boron nitride side. A method for producing a hard body coated with crystalline boron nitride.