JPH10204618A - Cubic boron nitride-coated composite material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cubic boron nitride (cBN)-coated composite material free from the peeling from a substrate immediately or within several days after cBN coating and high in adhesion and furthermore to provide a cutting tool and wear resistant parts coated with cBN withstanding practical use. SOLUTION: Multilayer coating forming a gradient composite compsn. in which the surface of a substrate 5 is coated with a Ti layer having 10 to 300nm thickness as a primary layer, is coated with TiBX(1.5<=X<=2) having 50nm to 2μm thickness as a secondary layer, is successively coated with TiYBZN1- Z (0.6<=Y<=1.5 and 0.05<=Z<=0.4) having 50nm to 2μm as a third layer and is coated with cBN having 500nm to 3μm thickness as a fourth layer is prepd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to abrasion resistance, heat resistance,
A composite material coated with boron nitride that has excellent electrical insulation and thermal conductivity, and can be used in fields requiring hard wear resistance, such as cutting tools and wear-resistant parts. The present invention relates to a material and a manufacturing method thereof.

[0002]

2. Description of the Related Art Cubic Boron Nitrid
e, hereinafter referred to as cBN) is useful as a heat sink material or a passivation film for ICs because of its excellent electrical insulation and thermal conductivity. Also, cBN is a substance having the second highest hardness next to diamond, and is thermally stable compared with diamond, has low reactivity with iron, and is widely used in cutting tools, grinding tools, wear-resistant tools and the like. .

[0003] cBN is artificially synthesized under a high temperature and a high pressure. The synthesis requires an extremely high pressure and temperature of 1700 ° C. and 50,000 atm, and requires the use of an expensive ultra-high pressure generator. there were. In addition, an ultrahigh-pressure device can form only a small disk-shaped product, and it is extremely difficult to form it into a commonly used cutting tool shape such as a drill or an end mill.

In recent years, a method of forming a cBN thin film on a substrate surface under reduced pressure by a vapor phase synthesis method has been studied. Although various problems remain, physical vapor deposition (PVD) and chemical vapor deposition (CVD) have been proposed. ) Enables cBN synthesis. The typical methods are listed below. (1) High frequency sputtering method
No. 4686) (2) Microwave CVD method (JP-A-60-24)
No. 3273) (3) Ion beam assisted vapor deposition method (JP-A-60-16)
(4) Reactive ion plating method (Japanese Patent Application Laid-Open No. 62-4 / 1987)
No. 7472) (5) Hot filament CVD method (Japanese Patent Laid-Open No. 63-6 / 1988)
No. 9972) (6) High frequency plasma jet method (Japanese Patent Laid-Open No. 60-27)
No. 7767)

[0005] If a cBN thin film can be formed on the surface of a cutting tool having a complicated shape such as a drill or an end mill by a gas phase synthesis method, cBN can be used for its hardness, heat resistance, oxidation resistance, friction coefficient, reactivity with iron, etc. Because of its excellent characteristics, a long life and improved performance can be expected.

However, in the cBN synthesis by the gas phase synthesis method, a cubic phase (Cubic Phase) is formed by the impact of excited or accelerated ions. Therefore, even if a cBN film is formed, the internal stress is large, and the adhesion to metals, including cemented carbides, and ceramic substrates is extremely poor. For this reason, it is peeled off from the substrate immediately after coating or within several days. For practical use of cutting tools and wear-resistant parts coated with cBN, it is particularly necessary to improve the bonding strength between the cBN film and the substrate material.

For this reason, as means for ensuring the adhesion of the cBN film to the substrate in the vapor phase synthesis method, (1) formation of a BN gradient intermediate layer coating (Japanese Patent Laid-Open No. 3-26)
(No. 0054) (2) Formation of Ti, TiN intermediate layer coating (JP-A-3-26
0054, JP-A-4-168263, JP-A-4-246
164, JP-A-4-221059, JP-A-6-5740
No. 8) (3) Formation of Si, Si ₃ N ₄ intermediate layer coating (Japanese Unexamined Patent Publication No.
Various methods for coating an inclined intermediate layer between a substrate and a cBN film have been proposed.

[0008]

However, all of these methods have a problem in that the adhesion is still low and cannot be put to practical use as a tool coated with a cBN film or a wear-resistant part.

An object of the present invention is to provide a cBN (cubic boron nitride) -coated composite material having high adhesion without peeling off from the substrate immediately or within several days after the cBN coating, and a method for producing the same. Furthermore, cB that can withstand practical use
An object of the present invention is to provide a cutting tool coated with N and wear-resistant parts.

[0010]

In order to solve the above-mentioned problems, in the invention of claim 1, first, a Ti (titanium) layer having a thickness of 10 nm or more and 300 nm or less is coated on a substrate surface as a first layer. A second layer is coated with TiB _x of 50 nm or more and 2 μm or less (here, the range of X is 1.5 ≦ X ≦ 2).
μm or less Ti _Y B _Z N _{1 -Z} film (here, the range of Y is 0.
6 ≦ Y ≦ 1.5, and the range of Z is 0.05 ≦ Z ≦ 0.4
And In addition, hereinafter, it is abbreviated as TiBN).
The fourth layer was coated with cBN (cubic boron nitride) of 500 nm or more and 3 μm or less.

As means for obtaining this coated composite material, in the invention according to claim 2, a Ti layer is formed on the surface of the substrate as a first layer to a thickness of 10 n by, for example, an ion plating method.
50 nm by evaporating Ti and boron (B) simultaneously as a second layer.
Above, covers the following TiB _X 2 [mu] m, followed by nitrogen gas supply and the plasma discharge by nitrogen ion generation or ion gun 50nm or more as a third layer in combination with nitrogen ions irradiation with, covers the following TiBN layer 2 [mu] m ,
The fourth layer was coated with cubic boron nitride (cBN) having a thickness of 500 nm or more and 3 μm or less by evaporation of B and generation of nitrogen ions by plasma discharge of the supplied nitrogen gas or irradiation of nitrogen ions using an ion gun.

In the present invention, as a means for ensuring the adhesion of the cBN film to the substrate, Ti-TiB _x -T
iBN-cBN was sequentially coated to form a multi-layer coating forming a gradient composite composition. Therefore, the first Ti layer and the second T layer
Meanwhile adhesion for TiBN layer comprises any of Ti iB _X layer and the third layer is very good, also T of the second layer
TiBN layer of iB _X layer and the third layer is extremely hard, it can be applied as a cutting tool or a wear-resistant member even only on that layer. In addition, since the fourth layer of cBN grows with the third layer containing a BN component as a base, there is little change in the constituent elements of the film, and the cBN film does not peel off despite its high internal stress.

Here, the range of X of TiB _X is 1.5 ≦ X ≦
2, and the range of Y of the Ti _Y B _Z N _{1 -Z} film is set to 0.6 ≦ Y ≦
As a result of various experiments that the range of Z was set to 0.05 ≦ Z ≦ 0.4 as 1.5, the hardness of the coating decreased even if each value was higher or lower, This is because the wear resistance has deteriorated.

[0014]

Next, an embodiment of the present invention will be described. Ti has the property of forming a hard film by combining with nitrogen and carbon. Ti is also an active metal and binds tightly to atoms on the surface of iron, cemented carbide and the materials contained as alloys. By evaporating such Ti in a vacuum and further ionizing the Ti positively, a method of forming a coating by electrically colliding this with a substrate to which a DC high voltage or a high frequency is applied, that is, by an ion plating method, First, a first layer of Ti is formed.
For the evaporation of Ti, there are a resistance heating method in which a Ti foil or a Ti wire is directly energized, a method in which Ti is placed on a W (tungsten) boat and evaporation by resistance heating, and an electron beam heating evaporation method. There may be.

However, the Ti film formed here is soft,
If the thickness of the Ti film is made unnecessarily thick, it will be destroyed where a very large shearing force acts between the coating surface and the counterpart material, such as a cutting tool or a wear-resistant member. Therefore, it was experimentally confirmed that the thickness of the pure Ti film had to be maintained at 10 nm or more and 300 nm or less.

Subsequently, simultaneously with the evaporation of Ti, B is evaporated from another evaporation source to ionize or excite the evaporated atoms of Ti and B, and are made to collide with a substrate to which a DC voltage or a high frequency is applied, thereby being deposited. Thereby, TiB _X of 50 nm or more and 2 μm or less is coated as the second layer.

Further, after forming the second layer, Ti and B
By introducing nitrogen gas into the reaction chamber while evaporating, a third layer of TiBN layer is formed. B at this time
The evaporation amount and the supply amount of nitrogen gas were adjusted so as to gradually shift from the second layer TiB _X film to the third layer TiBN film.

Here, when introducing nitrogen gas, Ti and B are supplied to a discharge space between a substrate to which a negative DC power supply or a high-frequency power supply is connected and a Ti and B evaporation source. At the same time as the ionization, the nitrogen gas is also ionized, and it is possible to electrically impinge these ions on the substrate for coating. Further, at this time, ionization of the introduced nitrogen gas is promoted by using an ion gun, and the film quality is improved by accelerated collision with the substrate, so that a coating film having stronger adhesion can be formed.

Subsequently, as a fourth layer, the evaporation of Ti is gradually reduced, and the process is shifted to cBN coating using only B evaporation and nitrogen gas supply. During the formation of the third layer, the supply of the B vapor and the nitrogen gas has already been started, and the ion gun is also operating, so that the transition to the cBN synthesis of the fourth layer can be made very easily.

By covering the surface of the substrate in the order of Ti, TiB _x , and TiBN between the first layer and the third layer in this manner, the material, type and surface condition of the cemented carbide used as the substrate can be determined. Regardless, cBN coating with excellent adhesion can be achieved. Thus, according to the present invention, cBN
The film was formed without exfoliation and produced cB
N can exhibit its inherent excellent wear resistance, heat resistance and oxidation resistance.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. (Embodiment 1) FIG. 1 is a schematic view of an apparatus for carrying out the first method of the present invention, and FIG. 2 is a schematic view of a thin film layer to be formed. FIG.
, The chamber 1 is provided with an exhaust port 11,
Is connected to an unillustrated evacuation device. A DC power supply or a high-frequency power supply 4 is connected to the upper part of the chamber 1,
A substrate 5 is provided which is mounted on the chamber 1 by a mechanism that rotates while maintaining electrical insulation. Chamber 1
A heater 12 is held above the substrate so that the temperature of the substrate 5 can be adjusted. Furthermore, the upper part of the chamber 1,
On the side of the substrate 5, a film thickness monitor 14 for measuring the evaporation rate of Ti and B is provided.

On the other hand, a Ti evaporation source 2
Is installed. The B evaporation source 6 is an electron beam heating evaporation source, and includes boron (B) 7 as an evaporation material.
Is melted and evaporated to generate a B vapor 17.

Further, an ion source 9 is provided below the chamber 1. The ion source 9 used here is a Kauffman-type ion source, which ionizes a nitrogen gas or a mixed gas 8 of nitrogen and a rare gas supplied from a gas introduction pipe 18 at the back thereof, accelerates it by an electric field, and forms ions 10 on the substrate 5. Irradiation is performed.

An implementation method of the first embodiment having such a configuration will be described. In FIG. 1, a power supply 4 connected to a substrate
, A high frequency power supply was used, connected to the substrate 5, a chip made of cemented carbide (K10) was attached to the substrate 5, and the substrate 5 was rotated during the coating process. First, after the inside of the chamber 1 was evacuated to 1 × 10 ⁻⁶ Torr, the substrate 5 was heated to 300 ° C. while rotating the substrate 5 in order to increase the adhesion between the substrate material and the Ti film. Subsequently, Ti 3 was evaporated from the Ti evaporation source 2 in the vacuum chamber 1. Ti
During the evaporation, the output of the high-frequency power supply 4 was set to 200 W. At this time, a self-bias of -400 V was generated on the substrate 5,
Discharge is generated between the substrate 5 and the Ti evaporation source 2, and T
The i-vapor 17 was ionized and made to collide with the substrate 5 to form a first layer (first layer shown in FIG. 2).

Here, the evaporation of Ti is 0.7φ × 200
(Mm) W (tungsten) wire was suspended by a Ti wire, and the W wire was supplied with an AC power of about 50 V and 40 A by a resistance heating method. Since the wire diameter of the W wire changes due to evaporation before and after the start of energization, the current was adjusted within a range of ± 15 A. The film thickness of Ti was monitored by a frequency change of a film thickness monitor 14 having a quartz oscillator, and the value was set to 100 nm.

Next, simultaneously with the evaporation of Ti, another evaporation source 6
, The boron (B) 7 is evaporated, and a discharge is caused between the substrate 5 connected to the high-frequency power supply 4 and the Ti and B evaporation sources 2 and 6 to ionize the Ti vapor 13 and the B vapor 17. And
By being incident on the surface of the substrate 5, 1
A μm TiB _1.5 film was formed (second layer shown in FIG. 2).

Here, the evaporation of Ti was the same as that of the first layer, and the evaporation rate was adjusted by adjusting the current flowing through the W line. B was evaporated using an electron beam heating evaporation method at an acceleration voltage of 8 kV and a current of 100 mA. Ti vapor 13 and B vapor 1
No. 7 was accelerated and collided with a substrate which was ionized by a high frequency applied to the substrate and negatively charged by a self-bias.
The evaporation rate of each of Ti and B is as follows.
Evaporated in a ratio of 5 to 2. During the coating of both the first layer and the second layer, the degree of vacuum in the chamber 1 is desirably as high as possible, and 1 × 10 ^{−6 to} 5 × 5 by a vacuum pump.
× 10 ⁻⁶ Torr was maintained.

Further, as a third layer, T
While evaporating i3 and B7, nitrogen gas 8 was introduced from the gas introduction pipe 18 into the vacuum chamber 1 to form a TiBN layer (third layer shown in FIG. 2). At this time, the amount of evaporated B was gradually reduced to about 20 to 30% of the number of B atoms supplied in the second layer, and the transition from the TiB _1.5 film of the second layer to the formation of a TiBN film of the third layer was gradually started.

Here, the nitrogen gas 8 was supplied to a discharge space between the substrate 5 and a Ti and B evaporation source to promote the ionization. In addition, ion gun 9
Was operated to ionize the nitrogen gas 8 and make it incident on the substrate. Nitrogen gas was supplied to the ion gun 9 at a flow rate of 5 cc / min, nitrogen ions were extracted at 0.8 kV from plasma in the ion gun formed at 70 V, 3 A, and the substrate 5 was irradiated with the ions. The high frequency power at this time is 20
0 W, and the degree of vacuum in the chamber 1 is 1 × 10 ⁻⁴ Torr
And

As a result, the thickness of the TiBN film (third layer) becomes 1 μm.
Coated with thickness. Incidentally, the ratio of Ti, B and N in the TiBN film is approximately 0.6: 0.4: 0.6.
And

Subsequently, after gradually reducing Ti evaporation,
Continue evaporation of B and introduction of nitrogen gas, and add Ar (argon)
A gas supply was added to adjust the synthesis conditions, and cBN coating was performed to form the fourth layer shown in FIG.

Here, the mixed gas 8 of nitrogen and Ar is supplied to a discharge space between the substrate 5 to which the high-frequency power source 4 is connected and the evaporation source 6 of B, so that nitrogen gas and Ar The gas can also be ionized and incident on the substrate 5. However, here, c with higher adhesion
In order to form a BN film, the introduced gas was ionized using an ion gun 9 and made to collide with the substrate as an ion beam 10 at an accelerated rate. Nitrogen gas 5cc / min and A
A mixed gas of r gas 5 cc / min is supplied to form a discharge plasma state of 70 V, 3 A inside the ion gun 9,
The generated mixed gas ions were extracted at an accelerating voltage of 1.2 kV, and accelerated irradiation was performed on the substrate 5.

Here, B was evaporated at an acceleration voltage of 8 kV and a current of 120 mA. At that time, the degree of vacuum in the chamber 1 was kept at 3 × 10 ⁻⁴ Torr. Also, during coating,
Electric power was supplied to the substrate 5 from the high-frequency power supply 4 at an output of 300 W, and a self-bias of -600 V was generated. Thus, cBN was coated to a thickness of 1.5 μm.
(4th layer shown in FIG. 2)

FIG. 3 shows the IR of the obtained topmost cBN film.
It is an absorption spectrum. As shown in FIG. 3, it was confirmed that the obtained outermost cBN film was a boron nitride film having a cubic crystal structure. Table 1 shows the film hardness (Vickers hardness), scratch test results, and cutting performance test results of the cBN film. As a comparative material, Comparative Example 1 was coated with a single-layered cBN film having a thickness of 2 μm, and Comparative Example 2 was coated with 1.5 μm on a 3 μm-thick TiN film.
Coating with a μm thick cBN film, Comparative Example 3
Used was coated with a single-layer TiN film having a thickness of 3 μm.

[0035]

[Table 1]

The cutting performance test for evaluating the performance of the produced cBN coated tool was carried out under the following conditions, and the coating film was evaluated by measuring the flank wear width. Work material: SNCM439, 55HRC Cutting speed: 100 m / min Cutting depth: 0.3 mm Feeding amount: 0.1 mm / rev Cooling method: Dry Fig. 10 shows the width of the flank wear amount with respect to the cutting time of the present invention and the comparative material. It is a comparison of the increase. As shown in FIG. 10, the flank wear amount of Example 1 was less than half of the flank wear amount with respect to the TiN-coated chip (Comparative Example 3) used as the comparative material. It was confirmed that a tool performance (cutting life) approximately 2.1 times that of the above was exhibited.

(Embodiment 2) FIG. 4 is a schematic view of an apparatus according to a second embodiment of the present invention, and FIG. 5 is a schematic view of a thin film layer formed in the second embodiment. The main device configuration is the same as that of the first embodiment, but only the method of evaporating Ti differs from the first embodiment.

In Example 2, the substrate 5 connected to the high frequency power supply 4 was made of a cemented carbide and was rotated during the coating process. After evacuating the chamber 1 to 1 × 10 ⁻⁶ Torr, Ti 3 is evaporated from the Ti evaporation source 2, and a discharge is caused between the substrate 5 connected to the high-frequency power source 4 and the Ti evaporation source 2, and the discharge is performed. The first layer was formed by colliding the ionized Ti with the substrate 5 which was negatively self-biased (FIG. 5).
1st layer).

Here, 0.2t × 15 ×
Pure Ti was put on a 100 (mm) W (tungsten) boat, and evaporated while supplying electric power of AC 4V 250A. The film thickness was monitored by changing the frequency of a film thickness monitor 14 having a quartz oscillator, and the film thickness was adjusted to 40 nm.

Subsequently, while continuing the evaporation of Ti, B (boron) 7 is evaporated from another evaporation source 6 and
A discharge is caused between the substrate 5 and the Ti and B evaporation sources 2 and 6 connected to the substrate 5 to ionize the Ti vapor 13 and the B vapor 17, and the 1.3 μm TiB ₂ as a second layer is formed on the substrate 5. (The second layer shown in FIG. 5).

Here, the Ti evaporation conditions were the same as the conditions for forming the first layer, and the evaporation rate was controlled by adjusting the W boat current. B was evaporated at an acceleration voltage of 8 kV and 120 mA using an electron beam heating evaporation method. Ti vapor 13, B
The vapor 17 was ionized by discharge between the substrate 5 connected to the high-frequency power supply 4 having an output of 300 W, and the surface of the substrate 5 was coated by irradiation. Here, the evaporation rate of Ti and B was such that the ratio of B to 2 was 1 for Ti.

During the coating of the first and second layers, the degree of vacuum in the chamber 1 was maintained at 5 × 10 ^-6 to 8 × 10 ^-6 Torr. By introducing nitrogen gas 8 into the vacuum chamber 1 while evaporating the Ti material 3 and the B material 7 after the second layer, the TiB _0.2 N _0.8 layer, which is the third layer, is placed in 1.
2 μm was formed (third layer shown in FIG. 5).

Here, the nitrogen gas was introduced into the ion gun 9 from the gas introduction pipe 18 to be ionized, and was irradiated to the substrate 5 supplied with 300 W of high frequency power. The operating conditions of the ion gun are the same as those of the third layer coating of the first embodiment. Also,
The evaporation of Ti was the same as that of the first layer, the evaporation rate was controlled by adjusting the current, and B was evaporated at an accelerating voltage of 8 kV and 120 mA using an electron beam heating evaporation method. At this time, the degree of vacuum in the chamber 1 was kept at 1 × 10 ⁻⁴ Torr.

The fourth layer gradually stops the evaporation 13 of Ti,
While continuing the evaporation of B and the introduction of nitrogen gas, Ar gas was added and the synthesis conditions were adjusted to shift to cBN film formation.

The supply gas is nitrogen 5 cc / min and Ar 5 c
A mixed gas of c / min was used, and the operating conditions of the ion gun 9 were the same as the conditions for forming the fourth layer coating in Example 1. At this time, the degree of vacuum in the chamber 1 is 3 × 10 ⁻⁴ Torr.
r. B was evaporated using an electron beam heating evaporation method at an acceleration voltage of 8 kV and 120 mA, and cBN was formed to a thickness of 2 μm.
(The fourth layer shown in FIG. 5).

FIG. 6 shows the IR of the obtained topmost cBN film.
It is an absorption spectrum. As shown in FIG. 6, it was confirmed that the obtained outermost cBN film was a boron nitride film having a cubic crystal structure. Table 1 shows the film hardness (Vickers hardness), scratch test results and cutting performance test results of the cBN film. The cutting performance test was performed under the same conditions as in Example 1.

In Example 2, as shown in Table 1 and FIG. 10, the wear was less than half that of the TiN-coated chip of Comparative Example 3 used as a comparative material, and the tool performance (life) was about 2.5 times. Was confirmed.

(Embodiment 3) FIG. 7 is a schematic view of an apparatus according to a third embodiment of the present invention, and FIG. 8 is a schematic view of a thin film layer formed in the second embodiment. The main configuration of the apparatus is the same as that of the first embodiment, except for the Ti evaporation source and the DC power supply connected to the substrate.

In the third embodiment, as shown in FIG.
A cemented carbide plate is attached to the substrate 5 and connected to the negative side of the DC power supply 4 while rotating during the coating process.
A voltage of 1000 V was applied. Further, after the inside of the chamber 1 is evacuated to 1 × 10 ⁻⁶ Torr, Ti 3 is evaporated from the electron beam heating evaporation source 2 of Ti, and discharge is performed between the substrate 5 connected to the DC power supply 4 and the Ti evaporation source 2. The substrate 5 is coated with the ionized Ti by colliding with the substrate.
A first layer was formed (first layer shown in FIG. 8).

Here, 8 kV, 150 kV is used for evaporation of Ti3.
The sample was irradiated with an electron beam of mA, heated and evaporated. The thickness of the Ti film was monitored by a frequency change of a film thickness monitor 14 having a quartz oscillator, and the thickness was adjusted to 250 nm. In order to improve the adhesion between the substrate material and the Ti film, the substrate 5 was previously heated to 300 ° C. by a heater.

Subsequently, simultaneously with the evaporation 13 of Ti, B (boron) 7 is evaporated from another electron beam heating evaporation source 6,
A discharge is caused between the substrate 5 connected to the DC power supply 4 and the electron beam heating evaporation sources 2 and 6 for Ti and B, thereby ionizing the Ti vapor 13 and the B vapor 17 and applying a negative voltage by the DC power supply. The substrate 5 was coated with the incident light by coating the substrate 5 with 2 μm of TiB ₂ as a second layer by an ion plating method (the second layer shown in FIG. 8).

Here, the conditions for evaporating Ti were an electron beam acceleration voltage of 8 kV and a current of 150 mA, and the evaporation rate was controlled by adjusting the electron beam current. B was evaporated using another electron beam heating evaporation source 6 at an acceleration voltage of 8 kV and a current of 120 mA. The Ti vapor 13 and the B vapor 17 were supplied between the DC power source 4 and the substrate 5 to which -600 V was applied, and the surface of the substrate 5 was coated while being ionized by discharge. During the coating of the first layer and the second layer, the degree of vacuum in the chamber 1 was maintained at 5 × 10 ⁻⁶ to 8 × 10 ⁻⁶ Torr.

A Ti _1.3 B _0.15 N _0.85 layer was formed as a third layer by introducing a nitrogen gas 8 into the vacuum chamber 1 while evaporating the Ti material 3 and the B material 7 after the second layer (FIG. 8). 3rd layer shown in FIG.

At this time, the amount of B evaporated is the amount of B supplied in the second layer.
About 10 to 15% of the number of atoms, and TiB2
The film gradually shifted to the formation of the third layer TiBN film. Nitrogen ions are generated by using the ion gun 9 to generate nitrogen gas introduced from the gas introduction pipe 18 at the back of the ion gun 9;
The substrate 5 connected to the 00 V DC power supply 4 was irradiated. The operating conditions of the ion gun were the same as the third layer coating of Example 1. The Ti evaporation was performed by the electron beam heating evaporation source 2 under the conditions of 8 kV and 200 mA, and the evaporation rate was controlled by adjusting the electron beam current. B was also evaporated at an accelerating voltage of 8 kV and 80 mA by electron beam heating. At this time, the degree of vacuum in the chamber 1 is 1 × 10 ⁻⁴ T
orr.

In the TiBN film, the ratio of Ti, B and N is approximately 1: 0.15: 0.85 and the thickness is 2
Coated with a thickness of μm.

The fourth layer gradually stops the evaporation 13 of Ti,
Ar gas was added while continuing B evaporation and nitrogen gas introduction,
By adjusting the synthesis conditions, the process was shifted to cBN film formation.
The supply gas was a mixed gas of 5 cc / min of nitrogen and 5 cc / min of Ar, and the operating conditions of the ion gun 9 were the same as the conditions for forming the fourth layer coating in Example 1. At this time, the degree of vacuum in the chamber 1 was 3 × 10 ⁻⁴ Torr. B uses an electron beam heating evaporation method and has an accelerating voltage of 8 kV and 12 kV.
Evaporated at 0 mA and coated cBN to a thickness of 3 μm (fourth layer shown in FIG. 8).

Since the ion plating films of the first to third layers are electrically conductive films, the power supply 4 connected to the rotating substrate 5 can be formed by a DC negative power supply.
However, the fourth layer cBN film is an electrically insulating film. When coating an insulating film by ion irradiation, positive ions are deposited on the surface of the insulating film. This is called a "charge-up phenomenon". When the charge-up occurs, the formation of the coating film does not proceed any more or the film is damaged due to dielectric breakdown. Here, a neutralizer with a thermionic emission function attached to the ion gun was operated to prevent charge-up. This neutralizer has a hot filament and emits negatively charged electrons by applying heat. This neutralizes the charge on the surface of the insulating film and continues coating.

FIG. 9 shows the cB of the outermost layer obtained in Example 3.
It is an IR absorption spectrum of an N film. As shown in FIG.
It was confirmed that the outermost cBN film obtained in Example 3 was a boron nitride film having a cubic crystal structure. Table 1 shows the film hardness (Vickers hardness), scratch test results and cutting performance test results of the cBN film. The cutting performance test was performed under the same conditions as in Example 1.

In Example 3, especially in the scratch test shown in Table 1, the value was 57 N, and the adhesion was extremely excellent. Further, as shown in Table 1 and FIG. 10, it was confirmed that the wear was less than half that of the TiN-coated chip of Comparative Example 3 used as the comparative material, and the tool performance (life) was about 2.3 times that of the chip. .

As described above, in the present invention, despite the cBN coating which is said to be easy to peel off, as shown in Table 1 and the like, the presence of a hard film such as TiB _X or TiBN causes the Vickers hardness. The measured value is also high,
The cutting performance was significantly improved as compared with any of the comparative examples. Further, the adhesion evaluation result by the scratch test using the AE (acoustic emission) detection method is 40 to 6
It shows a high critical load of 0N, extremely excellent adhesion,
The results were remarkably improved as compared with the cBN coating samples of Comparative Examples 1 and 2.

[0061]

According to the present invention, a Ti layer whose film thickness is accurately controlled, and a TiB _x , TiB
By coating N and forming a graded composite composition that coats the outermost surface, i.e., the outermost layer, with cBN,
The hardness of the intermediate layer is also extremely high, and Ti—TiB _x —TiB having extremely high adhesion is obtained by forming a film having a common element.
A boron nitride coated composite comprising an N-cBN multilayer coating is formed. That is, Ti is included in the lower layer to increase the adhesion to the substrate, hardness is provided in the intermediate layer, and cBN of the fourth layer is grown using the third layer containing the BN component as an underlayer. There was little change in the constituent elements of the film, and the cBN film was not peeled despite the high internal stress of the cBN film.

Accordingly, cB having high adhesion does not peel off from the substrate immediately or within a few days after cBN coating.
The present invention provides an N (cubic boron nitride) -coated composite material and a production method, and provides a cBN-coated cutting tool and wear-resistant parts that can withstand practical use. Furthermore, cB
This enables the formation of a composite material that can impart the excellent properties of the N film such as high hardness, high wear resistance, and high heat resistance.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a thin film layer formed in a first embodiment of the present invention.

FIG. 3 shows the cBN of the outermost layer obtained in the first embodiment of the present invention.
It is an IR absorption spectrum of a film.

FIG. 4 is a schematic view of an apparatus according to a second embodiment of the present invention.

FIG. 5 is a schematic view of a thin film layer formed in a second embodiment of the present invention.

FIG. 6 shows the cBN of the outermost layer obtained in the second embodiment of the present invention.
It is an IR absorption spectrum of a film.

FIG. 7 is a schematic view of an apparatus according to a third embodiment of the present invention.

FIG. 8 is a schematic view of a thin film layer formed in a third embodiment of the present invention.

FIG. 9 shows the cBN of the outermost layer obtained in the third embodiment of the present invention.
It is an IR absorption spectrum of a film.

FIG. 10 is a cutting test result showing the amount of wear on the flank of a carbide tip with respect to the cutting time in the first to third examples of the present invention and Comparative Example 3.

[Explanation of symbols]

 Reference Signs List 3 Ti (titanium) 5 substrate 7 B (boron) 8 N (nitrogen) / rare (Ar (argon)) gas 9 ion source (ion gun) 10 nitrogen ion or mixed ion of nitrogen and rare gas 13 Ti (titanium) vapor 17 B (boron) vapor

Claims (2)

[Claims] 1. A surface of a substrate is coated with a Ti layer having a thickness of 10 nm or more and 300 nm or less as a first layer.
TiB _x of 0 nm or more and 2 μm or less (provided that 1.5 ≦ X
≦ 2), followed by a third layer of 50 nm or more,
Ti _Y B _Z N _{1 -Z} film of 2 μm or less (provided that 0.6 ≦ Y ≦
1.5, 0.05 ≦ Z ≦ 0.4), and 5
Cubic boron nitride (cB
N) -coated cubic boron nitride-coated composite material. 2. A titanium layer as a first layer having a thickness of not less than 10 nm and not more than 300 nm on a substrate surface, and Ti and boron (B) are simultaneously evaporated as a second layer to form a first layer.
TiB _X of 0 nm or more and 2 μm or less is coated, and subsequently, nitrogen gas supply and nitrogen ion generation by plasma discharge or nitrogen ion irradiation using an ion gun are used in combination to form a third layer of Ti _Y B _Z of 50 nm or more and 2 μm or less. N
_{The 1-Z} layer is coated, and cubic boron nitride (cBN) of 500 nm or more and 3 μm or less is vapor-deposited on the fourth layer and nitrogen ions are generated by plasma discharge of the supplied nitrogen gas or nitrogen ions are irradiated using an ion gun. by coating of claim 1 wherein _{Ti-TiB X -Ti Y B Z} N 1-Z
-A method for producing a cubic boron nitride-coated composite material, comprising forming a cBN multilayer coating.