JPH05171444A - Wear resistance member coated with boron nitride film - Google Patents

Abstract

PURPOSE:To provide a wear resistant member having high performance to an iron family metal, etc., to which diamond is not applicable by enhancing the adhesion and quality of a boron nitride film on a base member with a hard carbon layer formed between them. CONSTITUTION:The surface of a base member 1 to be coated is coated with a hard carbon film 2 showing a peak due to diamond in the Raman spectroscopy and the surface of the film 2 is coated with a boron nitride film 3. By this coating method, the adhesion and quality of the boron nitride film 3 are enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a member such as a tool and a bearing which requires wear resistance.

[0002]

2. Description of the Related Art Conventionally, for members requiring wear resistance,
Diamond or c-BN is used. Although diamond has the highest hardness in the substance, it is chemically unstable, and it burns when heated in the atmosphere, and when processing iron group metals, the carbon that constitutes diamond diffuses into the iron group metal. The phenomenon of abrasion occurs.

On the other hand, boron nitride is thermally and chemically stable and does not burn or diffuse into iron group metals.
In particular, c-BN has the second highest hardness after diamond, and is applied to the cutting of iron group metals and the like that are difficult to process with chemically stable diamond. In recent years, vapor phase synthesis technology has developed,
It has become possible to synthesize various hard films such as hard carbon film.
Recently, it has a high hardness and has a sp of c-BN or BN.
^A so-called boron nitride film having a high film quality, which contains many ^3- bonds, can now be synthesized on a Si substrate by vapor phase synthesis. It is known that if a boron nitride film having a good film quality can be coated on the surface of the substrate, it is effective for processing an iron group metal or the like.

[0004]

However, if a boron nitride film is directly coated on the surface of a substrate such as metal, ceramics or cemented carbide, the adhesion is poor and the film is peeled off when used in a tool or the like. was there. Also, the film quality of the boron nitride film changes depending on the type of the coated substrate.
If the ceramics, cemented carbide, etc. are directly coated, the film quality is poor and the wear is severe.

In order to solve such conventional problems, the object of the present invention is to coat a boron nitride film having a good film quality with good adhesion, and to show excellent wear resistance in the processing of iron group metals and the like. To obtain a coated wear resistant member.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a coated wear-resistant member coated with a boron nitride film, wherein a peak due to diamond is present between the substrate and the boron nitride film in Raman spectroscopic analysis. The structure has a hard carbon layer in which defects are observed so that the adhesion and the quality of the boron nitride film can be improved.

[0007]

In the coated wear-resistant member constructed as described above, the crystal structures of diamond and c-BN are both cubic, the lattice mismatch is as small as 1.5%, and the sp ³ bond of diamond is Since the difference in interatomic distance of sp ³ bond of BN is also small, high hardness c-BN or sp ³ bond of BN is adhered to the exposed diamond part of the hard carbon film with high density, resulting in high adhesion. , The film quality will be improved.

[0008]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below. First, a JIS K-10 cemented carbide material was prepared, and this was processed into the shape of a throwaway tip SPGN120308 to obtain a coated substrate.

Next, the coated substrate was coated with a hard carbon film. The coating method of the hard carbon film is microwave plasma CV.
Method D was used. FIG. 2 shows a schematic view of an apparatus for the microwave plasma CVD method. The raw material gas is introduced from the upper part of the quartz tube 6 and exhausted from the lower part of the quartz tube 6 by the exhaust system 9. The microwave 12 is guided from the oscillator 10 by the waveguide 11,
The reaction chamber 7 in the center of the quartz tube is irradiated. In the reaction chamber 7, plasma 8 is generated by microwave discharge, and a film is synthesized on the substrate placed in the plasma.

The coating conditions of the hard carbon film are as follows: raw material gas: CH ₄ + H ₂ raw material gas mixing ratio: CH ₄ / H ₂ = 0.1 to 10 vo
1% gas pressure: 20 to 40 Torr gas flow rate: 100 to 500 SCCM microwave output: 300 to 600 W base material temperature: 700 to 900 ° C is preferable.

In the microwave plasma CVD method, the type of hard carbon film can be changed depending on the raw material gas mixture ratio. Table 1 shows the raw material gas mixing ratio, the coating time, and the film thickness in coating the hard carbon film. FIG. 3 shows the Raman spectrum of the hard carbon film coated on the surface of the cemented carbide at the raw material gas mixing ratio shown in Table 1. As the raw material gas mixing ratio becomes smaller, the peak due to diamond appears and becomes larger, and the broad peak due to the amorphous carbon component becomes smaller. The height ratio of the peak due to the diamond and the peak due to the amorphous carbon component is almost proportional to the composition ratio of the diamond and the amorphous carbon component. Therefore, the higher the peak ratio of diamond is, the more diamond is included. It is supposed to be.

Then, the surface coated with the hard carbon film was coated with a boron nitride film. A microwave plasma CVD method was used as a method for coating the boron nitride film. As Comparative Example 1, the surface of the cemented carbide was also coated directly with the boron nitride film. The coating conditions of the boron nitride film are as follows: raw material gas: H ₂ + B ₂ H ₆ + NH ₃ material gas mixture ratio: B ₂ H ₆ / (H ₂ + B ₂ H ₆ + NH ₃ ).
_{= 0.3 vol% NH 3 / (} H 2 + B 2 H 6 + NH 3) = 0.8 vol% Gas pressure: 30 Torr Gas flow rate: 300 SCCM Microwave output: 400 to 700 W substrate temperature: 900 to 1100 ° C Synthesis time: 25 hr Film thickness: 2 μm is preferable.

FIG. 4 shows the infrared absorption spectra of the various types of hard carbon films and the boron nitride film coated on the surface of the cemented carbide. As the amount of diamond contained in the hard carbon film was large, the boron nitride film coated on the surface of the hard carbon film was c-
Infrared absorption due to BN or sp ³ bond of BN becomes large, which is considered to be due to t-BN 1380c
Absorption around m ^{-1 and} around 800 cm ^-1 became smaller. Further, in the boron nitride film directly coated on the cemented carbide of Comparative Example 1, no peak due to the sp ³ bond of c-BN or BN was observed. It is generally known that the larger the peak due to the sp ³ bond of c-BN or BN, the higher the hardness and the better the film quality.

The boron nitride film-coated cemented carbide throwaway tip (Samples 1 to 4 and Comparative Example 1) produced as described above and the same type (SPGN120308) throwaway tip (Comparative Example 2) brazed with diamond at the cutting edge were used. The results of the cutting test under the following conditions are shown in Table 1. Cutting speed 400 m / min Depth of cut 0.25 mm Feed 0.1 mm / rev Work material SUS 304 Cutting distance 10000 m A film having a peak due to diamond in Raman spectroscopic analysis is coated, and the hard carbon film is used as a base and nitrided. When the boron film is coated, c-BN or BN sp ³
It can be seen that a boron nitride film having an infrared absorption peak due to the bond (having a good film quality) is formed, and even when the iron group metal is cut, there is no wear or peeling and it is a wear resistant member superior to diamond. Example 2 Tungsten throwaway tip S
The coated substrate was processed into the shape of PGN120308. The coating of the hard carbon film and the boron nitride film was performed by the same microwave plasma CVD method as in Example 1 under the same conditions as in Sample 2 (Sample 5). Also, as Comparative Example 3, a sample was prepared in which the surface of the tungsten substrate was directly coated with a boron nitride film under the same conditions as in Example 1. The hard carbon film and the boron nitride film coated with Sample 5 were subjected to Raman spectroscopic analysis and infrared absorption spectroscopic analysis, and the same results as in Sample 2 were obtained. In addition, when the boron nitride film coated in Comparative Example 3 was subjected to infrared absorption spectroscopic analysis, the same results as in Comparative Example 1 were obtained.

Table 2 shows the results of a cutting test conducted on the boron nitride film-covered throw-away tip (Sample 5, Comparative Example 3) produced as described above under the same conditions as in Example 1. Even if tungsten is used for the substrate, as in Example 1, when a film having a peak due to diamond in Raman spectroscopic analysis is coated and the hard carbon film is used as a base and a boron nitride film is coated, c-BN or BN is obtained. It can be seen that a boron nitride film having an infrared absorption peak due to sp ³ bonds (having a good film quality) is formed, and no wear or peeling occurs even when a cutting test is performed using an iron group metal. (Example 3) Si ₃ N ₄ based ceramics were processed into a shape of a throw-away tip SPGN120308 to obtain a coated substrate. Sample 2 was coated with the hard carbon film and the boron nitride film by the same microwave plasma CVD method as in Example 1.
Was performed under the same conditions as above (sample 6). In addition, as Comparative Example 4, a sample in which the surface of the Si ₃ N ₄ based ceramic substrate was directly coated with a boron nitride film under the same conditions as in Example 1 was also prepared. When the hard carbon film and the boron nitride film coated with Sample 6 were subjected to Raman spectroscopic analysis and infrared absorption spectroscopic analysis, the same results as in Sample 2 were obtained. In addition, when the boron nitride film coated in Comparative Example 4 was analyzed by infrared absorption spectroscopy, the same results as in Comparative Example 1 were obtained.

Table 2 shows the results of a cutting test conducted on the boron nitride film-coated throw-away tip (Sample 6, Comparative Example 4) produced as described above under the same conditions as in Example 1. Even if Si ₃ N ₄ system ceramics is used for the substrate, as in Example 1.
When a film having a peak due to diamond in Raman spectroscopic analysis is coated and the hard carbon film is used as a base and a boron nitride film is coated, an infrared absorption peak due to the sp ³ bond of c-BN or BN is obtained ( Good) Boron nitride film is formed, and wear occurs even when a cutting test is performed with an iron group metal.
It can be seen that there is no peeling.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

As described above, according to the present invention, in a coated wear-resistant member, a substrate is coated with a hard carbon film having a peak due to diamond in Raman spectroscopic analysis, and the hard carbon film is used as a base, By adopting a structure in which a boron nitride film that is more thermally and chemically stable than diamond is coated, the adhesion between the hard carbon film and the boron nitride film is good, and the adhesion and film quality are improved. The effect is tremendous, and it is possible to provide a high-performance coated wear-resistant member for iron group metals and the like, which diamond cannot be applied as a wear-resistant member.

The substrate used in the present invention may be of any type as long as it can withstand the coating temperature of the hard carbon film or boron nitride and can be coated with the hard carbon film or the coated substrate. The method for coating the hard carbon film does not depend on the type as long as it can coat the hard carbon film having Raman peaks caused by diamond. For example, the coating method of the hard carbon film is a hot filament method, EACV
There are a D method, a DC plasma CVD method, a plasma jet method, a high frequency plasma CVD method, an optical CVD method and the like, but any method may be used. Further, the type of the method for coating the boron nitride film is not selected. For example, there are a hot filament method, a DC plasma CVD method, a high frequency plasma CVD method, an ion plating method, and the like, but any method may be used. The good match between the hard carbon film (having a Raman peak of diamond) and the boron nitride film improves the adhesion and film quality. It is clear that it does not depend on the method.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a boron nitride film-coated wear-resistant member according to the present invention.

FIG. 2 is a schematic view of an apparatus for a microwave plasma CVD method according to the present invention.

FIG. 3 is a Raman spectrum of the hard carbon film according to the present invention.

FIG. 4 is an infrared absorption spectrum of the boron nitride film according to the present invention.

[Explanation of symbols]

1 Coated Substrate 2 Hard Carbon Film 3 Boron Nitride Film 4 H ₂ Gas Cylinder 5 CH ₄ Gas Cylinder 6 Quartz Tube 7 Reaction Chamber 8 Plasma 9 Exhaust System 10 Microwave Oscillator 11 Waveguide 12 Microwave

Claims (3)

[Claims] 1. A wear resistant member coated with a boron nitride film, characterized in that a hard carbon layer is provided between the substrate and the boron nitride film in a member having a surface of the substrate coated with a boron nitride film as a wear resistant film. 2. The boron nitride film-coated wear-resistant member according to claim 1, wherein the boron nitride film has absorption caused by c ³ BN or BN sp ³ bond in infrared absorption spectroscopy. 3. The boron nitride film-coated wear-resistant member according to claim 1, wherein the hard carbon film has a peak due to diamond in Raman spectroscopic analysis.