JPH05239646A - Manufacture of diamond coated member - Google Patents

Abstract

PURPOSE:To manufacture a coated member having a long service life and high performance by executing surface treatment of emitting laser and thereafter forming a diamond film by a vapor phase synthesizing method. CONSTITUTION:Fine pores of several to several hundreds mum size are regularly formed on the surface of a WC series sintered hard allay, as a substrate, suitable for a cutting machine or the like by YAG laser or TEA type CO2 laser having 10 to 50W pulse output and about 1 to 10KHz cyclic frequency Nd<3->. The substrate is brought into contact with a mixed gas of carbon monoxide and hydrogen at 450 to 950 deg.C under 1 to 800 Torr to form a diamond film on the prescribed surface of the substrate. The film thickness of the diamond film is selected to 5 to 50mum under severe using conditions such as ones in a cutting tool or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a diamond-coated member, and more specifically, it has excellent adhesion between a base material and a diamond film for coating the same, and has high performance and excellent durability in practical use. And a method for producing a diamond-coated member having a significantly improved service life.

[0002]

2. Description of the Related Art Conventionally, tools such as cutting tools, polishing tools, and dies, which require high hardness and wear resistance, sliding members, wear-resistant members made of cemented carbide,
Sintered diamond and single crystal diamond are used. Among these, diamond is particularly preferred because it is remarkably excellent in hardness and wear resistance.

Conventionally, such a diamond tool has been constructed by mounting sintered diamond or single crystal diamond on the surface of a base material made of a cemented carbide or a metal having a high hardness by brazing or the like. However, in the case of this kind of diamond tool, the diamond itself is expensive, and since a troublesome manufacturing process such as mounting the diamond on the base material is required, mass productivity is poor and the manufacturing cost is high. There was a problem. In addition, since diamond easily falls off the base material, durability is poor.
Due to the fact that there is a practical limit to increasing the area of the diamond surface, there are various drawbacks such as its application range being narrowly limited.

Under these circumstances, in recent years, C
A diamond film (diamond film) is formed on the surface of a substrate made of cemented carbide, high-hardness metal or ceramics, etc. by using a vapor phase diamond synthesis technique such as VD method or PVD method.
Attention has been focused on a technique for producing various diamond-coated members by depositing and forming. In the case of the diamond-coated member by the vapor phase synthesis method, it is easy to reduce the manufacturing cost and mass-produce it, and the diamond coating can be uniformly applied to the substrate surface of a large area. It is expected to have a wide range of applications not only for cemented carbide tools such as the above but also for various sliding members and wear resistant members, and various materials in the field of electronic and electrical equipment such as diamond semiconductor devices.

In order to realize such various advantages, a great variety of techniques have been proposed for diamond-coated members. However, in this type of diamond-coated member, there is generally a basic problem that the adhesion between the base material such as cemented carbide or ceramics and the diamond film is poor, and therefore, especially for cutting tools, polishing tools, etc. A serious problem that the diamond coating easily peels off or is damaged when used as carbide tools, sliding members, and wear resistant members, sufficient performance and durability cannot be obtained in practical use, and the service life is short. Was occurring.

[0006] Therefore, conventionally, it has been a problem to improve the adhesion between the base material and the diamond film, and an intermediate layer is provided between the base material and the diamond film, or a base material of an extremely special material is used. Various innovations such as use have been made. Nevertheless, many of these conventional diamond-coated members have insufficient improvement in adhesion and have not yet reached a practical level. Further, recently, although diamond-coated members have come to be marketed as tools and wear-resistant members, the adhesiveness between the base material and the diamond film is still insufficient in these commercially available products. It was difficult to say, and there was a problem that the service life was short.

That is, although the diamond-coated member is already in the stage of practical application, it is desired to further greatly improve the adhesion between the base material and the diamond film in order to further prolong the life. It has been done. In order to meet such a demand, as an improvement plan of the technique of providing the intermediate layer, for example, an intermediate layer made of the base material component and the carbon component is formed on the surface of the base material of various materials, and the intermediate layer is formed. There has been proposed an attempt to form a diamond film (diamond film) on the surface of the substrate by a vapor phase synthesis method and to improve the adhesion between the base material and the diamond film by an intermediate layer thereof (JP-A-60- 208473, JP 61-106478, JP 61-1
No. 06493, JP-A No. 61-106494, etc.).

However, in the technique using the intermediate layer, the intermediate layer is required to maintain high adhesion to both the substrate and the diamond-like film, and the strength of the intermediate layer itself must be sufficiently high. It is extremely difficult to select the optimum material because it is necessary to meet the strict requirement that it must be done. Actually, although various ideas have been made in the selection of the material of the intermediate layer and the formation method thereof as in the conventional method illustrated above, the diamond-coated member having the intermediate layer, which is obtained by the conventional method, is In the case of, the above and both have not been sufficiently satisfied, and especially when used under severe conditions such as cutting tools and sliding members, sufficient durability and service life cannot be obtained. was there.

On the other hand, a method of modifying the surface condition of the substrate has also been proposed to improve the adhesion between the substrate and the diamond film. For example, JP-A-3-183774
The publication discloses a method of electrolytically polishing a substrate. However, this method has a problem that the type of the base material is limited because the method can be applied only to the conductive base material in addition to the complicated operation.

The present invention has been made in view of the above circumstances. An object of the present invention is to form a diamond film on the surface of a base material made of cemented carbide or ceramics, that is, regardless of the type of the base material. A high-performance diamond-coated member that can achieve a significantly long life by exerting sufficient practical performance and durability as a carbide tool such as a cutting tool, a sliding member, a wear resistant member, etc. It is to provide a method of efficiently manufacturing in a process.

[0011]

SUMMARY OF THE INVENTION The present invention which solves the above-mentioned problems involves a surface treatment of irradiating a pulse oscillation laser on the surface of at least one selected from the group consisting of cemented carbide and ceramics in a substrate. After that, the diamond-based film is formed on the surface of the substrate after the surface treatment by a vapor phase synthesis method.

The present invention will be described in detail below. The base material in the present invention can be formed of at least one selected from the group consisting of cemented carbide and ceramics.
In this case, at least the surface of the base material is formed of at least one selected from the group consisting of cemented carbide and ceramics. Therefore, the base material in the present invention may be formed only of cemented carbide or ceramics, or the inside of the base material may be formed of cemented carbide and the surface portion of the base material may be formed of ceramics. Good again
The reverse structure may be used. Also, as this base material,
The inside of the base material is formed of an appropriate member different from cemented carbide and ceramics, which has heat resistance to withstand the high temperature at the time of forming the diamond film, and the surface portion of the base material is cemented carbide or It is also possible to use such a substrate formed of ceramics. The surface of the base material may be made of only cemented carbide or ceramics, and the portion made of cemented carbide and the other portion may be made of ceramics.

The structure of the substrate used in the method of the present invention can be appropriately determined according to the application of the diamond film coating member. However, if the diamond film coating member is used for cutting tools, polishing tools, tools such as dies that require high hardness and wear resistance, sliding members, wear resistant members, etc. Since a large force may act, it is desirable that the base material itself be formed of cemented carbide or ceramics as a base material in such applications.

The cemented carbide is not particularly limited,
Various types and compositions such as those generally known can be used, and for example, W, Mo, Cr, Co,
Ni, Fe, Ti, Zr, Hf, Nb, Ta, Al,
Cemented carbides composed of one or more metals such as B, Ga and Si, and cemented carbides of various compositions consisting of one or more of these metals and carbon, nitrogen oxygen and / or boron, etc. (Specifically, for example, WC, WW
WC system such as C, WC-C, W-WC-C, Co-C
System, Co-WC, Co-W-WC, Co-WC-C, C
o-W-WC-C or the like of the Co-WC system, T such as TaC _x
a-C system, TiC system such as TiC, MoC _x, Mo-M
oC _x, MoC _x -C system, and the like MoC system, S such as SiC
i-C system, Fe-FeC _x system, etc. FeC system, Al ₂ O
Al—Fe—O system such as _3- Fe system, Ti—Ni—C system such as TiC—Ni system, Ti—Co—C system such as TiC—Co system
System, BN system, B ₄ C-Fe system or the like of Fe-B-C system, Ti
Ti-N type such as N type, Al-N type such as AlN _x type, Ta
N _x system or the like of the Ta-N system, WC-TaC-Co-C system, etc. of the W-Ta-Co-C system, WC-TiC-Co-C system, etc. of the W-Ti-Co-C system, WC TiC-TaC-Co-
C-based W-Ti-Ta-Co-C-based, W-Ti-C-
N-type, W-Co-Ti-C-N type, etc.) can be mentioned. Among these, as a particularly preferable example, for example, a WC-based cemented carbide suitable for a cutting tool or the like (specifically, for example, JIS B
4104: use classification symbols P01, P10, P2
0, P30, P40, P50 and other P series, M10,
M series such as M20, M30, M40, K01, K1
Cemented carbide chips for cutting tools such as K series such as 0, K20, K30 and K40, cemented carbides for drawing dies such as V series such as V1, V2 and V3, for centers, cutting tools, etc. W-Co-C type cemented carbide such as WC-Co type such as chip, W-Ti such as WC-TiC-TaC-Co type
-Ta-Co-C type cemented carbide, or those in which a part of Ta is changed to Nb) and the like. In addition, these may contain elements other than the above and additive components. The material and shape of the cemented carbide to be adopted may be appropriately selected according to the purpose of use and the like.

Examples of the ceramics include S
i, Al, Ti, W, Mo, Co, Ge, Zr and C
Examples thereof include oxides, nitrides, and carbides of metals such as r, and mixtures or compositions thereof. Specific examples of these include alumina, β-alumina, mullite, silica, cordierite, spodumene, zirconia,
Examples thereof include tungsten carbide, titania, molybdenum oxide, chromium oxide, zirconium oxide, silicon carbide, tungsten carbide, titanium carbide, aluminum nitride, silicon nitride and sialon.

The shape of the base material is not particularly limited, and may be a disk shape, a rectangular shape, or the shape of a tool or a wear resistant member. In the present invention, the surface treatment of irradiating the surface of the substrate with the pulsed laser is first performed.

As the laser in this case, the laser beam can be narrowed down as much as possible, for example, 0.25.
There is no particular problem as long as the laser is capable of narrowing the beam diameter to about μm and capable of performing pulse irradiation, and lasers oscillated from various oscillators can be adopted. Specifically, a gas laser, a solid laser, and a semiconductor laser can be used. Examples of the gas laser include CO ₂ laser and I ₂ laser, and examples of the solid-state laser include Nd ³⁺ :
Examples thereof include YAG laser, Nd ³⁺ : Neodymium laser such as GGG laser, and Alexandrite laser.

The output of the laser may be a value sufficient to form a hole in the surface of the base material, and a suitable laser output value varies depending on the material of the base material and the like. However, it may be determined individually and experimentally according to the material of the base material. To give an example,
When the base material is a WC-TiC-Co system, for example,
Pulse output 10-50W, repetition frequency 1-10KH
zd Nd ³⁺ : YAG laser, TEA (transver
A preferable example is a sely excited atmospheric pressure type CO ₂ laser.

The laser beam applied to the substrate surface is
It is desirable to scan the diamond formation area on the substrate surface. By scanning the predetermined surface of the base material with a laser beam, a large number of fine holes are formed in the predetermined surface of the base material, whereby fine irregularities are formed on the surface of the base material. Here, the smaller the average diameter of the fine holes, the more preferable, but it is usually several μm to several hundred μm. Further, it is preferable that the holes to be formed are regularly arranged, and by doing so, the adhesion of the diamond film to the substrate surface is improved. Therefore, for example, the distance between holes arranged in a line is preferably about 1/10 to 10 times the laser beam spot. Thus, the holes formed on the surface of the substrate by the laser beam spot have a predetermined average diameter and the distance between the holes is appropriately selected, so that the adhesion of the diamond film to the substrate is further improved. improves. If the distance between the holes is too wide, the adhesion of the diamond film to the substrate may be poor, and if the distance between the holes is too narrow, the efficiency of the surface treatment by laser may be low.

As a laser device for performing the above-mentioned laser surface treatment, for example, Y manufactured by NEC Corporation is used.
Examples thereof include AG laser, excimer laser marker manufactured by Lambda Physik, and TEA CO ₂ laser marker manufactured by Lasertechnics. In this invention, the surface of the substrate is subjected to the above-mentioned laser surface treatment, and then a diamond film is formed on the surface of the substrate after the surface treatment.

The diamond film can be formed by various vapor phase synthesis methods such as the conventional vapor phase synthesis method, and among them, the CVD method is preferably adopted.
CVD as a vapor phase synthesis method for diamond films
Examples of the method include a microwave plasma CVD method,
High frequency plasma CVD method, hot filament CVD method, D
A wide variety of methods are known, such as the C-arc plasma CVD method. Any of these methods can be applied to the method of the present invention, and among them, a microwave plasma CVD method, a high frequency plasma CVD method, a hot filament CVD method, and the like are particularly preferably applied.

Further, it is known that in the vapor phase synthesis method of the diamond type film by the plasma CVD method, various kinds and compositions of raw materials containing at least a carbon source gas can be used as the raw material gas. There is. As the raw material gas, for example, a raw material gas containing a hydrocarbon as a carbon source gas such as a mixed gas of CH ₄ and H ₂ , or a carbon compound other than a hydrocarbon such as a mixed gas of CO and H ₂ as a carbon source. Raw material gas contained as gas,
Various source gases can be mentioned.

In the method of the present invention, if it is possible to form a diamond film, various source gases such as the source gases used in the conventional methods such as the source gases described above are appropriately used. To form a diamond film. Of these, a mixed gas of CO and H ₂ or a mixed gas of CH ₄ and H ₂ is preferable. In particular, when a mixed gas of CO and H ₂ is used as a raw material gas, the deposition rate of diamonds is higher than that when a hydrocarbon is used, and it is excellent in that a film can be efficiently formed. ..

As an example of the method for forming the diamond film, which is particularly preferable, a method of using CO and H ₂ as raw material gases will be described below.
That is, in the method of the present invention, the formation of the diamond film is a method of using a mixed gas of the following carbon monoxide and hydrogen gas as a source gas (hereinafter, this method,
Sometimes referred to as Method I. ) Particularly preferably.

That is, in this method I, carbon monoxide and hydrogen were added at a ratio of carbon monoxide gas of 1% by volume or more.
It is characterized in that the gas obtained by exciting the mixed gas contained therein is brought into contact with the substrate.

In this method I, the carbon monoxide to be used is not particularly limited, and, for example, the generator gas or water gas obtained by reacting coal or coke with air or steam at the time of heat is sufficiently purified. Any thing can be used. There is no particular limitation on the hydrogen to be used, for example, those obtained by gasification of petroleum, transformation of natural gas, water gas, electrolysis of water, reaction of iron and steam, complete gasification of coal, etc. are sufficient. What was refine | purified can be used.

In this method I, carbon monoxide and hydrogen are used as raw material gases, and the content of carbon monoxide gas is 1
By contacting a gas obtained by exciting the mixed gas contained therein at a ratio of not less than 3% by volume, preferably not less than 5% by volume, and more preferably not less than 5% by volume on the predetermined surface. Diamonds are deposited on. When the content of carbon monoxide gas in the mixed gas is less than 1% by volume, diamond is not produced, or even if diamond is produced, the deposition rate is extremely low.

Means for exciting the source gas to obtain the source gas containing excited carbon includes, for example, plasma CVD method, sputtering method, ionization deposition method, ion beam deposition method, hot filament method, chemical transport method. A conventionally known method such as the above can be used.

When the plasma CVD method is used,
The hydrogen forms plasma by irradiation with high frequency waves or microwaves, and when the CVD method such as the chemical transport method and the hot filament method is used, the hydrogen forms atomic hydrogen by heat or discharge. This atomic hydrogen is
It has a function of removing carbon having a graphite structure which is deposited at the same time as the deposition of diamond.

In this method I, an inert gas may be used as a carrier for the raw material gas. Specific examples of the inert gas include argon gas, neon gas, helium gas, xenon gas, nitrogen gas and the like. These may be used alone or in combination of two or more.

In this method I, the reaction proceeds under the following conditions to deposit diamonds on the substrate. That is, the temperature of the surface of the substrate cannot be unconditionally determined because it varies depending on the excitation means of the raw material gas, but when the plasma CVD method is used, it is usually 400 ° C to 1,000 ° C. Preferably 450 ° C-9
It is 50 ° C. If this temperature is below 400 ° C,
The deposition rate of diamond may be slow, or excited carbon may not be generated. On the other hand, if the temperature is higher than 1,000 ° C., the diamond deposited on the substrate may be scraped off by etching, and the deposition rate may not be improved. The reaction pressure is usually 10 ⁻³ to 10 ³ torr.
r, preferably 1 to 800 torr. When the reaction pressure is lower than 10 ⁻³ torr, the diamond deposition rate becomes slow, or the diamond does not precipitate. On the other hand, even if it is higher than 10 ³ torr, the effect equivalent to that cannot be obtained.

As described above, a diamond film can be suitably formed on the predetermined surface of the base material.
In the method of the present invention, the diamond type film may of course be formed by applying a method other than the above method I.

The thickness of the diamond film to be formed may be appropriately set according to the purpose of use and the like, and there is no particular limitation in this sense, but usually 1 to 100.
It is preferable to select in the range of μm. If this film thickness is too thin, the coating effect of the diamond film may not be sufficiently obtained, while if it is too thick, separation such as peeling of the diamond film may occur depending on the use conditions. is there. When used under severe conditions such as a cutting tool, it is usually preferable to select the thickness in the range of 5 to 50 μm.

As described above, the adhesion between the base material and the diamond film can be remarkably improved by forming the diamond film after heat treating the various base materials under the predetermined conditions. A high performance diamond coated member can be obtained. Further, according to the method of the present invention,
Various cemented carbides can be used as the base of the base material, and in particular, cemented carbides having excellent mechanical strength, such as WC-based cemented carbide suitable for cutting tools, etc., can also be suitably used. Since the mechanical strength of the titanium coating layer itself provided on the surface is sufficiently high, the diamond coating member as a whole can also be provided with high mechanical strength and high durability. Furthermore, this method also has manufacturing advantages such as being extremely simple to manufacture.

That is, the various diamond-coated members produced by the method of the present invention can be advantageously used in a wide range of applications utilizing the characteristics of the base material and the diamond-like film, and the machine having a high base material among them. Especially advantageous as various products or members such as cutting tools, cemented carbide tool members such as polishing tools, sliding members, and wear resistant members that require high strength and high adhesion between the base material and diamond film Can be used.

[0036]

The present invention will be described in more detail below with reference to examples of the present invention and comparative examples thereof, but the present invention is not limited to these examples. The evaluation of the adhesion of the diamond type film to the base material in the following examples and comparative examples was performed as follows.

Evaluation method of adhesion of diamond film (
(Dentation method) Pyramid type diamond Vickers indenter, load 3
Under the conditions of 0 kg · f and a holding time of 30 seconds, the test piece (diamond film-coated substrate) was pressed into the substrate from the diamond film surface, and the peeling area of the diamond film by the indenter was obtained. The quality (largeness) of the adhesion of the diamond film to the substrate was evaluated by the size.

Example 1 As a base material, 94% by weight of tungsten carbide, 1% by weight of titanium carbide and 5% by weight of cobalt
The length of one side made of cemented carbide consisting of 12.7m
An m-square substrate was used. On the surface of this substrate, a pulsed laser with a laser marker was used with a spot spacing of 50μ
Irradiation was performed so as to have a thickness of m to form fine unevenness. The substrate was linearly laser-irradiated not only on its upper surface but also on its side surface.

The base material subjected to such a surface treatment is placed on a base material support in a diamond synthesis reaction tube, and a mixed gas of carbon monoxide and hydrogen containing 15% by volume of carbon monoxide gas is contained in the reaction tube. Is introduced at a pressure of 40 Torr,
The base material temperature was set to 900 ° C. and the diamond synthesis reaction was performed by the microwave plasma CVD method over 5 hours.

The adhesion of the diamond thin film thus obtained was evaluated by the indentation method. As a result, it was revealed that the peeled area was 0.05 mm ² , which was a very small peeled area, and therefore the adhesiveness to the substrate was excellent.

[0041]

EFFECTS OF THE INVENTION According to the method of the present invention, excellent performance and sufficient durability are exhibited even when used under severe conditions encountered by cutting tools, sliding members, etc., and the service life is greatly extended. It is possible to obtain a diamond-coated member having excellent adhesiveness to a base material, which has the advantage of being improved.

Claims (1)

[Claims] 1. A surface of a base material, which is made of at least one selected from the group consisting of cemented carbide and ceramics, is irradiated with a pulsed laser, and then the surface of the base material after the surface treatment is exposed to air. A method for producing a diamond-coated member, which comprises forming a diamond film by a phase synthesis method.