JPH05247652A - Manufacture of coating member for diamond or the like - Google Patents

Abstract

PURPOSE:To provide the manufacturing method of a coating member of diamond, etc., which is superior in adhesibility between a base plate and the film of diamond, etc., coating on it and is excellent in wear resistance, as well and greatly improves the service life. CONSTITUTION:After an etching treatment as necessary, at least one kind of metal selected from metals of group VIA, VA and IVA of the periodic table and Si or its carbide, nitride or carbon nitride is vapor-deposited and then it is heat-treated at 700-1500 deg.C, thus an intermediate layer is provided on the surface of the base plate and subsequently a diamond thin film is formed on the surface of the intermediate layer by a vapor phase method.

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, more specifically, it has excellent adhesion between a base material and a diamond film coating the base material, and also has improved wear resistance and durability. The present invention relates to a method capable of easily producing a diamond-coated member having excellent properties and having a significantly improved service life.

[0002]

2. Description of the Related Art Conventionally, a cutting tool which is required to have high surface hardness and wear resistance,
Diamond, which is remarkably excellent in hardness and wear resistance, is used for wear-resistant members such as tools such as grinding tools and polishing tools and machine parts. For example, in general, CVD
There is known a method of forming a diamond film by depositing diamonds on the surface of a base material such as tools and wear-resistant members by utilizing a diamond synthesis technique by a vapor phase method such as a PVD method or a PVD method. By coating the base material with the diamond coating in this way, it is possible to impart high surface hardness and wear resistance to tools and wear-resistant members.

However, the adhesion between the surface of the substrate and the diamond coating is generally poor. Therefore, various proposals have been made to improve this adhesion. For example, in JP-A-60-208473, an average layer thickness of any one of W, Mo, Nb, and alloys thereof is 0.05 to 1 on at least the tool action surface of a cermet base member. The average layer thickness formed by the artificial diamond precipitation forming method is 1 to 2 through the vapor deposition layer of 2 μm.
An artificial diamond-coated tool member formed by coating a 10 μm artificial diamond coating is disclosed.

However, the vapor deposition layer is required to have sufficient adhesion to both the base material and the diamond thin film, but neither of them is sufficient.
Further, since the strength required for the vapor deposition layer itself cannot be said to be sufficient, there is a problem that practically sufficient durability cannot be obtained.

Japanese Unexamined Patent Publication (Kokai) No. 61-106478 discloses that a periodic table 4a is provided on the surface of a substrate made of a ceramics sintered body.
5a, 6a metal carbides, nitrides, oxides, borides and at least one monolayer or two or more of aluminum oxide, aluminum nitride, boron carbide, boron nitride, silicon oxide and their mutual solid solutions. A first inner layer composed of multiple layers, and a second inner layer composed of a single layer of at least one of silicon nitride, silicon carbide, and silicon oxycarbide, or a multiple layer of two or more layers, and the second inner layer on the surface of the first inner layer. Disclosed is a diamond-coated component, characterized in that the outer surface of the layer is coated with an outer layer made of diamond and / or diamond-like carbon.

However, there is a problem that the material used for the substrate is limited in order to obtain the adhesion between the substrate and the first inner layer, and as a result, the application of the diamond-coated member is limited. In addition, the first inner layer and the second
Adhesion between the inner layer and between the second inner layer and the outer diamond layer is not sufficient.

Further, in JP-A-62-47480, carbides of elements of groups 4a, 5a and 6a of the periodic table,
Fe, Ni, Co, Cr, Mo, W and at least one hard layer among nitrides, borides and mutual solid solutions thereof
Of the sintered alloy consisting of at least one bonding layer from the inside to 0.1 μm to 10 μm from the surface toward the inside is the removed portion of the bonded layer, and the removed portion of the bonded layer is diamond-like carbon and / or diamond. Disclosed is a method for producing a high-adhesion diamond-coated sintered alloy, which comprises forming an intermediate layer formed by burying a diamond, and coating the surface of the intermediate layer with an outer layer made of diamond-like carbon and / or diamond. In addition, a method for producing a high-adhesion diamond-coated sintered alloy, which is characterized by performing heat treatment in a non-oxidizing gas atmosphere or in a vacuum after coating in this way is disclosed.

However, this method has a drawback that the surface of the substrate becomes brittle. In this method, it is possible to obtain a diamond-coated member suitable for precision processing by removing fine cracks on the surface, but almost the effect of improving the adhesion between the base material and the diamond film is achieved. I can't.

In general, the conventional techniques have the following problems. It is difficult to select the material for the intermediate layer, because the adhesiveness to both the base material and the diamond is required. When the intermediate layer is used, the mechanical strength of the entire diamond-coated member is generally governed by the strength of the relatively weak intermediate layer, and therefore the intermediate layer itself is required to have strength.

An object of the present invention is to eliminate the above-mentioned conventional problems. That is, the object of the present invention is to improve the adhesion between the base material and the diamond film for coating the base material, and also to improve the wear resistance, the durability is excellent, and the diamond-coated member having a significantly improved service life. It is an object of the present invention to provide a method capable of easily manufacturing.

[0011]

The invention according to claim 1 for solving the above-mentioned problems is a group IVA, V-group of the periodic table.
At least one metal selected from metals belonging to Group A and Group VIA and Si, selected from metals belonging to Group IVA, Group VA and Group VIA of the Periodic Table, and carbides, nitrides and carbonitrides of Si. Forming a coating layer made of at least one selected from the group consisting of at least one metal compound on the surface of the substrate, and heat treating the substrate having the coating layer at 700 to 1,500 ° C. And a step of forming a diamond thin film on the coating layer by a vapor phase method after the heat treatment, the invention according to claim 2, wherein the substrate surface is etched. Processing steps,
At least one metal selected from Group IVA, Group VA and Group VIA of the Periodic Table and Si, metal belonging to Group IVA, Group VA and Group VIA of the Periodic Table, and a carbide of Si; A step of forming a coating layer consisting of at least one selected from the group consisting of at least one metal compound selected from nitrides and carbonitrides on the surface of the substrate after the etching treatment, and a substrate having a coating layer, A method for manufacturing a diamond-coated member, comprising: a step of heat treatment at 700 to 1,500 ° C .; and a step of forming a diamond thin film on the coating layer by a vapor phase method after the heat treatment.

The method of the present invention will be described in detail below. (1) Step of Etching Treatment of Base Material (Etching Treatment Step) In this etching treatment step, C existing on the surface of the base material
The content is to remove active metals such as o and Ni. It is possible to produce a diamond-coated member having a diamond layer having high adhesion without this etching treatment step. However, particularly in the case of various base materials containing a large amount of active metals such as Co and Ni. By adopting this etching process, diamonds can be efficiently deposited without decomposition of diamonds, which is advantageous. At the same time, the work-affected layer on the outermost surface of the base material is removed, and the adhesion between the base material and the intermediate layer is improved. Furthermore, when this diamond-coated member is used as a processing tool, it is possible to manufacture a diamond-coated member having extremely excellent adhesion in which the diamond layer does not peel off due to the high temperature during processing.

Whether the etching step is adopted or the etching step is omitted, examples of the base material used in the present invention include cemented carbide, cermet and ceramics.

The cemented carbide is not particularly limited,
Various commonly known types and compositions can be used, such as W, Mo, Cr, Co, Ni,
Fe, Ti, Zr, Hf, Nb, Ta, Al, B, G
a, Si, etc. cemented carbides made of one or more metals, cemented carbides of various compositions made of one or more of these metals, and carbon, nitrogen oxygen and / or boron (specifically Specifically, for example, WC, W-WC, W
W-C system such as C-C and W-WC-C, Co-C system, Co
-WC, Co-W-WC, Co-WC-C, Co-W-
Co-WC system such as WC-C, Ta-C such as TaC _x
System, TiC system such as TiC, MoC _x, Mo-MoC
_x , MoC _x- C system or other Mo-C system, SiC or other Si-
C system, Fe-FeC _x system, etc. FeC system, Al ₂ O ₃ -
Fe-based Al-Fe-O-based, TiC-Ni-based Ti, etc.
-Ni-C system, TiC-Co system such as TiC-Co system,
BN type, B ₄ C-Fe system or the like of Fe-B-C system, TiN type such as TiN-based, AlN _x system, etc. AlN-based, TaN _x
System such as Ta-N system, WC-TaC-Co-C system, etc. W-
W- such as Ta-Co-C system and WC-TiC-Co-C system
W-Ti-Ta-Co-C system such as Ti-Co-C system, WC-TiC-TaC-Co-C system, W-Ti-C-N
System, W-Co-Ti-CN system, etc.). Among these, as a particularly preferable example, for example, W suitable for a cutting tool is used.
C-based cemented carbide (specifically, for example, JIS B 4
In 053, use classification symbols P01, P10, P20,
P series such as P30, P40, P50, M10, M2
M series such as 0, M30, M40, K01, K10,
Carbide chips such as K20, K30, K40 and other K series cutting tools, etc., V1, V2, V3 and other V series wire drawing dies, centers, cutting tool etc. W-Co-C based cemented carbide such as WC-Co based, W-Ti-T such as WC-TiC-TaC-Co based
a-Co-C based 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.

Among the above, preferable base materials are Group IVA, Group VA and Group V of the Periodic Table (IUPAC).
Mention may be made of a tungsten carbide based cemented carbide containing a metal belonging to Group IA and one or more metals selected from Si.

Specific examples of preferable tungsten carbide type cemented carbide include WC, W-WC, WC-C and W-WC-.
WC system such as C, WC-Co, WC-Co-W, WC-
W-Co system such as Co-C, WC-Co-WC, WC-
W-Ta- such as TaC-Co and WC-TaC-Co-C
Co system, WC-TiC-Co, WC-TiC-Co, W
W-Ti-Co system such as C-TiCN-Co, WC-Ta
WT such as C-Co and WC-TiC-TaC-Co-C
Cemented carbides such as i-Ta-Co-C system and WC-Nb-Co can be mentioned. The tungsten carbide based cemented carbide can be obtained from tungsten carbide, tantalum carbide, titanium carbide, etc. as described above. Examples of the tungsten carbide-based cemented carbide used in the present invention include Ti, Co, and T.
Those containing a metal such as a, Mo, Cr and Ni are preferable.

In the present invention, among the tungsten carbide type cemented carbide used as the base material, specific examples of preferable compositions include WC-TiC-Co, WC-TaC-Co and WC-Co, WC-Nbc-. An example is a cemented carbide of Co. As a cemented carbide having a composition of WC-TiC-Co, tungsten carbide 50 to 95% by weight, preferably 70 to 94% by weight, titanium carbide 1 to 30% by weight, preferably 2 to 20% by weight, cobalt 2 to 20% by weight, preferably 4 to 10% by weight.

The cemented carbide having the composition of WC-TaC-Co is 80 to 93% by weight of tungsten carbide, preferably 85 to 92% by weight, and 1 to 20% by weight of tantalum carbide, preferably 2 to 10% by weight. And 3 to 10% by weight of cobalt, preferably 4 to 6% by weight.

As a cemented carbide having a composition of WC-Co, 90 to 98% by weight of tungsten carbide, preferably 9
Mention may be made of those containing 4 to 97% by weight and cobalt 2 to 10% by weight, preferably 3 to 6% by weight.

As the above-mentioned tungsten carbide, those used in conventional tools and the like can be used. Specifically, WC, WCx (where x is a positive real number other than 1, and is usually This x is a number greater than 1 or less than 1.) Stoichiometric compounds and non-stoichiometric compounds, or other elements such as oxygen bonded to these,
Those that have been replaced or invaded can be mentioned. Of these, WC is usually particularly preferably used. These may be used alone or in combination of two or more, or may be used as a mixture of two or more, a composition with a solid solution, and the like.

The titanium carbide is not particularly limited, and those used for producing ordinary alloys can be used. Specifically, TiC and TiCy (where y represents a positive real number other than 1 and usually y is 1
It is a number greater than or less than one. ), A stoichiometric compound and a non-stoichiometric compound, or a compound in which another element such as oxygen is bound, substituted or invaded. Of these, usually TiC
Are particularly preferably used.

The tantalum carbide is not particularly limited, and those used for producing ordinary alloys can be used. Specifically, TaC, TaCz (where z is a positive real number other than 1, and normally z is 1
It is a number greater than or less than one. ), A stoichiometric compound and a non-stoichiometric compound, or a compound in which another element such as oxygen is bound, substituted or invaded. Among these, usually TaC
Are particularly preferably used. The cobalt is not particularly limited, but a simple metal can be preferably used.

The tungsten carbide, the titanium carbide,
The tantalum carbide and the cobalt do not need to be particularly pure, and may contain impurities as long as the objects of the present invention are not impaired. For example, the tungsten carbide may contain a trace amount of excess carbon, excess metal, impurities such as oxides, and the like.

As the cermet used in the present invention,
For example, Ti, W, Mo, Cr, Ta, Nb, V, Z
For carbides and nitrides such as r and Hf, Co, Ni, C
A cermet material containing a metal such as r, Mo or Fe as a sintering aid can be mentioned, and any material generally known as a cermet material can be used without particular limitation.

Specific examples include WC, Mo ₂ C, Cr ₃
C ₂ , TaC, NbC, VC, TiC, ZrC, Hf
C, TaN, NbN, VN, TiN, ZrN, HfN,
Ta (C, O), Ti (C, O), Ti (N, O),
(W, Ti) C, (W, Ta, Ti) C, (W, Ta,
Nb, Ti) C, Ti (C, N), Ti (C, N,
O), (Ti, Zr) C, (Ti, Zr) (C, N), etc., contains Co and / or Ni as a sintering aid, and Cr, Mo, Fe, etc. in addition to Co and / or Ni. You can list the things that you did.

If the cermet is expressed differently from the above, the following description is also possible. That is, as the cermet that can be used in the present invention, Ti
WC, TaC and TiN are added to C and Ni is used as a binder phase.
Or Mo added, for example TiC-TaC-
Ni, TiC-TaC-Mo, TiC-TaC-Ni-
Mo, TiC-TiN-Ni, TiC-TiN-Mo,
TiC-TiN-Ni-Mo, TiC-TiN-TaC
-WC-Ni, TiC-TiN-TaC-WC-Mo,
TiC-TiN-TaC-WC-Ni-Mo, TiN-
TaN-Ni, TiN-TaN-Mo, TiN-TaN
-Ni-Mo, TiC-TaN-Ni, TiC-TaN
-Mo, TiC-TaN-Ni-Mo, TiC-Ni,
TiC-Mo, TiC-Ni-Mo, TiC-Ni, T
iC-Mo, TiC-Ni-Mo, TiC-TaN-N
i, TiC-TaN-Mo, TiC-TaN-Ni-M
o etc. can be mentioned. Note that these may contain other elements or their carbides.

Among these, titanium carbide, tungsten carbide and titanium nitride cermets are preferably used. Particularly preferred are TiC, TiN, T
A cermet material that uses Ni, Co, or Mo as a sintering aid for iCN or the like can be given. In addition, as the base material, a commercially available material can be used. Further, when a commercially available product is used, the base material can be obtained by a method such as sintering after the components are blended in an appropriate ratio.

Prior to sintering, together with the above components,
If necessary, an auxiliary binder containing paraffin, stearic acid, camphor, etc. as a main component may be contained.
The sintering method is not particularly limited and can be performed according to a conventionally known sintering method.

In the sintering method, each of the above components can be used in the form of powder, fine powder, ultrafine particles, whiskers, or other various shapes, but the average particle size is Usually, fine particles or ultrafine particles having a size of 0.05 to 4 μm, preferably 1 to 3 μm, whiskers having an aspect ratio of about 20 to 200, and the like can be preferably used.

The sintering temperature is usually 1,200 to 1,
600 ° C, preferably 1,300 to 1,600 ° C or 1,300 to 1,550 ° C or 1,350 to 1,
A temperature within the range of 550 ° C is suitable. Sintering time is
Usually, it is suitable to be within a range of 0.5 hours or more, preferably about 1 to 2 hours.

There is no particular limitation on the shape of the substrate used for producing the diamond-coated member. The base material can be, for example, previously formed into a desired shape upon sintering and then sintered, or after the sintering, if necessary, processed into a desired shape to obtain the diamonds of the present invention. It can be used as a base material for a covering member.

In this etching process, the surface of the base material is etched. Examples of the method for etching the surface of the base material include wet etching and dry etching. Examples of the wet etching include etching treatment with acid and electrolytic etching.

The acid used for the etching treatment with an acid is not particularly limited, and examples thereof include nitric acid, sulfuric acid, hydrochloric acid and hydrofluoric acid. In addition, the above acid,
One kind may be used alone, or two or more kinds may be mixed and used. Among the above acids, a mixed acid of nitric acid and hydrofluoric acid and a mixed acid obtained from hydrogen fluoride and nitric acid are particularly preferable.

The case of using a mixed acid of nitric acid and hydrofluoric acid or a mixed acid obtained from hydrogen fluoride and nitric acid will be described in detail below as an example of the acid etching treatment. However, the acid etching treatment in the present invention is not limited to this. As hydrogen fluoride when preparing a mixed acid obtained from hydrogen fluoride and nitric acid, hydrogen fluoride itself can be used, or it can be used in the form of hydrofluoric acid which is an aqueous solution of hydrogen fluoride. You can also

When the above mixed acid is used, the content of hydrogen fluoride in the mixed acid obtained from hydrogen fluoride and nitric acid is usually 5 to 50, assuming that hydrogen fluoride is not decomposed. Mol%, preferably 10-40 mol%
Is. The nitric acid concentration in this mixture is:
It is usually 5 to 65 mol%, preferably 15 to 60 mol%. When hydrogen fluoride and nitric acid are contained in the mixed acid within the above range, the coating layer can be formed on the substrate layer treated with such mixed acid with good adhesion.

In order to contain hydrogen fluoride within the above range, when hydrofluoric acid is used, 1
Hydrofluoric acid containing 0 to 50%, preferably 20 to 46% hydrogen fluoride is preferred. Also, as nitric acid,
Nitric acid having a concentration of 30 to 70%, particularly 30 to 61% is preferable. From a practical point of view, the mixed acid obtained from hydrogen fluoride and nitric acid is preferably a mixture consisting essentially of hydrofluoric acid and nitric acid, and other inorganic acids such as sulfuric acid may be mixed if necessary. It is also possible to use mixtures which consist of When a mixture consisting essentially of hydrofluoric acid and nitric acid is adopted, it is preferable to adjust the respective concentrations of hydrofluoric acid and nitric acid so that the contents of hydrogen fluoride and nitric acid are as described above.

As the etching treatment with an acid in the present invention, various methods such as a method of immersing the base material in the acid and a method of spraying the acid on the surface of the base material can be adopted. In short, it suffices if the predetermined surface of the base material on which the intermediate layer is provided can be brought into contact with the acid.

The temperature of the etching treatment with the acid is not particularly limited, but for example, when the above-mentioned mixed acid is used, it is usually preferably 20 to 100 ° C., particularly 50 to 9 ° C.
5 ° C is preferred. If the treatment temperature is lower than 20 ° C,
Since etching takes time, Co or the like may not be sufficiently etched. Further, when the treatment temperature is higher than 100 ° C., the controllability becomes poor because the etching of the surface of the base material progresses violently.

The time for the etching treatment with the acid is not particularly limited as long as the etching is sufficiently performed. For example, when the above-mentioned mixed acid is used, it is usually 0.5.
Seconds to 300 seconds are preferable, and 1 second to 120 seconds is particularly preferable. If the treatment time is shorter than 0.5 seconds, the etching treatment may be insufficient. On the other hand, if the time is longer than 300 seconds, the strength of the substrate may decrease due to excessive progress of the etching process.

On the other hand, examples of the electrolytic solution for electrolytic etching include inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid and hydrofluoric acid, and alcohols. These may be used alone or in combination of two or more. Among the above electrolytic solutions, a solution containing hydrogen fluoride, sulfuric acid and alcohol is suitable for the method of the present invention.

As the hydrogen fluoride when preparing the solution containing hydrogen fluoride, sulfuric acid and alcohol, hydrogen fluoride itself can be used, or hydrogen fluoride which is an aqueous solution of hydrogen fluoride can be used. It can also be used in the form. From a practical point of view, the solution containing hydrogen fluoride, sulfuric acid and alcohol is preferably a mixture of alcohol with hydrofluoric acid and sulfuric acid, and if necessary, other inorganic acid such as nitric acid. It is also possible to mix hydrochloric acid and the like.

As an example of electrolytic etching, the case where the electrolytic solution is a solution containing hydrogen fluoride, sulfuric acid and alcohol will be described in detail below. However, the electrolytic etching in the present invention is not limited to this. The concentration of hydrogen fluoride in the solution containing hydrogen fluoride, sulfuric acid and alcohol is usually 1 to 3 mol%, preferably 1 to 2 mol%. When preparing a solution consisting essentially of hydrofluoric acid and hydrogen fluoride, sulfuric acid, and alcohol, prepare hydrofluoric acid so that the concentration of hydrogen fluoride after mixing falls within the above concentration range. Good to use. The concentration of sulfuric acid in the solution of hydrogen fluoride, sulfuric acid and alcohol is usually 5 to 10 mol%, preferably 6 to 8 mol%.

The alcohol is not particularly limited as long as it does not impair the object of the present invention, and examples thereof include methanol, ethanol, propanol and butanol. Among them, methanol is particularly preferable. In this case, a counter electrode is provided in a solution composed of the hydrogen fluoride, sulfuric acid, and alcohol so that the base material is the positive electrode and the counter electrode is the negative electrode, and electrolytic etching of the surface of the base material is performed. To do.

The material of the electrode is not particularly limited as long as it does not generate a substance that inhibits the surface of the base material, such as a gas, during electrolytic etching.
Examples thereof include stainless steel. Usually, the voltage in the electrolytic etching is preferably 3 to 10 V, and particularly,
4-10V is preferable. If the voltage is lower than 3V, the etching rate is slow and inefficient. When the voltage is higher than 10 V, the etching rate becomes too fast and the controllability is poor, and etching may be performed more than necessary.

The electric current in the electrolytic etching is preferably 0.01 to 5 A / cm ² per unit area, and particularly preferably 0.1 to 1 A / cm ² . When the current per unit area is less than 0.01 A / cm ² , etching is not sufficiently performed. Further, if the current per unit area is larger than 5 A / cm ² , etching may proceed excessively and the strength of the substrate may be lowered.

The processing time in the electrolytic etching is
Although it cannot be unconditionally determined depending on the shape of the base material and the magnitude of the electric current, it is usually preferably 0.1 to 60 minutes, and particularly preferably 1 to 30 minutes. As the dry etching, for example, etching treatment by plasma can be mentioned.

In the plasma etching process, for example, an inert gas such as argon or nitrogen gas, carbon tetrafluoride, hydrogen gas, oxygen gas, carbon monoxide gas, carbon dioxide gas, methanol gas, water vapor, or the like is used. And a plasma such as a mixture thereof. Of these, argon, hydrogen gas and oxygen gas are particularly preferable.

There is no particular limitation on the method for converting to plasma, and plasma processing methods by various methods such as the plasmaization method utilized in the general vapor phase synthesis method of diamond or diamond film can be applied. Specifically, for example, microwave plasma CVD method, high frequency plasma C
The VD method, the hot filament method, the ECR method and the like, or a combination method thereof and the like can be mentioned. Among these, the microwave plasma CVD method and the high frequency plasma CVD method are particularly preferable. Further, if the same CVD method as that used in the vapor phase synthesis of diamond, which will be described later, is adopted, it is convenient in terms of device configuration.

The reaction conditions for the etching treatment with plasma may be those conventionally used. For example, the processing pressure is 10 to 100.
A range of torr is preferred. When the pressure is higher than the above range, the controllability of the treatment is poor, and when it is low, the treatment takes time. The temperature of the surface of the intermediate layer is 500 to 1,10.
Within the range of 0 ° C, preferably 700 to 900 ° C. When the temperature is higher than the above range, the controllability of the treatment is poor and the reproducibility is poor, and when the temperature is low, the treatment takes time. The processing time is 1 minute to 200 minutes, preferably 60 minutes.

By carrying out the above-described etching treatment in the present invention, the metal such as cobalt which causes a harmful binding phase when forming the diamond film on the base material is removed, and the surface of the base material is removed. Irregularities and pores occur on the As a result, the adhesion between the base material and the intermediate layer is improved, and further, the intermediate layer described later is formed according to the shapes of the irregularities and the pores, and is generated during the synthesis of the diamond film by the vapor phase method described later. The diamond film enters the irregularities and pores on the surface of the intermediate layer, and a diamond film having excellent adhesion to the substrate can be synthesized.

(2) Step of Forming Coating Layer on Substrate Surface (Coating Layer Forming Step) In this coating layer forming step, in the periodic table group IVA, VA
Metal belonging to Group VIA and Group VIA and at least one metal selected from Si, Group IVA of Group I, V
Forming a coating layer of at least one selected from the group consisting of metals belonging to Group A and Group VIA and at least one metal compound selected from carbides, nitrides and carbonitrides of Si on the surface of a substrate To do.

Among the materials forming these coating layers, more preferred are titanium metal, titanium nitride, titanium carbide and titanium carbonitride, and also metal tantalum, tantalum nitride, tantalum carbide and tantalum carbonitride. These may be used in one kind, or may be used in various compositions of two or more kinds.

As the titanium nitride, for example, Ti
N, or those represented by TiN _x , TiN-Ti, Ti-N and the like can be mentioned. Examples of the titanium carbide include TiC or Ti
_{C x, TiC-C, TiC} -Ti, TiC-TiC,
Examples thereof include those represented by Ti-C and the like. Examples of the titanium carbonitride include TiCN,
_{TiC · TiN, TiC X · TiN} x, TiC · TiN
-C, TiC / TiN-Ti, TiC / TiN-Ti-
Those represented by C, Ti-N-C and the like can be mentioned.

That is, the titanium-containing coating layer is usually preferably represented by Ti, TiN, TiC or TiCN, but may be composed of two or more of these, and further, One, or two or more, may contain Ti, C and / or N components in excess. In addition, the titanium-containing coating layer contains Ti and C within the range that does not impair the object of the present invention.
Other elements or components other than N and N may be contained.

As a method for forming the coating layer on the surface of the base material, a generally used method, for example, a commonly used ion plating method or sputtering method can be adopted. The thickness of the coating layer is not particularly limited, but is usually 100 to 50,000Å
It is preferably selected from the range of 1,000 to 30,000Å so that a solid solution layer having a desired thickness can be obtained. If the film thickness is less than 100Å, the effect of the intermediate layer cannot be expected,
On the other hand, if it exceeds 50,000Å, the strength of the intermediate layer itself decreases.

(3) Heat Treatment Step (Heat Treatment Step) The coating layer thus formed on the surface of the substrate is 700 to 1,500 ° C., preferably 1,200 to 1, in this heat treatment step. Heat treatment at 500 ° C. This heat treatment enhances the adhesion between the coating layer and the base material.

It is presumed that the reason why the adhesion of the coating layer to the base material is improved is that a part of the metal or compound constituting the coating layer is impregnated or permeated into the base material by this heat treatment. To be done. Therefore, the temperature of this heat treatment is extremely important in the method of the present invention,
At a heating temperature of less than 700 ° C., even if a heat treatment is performed, chemical bonding due to impregnation of the vapor-deposited metal or compound into the substrate does not occur, and sufficient adhesion is not exhibited. On the other hand, at a high temperature exceeding 1,500 ° C., the heat treatment at such a high temperature causes a disadvantage that the substrate is deformed.

The atmosphere for the heat treatment is preferably an inert gas such as argon, helium or nitrogen gas. The pressure during the heat treatment is appropriately selected from the range of 5 torr to 3,000 atm. These atmospheric gases and pressures
It is appropriately determined depending on the components of the coating layer. For example,
When the metal species is titanium, the heating temperature is 1,200.
The temperature is preferably in the range of 1 to 1,450 ° C., the atmosphere is preferably vacuum, argon gas or helium gas, and the pressure is preferably in the range of 5 torr to 3,000 atm. Furthermore, the rate of temperature rise during this heat treatment is 5 to 20 ° C /
It is preferable that the heating time is about 5 minutes, and the holding time at the heat treatment temperature is preferably 5 to 600 minutes.

When fine irregularities or pores are formed on the surface of the base material by etching, the coating layer bonded to the surface of the base material also has a shape corresponding to the shape of the irregularities or pores. .. Therefore, irregularities are formed on the surface of the coating layer after the heat treatment, the diamond thin film formed thereon has an anchor effect, and the adhesion between the base material and the diamond is improved. In addition, a chemical bond (carbide) is formed between the diamond thin film and the metal remaining without being impregnated, which can also be expected to improve the adhesion. Since the heat treatment also forms fine irregularities and pores on the surface of the base material, similar effects to those described above can be expected even when the etching treatment is not performed.

Furthermore, this coating layer can prevent active metals such as Co from depositing on the surface of the substrate from the inside of the substrate during heating of the substrate during the subsequent diamond synthesis. Can be expected to improve the adhesion of diamond thin films. The intermediate layer formed by performing such heat treatment may be further subjected to normal scratch treatment with diamond abrasive grains or the like, if necessary.

(4) Step of Forming Diamond Layer (Diamond Layer Forming Step) In the present invention, the surface of the intermediate layer heat-treated as described above is coated with a thin layer of diamond. The diamonds mentioned here include diamond and diamond-like carbon partially containing diamond-like carbon, in addition to diamond. As a method for forming a thin layer of diamonds, various methods have been conventionally known and are not particularly limited, but in the method of the present invention, as shown below, vapor phase synthesis using a carbon source gas is performed. The method can be preferably adopted.

Examples of the carbon source gas include paraffinic hydrocarbons such as methane, ethane, propane and butane; olefinic hydrocarbons such as ethylene, propylene and butylene; acetylene hydrocarbons such as acetylene and allylene; and butadiene. Diolefin hydrocarbons such as allene; cyclopropane, cyclobutane, cyclopentane,
Alicyclic hydrocarbons such as cyclohexane; aromatic hydrocarbons such as cyclobutadiene, benzene, toluene, xylene, and naphthalene; ketones such as acetone, diethyl ketone, benzophenone; alcohols such as methanol and ethanol; other oxygen-containing compounds Hydrocarbons; amines such as trimethylamine and triethylamine; other nitrogen-containing hydrocarbons; carbon dioxide gas, carbon monoxide, carbon peroxide and the like. Further, the above various compounds may be mixed and used.

Among these, preferred are paraffinic hydrocarbons such as methane, ethane and propane, alcohols such as ethanol and methanol, ketones such as acetone and benzophenone, amines such as trimethylamine and triethylamine, carbon dioxide, and It is carbon oxide, and carbon monoxide is particularly preferable.

Incidentally, these may be used alone,
You may use together 2 or more types as mixed gas. Further, these may be used as a mixture with an active gas such as hydrogen or an inert gas such as helium, argon, neon, xenon or nitrogen.

A known method for forming the thin layer of diamonds, for example, a CVD method, a PVD method, a PCVD method,
Alternatively, various diamond thin-layer vapor phase synthesis methods such as a combination thereof can be used, and among them, various hot filament methods including EACVD method and various methods including thermal plasma method are usually used. DC plasma CV
Microwave plasma CVD including D method and thermal plasma method
The method etc. can be used conveniently.

The conditions for forming the thin layer of diamonds are not particularly limited, and the reaction conditions usually used in the above vapor phase synthesis method can be applied. For example, the reaction pressure is usually preferably 10 ⁻⁶ to 10 ³ Torr,
In particular, it is preferably within the range of 1 to 800 Torr.
When the reaction pressure is lower than 10 ^-6 Torr, the formation rate of a thin layer of diamonds may be slow. In addition, if higher than 10 ³ Torr is, 10 ³ Torr
There is no more effect compared to the effect obtained at.

The surface temperature of the base material cannot be unconditionally specified because it depends on the means for activating the raw material gas and the like, but it is usually 300 to 1,000 ° C., preferably 450 to 950 ° C. It is better to stay within the range. If this temperature is lower than 300 ° C, the formation of a thin layer of crystalline diamond may be insufficient. Also,
When the temperature exceeds 1,000 ° C., etching of the formed thin layer of diamonds and graphitization of diamond are likely to occur.

The reaction time is not particularly limited, and it is preferable to appropriately set the reaction time so that the thin layer of diamonds has a desired thickness in accordance with the formation rate of the thin layer of diamonds. The thickness of the thin layer of diamonds formed on the surface of the base material cannot be uniformly determined because it depends on the purpose of use of the diamond-coated member and the like, but in the case of tools, it is usually 5 μm or more, preferably 10 to 50 μm
The above is appropriate. If the thin layer of diamonds is too thin, it may not be possible to sufficiently coat the surface of the substrate. In this way, when the thin diamond layer is formed on the surface of the intermediate layer, the carbon source gas of the raw material reacts with the metal of the intermediate layer, the metal of the intermediate layer is carbonized, and then diamond is formed. Therefore, the adhesion between the intermediate layer and the diamond thin layer is improved.

As described above, according to the method of the present invention,
A diamond coated member can be manufactured.

[0070]

EXAMPLES The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention in any way.

Example 1 As a base material, the raw material composition was as follows: silicon nitride (Si ₃ N ₄ ) 92 volume%, titanium nitride (TiN) 5 volume%, yttrium oxide (Y ₂ O) which was a sintering aid. ₃ ) A ceramic base material having a content of 3% by volume was used, and as the shape thereof, a throwaway chip of SPGN120308 (hereinafter, referred to as base material A) was used.

A silicon film having a thickness of 1 is formed on the surface of the base material.
After vapor deposition to 000 Å, it was heat-treated at 1,450 ° C. for 15 minutes in an argon atmosphere at 2,000 atm. The metal-deposited surface of this substrate was scratched with diamond abrasive grains having an average grain size of about 10 μm.

Next, this heat-treated substrate was placed on a substrate support in a diamond synthesis reaction tube, and a mixed gas of carbon monoxide gas containing 15% by volume of carbon monoxide gas and hydrogen gas was introduced into the reaction tube. Distributed. Then frequency 2.4
A 5 GHz microwave was introduced to form diamond by the plasma CVD method.

The pressure in the reaction tube was 40 torr, the temperature of the substrate was 900 ° C., and the reaction was carried out for 5 hours. As a result, a 12 μm thick diamond film was formed on the surface of the substrate. With respect to the obtained thin layer coating member of diamonds, the adhesion between the diamond film and the surface of the substrate was evaluated by the indentation method.

The evaluation method by the indentation method means that the surface of the sample is deformed by pressing a diamond indenter shaped into a hemisphere or a pyramid against the sample to be evaluated, and the state of the sample after the deformation. Is observed and the adhesion of the sample is evaluated.

In the present embodiment, since the sample is a thin layer coating member of diamonds, a pyramid-shaped indenter is pushed into the substrate with an appropriate load to deform the substrate, and the portion where the substrate is higher than the original state is observed. To do. In this part, the deformed substrate pushes up the thin layer of diamonds formed on the surface, so if the adhesion between the thin layer of diamonds and the substrate is poor, the thin layer of diamonds That is, the area of the portion separated from the substrate becomes large. Therefore, by measuring the size of the area of the exfoliated thin diamond layer, it is possible to evaluate the quality of the adhesion between the substrate and the thin layer of diamond formed on the surface of the substrate.

In the examples of the present application, as the measurement conditions, the load on the Vickers indenter was 30 kg · f, the holding time was 30 seconds, and the peeling area of the diamond thin layer by the indenter was obtained. The degree of adhesion was evaluated. The results are shown in Table 1. As shown in Table 1, the peeled area was 0.05 mm ² , and the adhesion between the diamond film and the surface of the substrate was large.

(Examples 2 to 8) The same procedure as in Example 1 was carried out except that the metal species to be deposited and the heat treatment conditions were changed as shown in Table 1. The results are shown in Table 1.

(Example 9) As a base material, a ceramic base material having a composition of 97% by volume of silicon nitride (Si ₃ N ₄ ) and 3% by volume of yttrium oxide (Y ₂ O ₃ ) which is a sintering aid. Was carried out in the same manner as in Example 1 except that a throwaway tip having a shape of SPGN120308 (hereinafter referred to as a base material B) was used. The results are shown in Table 1.

(Examples 10 to 15) Example 10 was repeated except that the metal species to be deposited and the heat treatment conditions were changed as shown in Table 1. The results are shown in Table 1.

(Examples 16 to 23) As a base material, a cemented carbide having a composition of 91.8% by weight of tungsten carbide, 2.9% by weight of titanium carbide and 4.9% by weight of cobalt was used, and the shape was The same procedure as in Example 1 was carried out except that the throwaway tip of SPGN120308 (hereinafter referred to as the base material C) was used. The results are shown in Table 2.
Shown in.

(Comparative Examples 1 to 15) Adhesiveness was evaluated in the same manner as in Examples for the products obtained as shown in Table 1. The results are shown in Tables 1 and 2.

(Examples 24 to 37) As a base material, a cutting tool chip of size 1 as shown in Table 3 was used.
A cemented carbide of 2.7 mm square was used, and the surface thereof was etched by the method shown in Table 3. Regarding the etching treatment in Table 3, in the method indicated as "HF + NHO ₃ ",
Immerse in a 1: 1 mixed solution of hydrofluoric acid having a concentration of 46% and nitric acid having a concentration of 61% for 3 seconds, and perform "electrolysis (HCl)".
_{3 In} the method indicated as “electrolysis (H ₂ So ₄ )”,
l and H ₂ So ₄ both are 10% aqueous solution 1,000
A mixed solution of 25 ml of H ₂ O ₂ with H ₂ O _{2 was} used as an electrolytic solution, and the voltage was 3 V and the electrolysis time was 5 seconds. Also, "N ₂ plasma"
In the method displayed as, the frequency 2.45G output 400W,
The processing time was 1 hour. The intermediate layer was vapor-deposited by the method of Table 3 and heat-treated under the conditions shown in Table 3. "Coating member" in Table 3
Items K10, P10, M10, K20 are JIS
It is based on B4053, and the details are as follows.

K10 WC-Co system (W: 87% by weight, Co: 6% by weight, Ta: 1% by weight, C: 6% by weight) K20 WC-Co system (W: 86% by weight, Co: 7% by weight) , Nb: 1 wt%, C: 6 wt%) P10 WC-TiC-TaC-Co system (W: 50 wt%, Ti: 23 wt%, Ta: 17 wt%, Co: 9
%, C: 11% by weight) M10 WC-TiC-TaC-Co system (W: 70% by weight, Ti: 7% by weight, Ta: 7% by weight, Co: 8% by weight, C: 8% by weight).

After the heat treatment, a diamond thin layer was formed on the surface of the base material under the same conditions as in Example 1 except that the reaction time was 10 hours to obtain each diamond-coated member. The film thickness was 25 μm. Next, with respect to the obtained diamond-coated member, the adhesion between the thin diamond layer and the substrate was evaluated by the indentation method under the same conditions as in Example 1. The results are shown in Table 3.

[0086]

[Table 1]

[0087]

[Table 2]

[0088]

[Table 3]

[0089]

According to the method of the present invention, the adhesion between the substrate and the diamond thin layer can be remarkably improved, and when used in cutting tools, cemented carbide tools, wear resistant tools, etc. It is possible to provide a diamond-like covering member that can exhibit durability and has a long life.

Claims (2)

[Claims] 1. A metal belonging to Group IVA, Group VA and Group VIA of the periodic table and at least one metal selected from Si, a metal belonging to Group IVA, Group VA and Group VIA of the periodic table. And a step of forming a coating layer made of at least one selected from the group consisting of at least one metal compound selected from carbides, nitrides and carbonitrides of Si on the surface of the substrate, and a substrate having the coating layer. , 700 to 1,500 ° C., and a step of forming a diamond thin film on the coating layer by a vapor phase method after the heat treatment. 2. A step of etching the surface of the substrate,
At least one metal selected from metals belonging to Group IVA, Group VA and Group VIA of the Periodic Table and Si, metals belonging to Group IVA, Groups VA and VIA of the Periodic Table, and carbides of Si; A step of forming a coating layer consisting of at least one selected from the group consisting of at least one metal compound selected from nitrides and carbonitrides on the surface of the substrate after the etching treatment, and a substrate having a coating layer, A method for manufacturing a diamond-coated member, comprising: a step of heat treatment at 700 to 1,500 ° C .; and a step of forming a diamond thin film on the coating layer by a vapor phase method after the heat treatment.