JP3353239B2 - Method for producing diamond-coated member - Google Patents

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 particularly, to a method of producing a diamond-coated film having excellent adhesion to a base material and a diamond film covering the same. The present invention relates to a method for easily producing a diamond-coated member having excellent properties and significantly improved service life.

[0002]

2. Description of the Related Art Conventionally, cutting tools that require high surface hardness and abrasion resistance,
2. Description of the Related Art 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 mechanical parts. For example, in general, CVD
There is known a method in which diamond is deposited on the surface of a base material such as tools and wear-resistant members by using a diamond synthesis technique based on a gas phase method such as a PVD method or a PVD method to form a diamond film. By coating the base material with the diamond coating as described above, a high degree of surface hardness and wear resistance can be imparted to tools and wear-resistant members.

However, the surface of the substrate and the diamond coating generally have poor adhesion. Therefore, various proposals have been made to improve the adhesion. For example, Japanese Patent Application Laid-Open No. 60-208473 discloses that at least the tool working surface of a cermet base member has an average thickness of 0.05 to 1 of any one of W, Mo, and Nb, and an alloy thereof. An average layer thickness of 1 to 2 μm formed by an artificial diamond deposition method via a 2 μm vapor deposition layer
An artificial diamond-coated tool member formed by coating an artificial diamond film having a thickness of 10 μm is disclosed.

[0004] However, it is required that the deposited layer has sufficient adhesion to both the substrate and the diamond thin film, but none 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 Patent Application Laid-Open No. 61-106478 discloses a periodic table 4a on the surface of a substrate made of a ceramic sintered body.
Group 5a, group 6a carbides, nitrides, oxides, borides and at least one single layer 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, a second inner layer composed of at least one kind of single layer or two or more kinds of silicon nitride, silicon carbide, and silicon nitride carbide on the surface of the first inner layer, and the second inner layer There is disclosed a diamond-coated part characterized in that the surface of the diamond-coated part is coated with an outer layer made of diamond and / or diamond-like carbon.

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

Further, Japanese Patent Application Laid-Open No. 62-47480 discloses a carbide of a group 4a, 5a, or 6a element of the periodic table.
At least one hard layer of nitride, boride and their mutual solid solution with Fe, Ni, Co, Cr, Mo, W
And from 0.1 μm to 10 μm from the surface to the inside of the sintered alloy comprising at least one bonding layer, the diamond-like carbon and / or diamond is removed from the bonding layer. A method for producing a high-adhesion diamond-coated sintered alloy, comprising forming an intermediate layer formed by embedding a diamond and then coating the surface of the intermediate layer with an outer layer made of diamond-like carbon and / or diamond. Further, there is disclosed a method for producing a high-adhesion diamond-coated sintered alloy, which comprises performing a heat treatment in a non-oxidizing gas atmosphere or in a vacuum after coating in this manner.

However, this method has a disadvantage that the surface of the substrate becomes brittle. In this method, even if a diamond-coated member suitable for precision processing can be obtained by removing fine cracks on the surface, almost no effect of improving the adhesion between the base material and the diamond film can be obtained. Can not.

A general overview of the prior art generally has the following problems. The intermediate layer is required to have good adhesion to both the substrate and the diamond, so that it is difficult to select a material. When an intermediate layer is used, the mechanical strength of the entire diamond-coated member is generally governed by the relatively low strength of the intermediate layer. Therefore, the intermediate layer itself is required to have high strength.

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

[0011]

Means for Solving the Problems According to the first aspect of the present invention, there is provided a method according to the first aspect of the present invention.
Selected from metals belonging to Group A and Group VIA and Si
And one of metals, Group IVA of the periodic table, Group VA, and at least the group as a kind of metal compound consists <br/> selected from the VIA nitride of a metal and Si belonging to Group and carbonitride Forming a coating layer composed of at least one selected from the group consisting of: a step of heating the substrate having the coating layer at 700 to 1,500 ° C .; And a step of forming a diamond thin film by a phase method. The method according to claim 2, wherein the step of etching the surface of the base material comprises the steps of :
Group VA, one metal selected from the metals and Si belonging to Group VA and Group VIA of the periodic table Group IVA,
Group VI and VIA metals and Si nitrides
Engineering of at least one consisting of a coating layer selected from the group consisting of at least one metal compound selected from halides and carbonitrides formed on the substrate surface after the etching treatment
Degree, a substrate having a coating layer, the diamond coating and having a step of forming a diamond film by 700～1,500 step of heat-treating at ° C., and a gas phase method on the coating layer after the heat treatment It is a manufacturing method of a member.

Hereinafter, the method of the present invention will be described in detail. (1) Step of Etching Substrate (Etching Step) This etching step is performed by etching C on the surface of the substrate.
It is intended to remove active metals such as o and Ni. This etching step can produce a diamond-coated member having a diamond layer with high adhesion without any particular need. Particularly, in the case of various substrates containing a large amount of active metals such as Co and Ni, By adopting this etching step, diamonds can be efficiently deposited without decomposing the diamonds, which is advantageous. At the same time, the damaged layer on the outermost surface of the substrate is removed, and the adhesion between the substrate and the intermediate layer is improved. Furthermore, when this diamond-coated member is used as a processing tool, it is possible to produce a diamond-coated member having extremely excellent adhesion without the diamond layer being peeled off at a high temperature during processing.

Regardless of whether this etching step is adopted or this etching step is omitted, examples of the substrate used in the present invention include a cemented carbide, a cermet, and a ceramic.

The cemented carbide is not particularly limited.
Various types and compositions generally known can be used. For example, W, Mo, Cr, Co, Ni,
Fe, Ti, Zr, Hf, Nb, Ta, Al, B, G
cemented carbides composed of one or more metals such as a and Si, and cemented carbides of various compositions composed of one or more of these metals and carbon, nitrogen oxygen and / or boron (specifically, Specifically, for example, WC, W-WC, W
WC system such as CC, W-WC-C, Co-C system, Co
-WC, Co-W-WC, Co-WC-C, Co-W-
WC-C, etc. Co-WC-based, TaC etc. TaC _x
System, TiC such as TiC, MoC _x , Mo-MoC
_x , MoC _x -C-based Mo-C-based, SiC-based Si-
C system, Fe-FeC _x system, etc. FeC system, Al ₂ O ₃ -
Al-Fe-O-based Ti, TiC-Ni-based Ti, etc.
-Ti-Co-C system such as Ni-C system and TiC-Co system;
Fe-BC system such as BN system, B ₄ C-Fe system, Ti-N system such as TiN system, Al-N system such as AlN _x system, TaN _x
System such as Ta-N system and WC-TaC-Co-C system such as W-
W- such as Ta-Co-C and WC-TiC-Co-C
W-Ti-Ta-Co-C system such as Ti-Co-C system, WC-TiC-TaC-Co-C system, W-Ti-CN
System, W-Co-Ti-CN system, etc.). Among these, as a particularly preferred example, for example, W
C-based cemented carbide (specifically, for example, JIS B 4
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,
Cemented carbide chips for cutting tools such as K series such as K20, K30, K40, etc., Cemented carbide chips for wire drawing dies such as V series such as V1, V2, V3, center, cutting tools, etc. W-Co-C cemented carbide such as WC-Co-based, W-Ti-T such as WC-TiC-TaC-Co-based
a-Co-C cemented carbides, or those obtained by partially changing Ta to Nb, etc.).
These may contain other elements and additional components other than the above. What kind of material and shape of cemented carbide should be adopted may be appropriately selected according to the purpose of use and the like.

Among the above, preferred base materials include Group IVA, Group VA and Group V of the Periodic Table (IUPAC).
Examples thereof include a tungsten carbide cemented carbide containing one or more metals selected from the group IA metals and Si.

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

In the present invention, of the tungsten carbide cemented carbide used as the substrate, specific examples of preferred compositions include WC-TiC-Co, WC-TaC-Co, WC-Co, WC-Nbc- Co cemented carbide may be mentioned. As a cemented carbide having a composition of WC-TiC-Co, tungsten carbide is 50 to 95% by weight, preferably 70 to 94% by weight; titanium carbide is 1 to 30% by weight, preferably 2 to 20% by weight; Those having 2 to 20% by weight, preferably 4 to 10% by weight can be mentioned.

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

As the cemented carbide having the composition of WC-Co, 90 to 98% by weight, preferably 9% by weight of tungsten carbide is used.
Those having 4 to 97% by weight and 2 to 10% by weight, preferably 3 to 6% by weight of cobalt can be mentioned.

As the above-mentioned tungsten carbide, those used for conventional tools and the like can be used. Specifically, WC, WCx (where x represents a positive real number other than 1; X is a number greater than 1 or less than 1.) The stoichiometric compound and the non-stoichiometric compound represented by
Substitution or intrusion can be mentioned. Of these, WC is 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 solid solution, or the like.

The titanium carbide is not particularly limited, and those used for producing ordinary alloys can be used. Specifically, TiC, TiCy (where y represents a positive real number other than 1;
Greater than or less than 1. And stoichiometric compounds and non-stoichiometric compounds represented by the formula (1), or compounds in which other elements such as oxygen are bonded, substituted or invaded. Among them, usually, TiC
Is particularly preferably used.

The tantalum carbide is not particularly limited, and those used for producing ordinary alloys can be used. More specifically, TaC, TaCz (where z represents a positive real number other than 1;
Greater than or less than 1. And stoichiometric compounds and non-stoichiometric compounds represented by the formula (1), or compounds in which other elements such as oxygen are bonded, substituted or invaded. Among these, usually, TaC
Is particularly preferably used. The cobalt is not particularly limited, but a simple metal can be suitably used.

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

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

As specific examples, 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., containing Co and / or Ni as a sintering aid, and Cr, Mo, Fe, etc. in addition to Co and / or Ni. And the like.

If the cermet is expressed differently from the above, the following description is also possible. That is, cermets that can be used in the present invention include Ti
WC, TaC or TiN is added to C, and Ni is used as a binder phase.
And 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 and the like. These may contain other elements or their carbides.

Of these, cermets based on titanium carbide, tungsten carbide and titanium nitride are preferably used. Particularly preferred are TiC, TiN, T
A cermet material using Ni, Co or Mo as a sintering aid in iCN or the like can be given. In addition, the said base material can also use what is marketed. When a non-commercially available material is used, the base material can be obtained by a method such as sintering after blending the above components in an appropriate ratio.

In addition, prior to sintering,
If necessary, an auxiliary binder mainly containing paraffin, stearic acid, camphor and the like 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. Usually, fine particles or ultrafine particles having a particle size of about 0.05 to 4 μm, preferably about 1 to 3 μm, or whisker particles having an aspect ratio of about 20 to 200 can be suitably used.

The sintering temperature is usually from 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,
Suitably, it is in the range of 550 ° C. The sintering time is
Usually, it is appropriate to set the time to 0.5 hours or more, preferably to 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 sintered after being formed into a desired shape at the time of sintering, 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 step, the surface of the base material is etched. Examples of the method of etching the surface of the base material include wet etching and dry etching. Examples of the wet etching include an etching treatment with an 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. Also, the acid
One kind may be used alone, or two or more kinds may be used in combination. 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.

Hereinafter, as an example of the etching treatment with an acid, a case where a mixed acid of nitric acid and hydrofluoric acid or a mixed acid obtained from hydrogen fluoride and nitric acid is used will be described in detail. However, the etching treatment with an acid in the present invention is not limited to this. When preparing a mixed acid obtained from hydrogen fluoride and nitric acid, hydrogen fluoride itself can be used, or hydrofluoric acid which is an aqueous solution of hydrogen fluoride can be used. Can also.

When the 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 to 40 mol%
It is. The nitric acid concentration in this mixture is
Usually, it is 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, a coating layer can be formed with good adhesion on the base material layer treated with such a mixed acid.

In order to contain hydrogen fluoride in the above range, when using hydrofluoric acid, 1
Hydrofluoric acid containing 0 to 50%, preferably 20 to 46% hydrogen fluoride is preferred. Also, as nitric acid,
Nitric acid with a concentration of 30-70%, especially 30-61%, is preferred. From a practical point of view, the mixed acid obtained from hydrogen fluoride and nitric acid is preferably a mixture substantially consisting of hydrofluoric acid and nitric acid, and if necessary, mixed with another inorganic acid such as sulfuric acid. It is also possible to use mixtures consisting of When a mixture substantially consisting of hydrofluoric acid and nitric acid is used, it is preferable to adjust the concentrations of hydrofluoric acid and nitric acid such that the contents of hydrogen fluoride and nitric acid are as described above.

As the etching treatment with the acid in the present invention, various methods such as a method of dipping the substrate in the acid and a method of spraying the acid on the surface of the substrate can be employed. In short, all that is required is that a predetermined surface of the substrate on which the intermediate layer is to be provided can be brought into contact with the acid.

The temperature of the etching treatment with the acid is not particularly limited. For example, when the mixed acid is used, the temperature is preferably 20 to 100 ° C., and particularly preferably 50 to 9 ° C.
5 ° C. is preferred. If the processing temperature is lower than 20 ° C,
Since etching takes time, Co and the like may not be sufficiently etched. If the processing temperature is higher than 100 ° C., the controllability deteriorates because the etching of the surface of the base material progresses violently.

The time of the etching treatment with the acid is not particularly limited, as long as the etching is sufficiently performed.
Seconds to 300 seconds are preferable, and 1 second to 120 seconds are particularly preferable. If the processing time is shorter than 0.5 seconds, the etching process may be insufficient. On the other hand, when the time is longer than 300 seconds, the etching process may proceed too much and the strength of the substrate may be reduced.

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

When preparing a solution containing hydrogen fluoride, sulfuric acid, and alcohol, hydrogen fluoride itself can be used, or hydrofluoric acid, which is an aqueous solution of hydrogen fluoride, can be used. It can also be used in form. From a practical point of view, the solution containing hydrogen fluoride, sulfuric acid and alcohol is preferably a mixture of alcohol, hydrofluoric acid and sulfuric acid, and if necessary, another inorganic acid such as nitric acid. , Hydrochloric acid and the like can also be mixed.

Hereinafter, as an example of the electrolytic etching, a case where the electrolytic solution is a solution containing hydrogen fluoride, sulfuric acid and alcohol will be described in detail. 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 composed of hydrogen fluoride, sulfuric acid and alcohol using substantially hydrofluoric acid, prepare hydrofluoric acid such that the concentration of hydrogen fluoride after mixing is within the above-mentioned concentration range. Good to use. The concentration of sulfuric acid in the solution comprising 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 the object of the present invention is not impaired, and examples thereof include methanol, ethanol, propanol and butanol. Among them, methanol is particularly preferred. In this case, in a solution comprising the hydrogen fluoride, sulfuric acid, and alcohol, a counter electrode is provided so that the base is a positive electrode, and the counter electrode is a negative electrode. 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 during electrolytic etching, for example, a gas.
Stainless steel and the like can be mentioned. The voltage in the electrolytic etching is usually preferably 3 to 10 V, particularly,
4-10V is preferred. When the voltage is lower than 3 V, the etching speed is slow and inefficient. On the other hand, when the voltage is higher than 10 V, the etching speed becomes too fast, the controllability is poor, and the etching may be performed more than necessary.

The current in the electrolytic etching preferably has a current per unit area of 0.01 to 5 A / cm ² , particularly preferably 0.1 to 1 A / cm ² . If the current per unit area is smaller than 0.01 A / cm ² , the etching is not sufficiently performed. On the other hand, if the current per unit area is larger than 5 A / cm ² , the etching may proceed too much, resulting in a decrease in the strength of the substrate.

The processing time in the electrolytic etching is as follows:
Although it cannot be unconditionally determined by the shape of the base material and the magnitude of the current, it is usually preferably 0.1 to 60 minutes, and particularly preferably 1 to 30 minutes. Examples of the dry etching include an etching process using plasma.

In the etching treatment using the plasma, 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, Plasma such as a mixture of the above. Among them, argon, hydrogen gas and oxygen gas are particularly preferable.

There is no particular limitation on the method of forming a plasma, and a plasma processing method by various methods such as a plasma method used in a general vapor phase synthesis method of diamond or a diamond film can be applied. Specifically, for example, microwave plasma CVD, high-frequency plasma C
Examples of the method include a VD method, a hot filament method, an ECR method, and a combination method thereof. Among these, a microwave plasma CVD method, a high frequency plasma CVD method and the like are particularly preferable. In addition, it is convenient from the viewpoint of the apparatus configuration if the same CVD method as used in the vapor phase synthesis of diamond described later is used.

The reaction conditions in the case of performing the etching process by using plasma can be the same as the conventional conditions. For example, the processing pressure is 10 to 100
It is preferably within the range of torr. When the pressure is higher than the above range, the controllability of the processing is poor, and when the pressure is lower, the processing takes time. The temperature of the surface of the intermediate layer is 500 to 1,10
The temperature is in the range of 0 ° C, preferably 700 to 900 ° C. If the temperature is higher than the above range, the controllability of the process is poor and reproducibility is poor, and if the temperature is low, the process takes time. The processing time is 1 minute to 200 minutes, preferably 60 minutes.

In the present invention, by performing the above-described etching treatment, a metal such as cobalt, which causes a harmful binder phase when a diamond film is formed on a substrate, is removed. Irregularities and pores occur in the surface. As a result, the adhesiveness between the base material and the intermediate layer is improved, and further, an intermediate layer described later is formed in accordance with the shape of the irregularities and pores, and is generated during the synthesis of a diamond film by a gas phase method described later. The diamond film enters the unevenness and pores on the surface of the intermediate layer, and a diamond film having excellent adhesion to the base material can be synthesized.

(2) Step of Forming Coating Layer on Base Material Surface (Coating Layer Forming Step) In this coating layer forming step, groups IVA and VA of the periodic table are used.
Selected from metals belonging to Group VIA and Group VIA and Si
Metals of the Periodic Table IVA, VA and
And VIA metals and Si nitrides and carbonitrides
At least one metallization selected from the group consisting of
At least one selected from the group consisting of
Is formed on the surface of the substrate.

Among these materials for forming the coating layer, more preferred are titanium metal, titanium nitride and titanium carbonitride, and also tantalum metal, tantalum nitride and tantalum carbonitride. These may be used singly or may be used with two or more kinds of various compositions.

As the titanium nitride, for example, Ti
N, or those represented by TiNx, TiN-Ti, Ti-N, and the like . Said
The charcoal titanium nitride, for example, TiCN, TiC ·
TiN, TiCX.TiNx, TiC.TiN-C,
TiC / TiN-Ti, TiC / TiN-Ti-C, T
One represented by i-N-C or the like can be given.

That is, the titanium-containing coating layer is usually preferably represented by Ti, TiN or TiCN, but may be composed of two or more of these. More than two types, Ti
And / or the N component may be excessively contained. The titanium-containing coating layer may contain other elements or components other than Ti and N as long as the object of the present invention is not impaired .

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

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

It is presumed that the reason why the adhesion of the coating layer to the substrate is improved is that a part of the metal or compound constituting the coating layer is impregnated or permeated into the substrate by this heat treatment. Is 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 when heat treatment is performed, chemical bonding due to impregnation of the base material with the deposited metal or compound does not occur, and sufficient adhesion is not exhibited. On the other hand, at a high temperature exceeding 1,500 ° C., a heat treatment at such a high temperature causes a disadvantage that the base material is deformed.

As an atmosphere for the heat treatment, an inert gas such as argon, helium, or nitrogen gas is preferable. The pressure during the heat treatment is appropriately selected from the range of 5 torr to 3,000 atm. These atmospheric gases and pressures are
It is appropriately determined according to the components of the coating layer. For example,
When the metal species is titanium, the heating temperature is 1,200.
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 /
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 substrate surface by etching, the coating layer bonded to the substrate surface 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, and the diamond thin film formed thereon has an anchor effect, thereby improving the adhesion between the substrate and the diamond. In addition, a chemical bond (carbide) is generated between the diamond thin film and the metal remaining without being impregnated, which can also be expected to improve the adhesion. Note that fine irregularities and fine pores are formed on the surface of the base material even by the heat treatment, so that an effect similar to the above case can be expected even when the etching treatment is not performed.

Further, this coating layer can prevent the active metal such as Co from precipitating from the inside of the substrate onto the surface of the substrate when the substrate is heated during the subsequent synthesis of diamond. Also, improvement in the adhesion of the diamond thin film can be expected. The intermediate layer formed by performing such a heat treatment may be further subjected to a normal scratching treatment using diamond abrasive grains or the like, if necessary.

(4) Step of Forming Diamond Layer (Step of Forming Diamond Layer) In the present invention, a thin layer of diamonds is coated on the surface of the intermediate layer heat-treated as described above. The diamonds 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. In the method of the present invention, as shown below, a gas phase synthesis using a carbon source gas is used. The method can be suitably 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; acetylenic hydrocarbons such as acetylene and allylene; butadiene; Diolefinic hydrocarbons such as allenes; cyclopropane, cyclobutane, cyclopentane,
Alicyclic hydrocarbons such as cyclohexane; aromatic hydrocarbons such as cyclobutadiene, benzene, toluene, xylene and naphthalene; ketones such as acetone, diethyl ketone and benzophenone; alcohols such as methanol and ethanol; Hydrocarbons; amines such as trimethylamine and triethylamine; other nitrogen-containing hydrocarbons; carbon dioxide, carbon monoxide, carbon peroxide and the like. Further, the above various compounds can be used as a mixture.

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; It is carbon oxide, and carbon monoxide is particularly preferable.

These may be used alone.
Two or more kinds may be used in combination as a mixed gas or the like. These may be mixed with an active gas such as hydrogen or an inert gas such as helium, argon, neon, xenon, or nitrogen.

The thin layer of diamonds is formed by a known method, for example, a CVD method, a PVD method, a PCVD method,
Alternatively, various diamond thin layer gas phase synthesis methods, such as a method combining these, can be used, and among these, generally, various hot filament methods including the EACVD method, and various types of the hot plasma method including the thermal plasma method can be used. DC plasma CV
Microwave plasma CVD including D method and thermal plasma method
Method or the like can be suitably used.

The conditions for forming the diamond thin layer are not particularly limited, and the reaction conditions usually used in the above-mentioned 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 further effect compared to the effect obtained at the time.

The surface temperature of the base material cannot be specified unconditionally because it varies depending 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 be 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 the diamond are likely to occur.

The reaction time is not particularly limited, and it is preferable to appropriately set the reaction time according to the forming speed of the diamond thin layer so that the diamond thin layer has a desired thickness. The thickness of the thin layer of diamonds formed on the surface of the base material cannot be uniformly determined because it varies depending on the purpose of use of the diamond-coated member, but in the case of a tool, it is usually 5 μm or more, preferably 10 to 10 μm. 50 μm
The above is appropriate. If the diamond thin layer is too thin, the surface of the substrate may not be sufficiently covered. In this way, when a diamond thin 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, whereby the metal of the intermediate layer is carbonized, and then diamond is generated. 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,
Diamond coated members can be manufactured.

[0070]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Example 1 A base material was composed of 92% by volume of silicon nitride (Si ₃ N ₄ ), 5% by volume of titanium nitride (TiN), and yttrium oxide (Y ₂ O) as a sintering aid. ₃ ) A 3% by volume ceramic substrate was used, and the shape thereof was a throw-away chip of SPGN120308 (hereinafter referred to as a substrate A).

On the surface of this base material, silicon was applied with a film thickness of 1,
After vapor deposition at 2,000 ° C., a heat treatment was performed at 1,450 ° C. for 15 minutes at 2,000 atm under an argon atmosphere. The metal-deposited surface of the substrate was scratched with diamond abrasive grains having an average particle size of about 10 μm.

Next, the heat-treated substrate is 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 is supplied to the reaction tube. It was distributed. After that, the frequency 2.4
A 5 GHz microwave was introduced to form diamond by a 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 diamond film having a thickness of 12 μm was formed on the surface of the substrate. With respect to the obtained thin-layered member of diamonds, the adhesion between the diamond film and the surface of the substrate was evaluated by an indentation method.

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

In the embodiment of the present application, the sample is a thin-layered member made of diamonds, so that a pyramid-shaped indenter is pressed into the substrate with an appropriate load to deform the substrate, and the portion where the substrate is raised from the original state is observed. I 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 This increases the area of the part that is peeled off from the substrate. Therefore, by measuring the size of the area of the peeled diamond thin layer, it is possible to evaluate whether the adhesion between the substrate and the diamond thin layer formed on the surface is good or bad.

In the examples of the present application, the measurement conditions were as follows: 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 determined. The magnitude of the adhesion was evaluated. Table 1 shows the results. 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 procedures as in Example 1 were carried out except that the kind of metal to be deposited and the heat treatment conditions were changed as shown in Table 1. Table 1 shows the results.

(Example 9) As a substrate, a ceramic substrate 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 ) as a sintering aid was used. , And the same operation as in Example 1 was performed, except that a throw-away tip having a shape of SPGN120308 (hereinafter, referred to as a base material B) was used. Table 1 shows the results.

(Examples 10 to 15) The same procedures as in Example 9 were carried out except that the metal species to be deposited and the heat treatment conditions were changed as shown in Table 1. Table 1 shows the results.

(Examples 16 to 23) As a base material, a cemented carbide whose composition was 91.8% by weight of tungsten carbide, 2.9% by weight of titanium carbide, and 4.9% by weight of cobalt was used. The procedure was performed in the same manner as in Example 1 except that a throw-away tip (hereinafter, referred to as a base material C) of SPGN120308 was used. Table 2 shows the results
Shown in

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

(Examples 24 to 31 ) As the base material, a cutting tool chip having a size 1 as shown in Table 3 was used.
A cemented carbide of 2.7 mm square was used, and its surface was etched by the method shown in Table 3. Regarding the etching process in Table 3, the method indicated as “HF + NHO ₃ ”
The sample was immersed 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.
l) ", " Electrolysis (H ₂ So ₄ ) "
HCl and H ₂ So _{4 are} both 10% aqueous solutions
A mixed solution of 00 ml and 25 ml of H ₂ O _{2 was} used as an electrolyte, the voltage was 3 V , and the electrolysis time was 5 seconds. Also, "N ₂
In the display the way as plasma ", frequency 2.45G H
z, output 400 W, processing time 1 hour. The intermediate layer was deposited by the method shown in Table 3 and heat-treated under the conditions shown in Table 3.
K10, P10, M10, K2 of the item of “ base material ” in Table 3
0 is based on JIS B 4053, and details thereof are as follows.

K10 WC-Co type (W: 87% by weight, Co: 6% by weight, Ta: 1% by weight, C: 6% by weight) K20 WC-Co type (W: 86% by weight, Co: 7% by weight) , Nb: 1% by weight, C: 6% by weight) P10 WC-TiC-TaC-Co system (W: 50% by weight, Ti: 23% by weight, Ta: 17% by weight, Co: 9)
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-like thin layer was formed on the surface of the substrate under the same conditions as in Example 1 except that the reaction time was changed to 10 hours to obtain each diamond-coated member. The thickness was 25 μm. Next, with respect to the obtained diamond-coated member, the adhesion between the diamond thin layer and the substrate was evaluated by an indentation method under the same conditions as in Example 1. Table 3 shows the results.

[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 for cutting tools, carbide tools, wear-resistant tools, etc., high performance can be obtained. And a long-life diamond-coated member that can exhibit durability.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 14/00-16/56 C30B 29/04

Claims (2)

(57) [Claims] 1. Group IVA, VA and V of the Periodic Table
At least the one metal selected from the metals and Si belonging to Group IA, Group IVA of the periodic table is selected from nitride and the group consisting of carbonitrides of Group VA and metals as well as Si belonging to Group VIA a step of at least one consisting of a coating layer formed on the substrate surface is selected from the group consisting of a kind of metal compound, a base material having a coating layer, 70
A method for producing a diamond-coated member, comprising: a step of treating at 0 to 1,500 ° C .; and a step of forming a diamond thin film on the coating layer after the heat treatment by a vapor phase method. 2. A process for the substrate surface is etched, periodic table Group IVA, and one metal selected from the metals and Si belonging to Group VA and Group VIA of the periodic table Group IVA, the at least one consisting of the coating layer is selected from the group consisting of at least one metal compound selected from group VA and nitrides of metals and Si belonging to group VIA and the group consisting of carbonitrides, after the etching treatment Step of molding on the surface of the substrate,
A step of heat treatment at 00~1,500 ℃, and method for producing the diamond coating member characterized by comprising the step of forming a diamond film by a vapor phase method on the coating layer after the heat treatment.