JPH07148623A - Diamond coating method and diamond coating tool - Google Patents

Abstract

PURPOSE:To increase adhesivity between a cemented caribide base substrate and a diamond film by forming an intermetallic compound in a space from a base substrate composed of a bond phase and a dispersion phase toward its inner side, and forming a diamond film by a vapor-phase synthesizing method thereafter. CONSTITUTION:In order to coat diamonds over the surface of a base substrate 1, the base substrate 1 is so constituted as to contain a dispersion phase including at least one kind from the group consisting of carbide and nitride of a IVa, a Va and a VI family metal in the periodic table, and of mutual solid solution of these materials, and contain a bond phase including at least one kind from the group consisting of Co, Ni, Fe and Cr. Next, an intermetallic compound 4 including bond phase elements is formed over the surface layer section of the base substrate 1 by immersing the base substrate 1 in solution containing elements which form the aforesaid bond elements and intermetallic compounds out of a III, a V and a VI family metal, and a diamond film 3 is coated thereon by a vapor-phase synthesizing method thereafter. Boron is used as an element forming bond phase elements and intermetallic compounds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for coating a diamond film and a diamond coating tool manufactured by using the method.

[0002]

2. Description of the Related Art Diamond has a high hardness and has a characteristic that it hardly reacts with soft metals such as Group IB, IIB and IIIB metals of the Periodic Table and alloys thereof. The powdered diamond thus obtained is widely put to practical use as a tool for cutting the above soft metal at high speed.

By the way, in recent years, a technique has been developed in which hydrogen gas is mixed with an organic compound gas containing hydrocarbon, oxygen, nitrogen, etc., and this is excited into plasma or the like to deposit diamond on the surface of a substrate such as metal. (Hereinafter referred to as "gas phase synthesis method"). A diamond-coated tool in which the surface of the tool substrate is coated with diamond using this technology is expected to be put to practical use as an inexpensive diamond tool that replaces the conventional tools using expensive single crystals of diamond or sintered bodies. .

Many attempts have been made to produce diamond coating tools by utilizing this vapor phase synthesis method. As a substrate for coating diamond, (1) cemented carbide (JP-A-61-242996) (2) ceramics (JP-A-57-95881) (3) cermet (JP-A-61-52363) Gazette) etc. are used.

Techniques for treating these coated surfaces include polishing with diamond abrasive grains or a whetstone (Japanese Patent Laid-Open No. Sho 60).
-86096), and vibrating diamond abrasive grains using ultrasonic waves (Japanese Patent Laid-Open No. 62-67174).
Then, the surface of the substrate is scratched.

When cemented carbide, cermet or the like is used as a base, amorphous carbon is formed on a metal such as iron group (for example, Fe, Ni, Co, Cr) which is the binding phase of the hard dispersed phase of each base. Are deposited, and it is difficult to deposit crystalline diamond. Therefore, elements such as the iron group on the surface layer of the substrate are removed by etching with an acid or the like (Japanese Patent Laid-Open No. 63-100182).

When the substrate is a cemented carbide, a base material dedicated to diamond coating having a low Co content is used (Japanese Patent Laid-Open No. 62-57804), or an intermediate layer is provided between the substrate and the diamond layer. Installation (Japanese Patent Laid-Open No. 58-1
26972).

The biggest problem in coating a cemented carbide substrate with diamond and using it as a cutting tool is the adhesion between the substrate and the diamond film. The following various proposals have been made for this problem as well.

In Japanese Patent Laid-Open No. 5-65646, an intermetallic compound is contained in a binder phase in a surface layer of 100 μm or less from the surface of a substrate to the inside, and then a coating film of diamond and / or diamond-like carbon is formed. A technique for manufacturing a diamond-coated cutting tool is disclosed. The inclusion of the intermetallic compound in the binder phase in the surface layer of the substrate suppresses the generation of graphite in the early stage of film formation by the intermetallic compound, densely nucleates diamond nuclei, and enhances the adhesion between the substrate and the diamond film. This is because. In this case, the following two manufacturing methods (A) and (B) are presented as specific manufacturing methods.

Manufacturing method (A) The surface of a WC-Co type cemented carbide substrate is coated with Al by a sputtering method. After that, the substrate is heated in vacuum at 1400 ° C. to contain a CoAl intermetallic compound phase in the surface layer of the substrate, and the surface thereof is coated with a diamond film by a microwave plasma CVD method.

Production Method (B) Powder of intermetallic compound (or powder containing precursor of intermetallic compound), hard phase forming powder constituting a cemented carbide substrate, and powder binding hard phase forming powder. Sinter the green compact consisting of. At the time of this sintering, the intermetallic compound is contained in the surface layer of the substrate by diffusion. Then, a diamond film is formed by the vapor phase method.

Further, Japanese Patent Laid-Open No. 2-101167 discloses a technique using a microwave plasma CVD method. That is, a WC-Co based cemented carbide substrate is installed in the reaction chamber, the pressure in the reaction chamber is 40 Torr, and the substrate temperature is 9 Torr.
Under the condition of 00 ° C. and in the presence of a volatile boron compound, microwave plasma CVD is performed for 20 minutes to form an intermetallic compound of Co and boron on the diamond film formation surface. After that, the surface is coated with a diamond film by a microwave plasma CVD method.

[0013]

However, in the above-mentioned conventional technique (Japanese Patent Laid-Open No. 63-100182), the interface layer becomes brittle because elements such as the iron group, which is the binding layer, are removed from the surface layer. However, since the adhesive strength between the substrate and the diamond coating film is not sufficient, there is a drawback that the diamond film peels off during cutting when a light alloy such as an Al-Si alloy is cut. Therefore, there is a problem that the tool life is short and it cannot be used for a wide range of practical applications.

Further, in the production method (A) of JP-A-5-65646, the Al coating thickness cannot be uniformly coated when the substrate has a complicated shape or a three-dimensional curved surface. Therefore, the intermetallic compound layer cannot be contained at a uniform depth from the surface of the substrate to the inside, and the strength and hardness of the substrate surface vary depending on the position. As a result, there is a problem that internal strain is likely to occur and the diamond film is easily peeled off. Further, in the present manufacturing method, an expensive sputtering device is used in the previous step for containing the intermetallic compound in the surface layer of the substrate. Furthermore, the steps of coating Al, performing a heat treatment for forming an intermetallic compound, and coating a diamond film are required, which causes a problem that the manufacturing process is long and the manufacturing cost is high.

According to the production method (B) of JP-A-5-65646, it is extremely difficult to incorporate the intermetallic compound from the surface of the substrate toward the inside with an accuracy of the μm unit. Physical and physical properties are different. Therefore, internal distortion is likely to occur,
There is a problem that the diamond film is easily peeled off.

In JP-A-2-101167, since the reaction pressure is as small as 40 Torr and the treatment time is as short as 20 minutes, the amount of the intermetallic compound of Co and boron formed in the surface layer of the substrate is small, and the compound is bonded to the surface layer of the substrate. A large amount of metallic Co in the phase remains. For this reason, it was not possible to suppress the generation of graphite in the initial stage of diamond coating formation, and it was not possible to sufficiently enhance the adhesion between the substrate and the diamond coating. Therefore, there is a problem that the tool life is short and the tool cannot be widely used. For example, when a light alloy such as an Al-Si alloy is cut at a high speed, the diamond film may be separated from the surface layer of the substrate during cutting. In addition, there is a problem that the manufacturing cost becomes high because a CVD apparatus having high equipment cost is used.

It is an object of the present invention to provide a diamond coating method with improved adhesion to a substrate.

An object of the present invention is to improve the adhesion between a cemented carbide substrate and a diamond coating, to cut a light alloy such as an Al-Si alloy at high speed, and to provide a long-life diamond-coated cutting tool and a method for producing the same. To provide.

[0019]

The present inventors have conducted various studies on methods for forming an intermetallic compound containing a binder phase element in the binder phase in the surface layer of a cemented carbide substrate. The present invention has been made as a result.

The outline of the present invention will be described with reference to FIG.

A substrate 1 composed of a binder phase and a dispersed phase (see FIG. 1)
The intermetallic compound 4 is formed from the surface (see (a)) toward the inside (see FIG. 1B). Then, after that, the diamond film 3 is formed by the vapor phase synthesis method.

The details will be described below.

The cemented carbide substrate of the diamond-coated cutting tool of the present invention includes the IVa, Va, and
A dispersed phase containing at least one kind of a group consisting of carbides and nitrides of VIa group metals and their mutual solid solutions, and at least one kind of a group consisting of Co, Ni, Fe and Cr. A binder phase and one consisting of are used.

The elements forming the intermetallic compound with the binder phase elements (Co, Ni, Fe, Cr) are III and I in the periodic table.
V, V, VI group elements such as In, Sb, Sn, V,
Zr, W, Ta, B, etc. are raised.

CoIn ₂ , CoIn, Co ₃ In ₂ , and CoS are intermetallic compounds of the above-mentioned binder phase element and boron element.
b ₃ , CoSb ₂ , CoSb, CoSn, CoV, CoV
₃ , Co ₃ V, Co ₃ W, Co ₇ W ₆ , Co ₂ Ta, Ni ₈ T
a, Ni ₃ Ta, Ni ₂ Ta, NiTa, NiTa, Ni
V ₃ , Ni ₂ V, Ni ₃ V, Ni ₄ W, NiZr, NiZr
₂ , FeW, FeZr ₂ , CrSb, Cr ₂ Ta, ZrC
r ₂ , CoB, Co ₂ B, Co ₃ B, CoB ₂ , NiB, N
i ₂ B, Ni ₃ B, Ni ₄ B ₃ , CrB, Cr ₂ B, Cr ₅ B
_{3, CrB, Cr 3 B 4} , CrB 2, Fe 2 B, FeB , and the like. Among these, especially CoB, Co ₂ B, Co ₃
B, CoB ₂ , NiB, Ni ₂ B, Ni ₃ B, Ni ₄ B ₃ ,
CrB, Cr ₂ B, Cr ₅ B ₃ , CrB, Cr ₃ B ₄ , Cr
B ₂ , Fe ₂ B, and FeB are preferable from the viewpoints of heat resistance, wear resistance, and uniformity of the diamond film that can be formed. In FIG. 1, it is drawn as if the intermetallic compound 4 is formed on the entire surface of the substrate 1. However, when viewed strictly for each extremely small area, the intermetallic compound is formed only in the portion where the binder phase element is present.

The melting point or decomposition temperature of the intermetallic compound formed is preferably as high as possible in view of the purpose of use as a tool. This is because, for example, when cutting a light alloy such as Al-Si at high speed, the cutting resistance is large and a large amount of heat is generated, so that the temperature of the diamond-coated cutting tool also rises considerably. If the melting point or the like is lower than the temperature at the time of processing, the intermetallic compound is decomposed or melted and the diamond film is peeled off, so that the tool life is shortened. For reference, melting points of the binder phase element, dispersed phase element, various intermetallic compounds, etc. are shown in Table 1.

[0027]

[Table 1]

The hardness of the intermetallic compound formed is preferably the same as or higher than the hardness of the binder phase elements (Co, Ni, Fe, Cr in the present invention). More specifically, for example, Vickers hardness of 1000 to 30
It may be 00HV. This is because the cutting proceeds in the state where a strong compressive stress acts between the work and the diamond-coated cutting tool. The compressive stress becomes particularly strong when cutting a hard light alloy such as Al-Si. If the hardness of the intermetallic compound is lower than that of Co or the like, the intermetallic compound of the binder phase is distorted and the diamond film is peeled off, resulting in a shorter tool life. For reference, hardnesses of the binder phase element, the dispersed phase element, various intermetallic compounds, etc. are shown in Tables 2 and 3. Also, in Table 3,
The hardness of a substrate (WC + Co) formed by applying the present invention to the surface layer of an intermetallic compound containing boron and a substrate (WC + Co) not provided with the intermetallic compound are also shown.

[0029]

[Table 2]

[0030]

[Table 3]

The distribution of the intermetallic compound in the depth direction preferably has a so-called gradient composition.
Since there is a large difference in strength and hardness between the inside of the substrate and the surface layer, internal strain occurs unless the composition is graded. As a result, even if the adhesion of the diamond film can be improved, the diamond film is likely to peel off from the surface layer of the substrate containing the intermetallic compound during the cutting work.

If the thickness of the intermetallic compound layer is too thin, the effect of suppressing the precipitation of graphite in the initial stage of diamond coating formation is small, and the adhesion between the substrate and the coating cannot be improved. On the other hand, if it is too thick, the heat generated during the cutting operation causes a large thermal strain between the inside of the substrate and the surface layer, and the surface layer of the substrate containing the intermetallic compound peels off. It will be easier. In addition, it takes a long time to manufacture a thick layer, and a diamond-coated cutting tool cannot be manufactured at low cost. From these viewpoints, it seems that the thickness of the intermetallic compound phase exceeds 1 mm.

Next, four methods of the present invention for incorporating an intermetallic compound in the surface layer of the substrate will be described. Here, description will be given taking boron as an example.

[Method 1] Metallic boron (or
It is embedded in a mixed powder of a boron compound), a boron supply regulator, and a boride formation accelerator, and heated at 700 to 1400 ° C. The boron compound used in this case is B ₄ C,
Ferroboron is preferred. It should be noted that the boron compound does not have to be of one type, and may contain a plurality of types of boron compounds. Further, both metallic boron and a boron compound may be contained. As the boron supply regulator, a material having a high melting point and not participating in the reaction (for example, silicon carbide or aluminum oxide) is preferable. Boron supply regulator
This is for adjusting (in this case, suppressing) the diffusion rate of boron. Examples of the boride formation promoter include chloride (eg, NaCl, KCl, NH ₄ Cl), carbonate (eg, Na ₂ CO ₃ ), fluoride (eg, BaF ₂ , BF,
NaBF, KBF ₄ , (NH ₄ ) BF ₄ ) and the like are raised.

[Method 2] As another method for producing an intermetallic compound, a method of immersing in a mixed melt of at least one type of boron compound and a boride formation accelerator may be used. The boron compound used in this case is Na ₂ B ₄ O ₇ · 10H ₂
O, Na ₂ B ₄ O ₇ , B ₂ O ₃ , HBO ₂ , B ₄ C, NaBF
Etc. are raised. Further, both metallic boron and a boron compound may be contained. In this case, the boride formation promoter may be a chloride (eg, NaCl, BaC).
l ₂ ), carbonate (eg, Na ₂ CO ₃ ), fluoride (eg, BaF ₂ , BF, NaBF, KBF ₄ , (NH ₄ ) B)
F ₄ ) etc. can be raised. In addition, also in this method 2,
From the same viewpoint as in Method 1, the mixed melt may contain a boron supply regulator.

By the methods 1 and 2 described above, a cemented carbide containing an intermetallic compound of a binder phase element and a boron element can be prepared in the surface layer portion of the substrate.

The above-mentioned graded composition and the like of the intermetallic compound can be realized by appropriately selecting the mixing ratio, the processing time, the processing temperature and the like in accordance with the materials and chemicals used.

Other intermetallic compounds with Group III, IV, and V elements can also be basically formed by the above [Method 1] and [Method 2]. However, it goes without saying that instead of the boride formation accelerator, a formation accelerator suitable for the relevant element is appropriately used. Depending on the element, it is possible to simply immerse it in the melt of the element (or bury it in powder and heat it) without using such a promoter.

[Method 3] III, IV, V on the surface of the substrate
An intermetallic compound can also be formed by implanting group element ions. In this case, as is well known, the implanted ions are not most abundant on the substrate surface, but are most abundant at a certain depth position determined by the energy at the time of implantation. . This is preferable for the purposes of the present invention. When the element is implanted into the substrate, the energy at the time of implantation is increased and the implantation time is shortened. On the contrary, when the implantation is performed on the surface of the substrate, the implantation energy is reduced and the implantation time is lengthened. As a result, the concentration of the implanted element can be graded. After the ion implantation, it is more preferable to perform heat treatment in a non-oxidizing atmosphere so that the implanted element can sufficiently react with the binder phase element.

[Method 4] Group III, IV and V elements are PV
It can also be formed by performing vapor deposition on the surface of the substrate by the D method and then performing heat treatment in a non-oxidizing atmosphere.

Next, a method for forming a diamond film will be described.

The diamond film (or diamond-like film) is formed by a vapor phase method, that is, by decomposing a mixed gas of hydrocarbon such as methane and hydrogen with plasma (or a hot filament, a photoexcited reaction, etc.). You can Plasma formation of mixed gas is performed by microwave,
Electromagnetic energy such as high frequency or direct current power can be used.

If the scratches due to diamond abrasive grains are formed on the surface of the substrate before the formation of the intermetallic compound, diamond is likely to be deposited. The diamond abrasive grains used preferably have a roughness of # 100 to # 1,200. Further, in order to obtain toughness suitable as a tool, the base body preferably contains 1 to 20% of a binder phase element (Fe, Ni, Co, Cr).

[0044]

[Function] Carbides and the like that constitute the dispersed phase (for example, WC)
The nucleation density of diamond is high on the top surface, and the diamond is easily deposited. However, the above bond phase element (C
o, Ni, Fe, Cr), the nucleation density of diamond is low, so at the initial stage of diamond film formation,
Graphite is easy to deposit and diamond is hard to deposit. Therefore, the dispersed phase containing the above-mentioned carbide and the like, and C
Even if the diamond film is directly coated on the surface of the substrate composed of the binder phase containing elements such as o, Ni, Fe, and Cr, a diamond film with high adhesion cannot be obtained. In the vapor phase synthesis method, a diamond nucleus grows considerably and then a film is formed only after the diamond nuclei coalesce. A void remains between the film and the film.

Therefore, the above-mentioned elements (Co, N
i, Fe, Cr), the present invention is applied to form a diamond film having high adhesion to the substrate by forming the above-mentioned intermetallic compound in which diamond is easily deposited on the substrate surface layer. Can be coated.

Further, by coating such a diamond having high adhesion, a cutting tool having a long life can be manufactured.

[0047]

The present invention will be specifically described below.

[Example 1] WC-Co cemented carbide substrate (C
(o: 6% by weight) after processing into a throw-away tip,
The cutting edge surface was rubbed with # 1,200 diamond abrasive grains to form scratch marks.

Next, the substrate is embedded in a mixed powder of B ₄ C, KBF ₄ (potassium boron fluoride) and SiC, and 9
It heat-processed at 00 degreeC for 2 hours, and cooled to room temperature after that. As a result, the CoB intermetallic compound was contained in the surface layer of the substrate.

The results of the analysis of the substrate on which the intermetallic compound is formed are shown in FIGS. 2, 3 and 4. Figure 2
It is a thin film X-ray diffraction pattern. From the analysis result, it can be seen that an intermetallic compound (CoB) is formed. Figure 3
Is the result of examining the distribution of boron in the depth direction from the surface. From this figure, it is found that boron (intermetallic compound Co
It was revealed that B) exists with a graded composition. FIG. 4 shows the results of examining the relationship between the depth from the surface and the hardness.

Next, the substrate prepared by the above-mentioned procedure is placed on the substrate support of a quartz glass plasma reaction vessel having an inner diameter of 50 mmφ and a length of 700 mm, and 98 vol% of hydrogen and 2 vol% of methane are mixed from the upper part of the reaction vessel. While supplying gas, microwave (2.45 GHz, 1.0
KW) is applied to generate plasma, and about 5
A diamond film having a thickness of μm was formed. The conditions for forming the diamond film are as follows: substrate temperature: 900 ° C., reactor pressure:
20 Torr, reaction time: 6 hours.

The diamond film was identified by thin film X-ray diffraction and Raman spectrum.

In order to evaluate the cutting performance of the produced diamond-coated cutting tool, a width of 100 mm and a length of 5
A milling cutting test was performed using a 00 mm Al-12% Si alloy. The test conditions are cutting speed: 700 (m /
min), feed: 0.2 (mm / blade), cut: 1.
It is 5 (mm). Further, for comparison, the same cutting performance test was performed on a tool produced under the same conditions as those of the examples except that no intermetallic compound was formed.

As a result of the test, in the tool to which the present invention is applied,
The diamond film was not peeled off even after cutting the work material for 30 passes, and the flank wear width was suppressed to 0.05 mm or less, and the initial cutting performance was maintained.

On the other hand, in the tool to which the present invention was not applied, the diamond film peeled off before the work material was cut for 30 passes, and the worn portion rapidly progressed to the tool life at the peeled portion. .

[Example 2] After processing a WC-Co cemented carbide substrate into a throw-away tip, the cutting edge surface is # 20.
Grinding scratches were made with a 0, # 1000 resin bond grindstone.
This was embedded in a borated mixed powder and heat-treated in the same manner as in Example 1 to contain a CoB intermetallic compound in the surface layer of the substrate. Further, a diamond film was formed on the surface of this substrate under the same conditions as in Example 1. And Example 1
Then, the cutting performance was evaluated by the same test method. As a result, similar to Example 1, the tool life was significantly extended.

[Embodiment 3] As in Embodiment 1, WC-Co
After processing the cemented carbide substrate into a throw-away tip, the cutting edge surface was scratched. This substrate was placed under B ₄ C and N at 900 ° C.
After dipping in a mixed melt of aCl and NaBF for 6 hours, it was cooled to room temperature. The boride treating agent adhering to the surface was removed, and a CoB intermetallic compound was contained in the surface layer of the substrate.
A diamond film was formed on the surface of this substrate under the same conditions as in Example 1, and the cutting performance was evaluated by the same test method as in Example 1. As a result, the tool life could be extended as in Example 1.

[Embodiment 4] As in Embodiment 1, WC-Co
After processing the cemented carbide substrate into a throw-away tip, the cutting edge surface was scratched.

Next, BF ₃ was used as a gas implantation ion source, the ion implantation pressure was 7.5 × 10 to ⁶ Torr, the ion implantation energy was 100 to 10 KeV, and the ion implantation amount was 5 × 10 ¹⁸ ions / cm ² above. Boron ions were implanted on the surface of the hard alloy substrate. Then, in vacuum, 700
The substrate surface layer was made to contain an intermetallic compound of CoB by performing a heat treatment for 2 hours under the condition of ° C. A diamond film was formed on the surface of this substrate under the same conditions as in Example 1 and the cutting performance was evaluated. As a result, the tool life could be extended as in Example 1.

[Example 5] WC-Co cemented carbide substrate (C
(o: 6% by weight) after processing into a throw-away tip,
Polish the cutting edge surface with # 1,200 diamond abrasive,
An abrasion mark was formed.

This substrate was immersed in a Sn melt held at 700 ° C. in an Ar gas atmosphere for 10 hours and cooled to room temperature. Sn that adheres to the surface is removed and WC is applied to the substrate surface layer.
And a CoSn-based intermetallic compound phase were formed.

This was placed on the substrate support of a quartz glass plasma reaction vessel having an inner diameter of 50 mmφ and a length of 700 mm, and 98 Vol% hydrogen + 2 Vo methane from the upper portion of the reaction vessel.
Microwave (2.45 GHz, 1.0 kW) was applied to the substrate while supplying 1% mixed gas to generate plasma, and a diamond film having a thickness of about 8 μm was formed on the substrate. The conditions for forming the diamond film are the substrate temperature:
900 ° C., pressure in reaction vessel: 20 Torr, reaction time:
10 hours.

The diamond film was identified by thin film X-ray diffraction and Raman spectrum. In order to evaluate the cutting performance of the manufactured diamond-coated tool, a width of 100
mm, length 500 mm, Al-12% Si alloy as a material to be cut, cutting speed: 700 (m / min), feed:
The milling cutting test was carried out under the conditions of 0.2 (mm / blade) and incision: 1.5 (mm).

For comparison, WC-Co cemented carbide (Co:
6 wt%) was processed into a throw-away tip, a diamond film was formed under the same conditions, and a cutting performance test was performed under the same conditions.

In the case of the diamond-coated tool according to the present invention, the diamond film is not peeled off even after cutting the work material for 30 passes, and the flank wear width is suppressed to 0.02 mm or less. I was holding. From this, the tool life was remarkably extended by coating diamond with Co, which is an intermetallic compound of Co and Sn, in the surface layer of the WC-Co cemented carbide throwaway tip.

On the other hand, in the case of the throw away tip coated with diamond without using Co as an intermetallic compound, the diamond film peels off before the work material is cut by 30 passes, and the abrasion is rapidly caused at the peeled portion. Progressed to the tool life.

[Embodiment 6] WC-Co as in Embodiment 5
After processing the cemented carbide substrate into a throw-away tip, the cutting edge surface was scratched. Next, SnC is used as the gas implantation ion source.
using l _4, ion implantation pressure 7.5 × 10 ~ ⁶ Tor
Under the conditions of r and an ion implantation amount of 5 × 10 ¹⁸ ions / cm ² , Sn ions were implanted into the cemented carbide substrate while the ion implantation energy was continuously reduced from 100 keV to 10 keV. After that, in an Ar gas atmosphere heat treatment furnace, 700
After heat treatment at 5 ° C. for 5 hours and cooling to room temperature, the substrate surface layer was made into a WC phase and a CoSn phase. Example 1 was applied to the surface of this substrate.
A diamond film was formed under the same conditions as above, and the cutting performance was evaluated. As a result, the tool life could be extended as in Example 1.

[Embodiment 7] WC-Co as in Embodiment 5
After processing the cemented carbide substrate into a throw-away tip, the cutting edge surface was scratched. Next, after depositing the metal V on the surface of the substrate by using a normal thin film forming apparatus, the substrate surface layer was heat-treated at 900 ° C. for 5 hours in an Ar gas atmosphere heat treatment furnace. _{A 3} V intermetallic compound phase was used.
A diamond film was formed on the surface of this substrate under the same conditions as in Example 1 and the cutting performance was evaluated. As a result, the tool life could be extended as in Example 1.

[0069]

According to the present invention, it is possible to coat a diamond film having a significantly improved adhesion strength between the diamond film and the substrate. Therefore, the diamond-coated cutting tool to which the present invention is applied can cut a light alloy such as an Al-Si alloy at high speed.

[Brief description of drawings]

FIG. 1 is a schematic view showing a manufacturing process of a diamond coating tool of the present invention.

FIG. 2 is a thin film X-ray diffraction pattern after a boriding treatment.

FIG. 3 is a measurement result of a distribution state of boron.

FIG. 4 is a hardness distribution of a cross section of a substrate that has been borated.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base | substrate (for example, WC-Co) 2 ... Interface 3 ... Diamond film 4 ... Intermetallic compound containing layer in a base | substrate surface layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location C30B 29/04 A 8216-4G (72) Inventor Yasuhiko Shima 4-1-1 Toyo, Koto-ku, Tokyo No. Toyo Central Building, 4th floor, within Hitachi Tool Co., Ltd. (72) Inventor, Megumi Eto 4-1-1 Toyo Central Building, Koto-ku, Tokyo Toyo Central Building, 4th floor Within Hitachi Tool Co., Ltd.

Claims (11)

[Claims] 1. A method for coating the surface of a substrate with diamond, wherein the substrate is at least one of the group consisting of carbides, nitrides of Group IVa, Va, and VIa metals of the Periodic Table and their mutual solid solutions. Disperse phase containing seeds, Co, N
and a binder phase containing at least one member selected from the group consisting of i, Fe and Cr (hereinafter, the elements contained in the binder phase are referred to as "bond phase elements"), III, IV Of the group V, V, and VI elements by immersing the substrate in a melt containing the binder phase element and an element that forms an intermetallic compound, so that the surface layer of the substrate contains the binder phase element. A method for coating diamond, comprising forming an intermetallic compound and then coating the surface of the substrate with a diamond film by a vapor phase synthesis method. 2. A method for coating the surface of a substrate with diamond, wherein the substrate is at least one of the group consisting of carbides, nitrides of Group IVa, Va, and VIa metals of the Periodic Table and their mutual solid solutions. Disperse phase containing seeds, Co, N
and a binder phase containing at least one member selected from the group consisting of i, Fe and Cr (hereinafter, the elements contained in the binder phase are referred to as "bond phase elements"), III, IV , V, and VI group elements are filled with the binder phase element and an element that forms an intermetallic compound, and the substrate is embedded in the powder and heated to form the surface layer portion of the substrate containing the binder phase element. Forming a intermetallic compound, and then coating the surface of the substrate with a diamond film by a vapor phase synthesis method. 3. The bonding phase element and the element that forms an intermetallic compound are boron, and the treatment temperature when the powder is embedded in the powder and heated is 700 to 1
It is 400 degreeC, The coating method of the diamond of Claim 3 characterized by the above-mentioned. 4. The diamond coating method according to claim 1, wherein the powder or melt further contains a boride formation promoter that promotes the formation of the intermetallic compound. 5. The boride formation accelerator is selected from the group consisting of chloride, carbonate and fluoride.
The diamond coating method according to claim 4, comprising at least one. 6. A method for coating a surface of a substrate with diamond, wherein the substrate is at least one selected from the group consisting of carbides, nitrides of Group IVa, Va, and VIa metals of the Periodic Table and their mutual solid solutions. Disperse phase containing seeds, Co, N
and a binder phase containing at least one member selected from the group consisting of i, Fe and Cr (hereinafter, the elements contained in the binder phase are referred to as "bond phase elements"), III, IV , V, VI group elements that form an intermetallic compound with the binder phase element are injected into the surface of the substrate, and the substrate is heat-treated in a non-oxidizing atmosphere. Forming an intermetallic compound containing the above binder phase element, and then coating the surface of the substrate with a diamond film by a vapor phase synthesis method. 7. A method for coating the surface of a substrate with diamond, wherein said substrate is at least one of the group consisting of carbides, nitrides of Group IVa, Va, and VIa metals of the Periodic Table and their mutual solid solutions. Disperse phase containing seeds, Co, N
and a binder phase containing at least one member selected from the group consisting of i, Fe and Cr (hereinafter, the elements contained in the binder phase are referred to as "bond phase elements"), III, IV , V, and VI group elements, which form an intermetallic compound with the binder phase element, are vapor-deposited on the surface of the substrate by the PVD method, and further heat-treated in a non-oxidizing atmosphere to form a surface layer on the substrate. A diamond coating method, comprising: forming an intermetallic compound containing the binder phase element, and then coating the surface of the substrate with a diamond film by a vapor phase synthesis method. 8. The intermetallic compound is In, Sn, Sb,
The method for coating diamond according to claim 1, 3, 6 or 7, further comprising at least one selected from the group consisting of V, Zr, W, Ta and B. 9. A diamond-coated tool having a surface coated with diamond, comprising a dispersed phase containing at least one selected from the group consisting of carbides, nitrides of Group IVa, Va and VIa metals and mutual solid solutions thereof. And a substrate composed of a binder phase containing at least one member selected from the group consisting of Co, Ni, Fe and Cr (hereinafter, referred to as "elements contained in the binder phase"
And a diamond film formed on the surface of the base body, wherein the base body has an intermetallic compound containing the binder phase element formed inward from the surface. A diamond coating tool having a layer. 10. The intermetallic compound is CoB, Co ₂ B, Co ₃ B, CoB ₂ , NiB, Ni.
₂ B, Ni ₃ B, Ni ₄ B ₃ , CrB, Cr ₂ B, Cr
₅ B ₃ , CrB, Cr ₃ B ₄ , CrB ₂ , Fe ₂ B, FeB,
CoIn ₂ , CoIn, Co ₃ In ₂ , CoSb ₃ , CoS
b ₂ , CoSb, CoSn, CoV, CoV ₃ , Co
₃ V, Co ₃ W, Co ₇ W ₆ , Co ₂ Ta, Ni ₈ Ta, Ni
₃ Ta, Ni ₂ Ta, NiTa, NiV ₃ , Ni ₂ V, Ni
₃ V, Ni ₄ W, NiZr, NiZr ₂ , FeW, FeZ
_{r 2, CrSb, Cr 2 Ta} , diamond coating tools, characterized in, that it comprises at least one of the group consisting of ZrCr _2,. 11. The diamond coating tool according to claim 9, wherein the hardness of the intermetallic compound is higher than the hardness of the elements contained in the binder phase of the substrate.