JP2591865B2 - Polycrystalline diamond tool and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides strength, wear resistance, chipping resistance, welding resistance,
Polycrystalline diamond for tools with remarkably improved heat resistance,
And its manufacturing method.

[0002]

BACKGROUND OF THE INVENTION Diamond for tools has conventionally been made by sintering. The diamond fine powder is put into a mold and sintered under high temperature and high pressure. Tools using sintered diamond are used for cutting tools, drill bits, drawing dies and the like of non-ferrous metals. For example, Japanese Patent Publication No. 52-12126 discloses a method in which diamond powder is sintered in a state of being in contact with a powder compact of a WC-Co cemented carbide, and a part of Co is caused to enter the diamond powder as a bonding metal. Accordingly, a diamond sintered body having about 10 to 15% by volume of Co is disclosed.

[0003] This diamond sintered body has practical performance as a cutting tool for non-ferrous metals. However, this had a problem in heat resistance. For example, when heated to 700 ° C. or higher, wear resistance and strength are reduced. Further, at a temperature of 900 ° C. or more, the sintered body is broken. The cause of such a decrease in heat resistance is considered as follows. One is Co, a binder
Diamond is graphitized at the interface between the diamond and the diamond particles. The other is that, because the thermal expansion coefficients of Co and diamond are different, a high temperature causes a strong thermal stress at the interface between the two.

[0004] In order to improve the heat resistance of such a diamond sintered body, Japanese Patent Application Laid-Open No. Sho 53-114589 proposes that the sintered body be treated with an acid to remove Co as a binding metal. In this case, since there is no interface between Co and diamond, the problems of graphitization and thermal stress should be eliminated. However, in this method, holes are formed after Co is removed. The heat resistance is improved, but the mechanical strength is reduced. The sintering method has such difficulties, and it is difficult to produce a material having excellent strength and heat resistance.

[0005] Recently, it has become possible to chemically synthesize diamond from the gas phase. It is referred to as chemical vapor deposition (CVD) or simply vapor synthesis. About 5% by volume
The following hydrocarbon gas is diluted with hydrogen gas to
The diamond is deposited on the substrate under a reduced pressure of orr. Various methods have been proposed for how to decompose and excite the source gas.
There is a VD method. It is heated or excited by electrons or plasma.

Japanese Unexamined Patent Publication (Kokai) No. 58-91100 discloses that a raw material gas is preliminarily heated by a thermionic emission material heated to 1000 ° C. or more, and the raw material gas is guided to the heated base material surface to thermally decompose hydrocarbons. A method of depositing diamond on a material has been proposed. JP-A-58-11049 proposes a method in which a hydrogen gas is passed through an electrodeless discharge by a microwave plasma CVD method, and then mixed with a hydrocarbon gas to precipitate diamond on a substrate.

JP-A-59-30398 discloses that microwaves are introduced into a mixed gas of hydrogen gas and an inert gas to generate plasma, and hydrocarbons are decomposed by the plasma.
A method for depositing diamond on a substrate heated to 300 ° C to 1300 ° C is disclosed. Thus, CVD
There are various methods for synthesizing a diamond film by the method. There are two ways to use the synthesized diamond film.

[0008] One is to peel off from the base material to make diamond alone. It is again mounted on a suitable tool. The other is to coat diamond with the cutting edge of a tool as a base material. JP-A-1-15
3228, Japanese Patent Application Laid-Open No. 1-210201 discloses a method in which diamond is deposited by a vapor phase synthesis method, and then the base material is removed by etching to obtain a single diamond. This is set as a tool by installing and fixing it at the tip of a separate tool main body. However, this also has insufficient fracture resistance and abrasion resistance and cannot exhibit the original performance of diamond. There is also provided a tool in which the tip of the tool is coated with polycrystalline diamond by a CVD method. The diamond is grown by the CVD method using the tool or a part of the tool as a base material. Since the cutting edge is diamond, it should have sufficient strength. However, the diamond film is thin and the adhesion strength between the diamond and the substrate is insufficient, so that sufficient performance as a tool has not been obtained. Since the base material and diamond are different, it is difficult to increase the adhesion strength.

Japanese Patent Application Laid-Open No. 22471/1990 attempts to increase the adhesion strength by coating a diamond film having a devised composition on a cemented carbide. However, the machinability is poor depending on the surface roughness of the workpiece. Furthermore, the cutting characteristics when a difficult-to-cut material (for example, a 17% Al-Si alloy, a 25% Al-Si alloy) is used as the material to be cut are insufficient.

[0010]

That is, in view of the conventional circumstances according to the present invention, the strength, fracture resistance, welding resistance, heat resistance and abrasion resistance have been improved. It is an object of the present invention to provide a polycrystalline diamond for a tool having excellent wear resistance and wear resistance. Even if a conventional diamond film is formed by vapor phase synthesis, the film quality does not change significantly in the thickness direction, and has a uniform film quality structure. In conventional diamond tools with a uniform film quality structure, diamonds that are inferior throughout the diamond have low wear resistance and low strength, while those that are entirely made of good quality diamond have poor fracture resistance. There are difficulties. The inventor has noticed that a diamond having a uniform film quality cannot satisfy the above conditions.

[0011]

A polycrystalline diamond tool according to the present invention comprises a tool base material and a polycrystalline diamond, and is fixed by abutting a base material installation fixing surface of the polycrystalline diamond on a base material surface of a tool edge. And a tool having a structure in which diamond is used as a cutting edge, wherein the thickness of the diamond is 40 μm or more, the film quality changes in the thickness direction of the diamond, and the film quality of the diamond on the rake face of the cutting edge is a base material installation fixed surface. It is better than the film quality of the diamond on the side. That is, the base material installation fixed surface side is inferior, and the rake surface side has more excellent film quality. The inferior diamond on the base material installation fixed surface side has many defects and a low elastic modulus, so that it is rich in toughness, reduces the stress applied to the rake face of the cutting edge, and improves the chipping resistance of the cutting edge. Since the rake face is made of high quality diamond, it has excellent strength, heat resistance and welding resistance. Diamonds on both sides make the best use of each other's strengths. The complementarity of the properties of the rake face and the base material installation fixing face is a feature of the present invention.

The diamond mentioned here includes a non-diamond component in addition to a pure diamond component. Depending on the synthesis conditions, non-diamond components (amorphous carbon components, crystalline carbon components having no diamond structure such as graphite, etc.) may be crystalline, depending on the synthesis conditions. This is because they are precipitated simultaneously with the precipitation of diamond. A high-quality diamond film is a diamond in which the precipitation of these non-diamond components is suppressed as much as possible. The diamond crystal itself has a high crystallinity with few distortions and defects. On the other hand, it is the opposite of a malicious diamond film, which has a high content of non-diamond components, low crystallinity and many defects. According to the present invention, the film quality is not constant as in the prior art, but is changed in the thickness direction of the diamond film. The surface installed on the diamond tool base material is a malicious diamond film,
The rake face on the opposite side, which actually cuts the work surface, has a high quality diamond film structure.

In this case, a characteristic quantity for evaluating the quality of the diamond is required. There are two characteristic quantities for this. Defect density Non-diamond component concentration. The non-diamond component means an amorphous carbon component, graphite and the like. Defects are crystal defects in the diamond structure. Although both are of course different physical quantities, they have a correlation with each other. The above-mentioned conditions define the present invention by the film quality of only both sides of the diamond, but the film quality in a partial region having a certain depth from both surfaces by giving a greater thickness, that is, the non-diamond component concentration, the magnitude of the defect density, Can also be defined. In order to form a diamond film having a different film quality in the thickness direction, in the simplest case, the molar fraction Q of the carbon atom-containing gas (B) in the hydrogen gas (A) usually used in the vapor phase synthesis is Q = (B) / ( A) may be changed during the synthesis. When Q is increased, the film quality deteriorates. Even if the oxygen content is reduced, the film quality is deteriorated. The film quality can be reduced by increasing the amount of nitrogen.

[0014]

FIG. 1 shows an example of a schematic view of a polycrystalline diamond tool. A polycrystalline diamond film 2 is fixedly installed at one corner of a base material 1 of a cemented carbide with a brazing layer 3. The face that appears on the outside of the polycrystalline diamond film 2 is the rake face 4
The base material fixed surface 5 is fixed to the base material.
In the present invention, the diamond film quality differs in the thickness direction. The diamond film quality is worse on the base material installation fixed surface, and the diamond quality on the rake face side is better. The diamond on the rake face minimizes the content of non-diamond components, and the base metal installation fixed face increases the content of non-diamond components on the rake face side. Alternatively, the defect density of diamond on the rake face side is suppressed as much as possible, and the defect density of diamond on the base material installation fixed face side is increased with respect to the rake face side.

If the content of the non-diamond component is large,
The defect density of diamond usually increases. However, there are diamond films having different defect densities in the diamond film even when the content of the non-diamond component is almost the same. For this reason, as described above, there are two methods for defining the film quality of diamond, based on non-diamond and defect density. The rake face 4 side is a low non-diamond low defect high quality film, and the base material installation fixed face 5 side is a low quality film having a non-diamond component or a higher defect density. Since the base material installation fixing surface has a high defect density and a high non-diamond component, the rigidity is low and the elasticity is high. Thereby, the stress applied to the rake face 4 can be reduced. That is, the base material installation fixed surface side functions as a stress relaxation layer. In the film structure described above, the rigidity of the film is low on the base material installation fixed surface side, and the toughness (T
OUGHNESS (neighborhood) can be improved. Since the rake face has higher rigidity, the wear resistance is sufficiently high. For this reason, fracture resistance can be improved without impairing the excellent wear resistance of diamond.

To more precisely define the rake face 4, z
= 0 and the z-axis is taken perpendicular to the plane. The x and y axes are taken in directions parallel to the plane. The non-diamond component concentration at point (X, Y, Z) is W (x, y, z), and the defect density is D (x,
y, z). Assuming that the film thickness of the diamond is T, z = T corresponds to the base material installation fixing surface. The first definition is G ₀ = ∫W (x, y, 0) dxdy / S (1) H ₀ = ∫W (x, y, T) dxdy / S (2) S = ∫dxdy (3) G ₀ is the non-diamond concentration on the rake face, H ₀
Is the non-diamond concentration on the base material installation fixed surface, S is the diamond area), and T> 40 μm (4) G ₀ <H ₀ (5)

The second definition is: U ₀ = ∫D (x, y, 0) dxdy / S (6) V ₀ = ∫D (x, y, T) dxdy / S (7) S = ∫dxdy ( (U ₀ is the defect density on the rake face, V ₀ is the defect density on the base material fixed surface) T> 40 μm (9) U ₀ <V ₀ (10)

However, it is sufficient that this formula is established not only on the surfaces on both sides but near the surfaces on both sides. In this case, W (x, y, 0) and D (x, y, 0) on the rake face are converted to ε ( T / 2> ε
> 0) to W (x, y, ε) or D (x, y, ε), and W (x, y, T) or D on the base metal installation fixed surface side
(X, y, T) is converted to W (x, y, T−ε) or D (x, y,
T-ε). Then, instead of (5) and (10), the content of the present invention can be described as Gε <Hε (11) Uε <Vε (12).

The reason why the film thickness T of the diamond is 40 μm or more is that if the thickness is less than 40 μm, the strength is reduced and the diamond is easily broken. Another reason is that the flank wear width during the life of a cutting tool is often 40 μm or more. When a higher degree of wear resistance is required, the film thickness T is set to 0.07 mm to 3.0 mm.
Is desirable. If there is no problem in cost, the thickness may be set to 3 mm or more. Diamond has the best thermal conductivity, and the larger the film thickness, the better the heat radiation characteristics. Then, the rise in the temperature of the cutting edge is suppressed, so that the blade is less likely to be worn.

The most characteristic feature of the present invention is that G ₀ <H ₀ or U ₀ <V ₀ . If G ₀ ≧ H ₀ or U ₀ ≧ V ₀ , the base material installation fixed surface side does not become a stress relieving layer, has poor toughness, easily cracks the diamond film, may be detached, and has abrasion resistance. It is easy to deteriorate.

The problem then becomes how to measure the non-diamond and defect density. Non-diamond components (amorphous carbon, carbon,
The content state of carbon component having no diamond structure such as graphite) cannot be measured by X-ray diffraction or the like, and Raman scattering spectrometry is most suitable. In short, Raman scattering is a phenomenon in which a light wave undergoes inelastic scattering in a substance, and the interaction between the excited phonons and the light wave causes light having a wavelength different from that of the incident light to be emitted (inelasticity). (Scattered light, Raman scattered light). In addition to phonons, plasmons and magnons also contribute to Raman scattering. When the medium is a liquid or a gas, Raman scattering occurs due to the interaction between the molecular vibration and the light wave instead of the phonon.

Usually, Raman spectrum measurement generally requires an excitation laser light source, a sample optical system, a spectral system, and a detection and measurement system. As the excitation laser light source, an argon laser of 488 nm or 514 nm is usually used. Then, this laser beam is irradiated to the sample, in this case, a diamond film fixedly installed on the tool edge, and after the generated Raman scattered light is separated, it is introduced into a multi-channel detector or the like.
Also, in contrast to the normal backscattering method, the laser light to be irradiated is passed through an optical system by an optical microscope, and the laser light is tens of μm.
There is also a micro-Raman measurement method for measuring a Raman spectrum of a small aperture portion.

The diamond on the rake face of the tool to be measured this time is also available on the rake face side when the laser beam is irradiated perpendicularly to the nose face. When performing Raman spectroscopy measurement on the fixed surface of the base metal
The latter method of microscopic Raman measurement, which can be narrowed down below, is more suitable for microanalysis. However, due to the concentration of the laser beam, the temperature tends to rise locally, so it is necessary to pay sufficient attention. This is because there is a possibility of causing a change in the film quality of the sample or a change in the shift position of the Raman peak. Strictly speaking, a gas such as helium may be blown onto the sample, the profile of the Raman spectrum may be confirmed to be symmetric, or the output of the laser beam may be changed to check whether the change is due to a temperature rise. Further, the adjustment of the optical axis system of the spectral system, the slit width, and the like also need to be sufficiently adjusted to increase the resolution.

The Raman spectrum of diamond is such that only one primary Raman line appears at 1332.5 cm ^-1 degenerates threefold, and the secondary Raman line is 1 / 500th of the primary.
The following are very weak. Therefore, the diamond itself may be evaluated by paying attention to this primary Raman line. There are two methods for evaluating diamond film quality by peaking by Raman scattering. One is by the half width of the peak corresponding to the diamond,
The other is evaluated by the height of the peak itself. The half-width of the diamond Raman spectrum used for measuring the defect density in the present invention is 1332.5
This is for peaks appearing in the vicinity of cm ^-1 .

Usually, when a defect or stress enters diamond and the diamond structure is disturbed,
It is known that the half-value width increases, and conversely, the half-value width decreases when the crystallinity is high. In the case where a large amount of non-diamond components and the like described later are present, remarkable spread is exhibited. However, even if the precipitation of non-diamond components is small, even if the crystal structure of diamond is actively destroyed by ion implantation or the like, it shows a remarkable spread.

One method of the present invention is to tilt the defect density distribution in the diamond crystal in the thickness direction. The state of this defect (dislocation, stacking fault, etc.) is determined by TEM
(Transmission Electron Mi
(Crosscopy) observation or the like. It can also be observed by measurement by X-ray diffraction.

The non-diamond component according to the present invention is a general term for a carbon component other than crystalline diamond, for example, an amorphous carbon component, graphite such as glassy carbon and activated carbon. A so-called amorphous carbon having a crystal structure as a basic structure and having a greatly disordered structure (highly carbon)
Disordered graphite component and crystalline carbon component such as graphite. The non-diamond component in question here is mainly amorphous carbon. Normally, diamond is precipitated from a non-equilibrium state in the vapor phase synthesis method, and depending on conditions, precipitation of non-diamond components occurs together with the deposition of diamond, as shown in Examples of the present invention. As another method of the present invention, this phenomenon is actively used.
These non-diamond components are substances that are structure-sensitive to Raman light like diamond, and are mainly 1000 c
It has a broad peak between m ^-1 and 2000 cm ^-1 . Although the appearance of the peak slightly changes depending on how the carbon structure is disordered, in the present invention, it can be considered that the non-diamond component is almost caused except for the sharp diamond Raman line near 1332.5 cm ^-1 .

The present invention is defined again below. One is a polycrystalline tool defined by the non-diamond components contained in diamond, and the other is a definition of the defect density in crystalline diamond.

[Definition by non-diamond component] A structure comprising a tool base material and polycrystalline diamond, which is fixed by contacting a base material installation fixing surface of the polycrystalline diamond with a base material surface of a tool cutting edge and using diamond as a cutting edge. A tool,
It is characterized in that the diamond has a thickness of 40 μm or more, and the non-diamond concentration increases in the diamond thickness direction from the rake face to the base material installation fixed face. More preferably, the content of the non-diamond component in the diamond at least in a portion of the diamond which is smaller than 30% or 40 μm or less of the average thickness of the diamond from the rake face of the cutting edge diamond toward the base material surface in the thickness direction is smaller than the diamond. A polycrystal characterized in that it is less in the non-diamond component content in diamond, whichever is smaller, within 30% or 40 μm of the average thickness of diamond, from the base material installation fixed surface to the cutting edge rake surface in the thickness direction. It is a diamond tool.

According to the Raman spectrum, Raman spectroscopic analysis shows that at least 30% of the average thickness of the diamond or 40 μm or less of the diamond from the rake face of the cutting edge diamond toward the base metal surface in the cross-sectional direction, whichever is smaller. Non-diamond component peak value (X1) diamond component peak value (Y1)
The peak value (X2) of the non-diamond component whose ratio (X1 / Y1) is smaller than the average thickness of diamond within 30% or 40 μm, whichever is smaller, from the fixed surface of the diamond base material to the rake face in the cross-sectional direction. Of the diamond component to the peak value (Y2) of the diamond component (X2 /
Film quality structure X1 / Y1 <X2 / Y2 smaller than Y2)
It is a polycrystalline diamond tool characterized by having.

Here, the X and Y peak values are set using the Raman spectrum of FIG. 5 as an example. A background baseline such as fluorescence is drawn and the diamond peak value (1
The highest broad peak other than the peak around 332.5 cm ^-1 is detected, and the height of this peak value from the baseline is X. Since carbon is a Raman-active substance, a broad peak appearing other than the peak value of diamond may be considered to be due to non-diamond components. The peak value of the non-diamond component is called amorphous carbon or amorphous carbon (having a graphite crystal structure as a basis and having a significantly disordered structure). The peak value is 1000 cm ⁻¹ to 2000 cm due to the disorder of the structure. It varies between ^-1 . Therefore, the highest peak appearing between 1000 cm ⁻¹ and 2000 cm ⁻¹ is defined as the peak height of the non-diamond component. FIG. 5 is a Raman spectrum in which the most typical non-diamond component is co-precipitated with diamond. Raman peak value of diamond component is 133
Appears at 2.5 cm ^-1 . This is the normal isotope ₁₂ C, ₁₃ C
Is the case of diamond composed of abundance ratio of _13C
It is known that as the number increases, the frequency shifts to the lower wavenumber side.
For this reason, the Raman shift value may shift slightly. Here, the peak value of the diamond is detected and the height Y with respect to the base line is obtained in the same manner as described above. However, since the above-mentioned peaks of the non-diamond components are often present at the same time, this is removed. The drawn baseline is newly drawn, and its height is set to Y. The method of drawing the base line differs between the case where X is obtained and the case where Y is obtained. These heights differ depending on how the base line is drawn. Although it is preferable to perform accurate peak separation, it is possible to make a qualitative comparison of the content ratio of non-diamond components even with a somewhat simplified type.

[Definition by Defect Density] A tool comprising a tool base material and polycrystalline diamond, and having a structure in which the base material installation and fixing surface of the polycrystalline diamond is brought into contact with and fixed to the base material surface of the tool cutting edge and the diamond is used as the cutting edge. Wherein the thickness of the diamond is 40 μm or more, and the defect density increases in the thickness direction of the diamond from the rake face to the base material installation fixed face. More preferably, the average thickness of the diamond is within 30% or 40 μm from the rake face of the diamond to the base material installation fixed face in the thickness direction.
The defect density at the smaller position within m is within 30% of the average film thickness of diamond or within 40 μm, whichever is smaller, toward the cutting edge rake surface in the thickness direction from the fixed surface of the diamond base material. This is a polycrystalline diamond tool characterized by having a small defect density.

According to the definition by Raman spectroscopy, at least 30% of the average thickness of diamond or 40 μm or less of the average thickness of diamond from the rake face of the cutting edge diamond to the fixing face of the base material in the thickness direction is determined by Raman spectroscopic analysis. The half value width (αcm ^-1 ) of the diamond component at a small portion is within 30% or 40 μm of the average thickness of the diamond from the diamond base material installation fixed surface toward the cutting edge rake surface in the thickness direction, whichever is smaller. A polycrystalline diamond tool characterized by having a film structure (α <β) smaller than the half width (βcm ⁻¹ ). Here, the half width α and the half width β are set using the Raman spectrum of FIG. 6 as an example. First, the height of Y is set as in the above-described setting of the peak value of the diamond, and the peak width at half the height is set to the half width α.
cm ⁻¹ and βcm ⁻¹ .

Next, the method for producing a diamond according to the present invention will be described with reference to FIG. Since the diamond film is grown by the vapor phase synthesis method, the carbon concentration in the source gas is monotonically changed (monotonically increased or monotonously decreased) in order to change the diamond film quality in the thickness direction as described above. ) Is the simplest. Of the two methods, the method of monotonously increasing the carbon concentration is more preferable. The reason will be described later. Further, the film quality can be controlled by the oxygen concentration and the nitrogen concentration in the source gas. The substrate 6 is heated in a CVD apparatus (to be described later), a raw material gas is flowed, excited and decomposed to grow diamond on the substrate (FIG. 2B). Generally, the carbon concentration in the raw material gas changes monotonically continuously or stepwise. After the diamond film 7 is grown by such a CVD method, the base material is removed by etching with hydrofluoric nitric acid, aqua regia, or the like to form a diamond single film. (FIG. 2 (c)). Next, in order to improve the wettability between the diamond and the base material, a metal film on one surface of the diamond film is subjected to a vapor deposition metallization process in advance (FIG. 2D). Thereafter, it is cut into a predetermined size by a YAG laser or the like (FIG. 2E). Here, there is no problem in the order in which the cutting step is performed before the dissolving step. Then, the surface of the metallized layer is installed and fixed on the base material surface of the tool (FIG. 2 (f)).

FIG. 3 is a cross-sectional view of a tool with a diamond film attached. The base material may be a hard material, but usually a cemented carbide is used. This base material has a diamond film mounting seat, where the diamond film is fixedly installed via a metallized layer. This fixing is preferably performed by brazing in consideration of heat resistance and strength resistance. FIG. 4 shows a geometric relationship for defining the present invention. The side farther from the base material is the rake face. The z-axis is set in the thickness direction with a line included in the rake face as a reference line. The rake face can be indicated by z = 0. The base material installation fixed surface can be represented by z = T on the opposite surface. The dashed line shows z =
0.3T or 40 μm, whichever is smaller, z =
0.7 T or the value obtained by subtracting 40 μm from the total film thickness T, whichever is larger. Laser light is incident parallel to the surface from the edge of the diamond. The problem is the non-diamond component-containing states G ₀ , H ₀ or the defect-containing states U ₀ , V ₀ in diamond in this partial region.

When diamond is grown by the CVD method, the non-diamond component or the state of defects contained in the diamond film is changed, but it is preferable that both are increased (monotonically). The reason is as follows. When diamond is grown on a substrate, the diamond film on the side placed on the substrate becomes a flat diamond surface if the surface treatment of the substrate is flat, but it is formed at the end of growth. The resulting diamond film exhibits a surface unique to polycrystalline diamond with irregularities having a 6-8-hedral structure unique to diamond. If this becomes a rake face, irregularities will occur on the work surface of the work material. In order to avoid this, the surface formed at the end of growth (the growth surface side, the surface farther from the substrate) is preferably metallized and fixed to the base material.

In the present invention, since the base material installation fixed surface has a structure in which the non-diamond component or the defect content in diamond is increased, when growing diamond, for example, the carbon concentration is first reduced, and finally the diamond concentration is reduced. You only have to raise it. If diamond is synthesized by this procedure, the diamond formation speed is increased, and there is an advantage that the synthesis cost is reduced. In addition, when installed on a tool, the grain size of polycrystalline diamond in the initial stage of diamond growth on the rake face side is small, and the grain size increases remarkably toward the base metal surface side. This leads to such stress dispersion and improvement in chipping resistance and wear resistance. Of course, this process order is not an essential condition. After growing the diamond film by the CVD method, the surface formed at the end of the growth is polished and flattened,
A rake face can also be used. In this case, when diamond is grown by the CVD method, for example, the carbon concentration is initially increased and then decreased. However, in this case, there is a disadvantage that the number of steps increases and the cost increases.

[Production Method of Diamond] The raw material gas used in the vapor phase synthesis of diamond by the CVD method is usually hydrogen gas, a carbon atom-containing gas, methane, ethane, acetylene,
Ethyl alcohol, methyl alcohol, acetone, etc. are common. Is not limited as long as it contains carbon and becomes gaseous. Even liquids at room temperature, such as alcohol and acetone, become gas when heated. The liquid can be converted into a gas by bubbling the liquid with a carrier gas such as hydrogen gas. In addition to the above-mentioned gases, inert gases (helium, neon, argon, krypton, xenon, radon) can be used as active species (hydrogen radicals, C radicals) during diamond synthesis, particularly in a process using plasma for activating the source gas. ₂ ) may be mixed with the above gas since it is effective in increasing the density, extending the life and synthesizing a uniform diamond.

The following materials can be used as a substrate for CVD growth. W, Mo, Ta, Nb, S
i, SiC, WC, W ₂ C, Mo ₂ C, TaC, Si ₃
N ₄ , AlN, Ti, TiC, TiN, B, BN, B ₄
C, diamond, Al ₂ O ₃ , SiO _{2 and the} like. By selecting further conditions, Cu, Al, etc. can be used as the base material. The substrate is not necessarily just flat. If the base material has an appropriate curvature, it can be applied to a tool having a blade surface having a curvature. For example, it can be applied to tools such as a twist blade and an end mill.

Now, with the vapor phase synthesis method of the present invention, it is easy to continuously increase the carbon concentration in the source gas when growing diamond on a substrate. In this case, the carbon concentration in the source gas is changed in three or two stages. The simplest is CVD growth in two stages, a stage with a low carbon concentration in the source gas and a stage with a higher concentration.

For example, in the first stage of diamond synthesis, synthesis is performed using a hydrogen-methane (methane / hydrogen = about 1%) system, and in the second half, diamond synthesis is performed using a hydrogen-methane (methane / hydrogen = about 2.5%) system. At this time, the crystallinity of the diamond film at the initial stage of growth is improved by adding a trace amount of an oxygen atom-containing gas, such as oxygen gas or H ₂ O, to the composition of the previous period, and the deposition of non-diamond components is suppressed. The density of defects in the medium can also be reduced. In this case, by increasing the oxygen atom concentration, it is also possible to increase the carbon concentration in the early period from the latter period.

For example, in the first stage of diamond synthesis, hydrogen-methane-oxygen (methane / hydrogen = about 2%, oxygen / hydrogen =
About 0.2%), and the latter stage is synthesized using hydrogen-methane (methane / hydrogen = about 3%).

Conversely, in order to reduce the crystallinity of the diamond at the latter stage of the diamond growth, a trace amount of a nitrogen atom-containing gas can be added to the latter stage composition. For example, in the first stage of diamond synthesis, hydrogen-methane (methane /
Hydrogen = about 1%, synthesized in the system, hydrogen-methane-nitrogen (methane / hydrogen = about 2%, nitrogen / hydrogen = about 0.5%)
Synthesize in a system. In this case, by increasing the concentration of the nitrogen atom-containing gas, it is possible to reduce the carbon concentration in the latter period from the former period.

[0044]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With respect to the CVD method, the present invention can be practiced in any method capable of synthesizing diamond.
The present invention was carried out for the following CVD method, filament CVD method (FIG. 7), microwave plasma CVD method (FIG. 8), thermal CVD method (FIG. 9), and thermal plasma CVD method (FIG. 10). The base material is the same for the methods (1) to (4). One side of polycrystalline silicon of 14 mm × 14 mm × 2.5 mm is wrapped with an abrasive containing abrasive grains having a particle size of 0.5 to 5 μm, and R _MAX <1. One having a thickness of 2 μm was used. The apparatus used for each method will be described below, and the results of applying the present invention to each method will be described.

[Embodiment] Filament CVD Method FIG. 7 is a schematic view of a filament CVD apparatus. A substrate support 12 is provided in the vacuum chamber 11. The substrate 13 is placed on this. The vacuum chamber 11 has a vacuum exhaust port 14 and is connected to a vacuum exhaust device (not shown). An electrode 15 is provided in the vacuum chamber 11. It is connected through a insulator 16 to a filament power supply. A filament 17 is stretched between the electrodes 15. A source gas is introduced into the vacuum chamber 11 from a source gas inlet 18. The pressure gauge 19 measures the degree of vacuum in the vacuum chamber 11. Cooling water is introduced into the substrate support and cools it. 4 for filament 17
N (purity 99.99%)-W, 4N-Ta, 4N-Re
Was used. The temperature of the filament was measured by an optical pyrometer. The temperature of the substrate was monitored by a chromel-alumel thermocouple fixed to the surface of the substrate.

The source gas supply system will be described with reference to FIG. This can be commonly used for the following CVD apparatuses. Hydrogen gas cylinder 55, inert gas cylinder 5
6. A carbon-containing gas cylinder 57 and an oxygen-containing inorganic gas cylinder 58 are provided. Gas from these gas cylinders is supplied to the reactor through valves and piping. Hydrogen gas is mixed with them as carrier gas. A portion of the hydrogen gas passes through the bubbling device 59 and is used to vaporize and carry the liquid at room temperature. Bubbling device 59
Contains a liquid 60 such as H ₂ O and C ₂ H ₅ OH. The pipe following the bubbling device 59 has a tape heater 6.
1, 62 are wound and can be heated and maintained at an arbitrary temperature. Diamond was grown on a silicon substrate by the present invention and the conventional method, while changing various growth conditions such as source gas, growth time, pressure, filament material, growth temperature and the like. Table 1 shows the results.

[0047]

[Table 1]

Sample No. AD Samples of the Invention Sample Nos. E to H Comparative Examples In Examples A to D of the present invention and Comparative Examples E and F, the raw material gas composition and the composition ratio were changed with time. For example, Example A shows the first stage 1 H ₂ 600 SCCM, CH ₄ 5
The base material is coated with the raw material gas of SCCM, and the next 20
Time is H ₂ 600 SCCM, CH ₄ 12 SCC in stage 2
That is, the coating is performed with the M raw material gas. In the other embodiments of the present invention, B and D are also changed in two stages, and C is changed in four stages. Comparative Example E was obtained by synthesizing all diamond films at a high carbon concentration. F is all synthesized at low carbon concentration. H changes the carbon concentration in the source gas stepwise, contrary to the present invention. After the growth, the silicon substrate is melted and removed. Since a rectangular diamond plate was formed, it was cut along a diagonal line to obtain an isosceles triangle.

The diamond samples A to H thus produced were mounted and fixed on a cemented carbide base material by the process shown in FIG. 2 to produce a cutting tip (brazing was used for fixing). However, at the time of growth, the surface that was in contact with the base material was used as the rake surface of the cutting tip, and the surface formed later in the growth was fixed to the base material surface of the cutting tip. These were subjected to film quality measurement and cutting test by Raman scattering as follows, and the quality was evaluated. The results are shown in Table 2 below.

[0050]

[Table 2]

Samples A to D are examples of the present invention and E to
H is a comparative example. As a comparative material for Raman spectroscopic measurement, a natural IIa diamond single crystal was similarly set and fixed on a base material to produce a cutting tip. Sample J (referred to as sample I) is another comparative material. In this method, sintered diamond produced by high-pressure sintering a diamond material having an average particle diameter of 10 μm containing 10% by volume of Co as a binder is attached to a tool to form a cutting tip. It is not CVD growth. In this method, sintered diamond produced by high-pressure sintering is attached to a tool to form a cutting tip, so that non-diamond components are uniformly large.

Here, the measurement points of the Raman spectroscopy are indicated by a distance Z (unit: μm) toward the inside in the thickness direction with respect to the rake face as shown in FIG. The first layer,
The second layer is a partial layer of diamond formed by switching the source gas and composition shown in Table 1. Since the film formed at the beginning of the growth is a rake face, it corresponds to the first layer and the second layer in Table 2 in order from the top in Table 1.
As a matter of course, in the embodiment of the present invention, the value of X / Y is smaller near the rake face. The non-diamond concentration on the rake face is low.

In Comparative Example E, all of the diamond films were synthesized at a high carbon concentration, and thus had many non-diamond components. However, the concentration distribution is in the opposite relationship to the present invention. Since Comparative Example F was synthesized at a low carbon concentration, the non-diamond component was low and the distribution was opposite to that of the present invention. In Comparative Example H, the carbon concentration in the raw material gas was changed stepwise, contrary to the present invention. The structure is reversed. In all of the examples of the present invention, the carbon concentration in the source gas is increased with the growth, but the diamond actually grown also corresponds to the source gas, and the non-diamond component and the half-width of the diamond Raman spectrum increase in the growth direction. It can be seen that it is increasing toward.

The performance of the diamond cutting tool thus produced was evaluated under the following conditions. A390 alloy (A) in which four grooves extending in the axial direction are formed on the outer peripheral surface as a work material
1-17% Si) round bars were selected. The cutting speed was 800 m / min. Cut: 0.2 mm Feed: 0.1 mm / rev. Since the amount of wear is an important evaluation parameter, the average wear width when cutting for 90 minutes or 30 minutes is measured. Table 3 shows the results.

[0055]

[Table 3]

As can be seen by comparing Tables 2 and 3, the peak value (X1) of the non-diamond component on the rake face side cutting edge (X1) and the peak value of the diamond component (Y
The film quality structure in which the ratio (X1 / Y1) to 1) is smaller than the ratio (X2 / Y2) of the peak value (X2) of the non-diamond component on the base material surface side to the diamond component.
1 <X2 / Y2, or the half width (αc) of the diamond Raman spectral peak on the rake face side
m ^-1 ) is the diamond Raman spectrum peak on the base metal side.
Α <β, which is smaller than the half width (βcm ^-1 )
In the example of the present invention having (cm ^-1 ), that is, samples A to D, A
In the cutting test of 390, there is no breakage and high wear resistance is exhibited. On the other hand, the opposite condition X1 / Y1 ≧
In Comparative Examples E to J in which X2 / Y2 or α ≧ β (cm ⁻¹ ), there were only those that were largely damaged in a short time and those that were greatly worn.

Comparative material J which is a sintered diamond sample
Although there was no chipping, the average wear width after 90 minutes cutting was as large as 90 μm. Co to form by sintering
And the like, and this is considered to be the cause of reducing the wear resistance. Further, as in Comparative Example E, the non-diamond component contained a large amount in the diamond thickness direction or had a large half-value width (almost
0 cm ^-1 or more) has a drawback of poor abrasion resistance. H also has many non-diamond components on the rake face side and a large half-value width, but this also has poor abrasion resistance. On the other hand, as in Comparative Example F, a diamond film having a small non-diamond content in the thickness direction or a small half-width (approximately 6 cm ^-1 or less) in the thickness direction of the diamond has insufficient toughness in the diamond film and is hard. It is considered that the fracture resistance is particularly insufficient for the work material.

In the diamond film quality structure of the present invention, the diamond film on the rake face side is basically of high quality and good quality, and the quality on the base material installation fixed face side is slightly reduced. It has a structure that relieves the stress applied to the high quality film on the rake face due to the elasticity of the base material installation fixed surface. The definition can be expressed not only by these Raman data but also by various other definitions. The following can be considered qualitatively. Rake face Side Base material fixed face side Young's modulus High Low CL emission intensity Weak Strong (440 nm) Crystal grain size Small Large Hydrogen content Low High (CL: Caso-Dolescence)

[Example] Microwave plasma CVD
Method Next, the present invention was implemented by a microwave (plasma) CVD method. FIG. 8 schematically shows a microwave CVD apparatus.
A substrate 24 is supported by a quartz rod 23 in the quartz tube 22. A source gas 26 is introduced into the quartz tube 22 from an upper gas inlet 25. This is discharged from the vacuum exhaust port 27 below the quartz tube 22. A water cooling jacket 28 is provided in the vicinity of the portion of the quartz tube 22 where the reaction takes place. The microwave is oscillated by the magnetron 29 and is guided to the vicinity of the base material 24 through the waveguide 30. Since the source gas is excited by the microwave, a high-density plasma is generated near the base material. In the case of the present embodiment, the microwave travels perpendicular to the quartz tube and perpendicular to the axial direction of the quartz tube. The geometrical positional relationship between the waveguide and the quartz tube may be determined by other methods as long as high-density microwave plasma is generated. Although the shape and length of the waveguide determine the mode of the microwave, the standing wave mode of the microwave can be defined by the plunger 32 (reflector) moving in the waveguide 30. ing. Such a microwave plasma CVD method is known. Further, the traveling direction of the microwave may be perpendicular to the substrate surface. The source gas is made of a gas containing carbon, hydrogen gas, or the like, as in the previous example. A magnet may be placed around the quartz tube to confine the plasma to form a cusp magnetic field or an axial magnetic field. This is also well known. Table 4 shows the synthesis conditions by the microwave CVD method. As the substrate, a polycrystalline silicon substrate was used as in the example. The substrate temperature was monitored with an optical optical thermometer during coating.

[0060]

[Table 4]

K to N are examples of the present invention. In these, the source gas composition is switched to two or four stages, and the carbon concentration in the latter half of growth is increased. An inert gas such as Ar facilitates stable excitation of microwave plasma, and Hα,
It is added to increase the concentration of active species such as C ₂ .
O to Q are comparative examples. O is all synthesized at a low carbon concentration, and P is all synthesized at a high carbon concentration. Q is a value obtained by synthesizing with a change in concentration opposite to that of the present invention. Next, in order to evaluate the tool performance, a cutting tip was produced in the same manner as in Example 1. Table 5 shows the measured values of the Raman spectrum in the thickness direction of the diamond in the same manner as in Example 1.

[0062]

[Table 5]

The cutting performance of each cutting tip was evaluated under the same conditions as in Example 1. Table 6 shows the results.

[0064]

[Table 6]

As can be seen by comparing Tables 5 and 6, the ratio (X1 / Y1) of the peak value (X1) of the non-diamond component on the rake face side edge to the peak value (Y1) of the diamond component was determined by Raman spectroscopy. ) Is smaller than the ratio (X2 / Y2) of the peak value (X2) of the non-diamond component to the diamond component on the base material surface side.
/ Y1 <X2 / Y2 or the half-width (αc) of the diamond Raman spectral peak on the rake face side.
m ^-1 ) is the diamond Raman spectrum peak on the base metal side.
Α <β, which is smaller than the half width (βcm ^-1 )
(Examples) The samples of the present invention having (cm ^-1 ), that is, samples K to N, exhibited high wear resistance without any breakage in the cutting test of A390. On the other hand, the opposite condition X1 / Y1
In Comparative Examples O to Q in which ≧ X2 / Y2 or α ≧ β (cm ⁻¹ )
All of them were worn out.

[Example] Process using thermal CVD together The diamond film quality must be at least 2 in order to apply the present invention.
It has to be changed in stages. Here, an example in which a diamond film is formed in two stages will be described. Here, the first-stage film formation was performed by a filament CVD method, and the second-stage film formation was performed by a thermal CVD method. FIG. 9 schematically shows a thermal CVD apparatus. A support 36 is provided in a quartz tube 35 which can be evacuated, and a substrate 37 is supported here.
A heater 38 is provided around the quartz tube 35. A raw material gas is introduced into the quartz tube 35 from a raw material gas inlet 39.
Waste gas is exhausted from the vacuum exhaust port 40. The raw material gas is excited by being heated by the heater, and polycrystalline diamond grows on the substrate by a gas phase reaction. In order to synthesize diamond at a low temperature by the thermal CVD method, it is preferable to add a fluorine-based gas. The base material is 14mm x 14m
It is polycrystalline Si of mx2.5 mm.

[0067] These continued to grow. The total film thickness is 180 μm. This was brazed to a cemented carbide base metal by the process shown in FIG. The ratio (X / Y) of the diamond component peak (Y) to the non-diamond component peak (X) by Raman spectroscopy, and the half widths α and β of the peaks of the Raman spectrum of diamond.
(Cm ^-1 ).

[0068] Met. High carbon concentration of source gas and low formation temperature 2
The X / Y and half width are also large in the layer.

In order to evaluate the tool characteristics, an A390 alloy (Al-17% Si) round bar having four grooves extending in the axial direction on the outer peripheral surface was cut as a work material. The cutting conditions are the same as in the previous example. Cutting speed 800 m / min Cutting depth 0.2 mm Feed 0.1 mm / rev. Dry cutting. The amount of Vb abrasion after 120 minutes was 15 μm. This is a very small value. That is, it is effective to apply the present invention to thermal CVD.

EXAMPLE Thermal Plasma CVD Method FIG. 10 shows a thermal plasma CVD apparatus. Vacuum chamber 4
2, a concentric electrode 43 is provided. A cooling support 44 is provided below, and a substrate 45 is placed thereon. The electrode 43 has a cathode at the center and an anode at the periphery, and a DC power supply 46 applies a voltage between the positive and negative electrodes. The source gas 47 is introduced into the vacuum chamber 42 from the gap between the electrodes 43 via the nozzle 51. Here, the source gas 47 is ionized and flows as a plasma gas flow 52 toward the base material. The waste gas is exhausted from the vacuum exhaust port 49. The base material is 25 mm × 25 mm × 5.0 mmt polycrystalline Si. To change the film quality in the growth direction of diamond 2
The step growth process was continued.

[0071] It is. These growths continued. 29 total film thickness
00 μm (2.9 mm). According to the process of FIG. 2, a tool was prepared by brazing polycrystalline diamond on a cemented carbide base material. 12. The half-value width of the Raman spectral peak of the diamond of the first layer and the second layer is 30 μm 4.9 cm ⁻¹ (α) from the first layer rake face, and the second layer is 2862 μm from the rake face. It was 6 cm ^-1 (β).

In order to evaluate the performance of this tool, an A390 alloy (A) having four axially extending grooves formed on the outer peripheral surface was used.
l-17% Si) Using a round bar as a work material, a cutting speed of 800 m / min, a depth of cut of 0.2 mm, a feed of 0.1 mm / rev. Dry cutting was performed under the following cutting conditions. The Vb abrasion amount after 120 minutes was 31 μm, which was sufficiently small. This means that the present invention can be effectively applied to the growth of diamond by thermal plasma CVD.

[0073]

According to the present invention, a diamond film is formed by a CVD method that changes the diamond film quality in the thickness direction. Thus, a diamond film having excellent strength, wear resistance, chipping resistance, welding resistance, and heat resistance can be produced. Now, the reason why the present invention can form such a diamond film will be described. Conventionally, diamond having a uniform film quality in the thickness direction has been produced. High-purity, highly crystalline diamond has high stiffness almost as theoretically high, but is easily broken by impact. That is, diamond with high crystallinity lacks fracture resistance. Any of the conventional examples is missing in a short period of time, but it is considered to be caused by too high rigidity because it is a perfect crystal. Then, it is not true that the crystallinity should be reduced to diamond having a large content of non-diamond components and many defects. If there are many of them, there is a problem that rigidity is reduced and wear resistance is inferior.

Both fracture resistance and wear resistance are required for tools. Optimum characteristics cannot be obtained by limiting non-diamond components or defects in the film to an appropriate range.
Wear resistance is essential on the surface that comes into contact with the workpiece. Unless the toughness of the entire film is increased, the fracture resistance does not improve. In addition, rigidity and toughness are contradictory properties, and it is very difficult to achieve both. Therefore, in the present invention, complementarity is provided in the thickness direction of the film. The rake face that comes into contact with the work is made of a non-diamond component or a diamond film having few defects, thereby improving the crystallinity of each diamond. Also, the base material side is reversed to improve the toughness. Since the inside (base metal surface side) has higher toughness, the diamond does not break due to the internal buffering action even if a shock is applied to the cutting edge. This gives the diamond tool of the present invention high performance. Although the wear resistance depends on the nature of the rake face, the rake face has high crystallinity and high rigidity, so that sufficient wear resistance can be obtained even with difficult-to-cut materials. Since the sintered diamond contains a binder, the wear resistance is inevitably reduced, but this is not the case in the present invention. Also,
In consideration of the tool life, high quality diamond is preferably used up to 40 μm on the rake face side or up to 30% of the diamond film thickness. Fields where properties such as wear resistance, chipping resistance, strength, and welding resistance are strongly required, especially cutting tools,
It is useful for tools such as turning tools, excavating tools, and dressers.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of an example of a polycrystalline diamond tool.

FIG. 2 is a schematic diagram of a manufacturing process of a polycrystalline diamond tool.

FIG. 3 is a sectional view of a cutting edge of a polycrystalline diamond tool.

FIG. 4 is a cross-sectional view illustrating Raman spectroscopic analysis measurement points of the crystal diamond tool.

FIG. 5 is an example of a diamond Raman spectrum of a polycrystalline diamond tool. A method of defining the peak height X of the non-diamond component and the height Y of the diamond component will be described.

FIG. 6 is an example of a diamond Raman spectrum of a polycrystalline diamond tool. A method for defining the half width of the peak with respect to the diamond component will be described.

FIG. 7 is a schematic sectional view of a filament CVD apparatus.

FIG. 8 is a schematic sectional view of a microwave plasma CVD apparatus.

FIG. 9 is a schematic sectional view of a thermal CVD apparatus.

FIG. 10 is a schematic sectional view of a thermal plasma CVD apparatus.

FIG. 11 is a configuration diagram illustrating an example of a gas supply system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 tool base material 2 diamond film 3 installation fixing layer 4 rake face 5 base material installation fixing layer 6 substrate 7 diamond film 8 metallization layer 11 vacuum chamber 12 substrate support base 13 substrate 14 vacuum exhaust port 15 electrode 16 insulator 17 filament Reference Signs List 18 source gas inlet 19 pressure gauge 20 cooling water 22 quartz tube 23 quartz rod 24 substrate 25 gas inlet 26 source gas 27 vacuum exhaust port 28 water cooling jacket 29 magnetron 30 waveguide 31 plasma 32 plunger 35 quartz tube 36 support base 37 Base material 38 Heater 39 Source gas inlet 40 Vacuum exhaust port 42 Vacuum chamber 43 Electrode 44 Cooling support base 45 Base material 46 DC power supply 47 Source gas 48 Electrode gap 49 Vacuum exhaust port 50 Cooling water 51 Nozzle 52 Plasma gas flow 55 Hydrogen Gas cylinder 56 Inert gas cylinder 57 carbon-containing gas cylinder 58 oxygen atom-containing inorganic gas cylinder 59 bubbler 61 Te - Puhi - motor 62 Te - Puhi - data

Claims (12)

(57) [Claims] 1. A structure comprising a tool base material and polycrystalline diamond, wherein a base material installation fixing surface of the polycrystalline diamond is brought into contact with and fixed to a base material surface of a tool edge, and a workpiece is machined by a diamond rake face. The diamond has a thickness of 40 μm or more, the film quality changes in the thickness direction of the diamond, and the diamond film quality on the rake face side of the cutting edge is better than the diamond film quality on the base material installation fixed surface side. Polycrystalline diamond tool characterized by a certain thing. 2. A structure comprising a tool base material and polycrystalline diamond, wherein a base material installation fixing surface of the polycrystalline diamond is brought into contact with and fixed to the base material surface of the tool edge, and the workpiece is machined by the rake face of the diamond. Wherein the thickness of the diamond is 40 μm or more, the film quality changes in the thickness direction of the diamond, and the amorphous carbon component, non-diamond carbon component, metal impurity, A polycrystalline diamond tool characterized in that the content of non-diamond components such as nitrogen atoms is smaller than the content of non-diamond components in the diamond on the base material fixed side. 3. Inclusion of non-diamond components in diamond at least at a point within 30% or 40 μm of the average thickness of diamond, whichever is smaller, from the rake face of the cutting edge diamond to the base material face in the thickness direction. The content of non-diamond components in diamond at the smaller of 30% or 40 μm, whichever is smaller, of the average thickness of diamond from the diamond base material fixed surface to the cutting edge rake surface in the thickness direction 3. The polycrystalline diamond tool according to claim 1, wherein the number is small. 4. An average film thickness of at least 30% or 40 μm from the rake face of the cutting edge diamond toward the base material face in the thickness direction by Raman spectroscopy.
The ratio (X1 / Y1) of the peak value (X1) of the non-diamond component to the peak value (Y1) of the diamond component at the smaller one of the diamonds within:
Peak value of non-diamond component (X2) peak value of diamond component within 30% or 40 μm, whichever is smaller, of the average thickness of diamond from the diamond base material installation fixed surface to the cutting edge rake surface in the thickness direction. 4. The polycrystalline diamond tool according to claim 1, wherein the polycrystalline diamond tool has a film structure X1 / Y1 <X2 / Y2 smaller than a ratio (X2 / Y2) to (Y2). 5. 5. A structure comprising a tool base material and polycrystalline diamond, wherein a base material installation fixing surface of the polycrystalline diamond is brought into contact with and fixed to the base material surface of the tool edge, and the workpiece is machined by the rake face of the diamond. The diamond has a thickness of 40 μm or more, the film quality changes in the thickness direction of the diamond, and the defect density in the diamond on the rake face side of the cutting edge is lower than the defect density in the diamond on the base material installation fixed surface side. Polycrystalline diamond tool characterized by a small number. 6. The defect density in the diamond at least at a point within 30% or 40 μm of the average thickness of the diamond, whichever is smaller, from the rake face of the cutting edge diamond toward the thickness direction base material installation fixed face,
At least 30% or 40% or less of the average diamond film thickness from the base metal installation fixed surface to the rake surface in the thickness direction.
6. The defect density in a diamond at a smaller position within .mu.m, whichever is smaller, is small.
2. The polycrystalline diamond tool according to 1. 7. In a Raman emission spectrum obtained by Raman spectroscopy, at least 30% or 40 μm of the average thickness of the diamond from the rake face of the cutting edge diamond to the base material face in the thickness direction. The half width (αcm ^-1 ) of the peak corresponding to the diamond component of the spectrum in a small portion is within 30% of the average thickness of the diamond or 4% from the fixed surface of the diamond base material to the rake face in the thickness direction.
The half width (βc) of the peak corresponding to the diamond component of the spectrum at the smaller point within 0 μm.
7. The polycrystalline diamond tool according to claim 1, wherein the polycrystalline diamond tool has a film structure smaller than (m ^-1 ) (α <β). 8. The method according to claim 1, wherein the method of mounting and fixing the polycrystalline diamond to the base material is brazing.
The polycrystalline diamond tool according to 4, 5, 6, or 7. 9. A method for increasing the concentration of the carbon-containing gas in the source gas, decreasing the oxygen content, or reducing the nitrogen-containing gas content by chemical vapor deposition using hydrogen gas and carbon-containing gas as the source gas. While changing the components in the raw material gas in the direction of decreasing the amount, the diamond is deposited on the base material and the base material is removed to form a diamond single film, and the diamond final growth surface side is applied to the base material surface of the tool edge. A method for producing a polycrystalline diamond tool, comprising: contacting and fixing a diamond on a substrate surface side as a rake face. 10. In a step of depositing diamond on a substrate by a chemical vapor deposition method, at least two kinds of mixed gas of a hydrogen gas (A) and a carbon atom-containing gas (B) are used as a source gas. The molar fraction ratio (B1) / (A1) of the hydrogen gas (A) and the carbon atom gas (B) until at least diamond was deposited in a 12 μm film shape was 1
Molar fraction ratio (B2) / (A) when depositing 2 μm or more
(B1) / (A1) <(B2) /
(A2) The method for producing a polycrystalline diamond tool according to claim 9, characterized in that: 11. In a step of depositing diamond on a substrate, a hydrogen gas (A) and a carbon atom-containing gas (B) are used until at least 12 μm diamond is deposited.
The method for producing a polycrystalline diamond tool according to claim 10, wherein an oxygen atom-containing gas (C) is introduced into the reaction system in addition to the seed gas. 12. In a step of depositing diamond on a substrate, a hydrogen gas (A) and a carbon atom-containing gas (B) after depositing at least 12 μm diamond.
The method for producing a polycrystalline diamond tool according to claim 10, wherein a nitrogen atom-containing gas (D) is introduced into the reaction system in addition to the seed gas.