JP3469310B2 - Ceramic base material for diamond coating and method for producing coating material - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to coating ceramic base substrates, more particularly hard coatings, especially diamond coatings and c.
The present invention relates to a ceramic base material for coating a BN (cubic boron nitride) film or the like. The ceramic base material of the present invention coated with a hard coating such as diamond or cBN can be used as various cutting tools such as a bite, end mill, cutter or drill, various wear resistant members or electronic members such as heat sinks. .

[0002]

2. Description of the Related Art A diamond-coated hard material obtained by coating a substrate with diamond has a weak adhesion strength of the diamond coating layer to the substrate, and the diamond coating layer is easily peeled from the substrate. Therefore, various techniques are known for the purpose of improving the adhesion strength of the diamond coating layer to the base material. Some of them are:

Japanese Unexamined Patent Publication No. 1-246361 discloses a sintered alloy having a specific coating film formed on the heat-treated surface of a sintered alloy having a specific composition.

Japanese Unexamined Patent Publication (Kokai) No. 4-231428 discloses the production of a cutting tool in which a cemented carbide tool having a specific composition is secondarily sintered under specific conditions, and further chemically etched and ultrasonically polished to form a diamond coating layer. The law is disclosed.

JP-A-4-263074 and JP-A-4-263074
Japanese Patent No. 263075 describes a hard material formed by forming a diamond coating layer on the surface of a base material having specific irregularities.

As a technique before these, Japanese Patent Laid-Open No. 54-
87719, JP-A-58-126972 (JP-B-6-6)
2-7267) are known.

[0007] Pages 159 to 163 of "Powder and Powder Metallurgy" Vol. 29, No. 5 report on the formation of a hard layer on the surface of a WC-β-Co alloy (β: WC-TiC solid solution). The above alloy at 5.1 kPa (5 × 10 ^-2
When heated at 1673 K in N _{2 (} atmospheric pressure), a hard layer with severe irregularities is formed on the surface.
_{2 The point where the} pressure is about 0.7 kPa (about 7 × 10 ^-3 atm) or more, and the WC-T increases as the N ₂ pressure is increased and heating is continued for a long time.
It is described that the iC-TiN solid solution (β (N)) particles are coarsened and the surface unevenness becomes remarkable and a Co pool is generated on the surface.

[0008]

Even with the above-mentioned conventional techniques, the adhesion strength of the diamond coating layer to the substrate is still insufficient, and the diamond coating layer easily peels from the substrate, resulting in poor durability. Was enough.

The method described in the above "Powder and powder metallurgy" is not originally disclosed as a method for producing a base material for coating a diamond film, and whether or not a diamond film can be well coated is determined. Besides, it is unknown, and since heating is performed under reduced pressure, it is difficult to control heating conditions and stable mass production is difficult.

It is an object of the present invention to provide a coating base material, a coating base material and a method for producing a coating base material, which solves the problems of the prior art.

[0011]

According to the present invention, the above object can be achieved by the following coating substrate, coating substrate and method for producing a coating substrate.

[0012] A coating ceramic base having a base uneven surface having a surface roughness (Rz) of 2 to 20 μm, and the surface roughness (Rz) of the corner portion is 40% or more of the surface roughness (Rz) other than the corner portion. Base material.

A coated substrate obtained by coating the above ceramic base substrate for coating with a hard coating.

(A) A contour line in a cross section of a corner of a WC-based cemented carbide containing WC as a main component has a radius of curvature R 0.0.
A chamfered shape including a curve of 05 mm or more, and (b) 0.5 wt % of the WC-based cemented carbide obtained in the step (a) containing 0.05 to 5% by volume of N ₂ gas. ~ 1.
In an atmosphere of 5 atm , heat treatment is performed at a temperature not lower than the temperature at which the liquid phase of the WC-based cemented carbide is generated and not higher than the firing temperature, and (c) a coating base for forming an N-containing uneven surface layer on the surface of the WC-based cemented carbide. Method of manufacturing wood.

The base irregular surface of the above-mentioned ceramic base substrate for coating is preferably minute irregularities (more preferably 1 to 10 μm) of the size of the crystal grains constituting the outermost surface (0.5 to 10 μm).
It has a double concavo-convex surface structure in which minute concavities and convexities of 5 μm and a value smaller than the roughness of the concavo-convex surface are provided on the concavo-convex surface.

The direction of such minute unevenness is not only the vertical direction with respect to the base uneven surface, but also the licking direction and the lateral direction.

The coating ceramic base material is for diamond coating, and comprises a ceramic base material body and a coating layer for coating the base material body, and the coating layer has the double concavo-convex surface structure. Is preferably the outermost layer.

The ceramic base substrate body is preferably W
C as a main component, Ti or Ta and Ta, Co and Ni
Is a WC-based cemented carbide.

The coating layer is preferably W-Ti-C-N.
It is composed mainly of at least one of a solid solution and a W-Ti-Ta-CN solid solution.

The hard coating of the coated substrate preferably comprises diamond.

In the above-mentioned method for producing a ceramic base material for coating, preferably, an N-containing uneven surface layer having a base uneven surface having a surface roughness (Rz) of 2 to 20 μm is formed on the surface of the WC-based cemented carbide. .

More preferably, the base uneven surface has minute unevenness (more preferably 1 to 5 μm and smaller than the roughness of the base uneven surface) of about the size of crystal grains (0.5 to 10 μm) forming the outermost surface. A N-containing uneven surface layer having a double uneven surface structure having minute unevenness of a value) is formed on the surface of the WC-based cemented carbide.

Further, preferably, as the WC-based cemented carbide, a cemented carbide mainly containing WC and containing Ti or Ti and Ta and at least one of Co and Ni is used.

Further, preferably, the N-containing uneven surface layer mainly composed of at least one of W-Ti-CN solid solution and W-Ti-Ta-CN solid solution is formed.

In the ceramic base material for coating of the present invention, if the surface roughness (Rz) of the uneven surface of the base is less than 2 μm, the adhesiveness cannot be improved, and if it exceeds 20 μm, the strength of the base material decreases. Since the surface roughness (Rz) of the corners is 40% or more of the surface roughness (Rz) other than the corners, the coating is difficult to peel off when the coating is applied. Here, the surface roughness (Rz) other than the corner portion is the surface roughness (Rz) of the portion apart from the corner portion.
It is preferable that the surface roughness (R
z).

Further, the fine unevenness of the base uneven surface is 0.5 μ.
When it is m or more, the adhesiveness when coating a hard film such as diamond can be further enhanced, but even when it exceeds 10 μm, the adhesiveness exceeding the adhesiveness when it is less than 10 μm cannot be obtained. The surface roughness (Rz) is a ten-point average roughness defined in JISB0601.

In the manufacturing method of the present invention, when the N ₂ gas in the atmospheric pressure heat treatment atmosphere is less than 0.05% by volume, the amount of N in the atmosphere is small and it is difficult to form the N-containing uneven surface layer. If it exceeds 5% by volume, a large amount of the binder phase (for example, Co) contained in the WC-based cemented carbide precipitates on the surface,
It reduces the adhesion when coated with diamond.

When the heat treatment temperature is lower than the liquid phase formation temperature of the WC-based cemented carbide, the unevenness of the N-containing uneven surface layer is insufficient, the adhesion at the time of diamond coating is insufficient, and the firing temperature is If it exceeds, the particles constituting the cemented carbide may grow and the properties such as strength may deteriorate. Since the heat treatment is carried out under normal pressure, not only batch furnaces but also tunnel furnaces or the like can be continuously processed, which is a great advantage in terms of cost and productivity.

When the radius of curvature R is less than 0.005 mm, the degree of unevenness of the N-containing uneven surface layer formed at the corners after the heat treatment is a portion other than the corners (for example, the coating base material is formed. Since it is smaller than the central part of the surface to be treated or its periphery), the adhesion of the coating decreases when the coating is applied.

The coating substrate obtained by the manufacturing method of the present invention coated with a hard coating such as diamond has a hard coating and an N-containing uneven surface layer fitted together, and an N-containing uneven surface layer. And WC-based cemented carbide are also fitted, and even higher adhesion is obtained due to the anchoring effect of both fittings.

W used in the method for producing a coating substrate of the present invention
Making the corner of the C-based cemented carbide chamfered so that the contour line in the corner cross section includes a curve with a radius of curvature R0.005 to 0.10 mm is particularly useful as a base material used for manufacturing a cutting tool. preferable.

That is, the cutting tool has a cutting edge portion which is a corner defined by the intersection of the rake face and the flank face. When the contour line in the blade edge partial cross section (corner cross section) in the direction perpendicular to the rake face or the flank is composed of a curve or a straight line with a radius of curvature of less than R 0.005 mm, the corner portion has a thin base material thickness, Since the thickness of the N-containing uneven surface layer formed by the heat treatment is thin, the surface unevenness is smaller than that of the N-containing uneven surface layer other than the corners. Therefore, when the coating layer is formed, the adhesiveness of the coating layer at the corners tends to be inferior to the adhesiveness other than at the corners.

The N formed at the corners by heat treatment
The reason why the thickness of the uneven surface layer containing is reduced is, for example, WC.
When the base cemented carbide containing WC as a main component and containing Ti is used, the thickness of the corners is thin, and the amount of Ti component transferred to the WC-based cemented carbide surface side by heat treatment is small. Conceivable.

On the other hand, when the contour line includes a curve having a radius of curvature of more than R0.10 mm, N formed by heat treatment is used.
The surface irregularity of the containing irregular surface layer has a sufficient degree of surface irregularity, and the adhesiveness between the corner portion and the coating layer is the same as the adhesiveness other than the corner portion. However, when the corner after coating is used as the cutting edge portion of the cutting tool, cutting resistance increases excessively and welding of cutting chips occurs, or the surface finish state of the work material after cutting tends to be rough. .

The chamfered shape of the corners can be performed by honing such as round honing.

In the present specification, the ceramic base material mainly refers to an ultra-hard ceramic material (carbide, nitride, boride and a compound compound of these compound compounds or oxides, a metal compound, etc.). It is a hard base material as a component, and basically includes cemented carbide, cermet, etc., which is obtained by sintering and has a carbide of a high melting point metal as a main component and a metal phase as a binder phase. The base material itself may be a composite structure having a coating layer. Also, the base uneven surface is JIS
It is a surface having a ten-point average roughness defined in B0601 of 2 to 20 μm. Normal pressure means 0.5 to 1.5 atmospheres.

[0037]

Preferred Embodiment

(Ceramic base substrate for coating) The ceramic base substrate for coating of the present invention can be composed of a substrate main body and a coating layer for coating the same, and one or more coating layers can be provided. It is preferable that the base body and the coating layer are fitted together.

The base material body is preferably made of a hard material such as cemented carbide, and can be, for example, WC—Co type cemented carbide containing TiC or TaC. When TaC is included, a part or all of Ta is V, Zr, Nb,
It may be replaced with at least one of Hf.

The coating layer is preferably W--Ti--C--N.
Mainly comprises at least one of a solid solution and a W-Ti-Ta-CN solid solution.

(Coated Substrate) The coated substrate of the present invention comprises the ceramic base substrate for coating of the present invention coated with a hard coating, and the material of the hard coating is diamond or cB.
N can be used.

(Method for producing base material for diamond coating) W
The C-based cemented carbide contains WC as a main component, and as other components, preferably, one containing Ti or Ta and Ta and at least one of Co and Ni as a binder phase can be used. In this case, the preferred composition of the WC-based cemented carbide is Ti or Ta and Ta in terms of carbide of 0.2 to 2
0% by weight (preferably 0.5 to 10% by weight, more preferably 1 to 5% by weight), and at least one of Co and Ni.
The seed is 2 to 15% by weight (preferably 3 to 10% by weight,
More preferably 4 to 7% by weight), and the alloy is W-
It has at least one of a Ti—C solid solution (β phase) and a W—Ti—Ta—C solid solution (β _t phase). The β phase and β _t
The preferable average crystal grain size of the phase is 0.5 to 10 μm (more preferably 1 to 5 μm).

When Ti is less than 0.2% by weight in terms of carbide, it is difficult to form the N-containing uneven surface layer by heat treatment, and the surface layer itself after heat treatment is easily peeled off.
The reason why it becomes easy to peel off is that most of the Ti component moves to the surface by heat treatment and W-Ti-CN solid solution (β
This is because the (N) phase) is formed on the surface, the Ti component and other alloy components are separated, and the fitting state is deteriorated. Further, when Ti exceeds 20% by weight in terms of carbide, it is already brittle before heat treatment, and the coefficient of thermal expansion becomes large, so that the difference from that of diamond becomes large, and it becomes difficult to form the base material during cooling after coating with diamond. Shear stress is likely to occur at the diamond film interface, causing film peeling.

The reason why the preferable upper limit value when Ta is contained in addition to Ti is 20% by weight is the same as above.

Incidentally, part or all of Ta can be replaced with at least one of V, Zr, Nb and Hf within a range that does not adversely affect the heat treatment. Also, WC, T
The WC-based cemented carbide obtained by densely sintering powders of iC, TaC, Co, etc. by a powder metallurgy method has low strength when the carbide crystal phase grows during the sintering, At least one of Cr and Mo that suppresses the grain growth can be contained as a carbide in a range that does not adversely affect the heat treatment in the present invention.

When the content of at least one of Co and Ni as the binder phase is less than 2% by weight, it is difficult to densify by sintering during the production of WC-based cemented carbide, and it is required as a base material. The properties such as strength are insufficient. On the other hand, 15
If the content exceeds 10% by weight, these components are likely to appear on the surface of the substrate during the heat treatment or the diamond film formation in the present invention, which may adversely affect the diamond film formation. May be large and may cause film peeling.

When the average particle size of the β phase or β _t phase is less than 0.5 μm, the unevenness of the N-containing surface layer formed after heat treatment becomes small, and the N-containing surface layer and the WC-based cemented carbide inner layer are In some cases, the mating may not be obtained sufficiently. If it exceeds 10 μm, the mating may be insufficient, or the W
The strength as a C-based cemented carbide may not be obtained in some cases.

Note that N containing a β (N) phase in advance is obtained by sintering by adding powder containing N such as TiN or TiC-TiN solid solution or sintering in an atmosphere containing nitrogen atoms.
In the case of containing cemented carbide or cermet, it becomes difficult to form irregularities in the surface layer even by the heat treatment in the present invention,
It may be difficult or unstable to control the unevenness due to the heat treatment atmosphere.

N _{2 in} the atmosphere for heat treatment of WC-based cemented carbide
To control the content accurately, the furnace used for heat treatment
It is composed of refractory materials that do not affect the N ₂ content in the atmosphere, and a furnace composed of refractory materials such as BN is not used.

The preferred heat treatment temperature for WC-based cemented carbide is 1
Although the temperature is 350 to 1450 ° C., the lower limit temperature varies depending on the amount of carbon in the alloy and the amount ratio of Co and Ni.

The heat treatment time is a factor that most affects the degree of unevenness of the N-containing surface layer, and by adjusting this, an N-containing surface layer having arbitrary unevenness can be formed. In order to efficiently and stably obtain the N-containing layer, the heat treatment temperature and the N ₂ content in the atmosphere are adjusted, and the heat treatment time is preferably 0.5 to 5 hours.

The atmosphere during the heat treatment is N ₂ at atmospheric pressure.
0.05 to 5% by volume, preferably 0.5 to 3% by volume
It is contained, and the balance is an inert gas such as Ar.

By the method for producing a coating base material of the present invention,
After the N-containing uneven surface layer is formed, N may be released from the surface layer by performing a heat treatment again in an inert atmosphere such as argon within a range that does not change the film adhesion of the surface layer.

As another method of obtaining the same effect as the above-mentioned reheat treatment (making sure that N is not included in the outermost surface), a hard coating such as TiC is formed on the uneven surface by a known method such as CVD or PVD. You may coat by the thickness which does not change the surface shape of a layer so much.

As a method for coating the diamond, a so-called CVD method can be used in which a gas obtained by exciting a mixed gas of a carbon source gas and a hydrogen gas is brought into contact with a base material.
Among them, the microwave plasma CVD method is preferable as a means for accurately controlling the synthesis conditions.

The diamond coating may be performed in two or more steps to form two or more coating layers.

[0056]

【Example】

(Reference Example) As raw material powder, WC powder having an average particle diameter of 2 μm, TiC-WC solid solution powder, TaC having an average particle diameter of 1 μm
Powder and Co powder are prepared, and these raw material powders are used as WC and T
iC, TaC, and Co were converted into the proportions shown in Table 1, and the mixed powders were wet mixed, dried, and then pressed into a green compact at a pressure of 1.5 ton / cm ^2. The green compact was sintered in a vacuum at 1400 to 1450 ° C. for 1 hour to produce a sintered body having the same composition as the above-mentioned composition. The surface of these sintered bodies is ground to ISO standard S
It was molded into a chip having the shape of PGN120308.

Put these chips in a carbon case,
Heat treatment was performed under the conditions shown in Table 2 using an electric furnace in which all parts exposed to high temperatures such as a heater and a heat insulating material were made of carbon to form surface-altered layers having the characteristics shown in Tables 2 and 3.

The obtained substrate (Sample Nos. 2 to 40) having the surface-altered layer and the chip not subjected to the heat treatment (Sample No. 1) were immersed in a solvent in which diamond fine powder having an average particle diameter of 10 μm was separated by floating. Then, ultrasonic treatment was applied to activate the surface.

The thus obtained chip is 2.45 GH
850 in a microwave plasma CVD apparatus
H ₂ -2% CH ₄ heated to ℃ and total pressure 50 Torr
10 hours in the mixed plasma of
A diamond-coated cutting tip was manufactured. In this test, it was confirmed by Raman spectroscopy that the coating layer deposited on the surface of the substrate was a diamond coating layer.

Tables 2 and 3 show the results of a cutting test conducted under the following conditions using these cutting chips.

Continuous cutting: Turning (processing the outer circumference of a cylindrical work material having a diameter of about 150 mm and a length of about 200 mm) Work material: A1-18 wt% Si alloy Cutting speed: 800 m / min Feed: 0.15 mm / rev Depth of cut: 0.5 mm Intermittent cutting: Milling (approximately 150 x 150 mm and thickness of approximately 5
The surface of a 0 mm square plate work material is processed. ) Work material: A1-18wt% Si alloy Cutting speed: 600m / min Feed: 0.1mm / tooth Depth of cut: 0.5mm

[0062]

[Table 1]

[0063]

[Table 2]

[0064]

[Table 3]

In Tables 2 and 3, α, β, and γ are symbols showing crystal phases, and have the following meanings. α: WC β: β phase, β _t phase and β (N) phase in which N is solid-solved therein, etc. γ: Co and / or Ni-bonded phase as a main component By the elemental analysis of the cross-section in the thickness direction of the base material by electron beam microprobe analysis (EPMA), it was observed that a Ti and / or Ta component segregated near the surface and a portion containing no Co was observed. When the particles containing Ti, Ti and / or Ta or the binder-containing phase containing Co showed no difference on the surface and inside and were relatively uniform, it was judged that there was no surface alteration layer.

(Electron Beam Microprobe Analysis) With respect to each of the base material of Sample No. 11 and the base material of Sample No. 1, elemental analysis of a cross section in the thickness direction of the base material was performed by electron beam microprobe analysis (EPMA). As a result, the base material of Sample No. 1 has a structure in which particles (β _t phase) containing Ti and Ta and a binder phase containing Co are dispersed relatively uniformly, and the surface does not have an altered layer. It turned out to be a thing.
On the other hand, it was found that the base material of Sample No. 11 had a surface-altered layer containing Ti and Ta on the surface, and this altered layer did not contain Co at all. It was also confirmed that nitrogen (N) was contained in the surface-altered layer. The results are shown in FIGS. 5 and 7.

(Example) A sintered body of the material F shown in Table 1 was manufactured in the same manner as in the above-mentioned reference example, and this sintered body was ground to produce I
A cemented carbide chip of SO standard SPGN120308 shape was obtained. The cutting edge of this tip is subjected to honing so that the contour line in the cross section of the cutting edge in the direction perpendicular to the rake face includes the line or curve of the radius of curvature (R) shown in Table 4, and these tips are cut into a carbon case ( The thickness is 4 mm, the inner diameter is φ92 × 31 mm), and an electric furnace in which all parts exposed to high temperature such as heater and heat insulating material are made of carbon is used at 1375 ° C. for 3 hours, 1% N ₂ -Ar atmosphere, 1 atm
A heat treatment was performed therein to form a surface-altered layer (N-containing uneven surface layer). Sample numbers 41, 44, and 46 of these chips are shown in FIGS. 14, 15, and 16 as a cross-sectional view in a direction perpendicular to the rake face of the tip of the chip.
Surface conditions are shown in 7, 18, and 19. Table 4 shows the thickness distribution and surface unevenness distribution of the surface-altered layer.

The honing process was carried out by using a "brush grinder" in which a liquid in which a free diamond grindstone was dispersed in oil was supplied to the tip and the disc-shaped brush was rotated to contact the tip. The number of brush rotations is as processing conditions:
The cutting edge was made to have a predetermined radius of curvature at 300 to 600 rpm, the free diamond grindstone number: 300 to 1000, and the processing time: 1 to 10 minutes. The surface condition of the work material was determined by the following criteria based on the surface roughness Rz of the work material (10-point average roughness specified in JIS B0601). Good: Rz ≦ 6 μm Fair: 6 μm <Rz ≦ 12 μm Poor: Rz> 12 μm A preferable cutting time range for film peeling is over 60 minutes (more preferably 120 mm) in the case of continuous cutting.
In the case of intermittent cutting, it is in the range of more than 40 minutes (more preferably in the range of more than 70 minutes).

[0069]

[Table 4]

The chip thus obtained is set to 2.45 GHz.
Installed in the microwave plasma CVD device at 850 ° C
98% by volume H ₂ -2 by heating to a total pressure of 50 Torr
It was kept in a mixed plasma of volume% CH ₄ for 10 hours to prepare a diamond-coated cutting tip with a film thickness of about 10 μm.

A cutting test was carried out using these cutting chips under the following conditions. As shown in Table 4, the diamond-coated chips of the present invention showed that the diamond film was not peeled off even under severe cutting conditions and the work material was cut. Can be cut with good surface roughness for a long time, in the comparative example the adhesion strength of the diamond film is insufficient, so it is easy to peel off, and the time for cutting the work material with good surface roughness may be short. Recognize. Continuous cutting: Turning (diameter about 150mm, length about 200mm
The outer circumference of the cylindrical work material is processed. ) Work material: Al-18 wt% Si alloy Cutting speed: 1500 m / min Feed: 0.15 mm / rev Depth of cut: 0.5 mm Interrupted cutting: Milling cutter (about 150 x 150 mm and thickness about 5)
The surface of a 0 mm square plate work material is processed. ) Work material: Al-18wt% Si alloy Cutting speed: 1000m / min Feed: 0.1mm / tooth Depth of cut: 0.5mm

The surface irregularities (surface roughness Rz) were measured by attaching a three-dimensional shape analyzer (RD-500 manufactured by Electron Optical Laboratory Co., Ltd.) to a scanning electron microscope (SEM). This device divides the backscattered electron detector of the SEM into four and measures changes in the electron beam scattering direction due to the surface shape, and makes it possible to perform three-dimensional shape measurement by performing data analysis by a computer. In the contact type using a contactor used for measuring the surface shape such as roughness, the tip radius of the contactor is about 5 to 10 μm, which makes it possible to measure minute irregularities that are difficult to measure.

The uneven waveform of the cross section is obtained from the obtained surface shape data, Fourier-transformed, the component having a period of 25 μm or more is removed by a filter, and then the inverse Fourier transform is performed. The prescribed ten-point average roughness (Rz) is calculated. By this method, Rz can be obtained for the uneven component having a period of 25 μm or less.

The surface roughness (Rz) of the cutting edge, which is the corner of each tip of sample numbers 41 to 46 in Table 4, is about 31% of the center surface roughness (Rz) (sample numbers 41 to 4).
2), about 47% (Sample No. 43), about 69% (Sample No. 44), about 84% (Sample No. 45), 100% (Sample No. 46).

[0075]

The ceramic base material for coating of the present invention has the above-mentioned specific base uneven surface, and the surface roughness (Rz) of the corner portion is 40% or more of the surface roughness (Rz) other than the corner portion. Therefore, when a hard coating layer such as diamond is formed on the surface, the coating layer strongly adheres to the surface of the substrate and is difficult to peel off.

The method for producing a coating base material of the present invention comprises (a)
The corner of the WC-based cemented carbide containing WC as a main component is chamfered so that the contour line in the corner cross section includes a curve having a radius of curvature R 0.005 mm or more, and (b) the step (a) above. The WC-based cemented carbide obtained in
Heat treatment at a temperature higher than the temperature at which the liquid phase of the WC-based cemented carbide is generated and at a temperature lower than or equal to the firing temperature in a normal pressure atmosphere containing ₂ gases,
(C) Since the N-containing uneven surface layer is formed on the surface of the WC-based cemented carbide, when a hard coating layer such as diamond is formed on the surface of the N-containing uneven surface layer, the coating layer has a strong effect on the surface layer. It is possible to manufacture a coating base material that adheres to and is difficult to peel off.

Therefore, according to the present invention, it is possible to manufacture various cutting tools, wear resistant members, and electronic members in which the hard coating layer of diamond or the like is less likely to peel off and which has a long service life.

[Brief description of drawings]

FIG. 1 is a photograph of a structure of a ceramic material showing a fine structure of the surface of a base material (Sample No. 10) of a reference example.

FIG. 2 is a photograph of the structure of a ceramic material showing the microstructure of the cross section after coating the base material (Sample No. 10) of the reference example with diamond.

FIG. 3 is a photograph of a microstructure of a ceramic material showing a microstructure of a cross section of a cutting edge after coating a base material (Sample No. 10) of Reference Example with diamond.

FIG. 4 is a photograph of the structure of a ceramic material showing the microstructure of the central cross section after coating the base material (Sample No. 10) of the reference example with diamond.

FIG. 5 is a photograph of the structure of the ceramic material showing the microstructure (upper left side) of the cross section of the base material (Sample No. 11) of the reference example and electron beam microprobe analysis (EPMA) which is extremely difficult to draw according to the drawing method. ) Elemental analysis results (the left central part is W, the lower left part is Ta, the right central part is T
i, the lower part on the right is an X-ray photograph showing Co).

FIG. 6 is a photograph of the structure of a ceramic material showing the fine structure of the surface of sample number 1 (comparative example).

7 is a photograph of a microstructure of a ceramic material showing a microstructure (upper left side, upper central part) of a cross section of Sample No. 1 (comparative example) and an EPM which is extremely difficult to draw according to a drawing method.
An X-ray photograph showing the result of elemental analysis by A (W on the left side, Ta on the left side, Ta on the left side, Ti on the center side, Co on the center side, C on the right side, and C on the right side) (The scale of each part is the same).

FIG. 8 is a photograph of a metallographic structure showing the surface (metallographic structure) of the substrate where the diamond film of Sample No. 1 (Comparative Example) coated with the diamond film is partially peeled and exposed.

FIG. 9 is a photograph of the structure of a ceramic material showing the fine structure of the surface of sample No. 2 (comparative example).

FIG. 10 is a photograph of the structure of a ceramic material showing the fine structure of the surface of sample No. 30 (comparative example).

FIG. 11 is a photograph of the structure of a ceramic material showing the fine structure of the surface of sample number 32 (comparative example).

FIG. 12 is a schematic view showing a microstructure of a cross section after coating a base material of the present invention with diamond.

FIG. 13 is a conceptual diagram of heat treatment conditions of the present invention.

FIG. 14 is a cross-sectional view of a blade edge portion of a chip of sample number 41.

FIG. 15 is a cross-sectional view of a cutting edge portion of a chip of sample number 44.

FIG. 16 is a cross-sectional view of the tip portion of the chip of sample number 46.

FIG. 17 is a photograph of the structure of a ceramic material showing the surface irregularities of the chip of sample No. 41.

FIG. 18 is a photograph of the structure of a ceramic material showing the surface irregularities of the chip of sample number 44.

FIG. 19 is a photograph of the structure of a ceramic material showing the surface irregularities of the sample No. 46 chip.

[Explanation of symbols]

1 ... Carbide base material 2… Surface alteration layer

Front page continuation (72) Inventor Shoichi Watanabe 14-18 Takatsuji-cho, Mizuho-ku, Nagoya City Japan Special Ceramics Co., Ltd. (56) Reference JP-A-3-86403 (JP, A) International Publication 93/002022 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) B22F 3/24 C23C 8 / 24,16 / 02,26 / 00 B23B 27/14

Claims (13)

(57) [Claims] 1. A surface roughness (Rz) having a base uneven surface of 2 to 20 μm, and the surface roughness (Rz) of the corner portion is 40% or more of the surface roughness (Rz) other than the corner portion. A characteristic ceramic base material for coating. Wherein said groups uneven surface is sized extent is 0 .5~10μ m of the fine irregularities made has with respect to the base uneven surface double uneven surface structure of the crystal particles constituting the outermost surface The ceramic base substrate for coating according to claim 1, which comprises: 3. A ceramic base substrate for coating according to claim 1, which is for coating diamond. 4. A ceramic base substrate body and a coating layer for coating the substrate body, wherein the coating layer having the base uneven surface is the outermost layer. A ceramic base material for coating according to the description. 5. The ceramic base material body is a WC-based cemented carbide containing WC as a main component and containing Ti or Ti and at least one of Co and Ni. The ceramic base material for coating according to claim 4. 6. The coating according to claim 4, wherein the coating layer is mainly composed of at least one of a W—Ti—C—N solid solution and a W—Ti—Ta—C—N solid solution. Ceramic base material. 7. A coated substrate obtained by coating the coating ceramic base substrate according to claim 1 with a hard coating. 8. The coated substrate according to claim 7, wherein the hard coating is made of diamond. 9. (a) A corner of a WC-based cemented carbide containing WC as a main component has a radius of curvature R 0.005 when the contour line in the cross section of the corner.
a chamfered shape including a curve of mm or more, (b) the WC-based cemented carbide obtained in the step (a),
0.5 to 1.5 gas containing 0.05 to 5% by volume of N ₂ gas
In an atmosphere of pressure , heat treatment is performed at a temperature not lower than a temperature at which a liquid phase of the WC-based cemented carbide is generated and not higher than a firing temperature, and (c) an N-containing uneven surface layer is formed on the surface of the WC-based cemented carbide. A method for producing a coating substrate. 10. The coating according to claim 9, wherein an N-containing uneven surface layer having a basic uneven surface having a surface roughness (Rz) of 2 to 20 μm is formed on the surface of the WC-based cemented carbide. A method for manufacturing a base material. Wherein said group uneven surface, sized extent is 0 .5~10μ m of the fine irregularities made has with respect to the base uneven surface double uneven surface structure of the crystal particles constituting the outermost surface With N
The method for producing a coating base material according to claim 10, wherein the containing uneven surface layer is formed on the surface of the WC-based cemented carbide. 12. The WC-based cemented carbide is a cemented carbide mainly composed of WC and containing Ti or Ti and Ta, and at least one of Co and Ni. 11. The method for producing a coating substrate according to any one of items 1 to 11. 13. A W-Ti-C-N solid solution and W-Ti-
10. An N-containing concave-convex surface layer mainly composed of at least one Ta-CN solid solution is formed.
12. The method for producing a coating base material as described in 1 above.