JPWO2000079022A1 - coated hard alloy - Google Patents

Abstract

(57) [Abstract] Provided is a coated hard alloy with excellent wear resistance, chipping resistance, welding resistance, and peeling resistance. The hard alloy surface comprises an inner layer, an intermediate layer, and an outer layer. The inner layer comprises one or more layers selected from carbides, nitrides, borides, oxides, and solid solutions of elements of Groups IVa, Va, and VIa of the periodic table. The intermediate layer comprises one or more layers selected from aluminum oxide, zirconium oxide, and solid solutions thereof. The outer layer comprises a titanium carbonitride layer having a columnar structure. In the cross-sectional structure of the coated hard alloy, the relationship between the maximum roughness Amax of the surface layer portion of the intermediate layer and the maximum roughness Bmax of the surface layer portion of the titanium carbonitride layer having a columnar structure in the outer layer satisfies Equation 1: (Bmax/Amax)<1 ...Equation 1, where 0.5 μm<Amax<4.5 μm and 0.5 μm≦Bmax≦4.5 μm.

Description

Detailed Description of the Invention

Technical Field The present invention relates to coated hard alloys. In particular, they are ideal for cutting tools and have excellent wear resistance.
It has excellent wear resistance, chipping resistance, adhesion resistance and peeling resistance, and maintains this excellent performance for a long period of time.
This paper relates to coated hard alloys that exhibit excellent cutting properties. Background Technology In order to improve the cutting properties of the outer surface of hard alloys, chemical vapor deposition or physical vapor deposition is used.
titanium carbide, titanium nitride, titanium carbonitride, aluminum oxide, etc.
Coated hard alloy tools with a single or multi-layer coating have been put to practical use.
This type of titanium-based coating film is useful as a non-oxidizing film, improving wear resistance and chipping resistance.
In addition, oxide films such as aluminum oxide and zirconium oxide are chemically stable.
It has excellent heat resistance, so it can withstand temperatures exceeding 700°C (high-speed cutting)
In recent years, advances in machine tools, reductions in production costs, and improvements in productivity have led to an increase in cutting work.
Dry cutting is becoming more and more efficient, and cutting oil is being used less due to environmental issues.
Due to this market trend, cutting tool cutting edges are becoming increasingly
There are an increasing number of cases where they are used in high temperature ranges. Therefore, oxide films such as aluminum oxide and zirconium oxide are used,
The film with excellent chemical stability and heat resistance is placed on the outer layer of the cutting tool, and the oxide film is made thicker.
This extends tool life and responds to market trends. However, the thickness of the oxide film (especially the aluminum oxide film) is 1.5 μm or more.
When the coating is made thick, the oxide crystal grains that make up the coating layer become coarser, and the tool surface becomes grainy.
The unevenness on the tool surface corresponds to the chip size.
Stress is applied locally by debris, which accelerates wear and reduces toughness.
Chips are welded to the uneven surface, and stress is applied from the welded area, causing film peeling or chipping.
This causes problems and reduces the life of the cutting tool. In response to this, Japanese Patent Publication No. 5-49750 describes a method for forming aluminum oxide films in several layers.
A method has been proposed in which the grains are divided to prevent coarsening of the grains.
According to this, aluminum oxide can be atomized, but on the other hand,
The number of interfaces between the film and other materials increases, making it easier for peeling to occur at the interface.
Damage progresses rapidly from this point onwards, shortening the tool life. In addition, Japanese Patent Laid-Open Publication No. 5-57507 describes a method for removing such irregularities in the oxide film by applying pressure to the cutting edge of the tool.
Only the tip is polished to make it smooth, extending the tool's lifespan.
It is true that the cutting edge can be made longer, but the recesses on the rake face, etc.
In areas where polishing cannot be performed, the unevenness of the oxide film as described above remains.
This caused wear such as crater wear to progress rapidly, shortening tool life. On the other hand, Japanese Patent Laid-Open Publication No. 11-124672 describes a high-strength coating using an alpha-type oxide film on the outer layer.
The orientation is determined using aluminum, but this method involves the outer layer of aluminum oxide.
The tool surface is roughened depending on the size of the aluminum crystal grains.
This caused a decrease in the lifespan of the device. In addition, Japanese Patent Laid-Open No. 8-158052 discloses a device having a film structure similar to that of the present invention.
However, the roughness of the middle layer is not improved in the outer layer, so high-speed cutting is difficult.
In the case of cutting or dry cutting, further research has been carried out to extend the life of the tool, and this invention has been developed.
In view of the above-mentioned circumstances, the present invention aims to reduce the irregularities inherent in oxide films in the outer layer,
By improving the overall wear resistance, chipping resistance, adhesion resistance, and peeling resistance,
The main objective is to provide coated hard alloy cutting tools that provide excellent performance over a long period of time.
Disclosure of the Invention The present invention relates to a coated hard alloy having a coating layer formed on the surface of the hard alloy.
The alloy comprises an inner layer, an intermediate layer and an outer layer in this order from the hard alloy side, and each of these layers has the following structure:
It is characterized by being composed of a material with a predetermined surface roughness. Inner layer: Carbides, nitrides, borides, and oxides of elements from groups IVa, Va, and VIa of the periodic table
It includes a layer composed of one or more materials selected from aluminum oxide, zirconium oxide, and solid solutions thereof. Intermediate layer: Selected from aluminum oxide, zirconium oxide, and solid solutions thereof
Outer layer: A layer composed of one or more titanium carbonitrides of the periodic table, including titanium carbonitride layers with a columnar structure.
Carbides, nitrides, borides, oxides and their solid solutions and oxides of Group Ia
It includes a layer composed of one or more materials selected from aluminum. Surface roughness: The maximum roughness of the surface layer (interface) of the intermediate layer in the cross-sectional structure of the coated hard alloy.
The thickness Amax and the surface layer (interface) of the titanium carbonitride layer with a columnar structure in the outer layer
) satisfies Formula 1. More preferably, it satisfies Formula 2.
. (Bmax/Amax)<1 ...Equation 1 However, 0.5μm<Amax<4.5μm, 0.5μm≦Bmax≦4.
5 μm (Bmax/Amax) < 0.8 ... Equation 2 The roughness is measured by mirror-polishing a cross section perpendicular to the tool flank and then measuring the optical
Measurements are made based on the photograph taken using a microscope at a magnification of 1500 times as shown in Figure 1.
The unit evaluation length of the fixed part is set to 0.02 mm, and the maximum and minimum peak heights between them are
The difference between the maximum roughness of the surface of the intermediate layer and the maximum roughness of the outer layer is called the maximum roughness in the present invention.
The maximum roughness of the surface layer of the columnar structure TiCN was measured and quantified using the above formula 1.
The roughness value is calculated using the average value of five different fields of view according to this measurement method.
The usual stylus method cannot measure the surface roughness of, for example, an interface.
Therefore, the present invention adopted the above method. When titanium carbonitride, which has high wear resistance, is used as the outer layer, it has high thermal conductivity, so it can be used at high speeds.
When used in high temperature cutting, the entire tool becomes hot and the base material becomes superheated.
The hard alloy undergoes plastic deformation, which increases the cutting resistance and leads to fracture.
Between titanium carbonitride and aluminum oxide and zirconium oxide, which have low thermal conductivity,
However, the above oxide and carbonitriding are not suitable for the intermediate layer.
Titanium has low bonding strength, so if it is coated using the usual method, it will peel off during use.
In addition, the surface roughness of the thick middle layer is large, and this surface roughness is directly transmitted to the outer layer.
This tends to result in a coated hard alloy with a rough outer layer. Therefore, the inventors conducted extensive research to solve this problem, and in making this invention,
In other words, in order to increase the bonding strength between the intermediate layer and the outer layer, the surface roughness of the intermediate layer was increased.
By increasing the thickness, the bonding area with the outer layer is increased and the anchor effect is enhanced.
The outer layer is made of carbon with a columnar structure that has a specific crystal orientation.
The surface of the outer layer is smoothed by using titanium nitride. According to the inventors' research, once the aluminum oxide intermediate layer is formed, it is cooled.
It was found that cracks occurred in the intermediate layer perpendicular to the film.
The outer layer, for example, TiN, fills the cracks.
It penetrates into the aluminum oxide and titanium carbonitride layers, providing a strong anchoring effect. As shown in Figure 1, the interface between the aluminum oxide and titanium carbonitride layers in the intermediate layer is
The maximum roughness is large, but the maximum roughness is small on the surface of the outer layer.
This is expressed by formulas 1 and 2. Titanium carbonitride has such exceptional properties.
The CN layer cannot be obtained by conventional methods.
This increases the crystal growth rate, and when a specific crystal orientation is achieved,
This can be achieved by using various materials that have a stronger bond strength with the oxide that makes up the intermediate layer than with cemented carbide.
The use of compounds has been done in the past. The above explanation can be summarized as follows: After coating the surface of the hard alloy with an inner layer, an intermediate layer is used to provide chemical stability and heat resistance.
The oxide film is coated with a coarse grain size with excellent properties, and has a columnar structure (columnar crystal structure).
The outer layer is coated with a titanium carbonitride layer to absorb the irregularities of the intermediate layer.
Figure 2 shows the columnar structure of the outer layer. This photograph shows the fracture surface of the coated hard alloy.
This actively creates unevenness in the oxide film, which is the intermediate layer, and improves adhesion, which was previously weak.
The adhesion between the aluminum oxide middle layer and the outer layer, which was previously only possible with conventional
Furthermore, smoothing the unevenness of the outer layer improves the abrasion resistance, chipping resistance, and
This improves welding resistance and allows for excellent performance over a long period of time. Here, the thickness of each layer is 0.1 to 10 μm for the inner layer, and 10 μm for the outer layer.
If it exceeds 0.1 μm, the strength decreases, and if it is less than 0.1 μm, there is no effect.
If the thickness of the intermediate layer is less than 1.5 μm, the heat conduction cannot be suppressed.
If the thickness exceeds 20 μm, the strength will decrease and the tool life will be shortened.
The thickness of the intermediate layer is more preferably in the range of 5 to 15 μm. The thickness of the outer layer is
If the thickness of the outer coating layer is less than 2 μm, the thickness of the intermediate layer, which is the lower layer, is 2 to 30 μm.
If the thickness exceeds 30 μm, the effect of improving the unevenness of the layer will be reduced.
Such a film thickness limit is necessary because the roughness increases.
The thickness of the outer coating layer is preferably 5 to 20 μm. The orientation index TC of the columnar titanium carbonitride layer in the outer layer is (22
The best surface is one of the (311) plane, (331) plane, and (422) plane.
If the maximum value is 1.3 or more and 3.5 or less, the unevenness of the intermediate layer can be improved.
It is more preferable that the TC of both the (311) plane and the (422) plane
This occurs when the orientation index TC is between 1.3 and 3.5. This orientation index TC is defined by the following equation 3:
. I(hkl), I(hkl)_xk_yl_z): Measured (hkl), (h_xk_yl_z
) Diffraction intensity of the plane Io(hkl), Io(h_xk_yl_z): According to ASTM standards (hkl), (h
_xk_yl_z) Average powder diffraction intensity of TiC and TiN on the surface (hkl), (h_xk_yl_z): (111), (200), (220), (31
The orientation index TC of the columnar structure titanium carbonitride layer is determined from the diffraction peaks measured by X-ray diffraction.
In this case, the diffraction peak of the (311) plane of TiCN was the same as that of the (11) plane of the WC substrate.
1) The peak overlaps with the (111) plane peak of WC, so it is corrected as follows:
The intensity is the strongest peak of WC, the (101) plane (shown as (A) in FIG. 3).
This means that the strength of the (311) plane of TiCN is 25% of that of WC.
The value obtained by multiplying the (101) plane intensity by 0.25 (this is the peak intensity of the (111) plane of WC)
The value obtained by subtracting the diffraction grating (corresponding to the diffraction grating) is used.
The peaks are shown in Figure 3. By setting the orientation index of the columnar titanium carbonitride layer within the above range,
The roughness of the oxide film, which is the layer, can be improved, and it becomes easier to obtain a coated hard alloy that satisfies the relationship of formula 1.
This improves wear resistance, chipping resistance and welding resistance, and provides excellent performance.
It is possible to form the titanium carbonitride layer using, for example, TiCl₄, organic carbonitride compounds, hydrogen gas,
The film is formed using nitrogen gas at 700 to 1000°C and a pressure of 667 hPa or less.
In particular, CH₃When CN is used, the
The crystal grains are easily made into columnar crystals.
(TiCl₄+CH₃CN)/(total gas volume) ratio is smaller than in the latter half.
Comb and first half N₂/ (total gas amount) ratio is set to more than twice that of the latter half,
The thickness is preferably less than 10 μm. The intermediate layer is preferably made essentially of α-type aluminum oxide, as this improves mechanical strength.
The orientation index TCa of this α-type aluminum oxide is TCa(012).
It is preferable that the orientation index is >1.3. This orientation index is defined by the following equation 4. I(hkl), I(hkl)_xk_yl_z): Measured (hkl), (h_xk_yl_z)
Diffraction intensity of the surface Io(hkl), Io(h_xk_yl_z): α-crystalline aluminum according to ASTM standards
Na's (hkl), (h_xk_yl_z) Powder diffraction intensity of the plane (hkl), (h_xk_yl_z): (012), (104), (110), (11
3), (024), and (116) In Figure 3, the diffraction peaks of aluminum oxide are difficult to see, but by removing the outer layer,
This is clearly evident. Furthermore, both TCa(104) and TCa(116) exceed 1.3.
It is also preferable to specify the orientation index in this way.
This also improves the peel resistance of the tool. The mechanical strength of the oxide film, which is the intermediate layer, is improved. The crystal grains in the intermediate layer can be coarsened. The mechanical adhesion between the intermediate layer and the outer layer can be improved. As a result, excellent chemical stability and heat resistance at high temperatures can be fully achieved.
This allows the aluminum oxide to exhibit its desired properties, thereby extending the tool life. The orientation of aluminum oxide can be controlled, for example, as follows: First,
After coating to the layer just below the aluminum, CO
₂The surface of the layer directly below is exposed to an atmosphere with a pressure of 0.4 to 0.8 hPa.
Oxidation is then carried out at 1000 to 1200°C, preferably 1050 to 1150°C.
This allows the aluminum oxide to be deposited regardless of the temperature at which the aluminum oxide is deposited.
First, an α-type aluminum oxide film is formed. At this time, the oxidation conditions of the surface of the layer just below are selected.
This allows for control of the orientation of aluminum oxide.
The orientation can also be changed by changing the film thickness of aluminum oxide.
. In addition to the above-mentioned limitations on the composition of each layer, further polishing after coating is also possible.
If the surface roughness Cmax of the outermost surface of the coating layer is improved so as to satisfy Equation 5, the tool life will be further improved.
This can improve tool life. Even if the treatment is applied only to the cutting edge, tool life can be further improved. Cmax/Bmax < 0.5 ... Equation 5 On the other hand, the base hard alloy is primarily composed of tungsten carbide, and is classified as IVa of the periodic table.
Hard metals containing at least one of carbides, nitrides and carbonitrides of metals of Groups 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28
and a binder phase containing at least one iron group metal.
Other suitable materials include titanium carbonitride as the main component and metals from groups IVa, Va, and VIa of the periodic table.
A hard phase containing at least one of carbide, nitride, carbonitride, and a solid solution thereof.
and a binder phase containing at least one iron-group metal.
These hard alloys can also be used without any problems as hard alloys. These hard alloys exhibit particularly well-balanced performance in terms of wear resistance and chipping resistance.
This allows for improved tool life. In addition, when a hard alloy containing tungsten carbide as the main component is used as the substrate, its hardness
A layer in which the hard phases other than tungsten carbide have decreased or disappeared on the surface of the alloy (hard phase
If the hard alloy has a reduced layer and the thickness of the layer is 50 μm or less,
It is possible to improve chipping resistance. If the thickness of this hard phase-reduced layer exceeds 50 μm, the substrate surface layer will break down during cutting.
There is a tendency for plastic deformation or elastic deformation to occur. To form a hard phase-reduced layer,
Conventionally known methods include using nitrogen-containing hard phase raw materials and heating during sintering.
It can be produced by first setting the atmosphere to nitrogen, and then changing the atmosphere to denitrification and decarburization after the liquid phase of the binder phase appears.
BEST MODE FOR CARRYING OUT THE INVENTION The following describes embodiments of the present invention in detail using examples. (Embodiment 1) A hard alloy substrate having a composition by weight of 92% WC, 2% TiC, and 6% Co.
A cemented carbide tool (model number: CNMG120408) was prepared.
After inserting it into the device and drawing a vacuum, it was heated to a temperature of 900°C and 3% of the volume of T
iCl₄A mixed gas of 20% nitrogen and the remainder hydrogen was introduced to form a 3 μm TiN film.
Then, 1.5% AlCl₄and 0.2% H₂S and 4% CO₂and the remaining water
A mixed gas of aluminum oxide was introduced into a CVD device at 1000°C.
A 5 μm thick layer was formed. If a titanium carbonitride film were formed directly on top of this, it would easily peel off, so a 0.5 μm thick layer was formed.
of titanium nitride with 1.5% TiCl₄and 20% N₂and the remainder is a mixed gas of hydrogen
The film was formed by introducing the film into a CVD apparatus at 950° C.
A columnar titanium carbonitride layer was deposited.₄0.5% ace
Trinitrile and 25% N₂The remaining gas mixture is hydrogen gas at a pressure of 70 hPa.
The film was formed at 900°C under pressure. Then, a TiN film was formed to a thickness of 1 μm under the same conditions as the inner layer.
In the present invention, when changing the type of film, the inside of the CVD device is evacuated and a pre-stage is performed.
Once exposed to the atmosphere, the surface layer is affected by atmospheric gases.
The oxygen inside the layer is absorbed and the desired results cannot be obtained.
The intermediate layer and outer layer were coated. The cross-sectional structure of the coated hard alloy obtained in this way is shown in Figure 2.
The side layer shows a coating layer containing a columnar structure.
When the maximum roughness of the surface was measured after polishing, Amax was 2 μm and Bmax was
The thickness was 1.5 μm. (Embodiment 2) A cemented carbide tool with a composition by weight of 85% WC, 5% TiCN, and 10% Co.
(Model number: WNMG120408) and a hard material having a hard phase reduced layer on the surface.
An alloy substrate was prepared. It was inserted into a CVD device, evacuated, and heated at a temperature of 1050
2.5% by volume of ZrCl₄25% nitrogen and the rest water
A mixed gas of 1% AlCl was introduced to form a 0.5 μm thick ZrN film.₄and
, 0.5% ZrCl₄and 0.2% H₂A mixture of S, 4% CO, and the balance hydrogen
was introduced into a CVD reactor at 1000°C to form aluminum oxide and zirconium oxide.
A 10 μm thick intermediate layer of a solid solution of titanium carbide and nitride was formed. If a titanium carbonitride film were formed directly on top of this, it would easily peel off, so a 1.5 μm thick intermediate layer was formed.
of zirconium carbide with 1.5% ZrCl₄and 3.5% CH₄and the remainder is hydrogen
The mixed gas was introduced into a film-forming chamber at 1100° C., and a film was formed thereon.
A columnar titanium carbonitride layer having 2.5% TiCl₄0.5 to
% tolunitrile and 25% N₂The remaining gas mixture was heated for 150 hours.
The coating was formed at 850°C under a pressure of 100 Pa. The outer layer of the resulting coated hard alloy has a columnar structure of titanium carbonitride, and the surface layer
The maximum roughness Bmax is 1.5 μm, and the maximum roughness Ama of the surface of the intermediate layer is
In addition, VN or CrN was further coated on the outermost layer.
We also fabricated a tool using this method, and obtained similar results. (Embodiment 3) The hard alloy substrate was 84% WC-4% TiC-2% ZrC-2% N (by weight).
A cemented carbide powder having a composition of bC-8%Co was pressed and heated to 1400°C in a vacuum atmosphere.
, sintered under the condition of holding for 1 hour, then polished flat and treated the cutting edge, ISO model number CNM
A cemented carbide substrate mainly composed of tungsten carbide in the shape of G120408 was prepared.
A hard coating layer was formed on the surface of this substrate using the CVD method. Table 1 shows typical manufacturing conditions for the coating layer used in the present invention.
Unless otherwise specified, the film was formed under the conditions shown in Table 1, adjusting only the time.
. Table 2 shows the composition and thickness of the inner layer, and Table 3 shows the composition, thickness, and aluminum oxide of the intermediate layer.
The orientation index of the outer layer is shown in Table 4, along with the film thickness and orientation index of titanium carbonitride.
In the "Composition and average film thickness" of Tables 2 to 4, the layer written on the left side is the substrate.
The layer on the right side is the surface of the coating.
The samples prepared by laminating the outer layer and the outer layer are shown in Table 5.
A typical cross-sectional photograph is shown in Figure 1. This Figure 1 is a cross-sectional micrograph of tool No. 10 in Table 5.
In addition, the surface of the coated hard alloy was mechanically polished using the inventions in Table 5.
The results of further improving the surface roughness of the tool surface are shown in Table 6.
Specific means for polishing include barrel processing, buffing, and elastic abrasives.
Stone, brush honing, lapping with diamond abrasive grains, etc. can be used. In addition, the oxide film (aluminum oxide film) of the intermediate layer of the present invention is made of aluminum chloride and
The film was formed at 1050°C using aluminum oxide and carbon dioxide as the main raw material gases.
The titanium carbonitride layer with a columnar structure in the outer layer was formed by controlling the orientation and grain size of the titanium film.
The main reaction is between organic CN compounds such as acrylonitrile and butyronitrile and titanium tetrachloride.
By using it as a gas and depositing it at 890°C, different orientations in the columnar structure were obtained.
A titanium carbonitride layer was formed, which improved surface roughness. Using the above samples, performance evaluation was performed under the following cutting conditions. (Cutting Conditions) Workpiece: SCM415 grooved round bar Cutting Speed: 400 m/min Feed: 0.30 mm/rev Depth of Cut: 1.5 mm Cutting Oil: None The evaluation results are shown in Tables 5 and 6. Crater wear was measured on the rake face of the tool.
The degree of welding and damage state are shown. These results show that the product of the present invention has better abrasion resistance and welding resistance (crater resistance) than the comparison product.
) and also has improved fracture resistance and peeling resistance.
It was found that this extended tool life. Industrial Applicability As described above, when machining is performed using cutting tools made of the coated hard alloy of this invention, excellent results are obtained.
It has excellent wear resistance, chipping resistance, adhesion resistance and peeling resistance, and is suitable for high-efficiency machining and dry machining.
This allows for the production of coated hard alloys suitable for machining, thereby extending the life of cutting tools.
This makes it possible to dramatically improve the performance.

[Brief explanation of the drawings]

Figure 1 is a photomicrograph showing a polished cross section of a coated hard alloy of the present invention. Figure 2 is a photomicrograph showing a fracture surface of a coated hard alloy of the present invention. Figure 3 is an X-ray diffraction chart of the coated hard alloy of the present invention.

─────────────────────────────────────────────────────── (Note) This publication is based on the publication published internationally by the International Bureau of Patents (WIPO). The effect of the international publication of the Japanese patent application (Japanese utility model registration application) related to this publication arises pursuant to Article 184-10, Paragraph 1 of the Patent Act (Article 48-13, Paragraph 2 of the Utility Model Act) and is unrelated to this publication.

Claims (11)

[Claims] [Claim 1] A coated hard alloy having a coating layer provided on the surface of the hard alloy, the coating layer comprising an inner layer, an intermediate layer, and an outer layer, in that order from the hard alloy side, the inner layer containing one or more layers selected from carbides, nitrides, borides, oxides and solid solutions thereof of Groups IVa, Va, and VIa of the periodic table, the intermediate layer containing one or more layers selected from aluminum oxide, zirconium oxide and solid solutions thereof, and the outer layer containing a titanium carbonitride layer having a columnar structure, the coating layer being selected from Groups IVa, V, and VIa of the periodic table.
and one or more layers selected from the group consisting of carbides, nitrides, borides, oxides and solid solutions thereof of Group VIa and VIa, and aluminum oxide, wherein the relationship between the maximum roughness Amax of the surface layer portion of the intermediate layer and the maximum roughness Bmax of the surface layer portion of the titanium carbonitride layer having a columnar structure in the outer layer in the cross-sectional structure of the coated hard alloy satisfies formula 1: (Bmax/Amax)<1 ... formula 1, where 0.5 μm<Amax<4.5 μm and 0.5 μm≦Bmax≦4
.5 μm 2. In the cross-sectional structure of the coated hard alloy, the maximum roughness Amax of the surface layer of the intermediate layer and the roughness Bmax of the surface layer of the titanium carbonitride layer having a columnar structure in the outer layer
The coated hard alloy according to claim 1, characterized in that the relationship between Bmax and Amax satisfies the formula 2: (Bmax/Amax)<0.8 ... formula 2 3. The thickness of said inner layer is 0.1 to 10 μm, and the thickness of said intermediate layer is 1.5 to 10 μm.
2. The coated hard alloy according to claim 1, wherein the thickness of the outer layer is 20 μm and the thickness of the outer layer is 2 to 30 μm. 4. The outer layer of the titanium carbonitride having a columnar structure has an orientation as shown in formula 3.
The TC is the (220) plane, (311) plane, (331) plane, and (422) plane.
The maximum value of either surface is 1.3 or 3.5.
The coated hard alloy according to claim 1. I(hkl), I(hkl)_xk_yl_z): Measured (hkl), (h_xk_yl_z
) Diffraction intensity of the plane Io(hkl), Io(h_xk_yl_z): According to ASTM standards (hkl), (h
_xk_yl_z) Average powder diffraction intensity of TiC and TiN on the surface (hkl), (h_xk_yl_z): (111), (200), (220), (31
8 faces: (1), (331), (420), (422), and (511) 5. The outer layer of the titanium carbonitride having a columnar structure has a (311) plane and a (
2. The coated hard alloy according to claim 1, wherein the orientation index TC of both the (422) planes is 1.3 or more and 3.5 or less. 6. The coated hard alloy according to claim 1, wherein said intermediate layer consists essentially of α-type aluminum oxide. 7. The coated hard alloy according to claim 1, wherein the intermediate layer has cracks perpendicular to the film, and the compounds of the first outer layer penetrate into the cracks. 8. The α-type aluminum oxide has an orientation index TCa of (0
12) The coated hard alloy according to claim 6, characterized in that the surface roughness is greater than 1.3.
I(hkl), _{I (hxkylz ) :} measured (hkl), ( _{hxkylz )}
Diffraction intensities _Io (hkl), Io _{( hxkylz )} : Powder diffraction intensities (hkl), (hxkylz) of the ( _hkl ), ( _hxkylz ) planes of α-crystal structure alumina according to _{ASTM standard} : ( ₀₁₂ ), (104), (110), (11
6 faces: (3), (024), (116) 9. The orientation index TCa is 1.0 on the (104) plane and the (116) plane.
9. The coated hard alloy of claim 8, wherein the .DELTA..times ... 10. The hard alloy of claim 1, wherein the hard alloy is composed mainly of tungsten carbide and is selected from the group consisting of tungsten carbide, ...
Carbides, nitrides, carbonitrides of group a, Va, VIa metals and their solid solutions (WC
2. The coated hard alloy according to claim 1, characterized in that it is a hard alloy comprising a hard phase containing at least one selected from the group consisting of iron-group metals (excluding iron-group metals) and a binder phase containing at least one selected from the group consisting of iron-group metals. 11. The coated hard alloy according to claim 1, wherein the surface roughness Cmax of the outermost surface of the coating layer satisfies the following formula: Cmax/Bmax<0.5...formula 5