JP2004188577A - Cutting tool of surface-coated cermet with hard coating layer having excellent thermal shock resistance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool of surface-coated cermet with a hard coating layer having excellent thermal shock performance. <P>SOLUTION: This cutting tool of surface-coated cermet is manufactured by forming the hard coating layer on the surface of a tool base body composed of WC-based cemented carbide or TiCN-based cermet. The hard coating layer is composed of (a) a primer layer composed of a Ti compound layer comprising one layer or two or more layers among a TiC layer, a TiN layer, a TiCN layer, a TiCO layer, and a TiCNO layer, all formed by chemical vapor deposition, and having total average layer thickness of 3-20μm, (b) an upper layer composed of heat-transformed α-type Al<SB>2</SB>O<SB>3</SB>layer having texture in which Al<SB>2</SB>O<SB>3</SB>having a κ-type or θ-type crystal structure as formed by chemical vapor deposition is heat-treated to transform the crystal structure into α-type crystal structure, and in which heat-transformation cracks are dispersed and distributed, and having average layer thickness of 1-15μm, and (c) a surface layer composed of a deposited κ-type Al<SB>2</SB>O<SB>3</SB>layer having a κ-type crystal structure as formed by chemical vapor deposition, and having average layer thickness of 0.1-2μm. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００２０】
【表２】

【００２１】
【表３】

【００２２】
【表４】

【００２３】
【表５】

【００２４】
【表６】

【００２５】
【発明の効果】
表４〜６に示される結果から、本発明被覆サーメット工具１〜１３は、硬質被覆層の上部層を構成する加熱変態α型Ａｌ_２Ｏ_３層中に分散分布する加熱変態生成クラックの作用で、熱衝撃がきわめて高く、かつ高い発熱を伴なう鋼の高速断続切削でも、硬質被覆層中に内蔵された状態で存在する前記加熱変態生成クラックの作用で、切刃部のチッピング発生が著しく抑制され、すぐれた耐摩耗性を発揮するのに対して、硬質被覆層の上部層が蒸着α型Ａｌ_２Ｏ_３層からなる従来被覆サーメット工具１〜１３においては、高速断続切削では前記蒸着α型Ａｌ_２Ｏ_３層が激しい熱衝撃に耐えられず、切刃部にチッピングが発生し、比較的短時間で使用寿命に至ることが明らかである。
上述のように、この発明の被覆サーメット工具は、各種鋼や鋳鉄などの通常の条件での連続切削や断続切削は勿論のこと、特に熱衝撃がきわめて高く、かつ高い発熱を伴なう切削条件の最も厳しい高速断続切削でもすぐれた耐チッピング性を示し、長期に亘ってすぐれた切削性能を発揮するものであるから、切削装置の高性能化並びに切削加工の省力化および省エネ化、さらに低コスト化に十分満足に対応できるものである。
【図面の簡単な説明】
【図１】本発明被覆サーメット工具３の硬質被覆層の上部層に相当する目標層厚が１５μｍの加熱変態α型Ａｌ_２Ｏ_３層のＸ線回折チャートを示す図である。
【図２】本発明被覆サーメット工具８の硬質被覆層の上部層に相当する目標層厚が１０μｍの加熱変態α型Ａｌ_２Ｏ_３層のＸ線回折チャートを示す図である。
【図３】本発明被覆サーメット工具１２の硬質被覆層の上部層に相当する目標層厚が５μｍの加熱変態α型Ａｌ_２Ｏ_３層のＸ線回折チャートを示す図である。
【図４】従来被覆サーメット工具の硬質被覆層の上部層を構成する蒸着α型Ａｌ_２Ｏ_３層について、本発明被覆サーメット工具３に対応して目標層厚を１５μｍとした蒸着α型Ａｌ_２Ｏ_３層のＸ線回折チャートを示す図である。
【図５】従来被覆サーメット工具の硬質被覆層の上部層を構成する蒸着α型Ａｌ_２Ｏ_３層について、本発明被覆サーメット工具８に対応して目標層厚を１０μｍとした蒸着α型Ａｌ_２Ｏ_３層のＸ線回折チャートを示す図である。
【図６】従来被覆サーメット工具の硬質被覆層の上部層を構成する蒸着α型Ａｌ_２Ｏ_３層について、本発明被覆サーメット工具１２に対応して目標層厚を５μｍとした蒸着α型Ａｌ_２Ｏ_３層のＸ線回折チャートを示す図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a hard coating layer that exhibits excellent chipping resistance against thermal shock repeatedly applied at a very short pitch to a cutting edge, particularly during high-speed intermittent cutting of steel or cast iron, that is, the hard coating layer is excellent. The present invention relates to a surface-coated cermet cutting tool having thermal shock resistance (hereinafter referred to as a coated cermet tool).
[0002]
[Prior art]
2. Description of the Related Art Conventionally, generally, a substrate (hereinafter, these are collectively referred to as a tool substrate) formed of a tungsten carbide (hereinafter, referred to as WC) -based cemented carbide or a titanium cermet (hereinafter, referred to as TiCN) -based cermet is generally provided on a surface of the substrate. ,
(A) All of them are Ti carbide (hereinafter, referred to as TiC) layer, nitride (hereinafter, also referred to as TiN) layer, carbonitride (hereinafter, referred to as TiCN) layer, carbon oxide (hereinafter, referred to as TiCN) formed by chemical vapor deposition. , TiCO) layer, and one or more of carbon oxynitride (hereinafter, TiCNO) layers, and a Ti compound layer having a total average layer thickness of 3 to 20 μm. Lower layer,
(B) Upper layer composed of a vapor-deposited α-type aluminum oxide (hereinafter, referred to as Al ₂ O ₃ ) layer having an α-type crystal structure in a state formed by chemical vapor deposition and having an average layer thickness of 1 to 17 μm. ,
There is known a coated cermet tool formed by vapor-depositing a hard coating layer composed of the lower layer of (a) and the upper layer of (b). The coated cermet tool can be used for continuous cutting of, for example, various kinds of steel and cast iron. Also, it is known that it is used for interrupted cutting (for example, see Patent Document 1).
[0003]
In general, the Ti compound layer and the Al ₂ O ₃ layer constituting the hard coating layer of the above-mentioned coated cermet tool have a granular crystal structure, and the TiCN layer constituting the Ti compound layer is further improved in strength by itself. For the purpose, using a mixed gas containing an organic carbonitride, for example, CH ₃ CN as a reaction gas, and performing chemical vapor deposition at a medium temperature range of 700 to 950 ° C. using a normal chemical vapor deposition apparatus, It is also known to have a growing crystal structure (for example, see Patent Document 2).
[0004]
[Patent Document 1]
JP-A-6-31503 [Patent Document 2]
JP-A-6-8010 [0005]
[Problems to be solved by the invention]
In recent years, the performance of cutting equipment has been remarkably improved, and on the other hand, there is a strong demand for labor saving, energy saving, and further cost reduction for cutting work.Accordingly, cutting work tends to be even faster, In the case of coated cermet tools, there is no problem if this is used for continuous cutting or interrupted cutting under ordinary conditions such as steel or cast iron. When used in high-speed interrupted cutting in which thermal shock is repeatedly applied at a very short pitch to the surface, the deposited α-type Al ₂ O ₃ layer constituting the upper layer of the hard coating layer is hard and has excellent heat resistance, Because of its brittleness, chipping (small chipping) easily occurs in the hard coating layer, and as a result, the service life of the hard coating layer is relatively short in the present situation.
[0006]
[Means for Solving the Problems]
In view of the above, the present inventors have conducted research to improve the thermal shock resistance of the Al ₂ O ₃ layer constituting the upper layer of the hard coating layer of the coated cermet tool from the above-described viewpoint.
After forming the Ti compound layer as a lower layer under ordinary conditions on the surface of the tool base using an ordinary chemical vapor deposition apparatus, first, under the same ordinary conditions, Al ₂ O having a κ-type or θ-type crystal structure. _{When three} layers are formed and subjected to a heat treatment in this state in a hydrogen atmosphere at a temperature of 1000 to 1100 ° C. and a holding time of 2 to 10 hours, a κ-type or θ-type crystal of the Al ₂ O ₃ layer is obtained. The structure is transformed into an α-type crystal structure, and cracks generated by heat transformation are distributed and distributed in the layer. The heat-transformed α-type Al ₂ O ₃ layer is used as an upper layer, and the surface of the upper layer is formed. Under the same conditions, when a relatively thin κ-type Al ₂ O ₃ layer is formed by vapor deposition as a surface layer, this vapor-deposited κ-type Al ₂ O ₃ layer is formed with the heat-transformed α-type Al ₂ O ₃ layer. Before penetrating sufficiently into cracks generated by heat transformation at the interface, Since so to retain the heat transformation product cracks remarkably stabilized state, the lower layer of the hard coating layer is composed of the Ti compound layer, the upper layer and the surface layer is above the heating transformation α-type Al ₂ O ₃ In a coated cermet tool composed of a layer and a vapor-deposited κ-type Al ₂ O ₃ layer, a heat-transformation generation crack dispersed and distributed in the heat-transformed α-type Al ₂ O ₃ layer constituting the upper layer is particularly high-speed intermittent cutting. A study result was obtained in which the intense thermal shock at the time was absorbed and alleviated, whereby the occurrence of chipping in the hard coating layer was significantly suppressed.
[0007]
The present invention has been made on the basis of the above research results, and has a tool base formed of a WC-based cemented carbide or a TiCN-based cermet,
(A) a Ti compound comprising at least one of a TiC layer, a TiN layer, a TiCN layer, a TiCO layer, and a TiCNO layer formed by chemical vapor deposition and having a total average layer thickness of 3 to 20 μm; Lower layer composed of layers,
(B) The Al ₂ O ₃ layer having a κ-type or θ-type crystal structure in a state formed by chemical vapor deposition is subjected to a heat transformation treatment to change the crystal structure to an α-type crystal structure, and cracks generated by heat transformation are dispersed and distributed. An upper layer composed of a texture and a heat-transformed α-type Al ₂ O ₃ layer having an average layer thickness of 1 to 15 μm;
(C) a surface layer composed of a vapor-deposited κ-type Al ₂ O ₃ layer having a κ-type crystal structure in a state formed by chemical vapor deposition and having an average layer thickness of 0.1 to 2 μm;
The present invention is characterized by a coated cermet tool in which the hard coating layer formed of the above (a) to (c) has excellent thermal shock resistance.
[0008]
The reason why the average layer thickness of the constituent layers of the hard coating layer of the coated cermet tool of the present invention is limited as described above is as follows.
(A) Lower layer (Ti compound layer)
The Ti compound layer itself has strength, and the presence of the Ti compound layer allows the hard coating layer to have strength. In addition, the Ti compound layer is firmly attached to both the tool base and the heating-transformed α-type Al ₂ O ₃ layer as the upper layer. Has a function of contributing to the improvement of the adhesion of the hard coating layer to the tool base, but if the total average layer thickness is less than 3 μm, the above effect cannot be sufficiently exerted. If the thickness exceeds 20 μm, it becomes easy to cause thermoplastic deformation, especially in high-speed interrupted cutting accompanied by high heat generation, and this causes uneven wear. Therefore, the total average layer thickness is set to 3 to 20 μm.
[0009]
(B) Upper layer (heat-transformed α-type Al ₂ O ₃ layer)
The heat-transformed α-type Al ₂ O ₃ layer has a function of absorbing thermal shock by the action of the heat-transformed cracks dispersed and distributed in the layer as described above, thereby preventing chipping from occurring in the hard coating layer. However, if the average layer thickness is less than 1 μm, the above effect cannot be sufficiently exerted. On the other hand, if the average layer thickness exceeds 15 μm and becomes too thick, the heat transformation generation cracks cause chipping. Therefore, the average layer thickness was determined to be 1 to 15 μm.
[0010]
(C) Surface layer (evaporated κ-type Al ₂ O ₃ layer)
As described above, the deposited κ-type Al ₂ O ₃ layer sufficiently penetrates into the heat-transformed cracks at the interface with the heat-transformed α-type Al ₂ O ₃ layer, and the heat-transformed cracks are significantly stabilized. To improve the thermal shock resistance provided by the heat-transformed α-type Al ₂ O ₃ layer, but if the average layer thickness is less than 0.1 μm, the heat transformed Since the stabilization of the heat transformation cracks in the α-type Al ₂ O ₃ layer is insufficient, chipping due to the heat transformation cracks is likely to occur, while the average layer thickness becomes larger than 2 μm. Even if it is too long, the cracks generated by the heat transformation easily propagate into the surface layer, and chipping easily occurs on the cracks. Therefore, the average layer thickness is set to 0.1 to 2 μm.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the coated cermet tool of the present invention will be specifically described with reference to examples.
As raw material powders, WC powders each having a predetermined average particle size in the range of 0.5 to 4 μm, (Ti, W) C (the same hereinafter, TiC / WC = 30/70 by mass ratio) powder, Ti, W) CN (TiC / TiN / WC = 24/20/56) powder, (Ta, Nb) C (TaC / NbC = 90/10) powder, Cr ₃ C ₂ powder, and Co powder, These raw material powders were blended in the composition shown in Table 1, wet-mixed in a ball mill for 72 hours, dried, and then pressed into a green compact of a predetermined shape at a pressure of 98 MPa. Medium, vacuum sintering at 1410 ° C. for 1 hour, and after sintering, a WC having a throw-away tip shape specified in ISO · CNMG120408 by subjecting the cutting edge to honing processing of R: 0.07 mm. Base cemented carbide The tool substrate A~F were produced, respectively.
[0012]
Further, as raw material powders, TiCN (TiC / TiN = 50/50 by mass ratio) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder each having an average particle diameter of 0.5 to 2 μm , Co powder, and Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 2, wet-mixed in a ball mill for 24 hours, dried, and pressed into a green compact at a pressure of 98 MPa. The green compact was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1540 ° C. for 1 hour, and after sintering, the cutting edge was subjected to a honing process of R: 0.07 mm to obtain an ISO. Tool bases a to f made of TiCN-based cermet having a tip shape of standard CNMG120412 were formed.
[0013]
Then, on the surfaces of the tool bases A to F and the tool bases a to f, an ordinary chemical vapor deposition apparatus was used, and Table 3 (l-TiCN in Table 3 is a vertically long one described in JP-A-6-8010). It shows the conditions for forming a TiCN layer having a growth crystal structure, and the other conditions show the conditions for forming a normal granular crystal structure.) A compound layer is formed by vapor deposition as a lower layer of the hard coating layer, and then a κ-type or θ-type Al ₂ O ₃ layer is formed by vapor deposition under the same conditions as shown in Table 3, and the layer is formed in a hydrogen atmosphere at a temperature of: A heat transformation treatment is performed at a temperature of 1050 ° C. for a predetermined time within a range of 2 to 10 hours to transform the κ-type or θ-type crystal structure into α-type. similarly Table heated transformation α-type _Al 2 _{O 3} layer and Formed as an upper layer of the hard coating layer at the target layer thickness shown in further similarly under the conditions shown in Table 3, and as the surface layer the target layer thickness deposited κ type the Al ₂ O ₃ layer as indicated in Table 4 By forming, the coated cermet tools 1 to 13 of the present invention were respectively manufactured.
Also, for comparison purposes, as shown in Table 5, instead of the upper layer and the surface layer constituting each hard coating layer of the coated cermet tools 1 to 13 of the present invention, the average shown in Table 5 was used. Conventional coated cermet tools 1 to 13 were manufactured under the same conditions except that a vapor-deposited α-type Al ₂ O ₃ layer having a layer thickness was formed.
[0014]
For the purpose of observing the difference between the heat-transformed α-type Al ₂ O ₃ layer and the vapor-deposited α-type Al ₂ O ₃ layer constituting the hard coating layer of the coated cermet tool of the present invention and the conventional coated cermet tool obtained as described above, X was used. Line diffraction was measured.
First, as a sample for X-ray diffraction measurement, a single crystal WC having a diffraction peak only on the (001) plane and the (002) plane on the X-ray diffraction chart was used as a substrate sample. cermet tools 3,8 and 12 the upper layer in which the target layer thickness is 15μm which constitutes the hard coating layer, 10 [mu] m, and 5μm under the same conditions as the conditions for forming the heat transformed α-type _{the Al} 2 _{O 3} layer of each target Heat-transformed α-type Al ₂ O ₃ layers having a layer thickness of 15 μm, 10 μm, and 5 μm are directly formed to obtain coating samples A to C of the present invention, and the upper layer of the hard coating layer of the conventional coated cermet tools 1 to 13 is formed. under the same conditions as the conditions for forming the deposited α-type _{the Al} 2 _{O 3} layer constituting the present invention coated cermet tool 3, 8, and 12 in response to, 15 [mu] m target layer thickness, respectively, 10 [mu] m, and 5μm It was prepared by a conventional coated samples a~c to form the deposited α-type the Al ₂ O ₃ layer directly.
[0015]
Next, the X-ray diffraction measurement of the above-mentioned heat-transformed α-type Al ₂ O ₃ layer and the vapor-deposited α-type Al ₂ O ₃ layer of these coated samples was carried out by using a usual X-ray diffractometer, and Cu was placed in an X-ray tube. By irradiating the anode (target) with thermoelectrons generated from the metal W filament under the conditions of voltage: 40 kV and current: 350 mA, characteristic X-rays having a wavelength of 0.154 nm from the Cu anode surface are obtained. X-rays that generate a certain Cu-Kα ray, irradiate the characteristic X-ray to the surface of the coated sample, and diffract at an angle equal to the X-ray incident angle θ with respect to the coated sample surface among the X-rays scattered from the coated sample Was measured with an X-ray detector. The measurement results are shown in FIGS.
FIGS. 1 to 3 show X-ray diffraction charts of the heat-transformed α-type Al ₂ O ₃ layers of coating samples A to C of the present invention, and X-ray diffraction charts of vapor-deposited α-type Al ₂ O ₃ layers of conventional coating samples a to c. 4 to 6, the heating-transformed α-type Al ₂ O ₃ layer shows clear diffraction peaks on the (006) plane and the (018) plane, whereas the vapor-deposited α-type Al ₂ the O ₃ layer is clear that these (006) plane and (018) diffraction peak at a surface are not present.
[0016]
Further, regarding the coated cermet tools 1 to 13 of the present invention and the conventional coated cermet tools 1 to 13, the constituent layers of the hard coating layer were observed using a scanning electron microscope (observing the longitudinal section of the layers). The former consists of a Ti compound layer, a heat-transformed α-type Al ₂ O ₃ layer in which cracks generated by heat transformation are dispersed and distributed in the layer, and a vapor-deposited κ-type Al ₂ O ₃ layer. It was confirmed that it was composed of an α-type Al ₂ O ₃ layer. In addition, when the thicknesses of the constituent layers of the hard coating layer of these coated cermet tools were measured using a scanning electron microscope (also in the longitudinal section), the average layer thickness was substantially the same as the target layer thickness. (Average value of five-point measurements).
[0017]
Next, the above coated cermet tools 1 to 7 according to the present invention and the conventional coated cermet tools 1 to 7 in a state where all of the above various coated cermet tools were screwed to the tip of a tool steel tool with a fixing jig. ,
Work material: JIS SCM440 4 rods with longitudinal grooves at regular intervals in the longitudinal direction,
Cutting speed: 350m / min,
Cut: 1.5 mm,
Feed: 0.25 mm / rev,
Cutting time: 3 minutes,
Dry high-speed interrupted cutting test of alloy steel under the conditions of
Work material: Round bar with four vertical grooves at equal intervals in the length direction of JIS / SUS304,
Cutting speed: 350m / min,
Notch: 2.0 mm,
Feed: 0.15 mm / rev,
Cutting time: 3 minutes,
A dry high-speed interrupted cutting test of stainless steel was performed under the following conditions.
[0018]
Further, for the coated cermet tools 8 to 13 of the present invention and the conventional coated cermet tools 8 to 13,
Work material: JIS SCM440 4 rods with longitudinal grooves at regular intervals in the longitudinal direction,
Cutting speed: 350m / min,
Cut: 1.0 mm,
Feed: 0.25 mm / rev,
Cutting time: 3 minutes,
Dry high-speed interrupted cutting test of alloy steel under the conditions of
Work material: Round bar with four vertical grooves at equal intervals in the length direction of JIS / SUS304,
Cutting speed: 350m / min,
Cut: 1.5 mm,
Feed: 0.1 mm / rev,
Cutting time: 3 minutes,
A dry high-speed intermittent cutting test of stainless steel was performed under the following conditions, and the flank wear width of the cutting edge was measured in each cutting test. Table 6 shows the measurement results.
[0019]
[Table 1]

[0020]
[Table 2]

[0021]
[Table 3]

[0022]
[Table 4]

[0023]
[Table 5]

[0024]
[Table 6]

[0025]
【The invention's effect】
From the results shown in Tables 4 to 6, the coated cermet tools 1 to 13 of the present invention showed that the heating transformation generated cracks dispersed and distributed in the heating transformation α-type Al ₂ O ₃ layer constituting the upper layer of the hard coating layer. Even in high-speed interrupted cutting of steel with extremely high thermal shock and high heat generation, chipping of the cutting edge portion is remarkably generated due to the action of the above-mentioned heat transformation generation crack existing in a state embedded in the hard coating layer. The conventional coated cermet tools 1 to 13 in which the upper layer of the hard coating layer is formed of a vapor-deposited α-type Al ₂ O ₃ layer, while exhibiting excellent wear resistance are suppressed, and the vapor-deposited α It is evident that the mold Al ₂ O ₃ layer cannot withstand severe thermal shock, chipping occurs at the cutting edge, and reaches a service life in a relatively short time.
As described above, the coated cermet tool of the present invention can be used not only for continuous cutting or interrupted cutting under ordinary conditions such as various types of steel and cast iron, but also for cutting conditions involving extremely high thermal shock and high heat generation. It shows excellent chipping resistance even in the most severe high-speed interrupted cutting, and exhibits excellent cutting performance over a long period of time. It can respond satisfactorily to the conversion.
[Brief description of the drawings]
FIG. 1 is a diagram showing an X-ray diffraction chart of a heat-transformed α-type Al ₂ O ₃ layer having a target layer thickness of 15 μm corresponding to the upper layer of the hard coating layer of the coated cermet tool 3 of the present invention.
FIG. 2 is an X-ray diffraction chart of a heat-transformed α-type Al ₂ O ₃ layer having a target layer thickness of 10 μm corresponding to the upper layer of the hard coating layer of the coated cermet tool 8 of the present invention.
FIG. 3 is a diagram showing an X-ray diffraction chart of a heat-transformed α-type Al ₂ O ₃ layer having a target layer thickness of 5 μm corresponding to the upper layer of the hard coating layer of the coated cermet tool 12 of the present invention.
[4] Conventional coating the cermet tools hard layer deposition α type the Al ₂ O ₃ layer constituting the upper layer of the present invention coated cermet tool 3 deposited α-type to the target layer thickness and 15μm in correspondence with Al ₂ X-ray diffraction chart of the O ₃ layer is a diagram showing a.
[5] Conventional coated cermet for hard coating layer deposited α-type the Al ₂ O ₃ layer constituting the upper layer of the tool, the present invention coated cermet tool 8 corresponds deposited α-type target layer thickness was 10 [mu] m Al ₂ X-ray diffraction chart of the O ₃ layer is a diagram showing a.
[6] Conventional coated cermet for hard coating layer deposited α-type the Al ₂ O ₃ layer constituting the upper layer of the tool, the present invention coated cermet tool 12 in response to the deposition α-type target layer thickness was 5 [mu] m Al ₂ X-ray diffraction chart of the O ₃ layer is a diagram showing a.

Claims (1)

On the surface of a tool substrate composed of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet,
(A) Each of them consists of one or more of a carbide layer, a nitride layer, a carbonitride layer, a carbonate layer and a carbonitride layer of Ti formed by chemical vapor deposition, and has a thickness of 3 to 20 μm. A lower layer composed of a Ti compound layer having a total average layer thickness of
(B) A structure in which aluminum oxide having a κ-type or θ-type crystal structure is subjected to heat treatment in a state formed by chemical vapor deposition to transform the crystal structure into an α-type crystal structure, and cracks generated by heat transformation are dispersed and distributed. And an upper layer composed of a heat-transformed α-type aluminum oxide layer having an average layer thickness of 1 to 15 μm,
(C) a surface layer comprising a deposited κ-type aluminum oxide layer having a κ-type crystal structure in a state formed by chemical vapor deposition and having an average layer thickness of 0.1 to 2 μm;
A cutting tool made of a surface-coated cermet having a hard coating layer having excellent thermal shock resistance, wherein the cutting tool is formed by forming the hard coating layer comprising (a) to (c).

Images