阅读说明：本技术 被覆切削工具 (Coated cutting tool ) 是由 片桐隆雄 于 2021-05-25 设计创作，主要内容包括：本发明提供一种提高了耐磨性以及耐缺损性的工具寿命较长的被覆切削工具。该被覆切削工具包含基材、以及形成于基材上的被覆层,被覆层具有含有Ti(C-(x1)N-(1-x1))的第1层以及含有(Ti-(1-y1)Al-(y1))N的第2层,第1层中的粒子的平均粒径为5nm以上且不足100nm以下,在第1层中,1.0≤I(111)/I(200)≤20.0,第1层的平均厚度为5nm以上1.0μm以下,在第2层中,0.1≤I(111)/I(200)≤1.0,第2层中的粒子的平均粒径超过100nm且为300nm以下,第2层的平均厚度为5nm以上2.0μm以下。(The invention provides a coated cutting tool with improved wear resistance and defect resistance and long tool life. The coated cutting tool comprises a substrate and a coating layer formed on the substrate, wherein the coating layer contains Ti (C) x1 N 1‑x1 ) And the 1 st layer of (A) and (Ti) 1‑y1 Al y1 ) N in the 2 nd layer, the average particle diameter of the particles in the 1 st layer is 5nm or more and less than 100nm, in the 1 st layer, 1.0. ltoreq. I (111)/I (200) or less than 20.0, and the average thickness of the 1 st layer is 5nm or more1.0 μm or less, in the 2 nd layer, I (111)/I (200) of 0.1. ltoreq. 1.0, the average particle diameter of the particles in the 2 nd layer is more than 100nm and 300nm or less, and the average thickness of the 2 nd layer is 5nm or more and 2.0 μm or less.)

1. A coated cutting tool in which, in a cutting tool,

the coated cutting tool comprises a substrate and a coating layer formed on the substrate,

the coating layer has a 1 st layer containing a compound having a composition represented by the following formula (1) and a 2 nd layer containing a compound having a composition represented by the following formula (2),

Ti(C_x1N_1-x1) (1)

in the formula (1), x1 represents an atomic ratio of a C element to the total amount of the C element and the N element, and satisfies 0.02. ltoreq. x 1. ltoreq.0.30,

(Ti₁-_y1Al_y1)N (2)

in the formula (2), y1 represents the atomic ratio of the Al element to the total of the Ti element and the Al element, and satisfies 0.25. ltoreq. y 1. ltoreq.0.75,

the average particle diameter of the particles in the 1 st layer is 5nm or more and less than 100nm,

in the layer 1, the ratio of the diffraction peak intensity I (111) of the (111) plane to the diffraction peak intensity I (200) of the (200) plane is 1.0. ltoreq.I (111)/I (200). ltoreq.20.0,

the 1 st layer has an average thickness of 5nm to 1.0 [ mu ] m,

in the 2 nd layer, the ratio of the diffraction peak intensity I (111) of the (111) plane to the diffraction peak intensity I (200) of the (200) plane is 0.1. ltoreq. I (111)/I (200). ltoreq.1.0,

the average particle diameter of the particles in the 2 nd layer is more than 100nm and less than 300nm,

the 2 nd layer has an average thickness of 5nm to 2.0 [ mu ] m.

2. The coated cutting tool of claim 1,

the average composition of the entire compound in the 1 st layer and the 2 nd layer is represented by the following formula (3),

(Ti₁-_y2Al_y2)(C_x2N_1-x2) (3)

in the formula (3), x2 represents an atomic ratio of a C element to the total amount of the C element and the N element, and satisfies 0.01. ltoreq. x 2. ltoreq.0.15, and y2 represents an atomic ratio of an Al element to the total amount of the Ti element and the Al element, and satisfies 0.12. ltoreq. y 2. ltoreq.0.38.

3. The coated cutting tool of claim 1 or 2,

the residual stress of the 1 st layer is-4.0 GPa to-2.0 GPa, and the residual stress of the 2 nd layer is-2.0 GPa to 0 GPa.

4. The coated cutting tool according to any one of claims 1 to 3,

the coating layer has an alternating laminated structure in which the 1 st layer and the 2 nd layer are alternately repeated 2 or more times.

5. The coated cutting tool according to any one of claims 1 to 4,

in the X-ray diffraction of the 1 st layer, the (111) plane shows the highest peak.

6. The coated cutting tool according to any one of claims 1 to 5,

in the X-ray diffraction of the 2 nd layer, the (200) plane shows the highest peak.

7. The coated cutting tool of claim 2,

the difference Δ C (x1-x2) between the atomic ratio x2 of the C element in the average composition represented by the formula (3) and the atomic ratio x1 of the C element in the composition represented by the formula (1) is 0.01 to 0.15.

8. The coated cutting tool of claim 2,

the difference Δ Al (y1-y2) between the atomic ratio y2 of the Al element in the average composition represented by the formula (3) and the atomic ratio y1 of the Al element in the composition represented by the formula (2) is 0.12 to 0.38.

9. The coated cutting tool according to any one of claims 1 to 8,

the average thickness of the entire coating layer is 2.0 μm or more and 10.0 μm or less.

10. The coated cutting tool according to any one of claims 1 to 9,

the base material is any one of cemented carbide, cermet, ceramics or a sintered cubic boron nitride body.

Technical Field

The present invention relates to a coated cutting tool.

Background

Conventionally, cutting tools made of cemented carbide or cubic boron nitride (cBN) sintered bodies have been widely used in cutting of steel and the like. Among them, surface-coated cutting tools including a hard coating such as 1 layer or 2 or more TiN layers or TiAlN layers on the surface of a cemented carbide substrate have high versatility and are used in various machining processes.

For example, patent document 1 proposes a substrate having a structure represented by (Al) on the substrate_aTi_bM_c) X [ wherein M represents at least one element selected from the group consisting of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, B and Si, X represents at least one element selected from the group consisting of C, N and O, a represents the atomic ratio of Al element to the total amount of Al element, Ti element and M element, B represents the atomic ratio of Ti element to the total amount of Al element, Ti element and M element, c represents the atomic ratio of M element to the total amount of Al element, Ti element and M element, and a, B and c satisfy 0.30. ltoreq. a.ltoreq.0.65, 0.35. ltoreq. b.ltoreq.0.70, 0. ltoreq. c.ltoreq.0.20, and a + B + c.1]And the average particle diameter of the layer is more than 200nm, the abrasion resistance is improved compared with the conventional one.

Further, patent document 2 proposes a cutting tool in which a coating layer is formed on a base material by vapor deposition, the cutting tool being more excellent in chipping resistance and wear resistance than the conventional cutting tool, the cutting tool being characterized in that the coating layer satisfies (Al) requirement_1-xTi_x)N[0.40≤x≤0.65]The layer is composed of an alternating laminated structure of a thin layer A composed of a granular structure of the composite nitride of Al and Ti and a thin layer B composed of a columnar structure, wherein the average grain diameter of granular crystals constituting the thin layer A is 30nm or less, and the average grain diameter of columnar crystals constituting the thin layer B is 50 to 500 nm.

Patent document

Patent document 1: international publication No. 2014/136755

Patent document 2: japanese patent No. 5594575

Disclosure of Invention

In recent years, cutting of difficult-to-machine materials such as stainless steel has been accelerated and advanced, and cutting conditions have been severer than ever before, and thus, there has been a demand for further improvement in wear resistance and fracture resistance and tool life as compared with the prior art. Since the coating layer of patent document 1 has a particle size of more than 200nm as a whole, it is expected that the coating layer will exhibit excellent wear resistance, but will also be susceptible to sudden chipping or chipping. In the coated cutting tool of patent document 2, the columnar crystal a layer and the granular crystal B layer are alternately stacked in the same composition, and the interface compatibility is high, and thus the deformation is small and the coating hardness is insufficient. Therefore, it is difficult to extend the tool life due to insufficient wear resistance.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a coated cutting tool having improved wear resistance and chipping resistance and having a long tool life.

The present inventors have conducted extensive studies on extension of the tool life of a coated cutting tool, and have found that if the coated cutting tool is formed into a specific structure, the wear resistance and fracture resistance can be improved, and therefore, the tool life of the coated cutting tool can be extended, and have completed the present invention.

That is, the gist of the present invention is as follows.

[1] A coated cutting tool in which, in a cutting tool,

the coated cutting tool comprises a substrate and a coating layer formed on the substrate,

the coating layer has a 1 st layer and a 2 nd layer, the 1 st layer contains a compound having a composition represented by the following formula (1), the 2 nd layer contains a compound having a composition represented by the following formula (2),

Ti(C_x1N_1-x1) (1)

(in the formula (1), x1 represents the atomic ratio of C element to the total amount of C element and N element, and satisfies 0.02. ltoreq. x 1. ltoreq.0.30),

(Ti₁-_y1Al_y1)N (2)

(in the formula (2), y1 represents the atomic ratio of the Al element to the total of the Ti element and the Al element, and satisfies 0.25. ltoreq. y 1. ltoreq.0.75),

the average particle diameter of the particles in the 1 st layer is 5nm or more and less than 100nm,

in the layer 1, the ratio of the diffraction peak intensity I (111) on the (111) plane to the diffraction peak intensity I (200) on the (200) plane is 1.0. ltoreq.I (111)/I (200). ltoreq.20.0,

the average thickness of the 1 st layer is 5nm to 1.0 [ mu ] m,

in the 2 nd layer, the ratio of the diffraction peak intensity I (111) on the (111) plane to the diffraction peak intensity I (200) on the (200) plane is 0.1. ltoreq. I (111)/I (200). ltoreq.1.0,

the average particle diameter of the particles in the 2 nd layer is more than 100nm and 300nm or less,

the average thickness of the 2 nd layer is 5nm to 2.0 μm.

[2] The coated cutting tool according to [1], wherein,

the average composition of the entire compounds in the 1 st layer and the 2 nd layer is represented by the following formula (3),

(Ti₁-_y2Al_y2)(C_x2N_1-x2) (3)

(in the formula (3), x2 represents an atomic ratio of a C element to the total amount of the C element and the N element, and satisfies 0.01. ltoreq. x 2. ltoreq.0.15, and y2 represents an atomic ratio of an Al element to the total amount of the Ti element and the Al element, and satisfies 0.12. ltoreq. y 2. ltoreq.0.38).

[3] The coated cutting tool according to [1] or [2], wherein,

the residual stress of the 1 st layer is-4.0 GPa or more and-2.0 GPa or less, and the residual stress of the 2 nd layer is-2.0 GPa or more and 0GPa or less.

[4] The coated cutting tool according to any one of [1] to [3],

the coating layer has an alternating laminated structure in which the 1 st layer and the 2 nd layer are alternately repeated 2 or more times.

[5] The coated cutting tool according to any one of [1] to [4],

in the above X-ray diffraction of the layer 1, the (111) plane shows the highest peak.

[6] The coated cutting tool according to any one of [1] to [5],

in the above X-ray diffraction of the 2 nd layer, the (200) plane shows the highest peak.

[7] The coated cutting tool according to [2], wherein,

the difference Δ C (x1-x2) between the atomic ratio x2 of the C element in the average composition represented by the formula (3) and the atomic ratio x1 of the C element in the composition represented by the formula (1) is 0.01 to 0.15.

[8] The coated cutting tool according to [2], wherein,

the difference Δ Al (y1-y2) between the atomic ratio y2 of the Al element in the average composition represented by the formula (3) and the atomic ratio y1 of the Al element in the composition represented by the formula (2) is 0.12 to 0.38.

[9] The coated cutting tool according to any one of [1] to [8],

the average thickness of the entire coating layer is 2.0 μm or more and 10.0 μm or less.

[10] The coated cutting tool according to any one of [1] to [9],

the base material is any one of cemented carbide, cermet, ceramics, and a sintered cubic boron nitride.

According to the present invention, a coated cutting tool having improved wear resistance and chipping resistance and having a long tool life can be provided.

Drawings

Fig. 1 is a schematic view showing an example of a coated cutting tool according to the present invention.

Detailed Description

Hereinafter, a mode for carrying out the present invention (hereinafter, simply referred to as "the present embodiment") will be described in detail, but the present invention is not limited to the present embodiment described below. The present invention can be variously modified within a range not departing from the gist thereof. In the drawings, the same elements are denoted by the same reference numerals, and redundant description thereof is omitted. Unless otherwise specified, the positional relationship such as up, down, left, and right is based on the positional relationship shown in the drawings. The dimensional scale of the drawings is not limited to the illustrated scale.

The coated cutting tool of the present embodiment includes a base material and a coating layer formed on the base material,

the coating layer has a 1 st layer containing a compound having a composition represented by the following formula (1) and a 2 nd layer containing a compound having a composition represented by the following formula (2),

Ti(C_x1N_1-x1) (1)

(in the formula (1), x1 represents the atomic ratio of C element to the total amount of C element and N element, and satisfies 0.02. ltoreq. x 1. ltoreq.0.30.)

(Ti₁-_y1Al_y1)N (2)

(in the formula (2), y1 represents the atomic ratio of the Al element to the total of the Ti element and the Al element, and satisfies 0.25. ltoreq. y 1. ltoreq.0.75.)

The average particle diameter of the particles in the 1 st layer is 5nm or more and less than 100nm,

in the layer 1, the ratio of the diffraction peak intensity I (111) of the (111) plane to the diffraction peak intensity I (200) of the (200) plane is 1.0. ltoreq.I (111)/I (200). ltoreq.20.0,

the average thickness of the 1 st layer is 5nm to 1.0 [ mu ] m,

in the 2 nd layer, the ratio of the diffraction peak intensity I (111) of the (111) plane to the diffraction peak intensity I (200) of the (200) plane is 0.1. ltoreq. I (111)/I (200). ltoreq.1.0,

the average particle diameter of the particles in the 2 nd layer is more than 100nm and 300nm or less,

the average thickness of the 2 nd layer is 5nm to 2.0 [ mu ] m.

Although the details of the factors that can improve the wear resistance and chipping resistance and have a long tool life of the coated cutting tool are not clear, the present inventors consider the following factors. But the main reason is not limited thereto. That is, in the 1 st layer forming the coating layer, if it contains a compound having a composition of Ti (C)_x1N_1-x1) When x1 in (b) is 0.02 or more, the hardness is increased, and therefore, the wear resistance of the coated cutting tool is improved, and further, the compression stress is easily applied by the micronization, and the progress of cracks is suppressed, and therefore, the chipping resistance is improved. Further, if Ti (C)_x1N_1-x1) When x1 in (2) is 0.3 or less, the adhesion to the 2 nd layer forming the coating layer is excellent, and hence the defect due to peeling is suppressed. In addition, in the coating layer-forming layer-2 nd layer, if it contains the composition of the compound (Ti)_1-y1Al_y1) When y1 in N is 0.25 or more, the heat resistance is improved, and therefore even in machining at a high cutting temperature such as high-speed machining or machining with a large load, the occurrence of reverse reaction can be suppressedShould wear and therefore will improve the wear resistance of the coated cutting tool. Furthermore, if (Ti)_1-y1Al_y1) Y1 in N is 0.75 or less, and as an effect of containing Ti, the reduction of high-temperature strength and the formation of hexagonal crystals are suppressed, thereby improving the wear resistance of the coated cutting tool. Further, if the average particle diameter of the particles in the 1 st layer is 5nm or more, the adhesion of the coating layer to the base material will be improved, and if it is less than 100nm, the compressive stress will be improved, and therefore, the chipping resistance of the coated cutting tool will be improved. In the layer 1, if the ratio (I (111)/I (200)) of the diffraction peak intensity I (111) of the (111) plane to the diffraction peak intensity I (200) of the (200) plane is 1.0 or more, it means that the layers are more oriented along the cubic crystal (111) plane. If the orientation is further along the cubic (111) plane, the closest arrangement plane is formed, and therefore, the hardness is increased while the deformation is prevented, and the wear resistance of the coated cutting tool is improved. On the other hand, if the ratio I (111)/I (200) is 20.0 or less, the production is easy. Further, if the average thickness of the 1 st layer is 5nm or more, the progress of cracks generated during processing can be suppressed, and therefore, the defect resistance is improved, and if it is 1.0 μm or less, compressive stress is easily applied, and therefore, the progress of cracks is suppressed, and thus, the defect resistance is improved.

In the layer 2, if the ratio (I (111)/I (200)) of the diffraction peak intensity I (111) of the (111) plane to the diffraction peak intensity I (200) of the (200) plane is 0.1 or more, the production is easy. In the layer 2, if I (111)/I (200) is 1.0 or less, it means that the layer is more oriented along the cubic crystal (200) plane. If the orientation is further along the cubic (200) plane, the toughness is improved, and the chipping resistance of the coated cutting tool is improved. Further, if the average particle diameter of the particles in the 2 nd layer exceeds 100nm, chipping due to falling off of the particles will be further suppressed, and hence the chipping resistance of the coated cutting tool will be improved. On the other hand, if the average particle diameter of the particles in the 2 nd layer is 300nm or less, a compressive stress is applied, and the chipping resistance of the coated cutting tool is improved. Further, if the average thickness of the 2 nd layer is 5nm or more, the progress of cracks generated during processing can be suppressed, and hence the defect resistance is improved, and if it is 2.0 μm or less, the adhesion with the 1 st layer can be improved, and defects due to peeling can be suppressed. In view of these effects, the coated cutting tool according to the present embodiment can improve wear resistance and chipping resistance, and thus has a long tool life.

The coated cutting tool of the present embodiment includes a substrate and a coating layer formed on a surface of the substrate. The base material used in the present embodiment is not particularly limited as long as it can be used as a base material of a coated cutting tool. As examples of such a base material, cemented carbide, cermet, ceramic, sintered cubic boron nitride, sintered diamond, and high-speed steel can be cited. Among them, if the base material is one or more selected from the group consisting of cemented carbide, cermet, ceramics and sintered cubic boron nitride, the coated cutting tool is more excellent in chipping resistance, and therefore, it is more preferable.

In the coating layer of the present embodiment, the average thickness of the entire coating layer is preferably 2.0 μm or more and 10.0 μm or less. In the coated cutting tool of the present embodiment, if the average thickness of the entire coating layer is 2.0 μm or more, the wear resistance tends to be further improved. On the other hand, in the coated cutting tool of the present embodiment, if the average thickness of the entire coating layer is 10.0 μm or less, the chipping resistance tends to be further improved. Therefore, the average thickness of the entire coating layer is preferably 2.0 μm or more and 10.0 μm or less. Among them, from the same viewpoint as above, it is more preferable if the average thickness of the entire coating layer is 2.5 μm or more and 9.5 μm or less.

[ layer 1]

In the coated cutting tool of the present embodiment, the coating layer has a 1 st layer, and the 1 st layer contains a compound having a composition represented by the following formula (1).

Ti(C_x1N_1-x1) (1)

(in the formula (1), x1 represents the atomic ratio of C element to the total amount of C element and N element, and satisfies 0.02. ltoreq. x 1. ltoreq.0.30.)

In the 1 st layer forming the coating layer, if it contains a compound having a composition of Ti (C)_x1N_1-x1) When x1 in (1) is 0.02 or more, the hardness is improved, and therefore the resistance of the coated cutting tool is improvedFurther, by making the particles fine, the grindability is improved because compressive stress is easily applied and the progress of cracks is suppressed. Further, if Ti (C)_x1N_1-x1) When x1 in (2) is 0.3 or less, the adhesion to the 2 nd layer forming the coating layer is excellent, and hence the defect due to peeling is suppressed. From the same viewpoint, Ti (C)_x1N_1-x1) X1 in (b) is preferably 0.04 to 0.3, more preferably 0.15 to 0.3.

In this embodiment, the composition of each compound layer is represented by Ti (C)_0.20N_0.80) In the case of (2), it means that the atomic ratio of the C element to the total amount of the C element and the N element is 0.20, and the atomic ratio of the N element to the total amount of the C element and the N element is 0.80. That is, the amount of the C element is 20 atomic% relative to the total amount of the C element and the N element, and the amount of the N element is 80 atomic% relative to the total amount of the C element and the N element.

In the coated cutting tool of the present embodiment, the average thickness of the 1 st layer (each layer in the case of the alternating stacked structure) is 5nm or more and 1.0 μm or less. If the average thickness of the 1 st layer is 5nm or more, the progress of cracks generated during processing can be suppressed, and thus the defect resistance is improved, and if it is 1.0 μm or less, compressive stress is easily applied, and therefore the progress of cracks is suppressed, and thus the defect resistance is improved. From the same viewpoint, when the 1 st layer is a single layer, it is more preferable if the average thickness thereof is 300nm to 1.0 μm, even more preferable if it is 500nm to 1.0 μm, and when the 1 st layer is a multilayer having an alternating laminated structure, it is more preferable if the average thickness of each of the 1 st layers is 20nm to 500nm, even more preferable if it is 50nm to 300 nm.

In the coated cutting tool of the present embodiment, the average particle diameter of the particles in the 1 st layer is 5nm or more and less than 100 nm. If the average particle diameter of the particles in the 1 st layer is 5nm or more, the adhesion between the coating layer and the substrate will be improved, and if it is less than 100nm, the compressive stress will be improved, and therefore the chipping resistance of the coated cutting tool will be improved. From the same viewpoint, the average particle diameter of the particles in the 1 st layer is preferably 7nm to 97nm, more preferably 10nm to 95 nm.

In the coated cutting tool of the present embodiment, in the layer 1, the ratio of the diffraction peak intensity I (111) on the (111) plane to the diffraction peak intensity I (200) on the (200) plane is 1.0. ltoreq.i (111)/I (200). ltoreq.20.0. In the layer 1, if I (111)/I (200) is 1.0 or more, it means that the layer is more oriented along the cubic (111) plane. If the orientation is further along the cubic (111) plane, it becomes the closest arrangement plane, and therefore, it is not easily deformed and the hardness is increased, thereby improving the wear resistance of the coated cutting tool. On the other hand, if the ratio I (111)/I (200) is 20.0 or less, the production is easy. From the same viewpoint, in the 1 st layer, I (111)/I (200) is preferably 1.1 to 19.5, and more preferably 1.2 to 19.4.

In the coated cutting tool of the present embodiment, the highest peak is preferably present in the (111) plane in the X-ray diffraction of the 1 st layer. In the coated cutting tool of the present embodiment, if the highest peak appears on the (111) plane in the X-ray diffraction of the 1 st layer, the hardness becomes high and the wear resistance tends to be improved.

In the coated cutting tool of the present embodiment, the residual stress of the 1 st layer is preferably-4.0 GPa to-2.0 GPa. If the residual stress of the 1 st layer is-4.0 GPa or more, cracks tend to be suppressed from entering the coating layer after the formation of the coating layer, and if-2.0 GPa or less, the progress of cracks can be suppressed by the effect of compressive stress, and thus the chipping resistance of the coated cutting tool tends to be improved.

[ layer 2]

In the coated cutting tool of the present embodiment, the coating layer has a 2 nd layer, and the 2 nd layer contains a compound having a composition represented by the following formula (2).

(Ti₁-_y1Al_y1)N (2)

(in the formula (2), y1 represents the atomic ratio of the Al element to the total of the Ti element and the Al element, and satisfies 0.25. ltoreq. y 1. ltoreq.0.75.)

In the coating layer-forming layer 2, if it contains a compound of composition (Ti)_1-y1Al_y1) When y1 in N is 0.25 or more, the heat resistance is improved, and therefore, the reaction wear can be suppressed even in a machining with a high cutting temperature such as a high-speed machining or a machining with a large load, and therefore, the wear resistance of the coated cutting tool is improved. Furthermore, if (Ti)_1-y1Al_y1) When y1 in N is 0.75 or less, the effect of Ti content suppresses a decrease in high-temperature strength and the formation of hexagonal crystals, thereby improving the wear resistance of the coated cutting tool. From the same viewpoint, (Ti)_1-y1Al_y1) Y1 in N is preferably 0.26 to 0.75, more preferably 0.27 to 0.74.

In the coated cutting tool of the present embodiment, when a lower layer to be described later is not formed, the 2 nd layer is preferably formed on the surface of the base material first. In the coated cutting tool of the present embodiment, if the 2 nd layer is formed on the surface of the base material first, the adhesiveness between the base material and the coating layer tends to be improved.

In the coated cutting tool of the present embodiment, the average thickness of the 2 nd layer (each layer in the case of the alternating stacked structure) is 5nm or more and 2.0 μm or less. If the average thickness of the 2 nd layer is 5nm or more, the progress of cracks generated during processing can be suppressed, and therefore, the defect resistance is improved, and if it is 2.0 μm or less, the adhesion with the 1 st layer can be improved, and defects due to peeling can be suppressed. From the same viewpoint, when the 2 nd layer is a single layer, it is more preferable if the average thickness thereof is 1.0 μm or more and 2.0 μm or less, and is still more preferable if it is 1.5 μm or more and 2.0 μm or less, and when the 2 nd layer is a multilayer having an alternating layered structure, it is still more preferable if the average thickness of each of the 2 nd layers is 20nm or more and 500nm or less, and is still more preferable if it is 50nm or more and 300nm or less.

In the coated cutting tool of the present embodiment, in the 2 nd layer, the ratio of the diffraction peak intensity I (111) on the (111) plane to the diffraction peak intensity I (200) on the (200) plane is 0.1. ltoreq. I (111)/I (200). ltoreq.1.0. In the 2 nd layer, if the ratio (I (111)/I (200)) of the diffraction peak intensity I (111) of the (111) plane to the diffraction peak intensity I (200) of the (200) plane is 0.1 or more, the production is easy. In the layer 2, if I (111)/I (200) is 1.0 or less, it means that the layer is more oriented along the cubic crystal (200) plane. If the orientation is further along the cubic (200) plane, the toughness is improved, and the chipping resistance of the coated cutting tool is improved. From the same viewpoint, in the 2 nd layer, I (111)/I (200) is preferably 0.1 to 0.9.

In the coated cutting tool of the present embodiment, the highest peak is preferably present in the (200) plane in the X-ray diffraction of the 2 nd layer. In the coated cutting tool of the present embodiment, if the highest peak appears on the (200) plane in the X-ray diffraction of the 2 nd layer, the toughness is increased and the chipping resistance tends to be improved.

The peak intensity of each crystal plane of the 1 st and 2 nd layers can be measured by using a commercially available X-ray diffraction apparatus. For example, if model numbers manufactured by kayako リガク are used: RINT TTRIII, the peak intensity of each crystal plane was measured by performing X-ray diffraction measurement using a 2 θ/θ focusing method optical system using Cu-Ka rays under the following conditions. The measurement conditions were: output power: 50kV, 250mA, incident side shuttle slit: 5 °, divergent longitudinal slit: 2/3 °, divergent longitudinal limit slit: 5mm, scattering slit: 2/3 °, light receiving side shuttle slit: 5 °, light receiving slit: 0.3mm, BENT monochromator, light receiving monochrome slit: 0.8mm, sampling width: 0.01 °, scanning speed: 4 °/min, 2 θ measurement range: 20 to 50 degrees. When the peak intensity of each crystal plane is obtained from the X-ray diffraction pattern, analysis software attached to the X-ray diffraction apparatus may be used. In the analysis software, background processing and K.alpha.removal are performed by using cubic spline approximation (cubic spline)₂The peak intensity can be obtained by fitting the peak shape using Pearson-VII function. Note that even in the case of the alternate stacked structure, the peak intensity of each crystal plane can be measured under the same conditions. For example, the intensity ratio can be calculated from the peak intensities of the respective crystal planes obtained by measuring arbitrary plural 1 st and 2 nd layers.

In the coated cutting tool of the present embodiment, the residual stress of the 2 nd layer is preferably-2.0 GPa to 0 GPa. If the residual stress of the 2 nd layer is-2.0 GPa or more, cracks can be suppressed from entering the coating layer after the coating layer having the effect of compressive stress is formed, and therefore the adhesion of the coating layer to the base material tends to be improved. On the other hand, if the residual stress of the 2 nd layer is 0GPa or less, the progress of cracks can be suppressed by the effect of having the compressive stress, and hence the chipping resistance of the coated cutting tool tends to be improved. From the same viewpoint, the residual stress of the 2 nd layer is more preferably-2.0 GPa or more and-0.1 GPa or less, and still more preferably-2.0 GPa or more and-0.2 GPa or less.

The residual stress is an internal stress (inherent strain) remaining in the coating layer, and a stress represented by a numerical value of "-" (negative) is generally referred to as a compressive stress, and a stress represented by a numerical value of "+" (positive) is generally referred to as a tensile stress. In the present embodiment, in the case of representing the magnitude of the residual stress, a larger value of "+" (positive) indicates a larger residual stress, and a larger value of "-" (negative) indicates a smaller residual stress.

The residual stress can be measured by sin using an X-ray diffraction apparatus²The ψ method was used for the measurement. Furthermore, such residual stress can be induced by sin as described above²The ψ method measures the stress of any three points included in a portion related to cutting (each of the three points is preferably spaced from each other by 0.5mm or more so that they can represent the stress of the portion), and measures the residual stress by averaging them. In the case of the alternate lamination structure, the residual stress can be measured under the same conditions. For example, the residual stress is calculated by measuring an arbitrary plurality of 2 nd layers and averaging the measured values.

In the coated cutting tool of the present embodiment, the average particle diameter of the particles in the 2 nd layer exceeds 100nm and is 300nm or less. If the average particle diameter of the particles in the 2 nd layer exceeds 100nm, chipping due to falling off of the particles can be further suppressed, and hence the chipping resistance of the coated cutting tool will be improved. On the other hand, if the average particle diameter of the particles in the 2 nd layer is 300nm or less, a compressive stress is applied, and the chipping resistance of the coated cutting tool is improved. From the same viewpoint, the average particle diameter of the particles in the 2 nd layer is preferably 103nm to 298nm, more preferably 105nm to 296 nm.

In the present embodiment, the average particle diameter of the particles in each layer of the coating layer is determined as a particle diameter in a direction parallel to the surface of the substrate, and can be measured by the method described in the examples below.

[ alternate Stacking Structure ]

In the coated cutting tool of the present embodiment, the coating layer preferably has an alternating laminated structure in which the 1 st layer and the 2 nd layer are alternately repeated 2 times or more. In the coated cutting tool of the present embodiment, if the coating layer has an alternating lamination structure in which the 1 st layer and the 2 nd layer are alternately repeated 2 times or more, the TiCN layer can be repeatedly formed and the thickness of the entire coating layer can be increased while suppressing the increase in the compressive stress, and therefore, the wear resistance tends to be improved without lowering the fracture resistance. In the coated cutting tool of the present embodiment, when the lower layer described later is not formed, the 2 nd layer is preferably formed most earlier than the surface of the base material. In the coated cutting tool of the present embodiment, if the 2 nd layer is formed first on the surface of the base material, the adhesion between the base material and the coating layer tends to be improved.

In the coated cutting tool of the present embodiment, the number of repetitions of the 1 st layer and the 2 nd layer in the alternately laminated structure is preferably 2 to 100 times, more preferably 3 to 70 times, still more preferably 5 to 50 times, and particularly preferably 6 to 47 times.

In this embodiment, when the 1 st layer and the 2 nd layer are each formed as one layer, "the number of repetitions" is 1.

In the coated cutting tool of the present embodiment, the average composition of the entire compound in the 1 st layer and the 2 nd layer is preferably a composition represented by the following formula (3).

(Ti₁-_y2Al_y2)(C_x2N_1-x2) (3)，

(in the formula (3), x2 represents an atomic ratio of C element to the total amount of C element and N element, and satisfies 0.01. ltoreq. x 2. ltoreq.0.15, and y2 represents an atomic ratio of Al element to the total amount of Ti element and Al element, and satisfies 0.12. ltoreq. y 2. ltoreq.0.38.)

In the case where the coating layers have the alternately laminated structure as described above, the coated cutting tool of the present embodiment has a structure in which the amount of Al and the amount of C periodically change. With such a configuration, even if the atomic ratio of C in TiCN is increased, the increase in the compressive stress can be suppressed, and the coating layer can have good adhesion to the substrate, so that the coating layer can be thickened. When the coating layer is thickened, the coated cutting tool of the present embodiment can further improve the wear resistance, and further improve the adhesion between the coating layer and the base material, so that the chipping due to the peeling tends to be suppressed.

If the average composition of the compound in the 1 st and 2 nd layers is the whole (Ti)_1-y2Al_y2)(C_x2N_1-x2) When x2 in (b) is 0.01 or more, the hardness is increased, and therefore, the wear resistance of the coated cutting tool is improved, and further, since compressive stress is easily applied, and the progress of cracks is suppressed, the chipping resistance tends to be improved, and when x2 is 0.15 or less, the adhesion between the 1 st layer and the 2 nd layer is excellent, and therefore, chipping by peeling tends to be suppressed. From the same viewpoint, average composition (Ti)_{1- y2}Al_y2)(C_x2N_1-x2) X2 in (1) is preferably 0.02 to 0.15.

If the average composition of the compound in the 1 st and 2 nd layers is the whole (Ti)_1-y2Al_y2)(C_x2N_1-x2) When y2 in (a) is 0.12 or more, the heat resistance is improved, and therefore, the reactive wear can be suppressed even in a machining process having a high cutting temperature, such as a high-speed machining process or a machining process having a large load, and therefore, the wear resistance of the coated cutting tool tends to be improved, and when x2 is 0.38 or less, the reduction of the high-temperature strength and the formation of hexagonal crystals can be suppressed as an effect due to the Ti content, and therefore, the wear resistance of the coated cutting tool tends to be improved. From the same viewpoint, average composition (Ti)_1-y2Al_y2)(C_x2N_1-x2) Y2 in (1) is preferably 0.14 to 0.37.

In the coated cutting tool of the present embodiment, the difference Δ C (x1-x2) between the atomic ratio x2 of the C element in the average composition represented by formula (3) and the atomic ratio x1 of the C element in the composition represented by formula (1) is preferably 0.01 to 0.15. In the coated cutting tool of the present embodiment, if Δ C is 0.01 or more, the particles of the coating layer are made fine, compressive stress is easily applied, and the progress of cracks is suppressed, so that the chipping resistance tends to be improved. On the other hand, in the coated cutting tool of the present embodiment, if Δ C is 0.15 or less, the coating layer has excellent adhesion to the base material, and thus the coated cutting tool tends to be inhibited from being damaged by peeling.

In the coated cutting tool of the present embodiment, the difference Δ Al (y1-y2) between the atomic ratio y2 of the Al element in the average composition represented by formula (3) and the atomic ratio y1 of the Al element in the composition represented by formula (2) is preferably 0.12 to 0.38. In the coated cutting tool of the present embodiment, if Δ Al is 0.12 or more, the interface strain is introduced to increase the hardness, and the wear resistance tends to be improved. On the other hand, in the coated cutting tool of the present embodiment, if Δ Al is 0.38 or less, the adhesion at the interface is improved and the peeling resistance is improved, and thus the chipping resistance tends to be improved.

Fig. 1 is a schematic cross-sectional view showing an example of a coated cutting tool according to the present embodiment. The coated cutting tool 6 includes a substrate 1 and a coating layer 5 formed on a surface of the substrate 1. The coating layer 5 has an alternating laminated structure 4, and the 1 st layer 2 and the 2 nd layer 3 are alternately formed 4 times in this alternating laminated structure 4 in this order from the substrate 1 side.

[ lower layer ]

The coating layer used in the present embodiment may be composed of only the 1 st layer and the 2 nd layer, but preferably has a lower layer between the substrate and the laminated structure of the 1 st layer and the 2 nd layer (in the case of an alternate laminated structure, between the substrate and the alternate laminated structure of the 1 st layer and the 2 nd layer). This further improves the adhesion between the substrate and the coating layer. From the same viewpoint as described above, it is preferable if the lower layer contains a compound composed of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y and at least one element selected from the group consisting of C, N, O and B, and it is more preferable if the lower layer contains a compound composed of at least one element selected from the group consisting of Ti, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y and at least one element selected from the group consisting of C, N, O and B, and it is further preferable if the lower layer contains a compound composed of at least one element selected from the group consisting of Ti, Ta, Cr, W, Al, Si, and Y and N. The lower layer may be a single layer or a multilayer having two or more layers.

In the present embodiment, it is preferable that the average thickness of the lower layer is 0.1 μm or more and 3.5 μm or less because the adhesion between the base material and the coating layer tends to be further improved. From the same viewpoint, the average thickness of the lower layer is more preferably 0.2 μm or more and 3.0 μm or less, and still more preferably 0.3 μm or more and 2.5 μm or less.

[ Upper layer ]

The coating layer used in the present embodiment may have an upper layer on the opposite side of the laminated structure of the 1 st layer and the 2 nd layer from the substrate (in the case of the alternate laminated structure, the opposite side of the laminated structure of the 1 st layer and the 2 nd layer from the substrate). The upper layer is more preferable since it has more excellent wear resistance if it contains a compound of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si and Y and at least one element selected from the group consisting of C, N, O and B. From the same viewpoint as described above, the upper layer preferably contains a compound of at least one element selected from the group consisting of Ti, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y and at least one element selected from the group consisting of C, N, O and B, and more preferably contains a compound of at least one element selected from the group consisting of Ti, Nb, Ta, Cr, W, Al, Si, and Y and N. The upper layer may be a single layer or a multilayer having two or more layers.

In the present embodiment, it is preferable that the average thickness of the upper layer is 0.1 μm or more and 3.5 μm or less because the wear resistance tends to be more excellent. From the same viewpoint, the average thickness of the upper layer is more preferably 0.2 μm or more and 3.0 μm or less, and still more preferably 0.3 μm or more and 2.5 μm or less.

[ method for producing coating layer ]

The method for producing the coating layer in the coated cutting tool of the present embodiment is not particularly limited, and examples thereof include physical vapor deposition methods such as ion plating, arc ion plating, sputtering, and ion mixing. If the coating layer is formed by physical vapor deposition, sharp edges (sharp edges) can be formed, which is preferable. Among them, the arc ion plating method is more preferable because the coating layer has more excellent adhesion to the substrate.

[ method for producing coated cutting tool ]

The method for manufacturing the coated cutting tool according to the present embodiment will be described below using specific examples. The method for manufacturing the coated cutting tool of the present embodiment is not particularly limited as long as the structure of the coated cutting tool can be realized.

First, a base material processed into a tool shape is accommodated in a reaction vessel of a physical vapor deposition apparatus, and a metal evaporation source is provided in the reaction vessel. Then, the inside of the reaction vessel was evacuated until the pressure reached 1.0X 10^-2Pa or less, and heating the substrate to a temperature of 200 to 700 ℃ by a heater in the reaction vessel. After heating, Ar gas is introduced into the reaction vessel so that the pressure in the reaction vessel becomes 0.5Pa to 5.0 Pa. Applying a bias voltage of-500V to-350V to the substrate under an Ar gas environment with a pressure of 0.5Pa to 5.0Pa, flowing a current of 40A to 50A through the tungsten filament in the reaction vessel, and performing ion bombardment treatment by the Ar gas on the surface of the substrate. After the ion bombardment treatment is applied to the surface of the substrate, the inside of the reaction vessel is evacuated until the pressure thereof reaches 1.0X 10^-2Vacuum below Pa.

In the case of forming the lower layer used in this embodiment, the substrate is heated to a temperature of 400 to 600 ℃. AddingAfter heating, a gas is introduced into the reaction vessel so that the pressure in the reaction vessel is 0.5Pa to 5.0 Pa. As the gas, for example, when the lower layer is composed of a compound of N and at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si and Y, N may be mentioned₂When the gas is composed of a compound of N and C, and the lower layer is composed of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si and Y, N is exemplified as N₂Gas and C₂H₂A mixture of gases. The volume ratio of the mixed gas is not particularly limited, and may be N, for example₂Gas C₂H₂The gas is 95: 5-85: 15. Then, a bias voltage of-80V to-40V is applied to the base material, and the metal evaporation source corresponding to the metal component of each layer is evaporated by arc discharge with an arc current of 100A to 200A to form the lower layer.

In the case of forming the layer 1 used in the present embodiment, the temperature of the substrate is controlled to 350 to 550 ℃ and nitrogen (N) gas is introduced into the reaction vessel₂) The pressure in the reaction vessel is set to 1.0Pa to 5.0 Pa. Then, a bias voltage of-80V to-35V is applied to the base material, and arc discharge of 80A to 150A is performed to evaporate the TiC evaporation source of the 1 st layer to form the 1 st layer.

In the case of forming the layer 2 used in the present embodiment, the temperature of the base material is controlled to 350 to 550 ℃. It should be noted that if the temperature of the substrate is set to be the same as the temperature of the substrate when the layer 1 is formed, the layer 1 and the layer 2 can be formed continuously, which is preferable. After controlling the temperature, N is added₂The gas is introduced into the reaction vessel so that the pressure in the reaction vessel is 2.0Pa to 4.0 Pa. Then, a bias voltage of-100V to-40V is applied to the substrate, and the metal evaporation source corresponding to the metal component of the 2 nd layer is evaporated by arc discharge with an arc current of 80A to 150A to form the 2 nd layer.

In order to form the alternate stacked structure of the 1 st layer and the 2 nd layer, each layer may be formed alternately by alternately evaporating a TiC evaporation source and a metal evaporation source by arc discharge under the above conditions. The thicknesses of the layers constituting the alternately laminated structure can be controlled by adjusting the arc discharge time of the TiC evaporation source and the metal evaporation source, respectively. The use of a TiC evaporation source is preferable because an alternate stacked structure having a thickness of 100nm or less per layer can be easily formed.

When the layer 1 is formed, if the pressure in the reaction vessel is increased, it is possible to decrease the proportion of the N element and increase the proportion of the C element (x1) in the composition represented by formula (1).

In order to set the diffraction intensity ratio I (111)/I (200) in the 1 st layer used in this embodiment to a predetermined value, the temperature of the base material or the bias voltage may be adjusted in the process of forming the 1 st layer. More specifically, in the process of forming the 1 st layer, if the temperature of the base material is lowered or the negative bias is increased (away from the zero side), I (111) in the 1 st layer tends to become large.

In order to set the diffraction intensity ratio I (111)/I (200) in the 2 nd layer used in this embodiment to a predetermined value, the temperature of the base material or the bias voltage may be adjusted during the formation of the 2 nd layer, and more specifically, if the temperature of the base material is lowered or the negative bias voltage is increased (away from zero) during the formation of the 2 nd layer, I (111) in the 2 nd layer tends to increase.

In order to set the average particle diameter of the particles in the 1 st layer used in this embodiment to a predetermined value, the bias voltage or the amount of the raw material of the C element may be adjusted in the process of forming the 1 st layer. More specifically, in the process of forming the 1 st layer, if the negative bias is increased (away from the zero side), the average particle diameter of the particles in the 1 st layer tends to become small. In the process of forming the 1 st layer, if the amount of the raw material of the C element is increased, the average particle diameter of the particles in the 1 st layer tends to become small.

In order to set the average particle diameter of the particles in the 2 nd layer used in this embodiment to a predetermined value, the bias voltage may be adjusted in the process of forming the 2 nd layer. More specifically, in the process of forming the 2 nd layer, if the negative bias is increased (away from the zero side), the average particle diameter of the particles in the 2 nd layer tends to become small. By making the average particle diameter of the particles in the 2 nd layer small, the aspect ratio becomes large. Further, in the case of the alternate laminated structure, if the average thickness of each of the 2 nd layers becomes extremely thin, the average particle diameter of the particles in the 2 nd layer tends to become small.

In order to set the residual stress in the 1 st layer used in this embodiment to a predetermined value, the bias voltage may be adjusted in the process of forming the 1 st layer. More specifically, in the process of forming the 1 st layer, if the negative bias is increased (away from the zero side), the residual stress in the 1 st layer tends to become small. Further, in the case of forming the alternate laminated structure, if the average thickness of each of the 1 st layers is increased, the residual stress in the 1 st layer tends to become small.

In order to set the residual stress in the 2 nd layer used in this embodiment to a predetermined value, the bias voltage may be adjusted in the process of forming the 2 nd layer. More specifically, in the process of forming the 2 nd layer, if the negative bias is increased (away from the zero side), the residual stress in the 2 nd layer tends to become small.

The upper layer used in this embodiment may be formed under the same manufacturing conditions as those for the lower layer. That is, first, the substrate is heated to a temperature of 400 to 600 ℃. After heating, a gas is introduced into the reaction vessel so that the pressure in the reaction vessel is 0.5Pa to 5.0 Pa. The gas is, for example, a compound of N and at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si and Y in the upper layer₂When the gas is composed of a compound of N and C, and at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si and Y as an upper layer, N is exemplified₂Gas and C₂H₂A mixture of gases. The volume ratio of the mixed gas is not particularly limited, and may be N, for example₂Gas C₂H₂The gas is 95: 5-85: 15. Then, a bias voltage of-80V to-40V is applied to the base material, and the metal evaporation source corresponding to the metal component of each layer is evaporated by arc discharge with an arc current of 100A to 200A to form the upper layer.

The thickness of each layer constituting the coating layer in the coated cutting tool of the present embodiment can be measured from the cross-sectional structure of the coated cutting tool by using an optical microscope, a Scanning Electron Microscope (SEM), a Transmission Electron Microscope (TEM), or the like. The average thickness of each layer in the coated cutting tool of the present embodiment can be determined by measuring the thickness of each layer from a section of 3 or more points in the vicinity of a position 50 μm from the edge line portion of the surface facing the metal evaporation source toward the center portion of the surface, and calculating the average value (arithmetic mean value) of the measured thicknesses.

The composition of each layer constituting the coating layer in the coated cutting tool of the present embodiment can be measured from the cross-sectional structure of the coated cutting tool of the present embodiment by using an energy dispersive X-ray analyzer (EDS), a wavelength dispersive X-ray analyzer (WDS), or the like.

The average composition of the compound layers in the 1 st and 2 nd layers as a whole can be determined by using commercially available SEM or TEM attached to EDS. Specifically, for example, a cross section of the coating layer is prepared (the same as when the thickness of the coating layer is measured), and a surface analysis is performed on a laminated structure or an alternate laminated structure of the 1 st layer and the 2 nd layer. In this case, the measurement range is "length of 90% of the thickness of the 1 st layer and the 2 nd layer or the alternate lamination structure" × "1 μm (length in the direction parallel to the substrate surface) or more". The average composition (Ti) of the entire compound layers in the 1 st and 2 nd layers can be obtained from the surface analysis results_1-y2Al_y2)(C_x2N_1-x2) The atomic ratio of (a).

The coated cutting tool of the present embodiment is considered to exhibit an effect of being able to extend the working life as compared with the conventional one because at least the coated cutting tool is excellent in wear resistance and chipping resistance (however, the factor of being able to extend the working life is not limited to the above-mentioned factor). Specific examples of the type of the coated cutting tool according to the present embodiment include replaceable cutting inserts for milling or turning, drills, end mills, and the like.

[ examples ]

The present invention will be described in further detail with reference to examples, but the present invention is not limited to these examples.

(example 1)

As a substrate, a CNMG120408-SM insert (89.6 WC-9.8Co-0.6 Cr-containing)₃C₂(the above is mass%). In a reaction vessel of the arc ion plating apparatus, a TiC evaporation source and a metal evaporation source were arranged so as to have the compositions of the respective layers shown in tables 1 and 2. The prepared substrate is fixed to a fixing member of a rotary table in the reaction vessel.

Then, the inside of the reaction vessel was evacuated until the pressure reached 5.0X 10^-3Vacuum below Pa. After evacuation, the substrate was heated to a temperature of 450 ℃ by means of a heater in the reaction vessel. After heating, Ar gas was introduced into the reaction vessel so that the pressure thereof became 2.7 Pa.

A bias voltage of-400V was applied to the substrate in an Ar gas atmosphere at a pressure of 2.7Pa, and a current of 40A was passed through a tungsten filament in a reaction vessel, thereby applying an Ar gas-based ion bombardment treatment to the surface of the substrate for 30 minutes. After the ion bombardment treatment is finished, the reaction vessel is vacuumized until the pressure reaches 5.0 x 10^-3Vacuum below Pa.

After vacuuming the inventive products 1 to 14, the temperature of the substrate was controlled to the temperature shown in table 3 (temperature at the start of film formation), and nitrogen gas (N) was introduced₂) The reaction mixture was introduced into a reaction vessel, and the pressure in the reaction vessel was adjusted to a pressure shown in Table 3. Then, the bias voltage shown in table 3 was applied to the substrate, and the TiC evaporation source of the 1 st layer having the composition shown in table 1 and the metal evaporation source of the 2 nd layer having the composition shown in table 1 were evaporated in the order in which the lowermost layer shown in table 1 was first formed on the surface of the substrate by arc discharge with the arc current shown in table 3, thereby forming the 1 st layer and the 2 nd layer in the order in which the lowermost layer shown in table 1 was the first surface of the substrate. At this time, the pressure in the reaction vessel was controlled as shown in Table 3. Further, the respective arc discharge times were adjusted and controlled so that the thickness of the 1 st layer and the thickness of the 2 nd layer reached the thicknesses shown in table 1.

For comparisonAfter vacuuming the products 1 to 11, the temperature of the substrate was controlled to the temperature shown in Table 4 (temperature at the start of film formation), and nitrogen gas (N) was added₂) The reaction mixture was introduced into a reaction vessel, and the pressure in the reaction vessel was adjusted to a pressure shown in Table 4. Then, the bias voltage shown in table 4 was applied to the substrate, and the TiCN evaporation source for the a layer having the composition shown in table 2 and the metal evaporation source for the B layer having the composition shown in table 2 were evaporated in the order in which the lowermost layer shown in table 2 was first formed on the surface of the substrate by arc discharge with the arc current shown in table 4, thereby forming the a layer and the B layer in the order in which the lowermost layer shown in table 1 was the first surface of the substrate. At this time, the pressure in the reaction vessel was controlled as shown in Table 4. The arc discharge time was adjusted and controlled so that the thickness of the a layer and the thickness of the B layer became the thicknesses shown in table 2.

After the layers were formed on the surface of the substrate until the average thickness was as specified in tables 1 and 2, the heater was turned off, and the sample temperature was 100 ℃ or lower, the sample was taken out from the reaction vessel.

[ Table 1]

[ Table 2]

[ Table 3]

[ Table 4]

The average thickness of each layer of the obtained sample was determined by measuring the thickness of each layer by TEM observation of a cross section at 3 points in the vicinity of a position 50 μm from the edge line portion of the cutting tip of the surface of the coated cutting tool facing the metal evaporation source toward the center of the surface, and calculating the average value (arithmetic average value) thereof. These results are also shown in tables 1 and 2.

The composition of each layer of the obtained sample was measured by EDS attached to TEM in a cross section near a position 50 μm from the edge line portion of the cutting tip covering the surface of the cutting tool facing the metal evaporation source to the center portion. The average composition of the compound layers in the 1 st and 2 nd layers was determined using commercially available TEM attached to EDS. Specifically, a cross section of the coating layer was prepared (the same as when the thickness of the coating layer was measured), and the laminated structure of the 1 st layer and the 2 nd layer was subjected to surface analysis. In this case, the measurement range is "length of 90% of the thickness of the laminated structure of the 1 st layer and the 2 nd layer" × "1 μm (length in the direction parallel to the substrate surface) or more". The average composition (Ti) of the entire compound layers in the 1 st and 2 nd layers was obtained from the results of surface analysis_1-y2Al_y2)(C_x2N_1-x2) The atomic ratio of (a). These results are also shown in tables 1, 2, 5 and 6. The composition ratios of the metal elements in each of tables 1, 2, 5, and 6 show the atomic ratios of the respective metal elements to the entire metal elements in the metal compound constituting each layer.

[ Table 5]

[ Table 6]

[I(111)/I(200)]

The ratio I (111)/I (200) in each layer of the obtained sample was determined by using a model manufactured by Kabushiki Kaisha リガク: RINT TTRIII by X-ray diffraction. Specifically, the peak intensity I (200) of the (200) plane of each layer and the peak intensity I (111) of the (111) plane of each layer were measured by X-ray diffraction of an optical system using a 2 θ/θ focusing method using Cu — K α rays under the following conditions, and thereby the ratio I (111)/I (200) was calculated: output power: 50kV, 250mA, incident side shuttle slit: 5 °, divergent longitudinal slit: 2/3 °, divergent longitudinal limit slit: 5mm, scattering slit: 2/3 °, light receiving side shuttle slit: 5 °, light receiving slit: 0.3mm, BENT monochromator, light receiving monochrome slit: 0.8mm, sampling width: 0.01 °, scanning speed: 4 °/min, 2 θ measurement range: 20 to 50 degrees. The results are shown in tables 7 and 8.

[ residual stress ]

The obtained sample was processed by sin using an X-ray diffraction apparatus²Psi method, the residual stress of each layer was measured. The residual stress was measured at 3 arbitrary points included in the portion related to cutting, and the average value (arithmetic average) thereof was used as the residual stress of each layer. The results are shown in tables 7 and 8.

[ average particle diameter ]

The average particle size of the particles in each layer of the obtained sample was measured by a commercially available Transmission Electron Microscope (TEM) as described below. First, a thin film sample having a cross section of the coating layer (a cross section in the same direction as that in the case of observing the thickness of the coating layer: a direction perpendicular to the substrate surface) as an observation surface was prepared using a Focused Ion Beam (FIB) processing machine. A Scanning Transmission Electron Microscope (STEM) photograph was taken of the observation surface of the prepared sample. On the photographed photograph, a straight line was drawn in a direction parallel to the surface of the substrate and the number of particles constituting each layer was measured. The average particle diameter is defined as the value obtained by dividing the length of the straight line by the number of particles. In this case, the length of the straight line is set to 10 μm or more. The measurement results are shown in tables 7 and 8.

[ Table 7]

[ Table 8]

The obtained sample was subjected to the following cutting test and evaluated.

[ cutting test 1]

Material to be cut: the SUS304 may be used as the basis,

shape of material to be cut: a round bar of 120mm x 400mm,

cutting speed: the flow rate of the mixture is 120m/min,

feed per blade: 0.3mm/rev of the sample,

cutting depth: 2.0mm of the total weight of the steel,

cooling agent: use of

Evaluation items: the tool life was determined as the time required for the sample to be broken (the cutting edge of the sample was chipped) or the flank wear width reached 0.30mm, and the machining time until the tool life was reached was measured. Further, the damage form at the time of 10 minutes was observed by SEM. Note that the damage form "chipping" at the time of 10 minutes means that this is a notch of such a degree that the processing can be continued. In addition, a longer working time means excellent chipping resistance and wear resistance. The results of the obtained evaluations are shown in tables 9 and 10.

[ Table 9]

[ Table 10]

From the results shown in tables 9 and 10, the processing time of the invention product was 22 minutes or longer than that of all the comparative products.

From the above results, it is understood that the tool life of the invention product is prolonged by improving the wear resistance and the chipping resistance.

(example 2)

As a substrate, a CNMG120408-SM insert (89.6 WC-9.8Co-0.6 Cr-containing)₃C₂(the aboveMass%) of cemented carbide). In the reaction vessel of the arc ion plating apparatus, a TiC evaporation source and a metal evaporation source were arranged so as to have the compositions of the respective layers shown in tables 11 and 12. The prepared substrate is fixed to a fixing member of a rotary table in the reaction vessel.

Then, the inside of the reaction vessel was evacuated until the pressure reached 5.0X 10^-3Vacuum below Pa. After evacuation, the substrate was heated to a temperature of 450 ℃ by means of a heater in the reaction vessel. After heating, Ar gas was introduced into the reaction vessel so that the pressure thereof became 2.7 Pa.

A bias voltage of-400V was applied to the substrate in an Ar gas atmosphere at a pressure of 2.7Pa, and a current of 40A was passed through a tungsten filament in a reaction vessel, thereby applying an Ar gas-based ion bombardment treatment to the surface of the substrate for 30 minutes. After the ion bombardment treatment is finished, the reaction vessel is vacuumized until the pressure reaches 5.0 x 10^-3Vacuum below Pa.

After vacuuming the inventive products 15 to 31, the temperature of the substrate was controlled to the temperature shown in table 3 (temperature at the start of film formation), and nitrogen gas (N) was introduced₂) The reaction mixture was introduced into a reaction vessel, and the pressure in the reaction vessel was adjusted to a pressure shown in Table 3. Then, the bias voltage shown in table 13 was applied to the substrate, and the TiC evaporation source of the 1 st layer having the composition shown in table 11 and the metal evaporation source of the 2 nd layer having the composition shown in table 11 were alternately evaporated in the order in which the lowermost layer shown in table 11 was first formed on the surface of the substrate by arc discharge with the arc current shown in table 13, thereby alternately forming the 1 st layer and the 2 nd layer in the order in which the lowermost layer shown in table 11 was the first surface of the substrate. At this time, the pressure in the reaction vessel was controlled as shown in Table 13. Further, the respective arc discharge times were adjusted and controlled so that the thickness of the 1 st layer and the thickness of the 2 nd layer became the thicknesses shown in table 11.

Comparative products 12 to 21 were evacuated, and then the temperature of the substrate was controlled to a temperature (temperature at the start of film formation) shown in Table 14, and nitrogen gas (N) was introduced₂) The reaction mixture was introduced into a reaction vessel, and the pressure in the reaction vessel was adjusted to a pressure shown in Table 14. Then, the substrate was biased as shown in Table 14, passing through the tableArc discharge with arc current shown in table 14 alternately evaporates the TiCN evaporation source for the a layer having the composition shown in table 12 and the metal evaporation source for the B layer having the composition shown in table 12 in the order in which the lowermost layer shown in table 12 was formed first on the surface of the base material, and alternately forms the a layer and the B layer in the order in which the lowermost layer shown in table 12 was the first surface of the base material. At this time, the pressure in the reaction vessel was controlled as shown in Table 14. The arc discharge time was adjusted and controlled so that the thickness of the a layer and the thickness of the B layer became the thicknesses shown in table 12.

After the layers were formed on the surface of the substrate until the average thickness was as specified in tables 11 and 12, the heater was turned off, and the sample temperature was 100 ℃ or lower, the sample was taken out from the reaction vessel.

[ Table 11]

[ Table 12]

[ Table 13]

[ Table 14]

The average thickness of each layer of the obtained sample was determined by measuring the thickness of each layer by TEM observation of a cross section at 3 points in the vicinity of a position 50 μm from the edge line portion of the cutting tip of the surface of the coated cutting tool facing the metal evaporation source toward the center of the surface, and calculating the average value (arithmetic average value) thereof. The average thickness of each of the 1 st layers is calculated by dividing the total thickness of the individual 1 st layers added together with the thickness t1 by the number of 1 st layers (number of repetitions). The average thickness of each of the 2 nd layers is calculated by dividing the total thickness of the 2 nd layer thicknesses t2 by the number of the 2 nd layers (the number of repetitions) in the same manner. These results are also shown in tables 11 and 12.

The composition of each layer of the obtained sample was measured by EDS using TEM in a cross section near a position 50 μm from the edge line portion of the cutting tip covering the surface of the cutting tool facing the metal evaporation source to the center portion. The average composition of the compound layers in the 1 st and 2 nd layers was determined using commercially available TEM attached to EDS. Specifically, a cross section of the coating layer was prepared (the same as when the thickness of the coating layer was measured), and the laminated structure of the 1 st layer and the 2 nd layer was subjected to surface analysis. In this case, the measurement range is "length of 90% of the thickness of the laminated structure of the 1 st layer and the 2 nd layer" × "1 μm (length in the direction parallel to the substrate surface) or more". The average composition (Ti) of the entire compound layers in the 1 st and 2 nd layers was obtained from the results of surface analysis_1-y2Al_y2)(C_x2N_1-x2) The atomic ratio of (a). These results are also shown in tables 11, 12, 15 and 16. The composition ratios of the metal elements in each of tables 11, 12, 15, and 16 show the atomic ratios of the respective metal elements to the entire metal elements in the metal compound constituting each layer.

[ Table 15]

[ Table 16]

[I(111)/I(200)]

The ratio I (111)/I (200) in each layer of the obtained sample was determined by using a model manufactured by Kabushiki Kaisha リガク: RINT TTRIII by X-ray diffraction. Specifically, the peak intensity I (200) of the (200) plane of each layer and the peak intensity I (111) of the (111) plane of each layer were measured by X-ray diffraction of an optical system using a 2 θ/θ focusing method using Cu — K α rays under the following conditions, and thereby the ratio I (111)/I (200) was calculated: output power: 50kV, 250mA, incident side shuttle slit: 5 °, divergent longitudinal slit: 2/3 °, divergent longitudinal limit slit: 5mm, scattering slit: 2/3 °, light receiving side shuttle slit: 5 °, light receiving slit: 0.3mm, BENT monochromator, light receiving monochrome slit: 0.8mm, sampling width: 0.01 °, scanning speed: 4 °/min, 2 θ measurement range: 20 to 50 degrees. The results are shown in tables 17 and 18.

[ residual stress ]

The obtained sample was processed by sin using an X-ray diffraction apparatus²Psi method, the residual stress of each layer was measured. The residual stress was measured at 3 arbitrary points included in the portion related to cutting, and the average value (arithmetic average) thereof was used as the residual stress of each layer. The results are shown in tables 17 and 18.

[ average particle diameter ]

The average particle size of the particles in each layer of the obtained sample was measured by a commercially available Transmission Electron Microscope (TEM) as described below. First, a thin film sample having a cross section of the coating layer (a cross section in the same direction as that in the case of observing the thickness of the coating layer: a direction perpendicular to the substrate surface) as an observation surface was prepared using a Focused Ion Beam (FIB) processing machine. A Scanning Transmission Electron Microscope (STEM) photograph was taken of the observation surface of the prepared sample. On the photographed photograph, a straight line was drawn in a direction parallel to the surface of the substrate and the number of particles constituting each layer was measured. The average particle diameter is defined as the value obtained by dividing the length of the straight line by the number of particles. In this case, the length of the straight line is set to 10 μm or more. The measurement results are shown in tables 17 and 18.

[ Table 17]

[ Table 18]

The obtained sample was subjected to the following cutting test and evaluated.

[ cutting test 2]

Material to be cut: the SUS304 may be used as the basis,

shape of material to be cut: a round bar of 120mm x 400mm,

cutting speed: the flow rate of the mixture is 150m/min,

feed per blade: 0.3mm/rev of the sample,

cutting depth: 2.0mm of the total weight of the steel,

cooling agent: use of

Evaluation items: the tool life was determined as the time required for the sample to be broken (the cutting edge of the sample was chipped) or the flank wear width reached 0.30mm, and the machining time until the tool life was reached was measured. Further, the damage form at the time of 10 minutes was observed by SEM. Note that the damage form "chipping" at the time of 10 minutes means that this is a notch of such a degree that the processing can be continued. In addition, a longer working time means excellent chipping resistance and wear resistance. The results of the obtained evaluations are shown in tables 19 and 20.

[ Table 19]

[ Table 20]

From the results shown in tables 19 and 20, the processing time of the invention product was 18 minutes or more, which was longer than the processing time of all the comparative products.

From the above results, it is understood that the tool life of the invention product is prolonged by improving the wear resistance and the chipping resistance.

[ industrial applicability ]

The coated cutting tool of the present invention has excellent wear resistance and chipping resistance, and therefore, the tool life can be extended as compared with conventional coated cutting tools.

Description of the symbols

1 … substrate, 2 … 1 st layer, 3 … nd 2 nd layer, 4 … alternate laminated structure, 5 … coating layer, 6 … coated cutting tool.