WO2022244190A1

WO2022244190A1 - Cutting tool

Info

Publication number: WO2022244190A1
Application number: PCT/JP2021/019172
Authority: WO
Inventors: 治世福井; 大二田林; 桃子飯田; 大勢田中
Original assignee: 住友電工ハードメタル株式会社
Priority date: 2021-05-20
Filing date: 2021-05-20
Publication date: 2022-11-24

Abstract

A cutting tool provided with a base material and a coating that is disposed on the base material, wherein the coating includes a MoC1-x layer formed from a compound represented by MoC1-x, x is between 0.40 and 0.60 inclusive, and the compound represented by MoC1-x is formed from a hexagonal crystal structure.

Description

Cutting tools

The present disclosure relates to cutting tools.

Conventionally, various studies have been made for the purpose of prolonging the life of cutting tools. For example, Patent Document 1 discloses a cutting tool having a coating comprising a WC _1-x layer disposed on a substrate.

WO2019/181742

A cutting tool of the present disclosure comprises a substrate and a coating disposed on the substrate,
The coating comprises a MoC ₁ _-x layer made of a compound represented by MoC 1-x,
The x is 0.40 or more and 0.60 or less,
The compound represented by MoC _1-x is a cutting tool having a hexagonal crystal structure.

FIG. 1 is a perspective view illustrating one mode of a cutting tool. FIG. 2 is a schematic cross-sectional view of a cutting tool in one aspect of the present embodiment. FIG. 3 is a schematic cross-sectional view of a cutting tool in another aspect of this embodiment. FIG. 4 is a schematic cross-sectional view of a cutting tool in another aspect of this embodiment.

[Problems to be Solved by the Present Disclosure]
In recent years, the demand for high-load, high-speed, and high-efficiency machining has been increasing, and there is a demand for cutting tools that can have a long tool life even when high-speed, high-efficiency machining is possible.

[Effect of the present disclosure]
According to the present disclosure, it is possible to provide a cutting tool having a long tool life even in high-load, high-speed, high-efficiency machining.

[Description of Embodiments of the Present Disclosure]
First, the embodiments of the present disclosure are listed and described.
(1) A cutting tool of the present disclosure comprises a substrate and a coating disposed on the substrate,
The coating comprises a MoC ₁ _-x layer made of a compound represented by MoC 1-x,
The x is 0.40 or more and 0.60 or less,
The compound represented by MoC _1-x is a cutting tool having a hexagonal crystal structure.

According to the present disclosure, it is possible to provide a cutting tool having a long tool life even in high-speed, high-efficiency machining.

(2) The MoC _1-x layer preferably does not contain free carbon. According to this, the chipping resistance and wear resistance of the cutting tool are improved.

(3) The MoC _1-x layer preferably has a film hardness of 2700 mgf/μm ² or more and 4200 mgf/μm ² or less. According to this, the chipping resistance and wear resistance of the cutting tool are improved.

(4) the MoC _1-x layer may contact the substrate; According to this, the cutting tool can have excellent fracture resistance and wear resistance.

(5) the coating further comprises a hard coating layer disposed between the substrate and the MoC _1-x layer;
The hard coating layer includes a first unit layer,
The composition of the first unit layer is different from the composition of the MoC _1-x layer,
The first unit layer is composed of at least one element selected from the group consisting of periodic table 4 group elements, 5 group elements, 6 group elements, aluminum and silicon, or periodic table 4 group elements, 5 group elements, It is preferably composed of a compound consisting of at least one element selected from the group consisting of Group 6 elements, aluminum and silicon, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron.

According to this, the chipping resistance and wear resistance of the cutting tool are improved.

(6) the hard coating layer is composed of the first unit layer;
The thickness of the first unit layer is preferably 0.1 μm or more and 10 μm or less.

(7) The hard coating layer further includes a second unit layer,
The composition of the second unit layer is different from the composition of the MoC _1-x layer and the composition of the first unit layer,
The second unit layer is composed of at least one element selected from the group consisting of periodic table 4 group elements, 5 group elements, 6 group elements, aluminum and silicon, or periodic table 4 group elements, 5 group elements, A compound consisting of at least one element selected from the group consisting of Group 6 elements, aluminum and silicon, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron,
It is preferable that the first unit layer and the second unit layer each form a multi-layer structure in which one or more layers are alternately laminated.

(8) the first unit layer has a thickness of 1 nm or more and 100 nm or less;
The thickness of the second unit layer is preferably 1 nm or more and 100 nm or less. According to this, the chipping resistance and wear resistance of the cutting tool are improved.

(9) the MoC _1-x layer has a thickness of 0.1 μm or more and 10 μm or less;
The thickness of the hard coating layer is preferably 0.1 μm or more and 10 μm or less. According to this, the chipping resistance and wear resistance of the cutting tool are improved.

(10) The thickness of the coating is preferably 0.2 µm or more and 20 µm or less. According to this, the chipping resistance and wear resistance of the cutting tool are improved.

(11) The base material preferably contains at least one selected from the group consisting of cemented carbide, cermet, high-speed steel, ceramics, cBN sintered bodies and diamond sintered bodies. According to this, the cutting tool can have excellent hardness and strength even at high temperatures.

[Details of the embodiment of the present disclosure]
A specific example of the cutting tool of the present disclosure will be described below with reference to the drawings. In the drawings of this disclosure, the same reference numerals represent the same or equivalent parts. Also, dimensional relationships such as length, width, thickness, and depth are appropriately changed for clarity and simplification of the drawings, and do not necessarily represent actual dimensional relationships.

In this specification, the notation of the form "A to B" means the upper and lower limits of the range (that is, from A to B). and the unit of B are the same.

In the present specification, when a compound or the like is represented by a chemical formula, it shall include any conventionally known atomic ratio unless the atomic ratio is particularly limited, and should not necessarily be limited only to those within the stoichiometric range. For example, when "TiAlN" is described, the ratio of the number of atoms constituting TiAlN includes all conventionally known atomic ratios.

[Embodiment 1: Cutting tool]
A cutting tool according to the present disclosure includes a substrate and a coating disposed on the substrate,
The coating comprises a MoC ₁ _-x layer made of a compound represented by MoC 1-x,
The x is 0.40 or more and 0.60 or less,
The compound represented by MoC _1-x is a cutting tool having a hexagonal crystal structure.

The cutting tool of the present embodiment (hereinafter sometimes simply referred to as "cutting tool") includes a base material and a coating disposed on the base material. Examples of the cutting tools include drills, end mills, indexable cutting inserts for drills, indexable cutting inserts for end mills, indexable cutting inserts for milling, indexable cutting inserts for turning, metal saws, and gear cutting tools. , reamers, taps, and the like.

FIG. 1 is a perspective view illustrating one aspect of a cutting tool. A cutting tool having such a shape is used, for example, as an indexable cutting tip. The cutting tool 10 has a rake face 1, a flank face 2, and a cutting edge ridge 3 where the rake face 1 and the flank face 2 intersect. That is, the rake face 1 and the flank face 2 are surfaces connected with the cutting edge ridge 3 interposed therebetween. The cutting edge ridge 3 constitutes the cutting edge of the cutting tool 10 . Such a shape of the cutting tool 10 can also be grasped as the shape of the base material of the cutting tool. That is, the substrate has a rake face, a flank face, and a cutting edge ridge connecting the rake face and the flank face.

<Base material>
Any conventionally known base material of this type can be used as the base material of the present embodiment. For example, the base material is a cemented carbide (for example, a tungsten carbide (WC)-based cemented carbide, a cemented carbide containing Co in addition to WC, a carbonitride such as Cr, Ti, Ta, Nb in addition to TaC). cemented carbide, etc.), cermet (mainly composed of TiC, TiN, TiCN, etc.), high-speed steel, ceramics (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, etc.), cubic It preferably contains at least one selected from the group consisting of type boron nitride sintered bodies (cBN sintered bodies) and diamond sintered bodies, and at least one selected from the group consisting of cemented carbide, cermet and cBN sintered bodies It is more preferred to contain seeds.

When a cemented carbide is used as the base material, the effect of the present embodiment is exhibited even if such a cemented carbide contains an abnormal phase called free carbon or η phase in the structure. In addition, the base material used in this embodiment may have a modified surface. For example, in the case of cemented carbide, a β-free layer may be formed on the surface, and in the case of cermet, a surface-hardened layer may be formed. The effect of is shown.

When the cutting tool is an indexable cutting insert (such as an indexable cutting insert for milling), the substrate may or may not have a chip breaker. The shape of the ridge line of the cutting edge is sharp edge (the ridge where the rake face and the flank face intersect), honing (sharp edge rounded shape), negative land (chamfered shape), and a combination of honing and negative land. any shape is included.

<Coating>
The "coating" according to the present embodiment covers at least a portion of the surface of the base material, thereby improving various properties of the cutting tool such as chipping resistance and wear resistance. Here, "at least a portion of the surface of the base material" includes a portion that comes into contact with the work material during cutting. The portion in contact with the work material can be, for example, a region within 2 mm from the ridgeline of the cutting edge on the surface of the base material. It should be noted that even if a part of the base material is not covered with the coating or the composition of the coating is partially different, this does not depart from the scope of the present embodiment.

As shown in FIG. 2, coating 4 may consist of MoC _1-x layer 12 . As shown in FIGS. 3 and 4, the coating 4 can include a MoC _1-x layer 12 and a hard coating layer 13 disposed between the MoC _1-x layer 12 and the substrate 11. . Coating 4 may include other layers in addition to MoC _1-x layer 12 . Other layers include, for example, an underlayer (not shown) placed between the MoC _1-x layer and the substrate, an intermediate layer (not shown) placed between the MoC _1-x layer and the hard coating layer ( (not shown), a surface layer (not shown) disposed over the MoC _1-x layer, and the like.

The thickness of the coating is preferably 0.1 μm or more and 20 μm or less, preferably 0.1 μm or more and 10 μm or less, preferably 0.2 μm or more and 20 μm or less, preferably 0.2 μm or more and 10 μm or less, and more preferably 0.3 μm or more and 10 μm or less. It is preferably 0.5 μm or more and 10 μm or less, even more preferably 1 μm or more and 6 μm or less, and particularly preferably 1.5 μm or more and 4 μm or less. When the thickness is 0.1 μm or more, the wear resistance of the cutting tool is improved. When the thickness is 20 μm or less, it is easy to suppress peeling or breakage of the coating when a large stress is applied between the coating and the substrate during intermittent machining. Here, the thickness of the coating means the sum of the thicknesses of the layers constituting the coating such as the MoC _1-x layer, the hard coating layer and the base layer. The thickness of the coating is measured using a transmission electron microscope (TEM) at any three points in a cross-sectional sample parallel to the normal direction of the surface of the substrate, and the average thickness of the three measured points. Find by taking the value. The same is true when measuring the thickness of each of the MoC _1-x layer, the hard coating layer (first unit layer, second unit layer) and the underlying layer, which will be described later. Examples of transmission electron microscopes include JEM-2100F (trademark), a spherical aberration corrector manufactured by JEOL Ltd.

As long as the measurement is performed on the same sample, there is almost no variation in the measurement results even if the measurement area is changed and repeated multiple times. was confirmed.

<MoC _1-x layer>
The coating includes a MoC ₁ _-x layer consisting of a compound denoted MoC 1-x. The “compound represented by MoC _1-x ” (hereinafter sometimes referred to as “MoC _1-x ”) means that when the element ratio of molybdenum element (Mo) is 1, the amount of carbon element (C) It means molybdenum carbide with an elemental ratio of 1-x. The MoC _1-x layer may contain unavoidable impurities within a range that does not impair the effects of the cutting tool according to the present embodiment. The content of the inevitable impurities is preferably 0% by mass or more and 0.2% by mass or less with respect to the total mass of the MoC _1-x layer. Similarly, the terms "hard coating layer" and "other layers" described later may also contain unavoidable impurities within a range that does not impair the effects of the cutting tool according to the present embodiment.

The above x is 0.40 or more and 0.60 or less, preferably 0.45 or more and 0.55 or less, and more preferably 0.50 or more and 0.55 or less. When x is less than 0.40, free carbon tends to precipitate at grain boundaries of MoC _1-x and the strength tends to decrease. Moreover, when x exceeds 0.60, the strength of the grain boundary tends to decrease. Therefore, when x is outside the range of 0.40 or more and 0.60 or less, crack growth cannot be suppressed, and the toughness tends to be low. The present inventors presume that such a tendency is caused by an inappropriate balance between crystal homogeneity and strain.

The above x obtains a cross-sectional sample parallel to the normal direction of the surface of the substrate in the MoC _1-x layer, and scans the grains appearing in this cross-sectional sample with a scanning electron microscope (SEM) or TEM. It can be determined by analysis using an energy dispersive X-ray spectroscopy (EDX) device. Specifically, the value of x is obtained by measuring each of arbitrary three points in the MoC _1-x layer of the cross-sectional sample, and the average value of the values of the three points obtained is the MoC _1-x of the cross-sectional sample. Let x be in the layer. Here, for the “arbitrary three points”, three arbitrary 30 nm×30 nm regions in the MoC _1-x layer are selected. Examples of the EDX apparatus include JED-2200 (trademark), a silicon drift detector manufactured by JEOL Ltd. The measurement conditions are as follows.

EDX method measurement conditions Accelerating voltage: 200 kV
Probe current: 0.29nA
Probe size: 0.2 nm

The compound represented by MoC _1-x has a hexagonal crystal structure. Here, the compound represented by MoC _1-x has a hexagonal crystal structure, which means that the percentage of the hexagonal crystal structure in the compound represented by MoC _1-x is 100% by mass, and other does not contain a crystal structure of the crystal form of The compound represented by MoC _1-x has a hexagonal crystal structure, for example, by performing X-ray diffraction measurement (XRD measurement) on any three points in the MoC _1-x layer. is confirmed by When the compound represented by MoC _1-x has a hexagonal crystal structure, in XRD measurement, (100), (002), (101), (102), (111) ) and other crystal planes are observed. Examples of the apparatus used for the X-ray diffraction measurement include "SmartLab" (trade name) manufactured by Rigaku Corporation and "X'pert" (trade name) manufactured by PANalytical. The measurement conditions are as follows.

XRD method measurement conditions Scanning axis: 2θ-θ
X-ray source: Cu-Kα ray (1.541862 Å)
Detector: Zero-dimensional detector (scintillation counter)
Tube voltage: 45kV
Tube current: 40mA
Incident optical system: use of mirrors Receiving optical system: use of analyzer crystal (PW3098/27) Step: 0.03°
Accumulation time: 2 seconds Scan range (2θ): 10° to 120°

As long as the measurement is performed on the same sample, there is almost no variation in the measurement results even if the measurement points are changed and repeated multiple times. was confirmed.

FIG. 2 is a schematic cross-sectional view of a cutting tool in one aspect of the present embodiment. Preferably, the MoC _1-x layer 12 is in contact with the substrate 11, as shown in FIG. In other words, the MoC _1-x layer 12 is preferably provided directly on the substrate 11 .

The MoC _1-x layer preferably contains no free carbon. Here, the description "free carbon free" includes not only the MoC _1-x layer containing no free carbon, but also the case where the free carbon is below the detection limit. By "free carbon" is meant carbon that exists as an element without being a constituent element of MoC _1-x . Examples of free carbon include simple substances of carbon containing carbon-carbon double bonds such as graphite and soot. The presence or absence of free carbon is determined by the presence or absence of carbon-carbon double bonds at any three points on the surface of the MoC _1-x layer using X-ray photoelectron spectroscopy (XPS method) (presence or absence of C=C peak in XPS C1s). This is confirmed by examining the Here, when the MoC _1-x layer is provided on the outermost surface, the measurement is performed after removing the natural oxide layer by Ar ^{2 +} sputtering or the like. If the MoC _1-x layer is not the outermost surface, the MoC _1-x layer is exposed by Ar ^{2 +} sputtering or the like before measurement. As an apparatus used for the XPS method, for example, Versa Probe III (trade name) manufactured by ULVAC-Phi, Inc. can be mentioned. The measurement conditions are as follows.

XPS method measurement conditions X-ray source used: mono-AlKα ray (hν = 1486.6 eV)
Detection depth: 1 nm to 10 nm
X-ray beam diameter: about 100 μmφ
Neutralization gun: Dual type used Ar ⁺ : Accelerating voltage 4 kV
Raster size: 1 x 1 mm
Sputtering speed (Ar ⁺ ): SiO ₂ sputter conversion value 28.3 nm/min

The film hardness of the MoC _1-x layer is preferably 2700 mgf/μm ² or more and 4200 mgf/μm ² or less, more preferably 2700 mgf/μm ² or more and 4100 mgf/μm ² or less, and 2800 mgf/μm ² or more and 4000 mgf/μm 2 or more. It is more preferably μm ² or less. The film hardness is measured with a nanoindenter. Specifically, first, arbitrary 10 points on the surface of the MoC _1-x layer are measured to obtain the film hardness. Thereafter, the average value of 10 points of film hardness obtained is defined as the film hardness of the MoC _1-x layer of the cross-sectional sample. If the MoC _1-x layer is not the outermost surface, the MoC _1-x layer is exposed by mechanical polishing or the like, and then the nanoindenter is used for measurement. Examples of the nanoindenter include ENT1100 (trade name) manufactured by Elionix Co., Ltd. The measurement conditions are as follows.

Nanoindenter measurement conditions Indenter: Berkovich load: 1 gf
Load time: 10sec
Holding time: 2 sec
Unloading time: 10sec

The thickness of the MoC _1-x layer is preferably 0.1 μm or more and 10 μm or less, more preferably 0.1 μm or more and 7.0 μm or less, and still more preferably 0.5 μm or more and 3 μm or less.

<Hard coating layer>
Preferably, the coating further comprises a hard coating layer positioned between the substrate and the MoC _1-x layer. The hard coating layer preferably includes a first unit layer. The composition of the first unit layer is preferably different from the composition of the MoC _1-x layer. Here, "disposed between the substrate and the MoC _1-x layer" means that the hard coating layer is disposed between the substrate and the MoC _1-x layer, and the hard coating layer is It need not be in contact with the substrate and the MoC _1-x layer. Other layers may be arranged between the substrate and the hardcoat layer, and other layers may be arranged between the hardcoat layer and the MoC _1-x layer. The hard coating layer may be the outermost layer (surface layer).

<First unit layer>
The first unit layer is composed of at least one element selected from the group consisting of periodic table 4 group elements, 5 group elements, 6 group elements, aluminum and silicon, or periodic table 4 group elements, 5 group elements, 6 It is preferably composed of a compound consisting of at least one element selected from the group consisting of group elements, aluminum and silicon, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron. The first unit layer contains at least one element selected from the group consisting of chromium, aluminum, titanium and silicon, or at least one element selected from the group consisting of chromium, aluminum, titanium and silicon, carbon and nitrogen. , and at least one element selected from the group consisting of oxygen and boron. Examples of Group 4 elements of the periodic table include titanium (Ti), zirconium (Zr), hafnium (Hf), and the like. Vanadium (V), niobium (Nb), tantalum (Ta), etc. are mentioned as a periodic table V group element. Examples of Group 6 elements of the periodic table include chromium (Cr), molybdenum (Mo), tungsten (W), and the like.

Examples of compounds contained in the first unit layer include TiAlN, TiAlSiCN, TiAlSiON, TiAlSiN, TiCrSiN, TiAlCrSiN, AlCrN, AlCrO, AlCrSiN, TiZrN, TiAlMoN, TiAlNbN, TiSiN, AlCrTaN, AlTiVN, TiB ₂ , TiCrHfN, CrSiWN, TiAlCN, TiSiCN, AlZrON, AlCrCN, AlHfN, CrSiBON, CrAlBN, TiAlWN, AlCrMoCN, TiAlBN, TiAlCrSiBCNO, ZrN, ZrB ₂ , ZrCN, CrSiBN, AlCrBN, and the like.

When the hard coating layer consists only of the first unit layer (for example, in the case of FIG. 3), the thickness of the first unit layer (that is, the hard coating layer) is preferably 0.1 μm or more and 10 μm or less. , 0.5 μm or more and 7 μm or less.

<Second unit layer>
Preferably, the hard coating layer further includes a second unit layer. The composition of the second unit layer is preferably different from the composition of the MoC _1-x layer and the composition of the first unit layer. The second unit layer is composed of at least one element selected from the group consisting of periodic table 4 group elements, 5 group elements, 6 group elements, aluminum and silicon, or periodic table 4 group elements, 5 group elements, 6 It is preferably composed of a compound consisting of at least one element selected from the group consisting of group elements, aluminum and silicon, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron. The second unit layer contains at least one element selected from the group consisting of chromium, aluminum, titanium, and silicon, or at least one element selected from the group consisting of chromium, aluminum, titanium, and silicon, carbon, and nitrogen. , and at least one element selected from the group consisting of oxygen and boron. Specific examples of the Group 4 elements, Group 5 elements, and Group 6 elements of the periodic table include the elements described above.

Examples of the compound contained in the second unit layer include the above compounds exemplified as the compound contained in the first unit layer.

It is preferable that the first unit layer and the second unit layer form a multilayer structure in which one or more layers are alternately laminated. That is, as shown in FIG. 4, the hard coating layer 13 preferably includes a multi-layer structure consisting of a first unit layer 131 and a second unit layer 132. As shown in FIG. Here, lamination of the multilayer structure may start from either the first unit layer or the second unit layer. That is, the interface on the MoC _1-x layer side in the multilayer structure may be composed of either the first unit layer or the second unit layer. Further, the interface on the side opposite to the MoC _1-x layer side in the multilayer structure may be composed of either the first unit layer or the second unit layer.

When the hard coating layer has a multilayer structure, the thickness of the hard coating layer is preferably 0.1 μm or more and 10 μm or less, more preferably 0.5 μm or more and 7 μm or less. When the hard coating layer includes a multilayer structure, the thickness of the MoC _1-x layer is preferably 0.1 μm or more and 10 μm or less, and the thickness of the hard coating layer is preferably 0.1 μm or more and 10 μm or less. According to this, the chipping resistance and wear resistance of the cutting tool are improved.

When the hard coating layer includes a multilayer structure, the thickness of the first unit layer is preferably 1 nm or more and 100 nm or less, more preferably 2 nm or more and 25 nm or less. Further, the thickness of the second unit layer is preferably 1 nm or more and 100 nm or less, more preferably 2 nm or more and 25 nm or less. In one aspect of the present embodiment, when the hard coating layer includes a multilayer structure, the thickness of the first unit layer is 1 nm or more and 100 nm or less, and the thickness of the second unit layer is 1 nm or more and 100 nm or less. preferable. Here, the "thickness of the first unit layer" means the thickness of one of the first unit layers. The "thickness of the second unit layer" means the thickness of one of the second unit layers.

As long as the thickness of the entire hard coating layer is within the above range, the number of laminated layers in the multilayer structure includes a mode in which one layer each of the first unit layer and the second unit layer is laminated, and preferably both layers are laminated. 20 to 2500 layers can be laminated.

<Other layers>
The film may further include other layers as long as the effects of the present embodiment are not impaired. The other layer may be different or the same in composition as the MoC _1-x layer and the hard coat layer. The positions of other layers in the coating are also not particularly limited. For example, other layers include a base layer provided between the base material and the MoC _1-x layer, and an intermediate layer provided between the MoC _1-x layer and the hard coating layer. , a surface layer provided on the hard MoC _1-x layer, and the like. Other layers include, for example, a TiN layer, a _TiWCN layer, a TiCN layer, a ZrB2 layer, a TiSiN phase, an AlCrN layer, and the like.

The thickness of other layers is not particularly limited as long as it does not impair the effects of the present embodiment. For example, 0.002 μm or more and 1 μm or less can be mentioned. Preferably, it is 0.003 μm or more and 0.01 μm or less.

[Embodiment 2: Manufacturing method of cutting tool]
The manufacturing method of the cutting tool according to this embodiment includes a substrate preparation step and a MoC _1-x layer coating step. Each step will be described below.

<Base material preparation process>
In the base material preparation step, the base material is prepared. As the base material, any base material can be used as long as it is conventionally known as this type of base material, as described above. For example, when the base material is made of a cemented carbide, first, raw material powders having a predetermined composition (% by mass) are uniformly mixed using a commercially available attritor. Subsequently, this mixed powder is pressure-molded into a predetermined shape (eg, SEET13T3AGSN, CNMG120408N-EG, etc.). Thereafter, by sintering the pressure-molded mixed powder for 1 to 2 hours in a predetermined sintering furnace at 1300 to 1500° C. or less, the substrate made of cemented carbide can be obtained. Moreover, a commercially available product may be used as it is for the base material. Commercially available products include EH520 (trademark) manufactured by Sumitomo Electric Hardmetal Co., Ltd., for example.

<MoC _1-x layer coating step>
In the MoC _1-x layer coating step, at least part of the surface of the substrate is coated with a MoC _1-x layer (0.40≦x≦0.60) to obtain a cutting tool. Here, "at least a portion of the surface of the base material" includes a portion that comes into contact with the work material during cutting. The portion in contact with the work material can be, for example, a region within 2 mm from the ridgeline of the cutting edge on the surface of the base material.

The method for coating at least part of the base material with the MoC _1-x layer is not particularly limited. For example, a MoC _1-x layer may be formed by physical vapor deposition (PVD).

As the physical vapor deposition method, conventionally known physical vapor deposition methods can be used without particular limitation. Examples of such a physical vapor deposition method include a sputtering method, an ion plating method, an arc ion plating method, an electron ion beam vapor deposition method, and the like. In particular, when the cathodic arc ion plating method or sputtering method, which has a high ion rate of the raw material element, is used, metal bombardment treatment and/or gas ion bombardment treatment can be performed on the substrate surface before forming the coating. , is preferable because the adhesion between the coating and the substrate is remarkably improved.

Mo has a high melting point and is difficult to melt. Therefore, a stable discharge could not be maintained in the physical vapor deposition method, and a MoC layer composed of hexagonal MoC and having good film quality could not be formed. As a result of intensive studies, the present inventors have found a method for stably producing a MoC layer of hexagonal MoC having good film quality. As an example of the method, the case of forming a MoC _1-x layer (0.40≦x≦0.60) having a hexagonal crystal structure by arc ion plating will be described below.

First, the MoC target is set in the arc-type evaporation source in the apparatus, the substrate (base material) temperature is set to 450 to 600° C., and the apparatus is evacuated. Subsequently, for example, one or both of argon gas and krypton gas are introduced to set the gas pressure in the apparatus to 1.0-3.0 Pa. Then, a negative bias voltage of 200 to 1000 V is applied to the substrate via a DC power supply to clean the surface of the substrate for 40 minutes. After that, an arc current of 80 to 200 A is supplied to the cathode electrode to generate metal ions and the like from the arc evaporation source, thereby forming a hexagonal MoC _1-x layer (0.40 ≤ x ≤ 0.60). can do. At this time, at the beginning of the formation of the MoC _1-x layer (thickness range of 0.1 μm or less), the substrate temperature is set to 400 to 450° C., the substrate bias is set to −50 V, and the temperature is gradually raised to 450 toward the end of the formation. °C to 550 °C, the substrate bias is increased to -60 to -75V. An apparatus used for the arc ion plating method includes, for example, AIP (trade name) manufactured by Kobe Steel, Ltd.

<Hard coating layer coating step>
The cutting tool manufacturing method according to the present embodiment preferably further includes a hard coating layer coating step before the MoC _1-x layer coating step. The method for forming the hard coating layer is not particularly limited, and conventional methods can be used. Specifically, for example, the hard coating layer is formed by the PVD method described above.

<Other processes>
In addition to the above-described steps, the manufacturing method according to the present embodiment includes a base layer coating step of forming a base layer between the base material and the MoC _1-x layer, the MoC _1-x layer and the hard coating and a surface layer coating step of forming a surface layer on the MoC _1-x layer. When forming other layers such as the underlayer, intermediate layer and surface layer described above, the other layers may be formed by conventional methods. Specifically, for example, the other layer may be formed by the PVD method described above.

Furthermore, the manufacturing method according to the present embodiment can appropriately include steps such as metal bombardment treatment, peening treatment, and surface treatment. The metal bombardment treatment includes, for example, a method of subjecting Ti to cathode evaporation in an argon gas atmosphere and mixing the substrate surface to form a mixing layer. Examples of surface treatment include polishing with abrasive grains and brush polishing. More specifically, there is a method of using a medium in which diamond powder is supported on an elastic material. As an apparatus for performing the surface treatment, for example, Sirius Z manufactured by Fuji Seisakusho Co., Ltd., etc. can be cited.

[Appendix 1]
In the cutting tool of the present disclosure, the MoC _1-x layer preferably has a thickness of 0.1 μm or more and 10.0 μm or less.
In the cutting tool of the present disclosure, the MoC _1-x layer preferably has a thickness of 0.1 μm or more and 7.0 μm or less.
In the cutting tool of the present disclosure, the MoC _1-x layer preferably has a thickness of 0.6 μm or more and 6.5 μm or less.
In the cutting tool of the present disclosure, the MoC _1-x layer preferably has a thickness of 0.5 μm or more and 3 μm or less.

[Appendix 2]
In the cutting tool of the present disclosure, the coating consists only of the MoC _1-x layer, and the thickness of the coating is preferably 0.1 μm or more and 10 μm or less.
In the cutting tool of the present disclosure, the coating consists only of the MoC _1-x layer, and the thickness of the coating is preferably 0.3 μm or more and 10 μm or less.
In the cutting tool of the present disclosure, the coating consists only of the MoC _1-x layer, and the thickness of the coating is preferably 0.5 μm or more and 10 μm or less.
In the cutting tool of the present disclosure, the coating consists of only the MoC _1-x layer, and the thickness of the coating is preferably 1 μm or more and 6 μm or less.
In the cutting tool of the present disclosure, the coating consists of only the MoC _1-x layer, and the thickness of the coating is preferably 1.5 μm or more and 4 μm or less.

[Appendix 3]
In the cutting tool of the present disclosure, the coating includes a MoC _1-x layer and a hard coating layer, and the thickness of the coating is preferably 0.1 μm or more and 20 μm or less.
In the cutting tool of the present disclosure, the coating includes a MoC _1-x layer and a hard coating layer, and the thickness of the coating is preferably 0.1 μm or more and 17 μm or less.
In the cutting tool of the present disclosure, the coating includes a MoC _1-x layer and a hard coating layer, and the thickness of the coating is preferably 0.1 μm or more and 12 μm or less.
In the cutting tool of the present disclosure, the coating includes a MoC _1-x layer and a hard coating layer, and the thickness of the coating is preferably 0.2 μm or more and 20 μm or less.
In the cutting tool of the present disclosure, the coating includes a MoC _1-x layer and a hard coating layer, and the thickness of the coating is preferably 0.2 μm or more and 17 μm or less.
In the cutting tool of the present disclosure, the coating includes a MoC _1-x layer and a hard coating layer, and the thickness of the coating is preferably 0.2 μm or more and 12 μm or less.
In the cutting tool of the present disclosure, the coating includes a MoC _1-x layer and a hard coating layer, the MoC _1-x layer has a thickness of 0.1 μm or more and 10 μm or less, and the hard coating layer has a thickness of 0.1 μm or more and 10 μm or less. It is 1 μm or more and 10 μm or less, and the thickness of the coating is preferably 0.2 μm or more and 20 μm or less.

The present embodiment will be described more specifically with examples. However, this embodiment is not limited by these examples.

≪Manufacturing cutting tools≫
[Samples 1 to 26]
<Base material preparation process>
As a base material, JIS standard K10 cemented carbide (shape: JIS standard SEET13T3AGSN-L, CNMG120408N-EG) was prepared. Next, the base material is set at a predetermined position of an arc ion plating apparatus (manufactured by Kobe Steel, Ltd., trade name: AIP).

<MoC _1-x layer coating step>
A MoC _1-x layer was formed on the substrate by an arc ion plating method. Specifically, the method is as follows. First, the MoC target is set in the arc-type evaporation source in the apparatus, the substrate (base material) temperature is set to 450 to 600° C., and the apparatus is evacuated. Subsequently, for example, one or both of argon gas and krypton gas are introduced to set the gas pressure in the apparatus to 1.0-3.0 Pa. Then, a negative bias voltage of 200 to 1000 V is applied to the substrate via a DC power supply to clean the surface of the substrate for 40 minutes. After that, an arc current of 80 to 200 A is supplied to the cathode electrode to generate metal ions and the like from the arc evaporation source, thereby forming a MoC _1-x layer (0.40≦x≦0.60). At this time, at the beginning of the formation of the MoC _1-x layer (thickness range of 0.1 μm or less), the substrate temperature is set to 400 to 450° C., the substrate bias is set to −50 V, and the temperature is gradually raised to 450 toward the end of the formation. °C to 550 °C, the substrate bias is increased to -60 to -75V. The MoC _1-x layer was formed to the thickness described in the "thickness" column of "MoC _1-x layer" in Tables 1 and 2 by the above method. As an apparatus used for the arc ion plating method, AIP (trade name) manufactured by Kobe Steel, Ltd. was used.

<Base layer coating step>
For samples (Samples 5 and 6) in which an underlayer was formed between the substrate and the MoC _1-x layer, the following procedure was performed on the substrate before the MoC _1-x layer coating step. A base layer was formed. First, a target containing the metal composition in the column of composition of the underlayer shown in Table 1 was set in the arc-type evaporation source of the arc ion plating apparatus. Next, the substrate temperature was set to 600° C. and the gas pressure in the apparatus was set to 1 Pa. In the case of the nitride underlayer (Sample 5), a mixed gas of nitrogen gas and argon gas was introduced. In the case of the underlayer of carbonitride (Sample 6), a mixed gas of nitrogen gas, methane gas and argon gas was introduced as the reaction gas. After that, an arc current of 150 A was supplied to the cathode electrode. By supplying an arc current to generate metal ions and the like from an arc-type evaporation source, an underlayer was formed to a thickness described in parentheses under "Underlayer" in Table 1.

<Hard coating layer coating step>
For the samples (Samples 7 to 13, Samples 16 to 22, Samples 25, and 26) having a hard coating layer between the substrate and the MoC _1-x layer, the MoC _1-x layer coating step is performed. A hard coating layer was previously formed on the substrate by the following procedure. First, a target containing the metal composition in the composition column of the hard coating layer shown in Tables 1 and 2 was set in the arc-type evaporation source of the arc ion plating apparatus. Next, the substrate temperature was set to 550° C. and the gas pressure in the apparatus was set to 4.0 Pa. As a reaction gas, nitrogen gas was introduced in the case of a nitride hard coating layer. In the case of the carbonitride hard coating layer, a mixed gas of nitrogen gas and methane gas was introduced as the reaction gas. In the case of the oxynitride hard film layer, a mixed gas of oxygen gas and nitrogen gas was introduced as the reaction gas. After that, an arc current of 150 A was supplied to the cathode electrode. By supplying an arc current to generate metal ions and the like from an arc-type evaporation source, a hard coating layer was formed to a thickness described in parentheses of "Hard coating layer" in Tables 1 and 2.

In addition, when forming a hard coating layer with a multilayer structure, the first unit layer and the second unit layer are laminated in order from the left side in Tables 1 and 2 until the desired thickness is obtained. to form a multi-layered structure. For example, in sample 11, a first unit layer made of TiAlBN with a thickness of 5 nm and a second unit layer made of TiSiN with a thickness of 5 nm are alternately laminated to form a multilayer structure with a thickness of 1.0 μm. did.

<Surface layer coating step>
For the samples having a surface layer on the MoC _1-x layer (Sample 5, Sample 7, Sample 8, Sample 11, and Sample 12), MoC 1-x was coated in the following procedure after the MoC ₁ _-x layer coating step. A surface layer was formed on the layer. First, a target containing the metal composition in the surface layer composition column shown in Table 1 was set in an arc-type evaporation source of an arc ion plating apparatus. Next, the substrate temperature was set to 550° C. and the gas pressure in the apparatus was set to 4.0 Pa. As a reaction gas, a mixed gas of nitrogen gas and argon gas was introduced in the case of a nitride surface layer. After that, an arc current of 150 A was supplied to the cathode electrode. A surface layer was formed up to the thickness shown in parentheses under "Surface layer" in Table 1 by generating metal ions and the like from an arc evaporation source by supplying an arc current.

[Sample 1-1]
As a base material, the same base material as sample 1 was prepared. A MoC _1-x layer was formed on the substrate by an arc ion plating method. Specifically, the following method was used. First, the MoC target was set in the arc-type evaporation source of the arc ion plating device. Next, the substrate temperature was set to 390° C. and the gas pressure in the apparatus was set to 2 Pa. Argon gas was introduced as the gas. Then, while maintaining the substrate bias voltage at -50V, an arc current of 120A was supplied to the cathode electrode. A cutting tool was obtained by forming a MoC _1-x layer by generating metal ions and the like from an arc evaporation source by supplying an arc current.

[Sample 1-2]
As a base material, the same base material as sample 1 was prepared. A MoC _1-x layer was formed on the substrate by an arc ion plating method. Specifically, the following method was used. First, the MoC target was set in the arc-type evaporation source of the arc ion plating device. Next, the substrate temperature was set to 620° C. and the gas pressure in the apparatus was set to 0.5 Pa. Argon gas was introduced as the gas. Then, while maintaining the substrate bias voltage at -40V, an arc current of 130A was supplied to the cathode electrode. A cutting tool was obtained by forming a MoC _1-x layer by generating metal ions and the like from an arc evaporation source by supplying an arc current.

[Sample 1-3]
As a base material, the same base material as sample 1 was prepared. A cutting tool was obtained by forming a WC _0.56 layer on the substrate by the method described in Patent Document 1.

[Sample 1-4]
As a base material, the same base material as sample 1 was prepared. A TiN layer (base layer) and an AlTiN layer were formed on the substrate in the above order. The TiN layer was formed by the same method as sample 5. The AlTiN layer was formed in the same manner as the first unit layer of Sample 12.

≪Characteristic evaluation of cutting tools≫
For the MoC _1-x layer of each sample produced as described above, the composition x, the crystal structure, the content of the crystal structure, the presence or absence of free carbon, and the hardness were measured. Regarding hardness, the hardness of the hard coating layer was measured for Samples 1-3 and 1-4. Since a specific measuring method is described in Embodiment 1, the description thereof will not be repeated. The results are shown in Tables 1 and 2 in the "Composition x", "Crystal structure", "Content rate (% by mass)", "Free carbon" and "Hardness (mgf/μm ² )" columns of the "MoC _1-x layer". shown in In Tables 1 and 2, the notation "no" in the "free carbon" column indicates that the MoC _1-x layer does not contain free carbon, and the notation "present" indicates that MoC ₁ - Indicates that the _x layer contains free carbon. In samples 1 to 24, samples 1-1 and 1-2, it was confirmed that the MoC _1-x layer consisted of 100% by mass of a hexagonal crystal structure.

The thicknesses of the MoC _1-x layer, underlayer, hard coating layer (first unit layer, second unit layer) and coating were measured. Since a specific measuring method is described in Embodiment 1, the description thereof will not be repeated. The results are shown in Tables 1 and 2. In Tables 1 and 2, the notation "-" in the "base layer" and "hard coating layer" indicates that the corresponding layer does not exist in the coating. In addition, notations such as “TiAlBN (5 nm) / TiSiN (5 nm) multilayer structure (1.0 μm)” in “hard coating layer” mean that the hard coating layer is a 5 nm thick TiAlBN layer (first unit layer) and a thick It shows that it is formed of a multilayer structure (total thickness of 1.0 μm) in which TiSiN layers (second unit layers) with a thickness of 5 nm are alternately laminated.

≪Cutting test 1≫
Using the cutting tool of each sample prepared as described above, the cutting time until chipping of the cutting tool was measured under the following cutting conditions, and chipping resistance of the cutting tool was evaluated. The following cutting conditions correspond to high-speed, high-efficiency machining. The results are shown in Tables 1 and 2. Longer cutting time indicates better chipping resistance.

(Cutting conditions for fracture resistance test (face milling test))
Insert: SEET13T3AGSN-L
Work material (material): Ti-6Al-4V
Speed: 70m/min
Feed: 0.1 mm/blade depth of cut: depth of cut: 5 mm, depth of cut in radial direction: 10 mm

≪Cutting test 2≫
Using the cutting tool of each sample prepared as described above, a cutting test was conducted under the following cutting conditions to evaluate the wear resistance of the cutting tool. The following cutting conditions correspond to high-speed, high-efficiency machining. The results are shown in Tables 1 and 2. A longer cutting time indicates better wear resistance.

(Cutting conditions for wear resistance test (outer diameter turning test))
Insert: CNMG120408N-EG
Work material (material): Ti-6Al-4V
Speed: 140m/min
Feed: 0.15mm/blade depth: depth of cut: 0.8mm
Criteria for life judgment: Time when flank wear exceeds 0.2 mm

From the results of the above cutting test, the cutting tools of Samples 1 to 26 corresponding to Examples are compared to the cutting tools of Samples 1-1 to 1-4 corresponding to Comparative Examples, even in high-speed and high-efficiency machining. It was confirmed that the chipping resistance and wear resistance are excellent, and that the tool life is long. From this, the cutting tools of Samples 1 to 24 corresponding to the examples are suitable for high-load, high-speed, high-efficiency machining applications, especially those requiring chipping resistance and wear resistance. It was suggested.

Although the embodiments and examples of the present invention have been described as above, it is planned from the beginning to appropriately combine the configurations of the above-described embodiments and examples.

It should be considered that the embodiments and examples disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above-described embodiments and examples, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

1 rake face, 2 flank face, 3 cutting edge ridge, 4 coating, 10 cutting tool, 11 base material, 12 MoC _1-x layer, 13 hard coating layer, 131 first unit layer, 132 second unit layer

Claims

A cutting tool comprising a substrate and a coating disposed on the substrate,
The coating comprises a MoC 1 -x layer made of a compound represented by MoC 1-x,
The x is 0.40 or more and 0.60 or less,
A cutting tool, wherein the compound represented by MoC 1-x has a hexagonal crystal structure.
2. The cutting tool of claim 1, wherein the MoC 1-x layer does not contain free carbon.
3. The cutting tool according to claim 1, wherein the MoC 1-x layer has a film hardness of 2700 mgf/μm 2 or more and 4200 mgf/μm 2 or less.
A cutting tool according to any preceding claim, wherein the MoC 1-x layer is in contact with the substrate.
the coating further comprises a hard coating layer disposed between the substrate and the MoC 1-x layer;
The hard coating layer includes a first unit layer,
The composition of the first unit layer is different from the composition of the MoC 1-x layer,
The first unit layer is composed of at least one element selected from the group consisting of periodic table 4 group elements, 5 group elements, 6 group elements, aluminum and silicon, or periodic table 4 group elements, 5 group elements, A compound comprising at least one element selected from the group consisting of Group 6 elements, aluminum and silicon, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron. Item 3. The cutting tool according to any one of items 3.
The hard coating layer consists of the first unit layer,
The cutting tool according to claim 5, wherein the thickness of the first unit layer is 0.1 µm or more and 10 µm or less.
The hard coating layer further includes a second unit layer,
The composition of the second unit layer is different from the composition of the MoC 1-x layer and the composition of the first unit layer,
The second unit layer is composed of at least one element selected from the group consisting of periodic table 4 group elements, 5 group elements, 6 group elements, aluminum and silicon, or periodic table 4 group elements, 5 group elements, A compound consisting of at least one element selected from the group consisting of Group 6 elements, aluminum and silicon, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron,
The cutting tool according to claim 5, wherein the first unit layer and the second unit layer each form a multilayer structure in which one or more layers are alternately laminated.
the first unit layer has a thickness of 1 nm or more and 100 nm or less;
The cutting tool according to claim 7, wherein the second unit layer has a thickness of 1 nm or more and 100 nm or less.
The MoC 1-x layer has a thickness of 0.1 μm or more and 10 μm or less,
The cutting tool according to claim 7 or 8, wherein the hard coating layer has a thickness of 0.1 µm or more and 10 µm or less.
The cutting tool according to claim 9, wherein the coating has a thickness of 0.2 µm or more and 20 µm or less.
11. Any one of claims 1 to 10, wherein the substrate comprises at least one selected from the group consisting of cemented carbide, cermet, high-speed steel, ceramics, cBN sintered bodies and diamond sintered bodies. The cutting tool described in .