JP7326693B2 - Cutting tool and its manufacturing method - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to cutting tools and methods of manufacturing the same.

2. Description of the Related Art Conventionally, cutting tools made of cemented carbide are used to cut steel, castings, and the like. During cutting, the cutting edge of such a cutting tool is exposed to severe environments such as high temperature and high stress, which causes wear and chipping of the cutting edge.

Therefore, it is important to suppress wear and chipping of the cutting edge to improve the life of the cutting tool. For the purpose of improving the cutting performance of cutting tools, the development of coatings for coating the surfaces of substrates such as cemented carbide is underway. Among them, a coating made of a compound of aluminum (Al), titanium (Ti), and nitrogen (N) (hereinafter also referred to as “AlTiN”) can have high hardness and increase the Al content. Oxidation resistance can be improved thereby.

For example, Japanese Patent Application Publication No. 2008-545063 (Patent Document 1) describes an object coated with a hard film having a layer structure of a single layer or multiple layers, the layer structure being produced by CVD without plasma excitation. having at least one Ti _1-x Al _x N hard coating, said Ti _1-x Al _x N hard coating having a stoichiometric coefficient of x>0.75-x=0.93 and 0.412 nm-0 The Ti 1-x Al x N hard coating is present as a single-phase layer of cubic NaCl structure with a lattice constant a _fcc of 0.405 nm, or said Ti _1-x Al _x N hard coating has its major phase x>0.75-x= consisting of Ti _1-x Al _x N with a cubic NaCl structure with a stoichiometric coefficient of 0.93 and a lattice constant a _fcc of 0.412 nm to 0.405 nm, and Ti _1-x Al _x as a separate phase A multiphase layer in which N is contained as a wurtzite structure and/or as TiN _x with a NaCl structure, and the chlorine content of the Ti _1-x Al _x N hard coating is 0.05 to 0.9 Hard film coated bodies are disclosed in the atomic % range.

Japanese Patent Application Laid-Open No. 2014-129562 (Patent Document 2) discloses a surface-coated member including a base material and a hard coating formed on the surface thereof, wherein the hard coating is composed of one or more layers. , at least one of the layers is a layer containing hard particles, the hard particles include a multilayer structure in which first unit layers and second unit layers are alternately laminated, and the first unit layer is , one or more elements selected from the group consisting of Group 4 elements, Group 5 elements, Group 6 elements and Al of the periodic table, and one or more elements selected from the group consisting of B, C, N and O The second unit layer includes at least one element selected from the group consisting of Group 4 elements, Group 5 elements, Group 6 elements and Al of the periodic table, and B, C, N and O A surface-coated member containing a second compound consisting of one or more elements selected from the group consisting of is disclosed.

WO2018/158976 (Patent Document 3) discloses a surface-coated cutting tool comprising a substrate and a coating formed on the surface thereof, wherein the coating comprises one or more layers, At least one of the layers is an Al-rich layer containing hard particles, the hard particles having a sodium chloride type crystal structure, a plurality of massive first unit phases, and the first unit phase interphase The first unit phase is composed of a nitride or carbonitride of Al _x Ti _1-x , and the atomic ratio x of Al in the first unit phase is 0.7 0.96 or less, the second unit phase is composed of a nitride or carbonitride of Al _y Ti _1-y , and the atomic ratio y of Al in the second unit phase is more than 0.5 and 0 is less than .7, and the Al-rich layer exhibits a maximum peak in the (220) plane when analyzed from the normal direction of the surface of the coating using X-ray diffraction method. there is

Japanese Patent Publication No. 2008-545063 JP 2014-129562 A WO2018/158976

In recent years, there has been a demand for more efficient (larger feed rate) cutting, and further improvement in performance (for example, suppression of chipping and wear of the cutting edge) is expected. In addition, there is a demand for the development of cutting tools suitable for the material of the work material.

The present disclosure has been made in view of the circumstances described above, and an object thereof is to provide a cutting tool having excellent resistance to initial wear and thermal wear, and a method for manufacturing the same.

The cutting tool according to the present disclosure is
A cutting tool comprising a substrate and a coating layer disposed on the substrate,
The coating layer is made of cubic hard particles,
The cubic hard particles consist of a multilayer structure and a matrix-domain structure,
the multilayer structure is in contact with the matrix-domain structure on the side opposite the substrate,
The multilayer structure includes a first unit layer and a second unit layer,
the matrix-domain structure includes a matrix region and a domain region surrounded by the matrix region;
The cubic hard particles are made of nitrides or carbides containing aluminum and titanium as constituent elements,
The atomic ratio x of the aluminum is 0.7 or more and 0.96 or less based on the total of the aluminum and the titanium in the cubic hard particles,
When the coating layer is analyzed by an X-ray diffraction method, the peak intensity derived from the (220) orientation exhibits the maximum value compared to the peak intensities derived from other orientations.

A method for manufacturing a cutting tool according to the present disclosure includes:
A method for manufacturing the cutting tool,
a first step of preparing the substrate;
a second step of forming a precursor of the coating layer on the substrate using chemical vapor deposition;
a third step of intermittently irradiating the surface of the precursor of the coating layer with energetic particles;
including.

ADVANTAGE OF THE INVENTION According to this disclosure, it becomes possible to provide a cutting tool having excellent resistance to initial wear and thermal wear and a method for manufacturing the same.

FIG. 1 is a perspective view illustrating one aspect of a substrate 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 enlarged view of the coating layer of the cutting tool according to this embodiment. FIG. 5 is a schematic diagram of hard particles in the coating layer according to this embodiment. FIG. 6 is a transmission electron microscope photograph and an X-ray diffraction pattern photograph (bottom right) of the multilayer structure in the hard particles according to the present embodiment. FIG. 7 is a transmission electron microscope photograph and an X-ray diffraction pattern photograph (bottom right) of the matrix-domain structure in the hard particles according to the present embodiment. FIG. 8 is a schematic cross-sectional view of a CVD apparatus used for manufacturing the cutting tool according to this embodiment. FIG. 9 is a graph showing the correlation between the cutting time and the amount of flank wear in the example.

[Description of Embodiments of the Present Disclosure]
First, the contents of one aspect of the present disclosure are listed and described.
[1] The cutting tool according to the present disclosure is
A cutting tool comprising a substrate and a coating layer disposed on the substrate,
The coating layer is made of cubic hard particles,
The cubic hard particles consist of a multilayer structure and a matrix-domain structure,
the multilayer structure is in contact with the matrix-domain structure on the side opposite the substrate,
The multilayer structure includes a first unit layer and a second unit layer,
the matrix-domain structure includes a matrix region and a domain region surrounded by the matrix region;
The cubic hard particles are made of nitrides or carbides containing aluminum and titanium as constituent elements,
The atomic ratio x of the aluminum is 0.7 or more and 0.96 or less based on the total of the aluminum and the titanium in the cubic hard particles,
When the coating layer is analyzed by an X-ray diffraction method, the peak intensity derived from the (220) orientation exhibits the maximum value compared to the peak intensities derived from other orientations.

The above-described cutting tool can have excellent resistance to initial wear and thermal wear by having the configuration as described above. The cutting tool is particularly suitable for cutting cast iron work and carbon steel work. Here, "initial wear" means wear that occurs at the start of cutting. "Thermal wear" means wear at elevated temperatures.

[2] When the coating layer contains hexagonal hard particles, the content of the hexagonal hard particles is based on the total amount of the cubic hard particles and the hexagonal hard particles. , it is preferably more than 0% by volume and 20% by volume or less. By stipulating in this way, the cutting tool is even more excellent against initial wear and thermal wear.

[3] The thickness of the matrix-domain structure is preferably 0.1 μm or more and 2 μm or less. By defining in this way, the cutting tool becomes more excellent in resistance to initial wear.

[4] A method for manufacturing a cutting tool according to the present disclosure is a method for manufacturing the cutting tool,
a first step of preparing the substrate;
a second step of forming a precursor of the coating layer on the substrate using chemical vapor deposition;
a third step of intermittently irradiating the surface of the precursor of the coating layer with energetic particles;
including.
With the configuration as described above, the cutting tool manufacturing method can manufacture a cutting tool having excellent resistance to initial wear and thermal wear. The cutting tool manufacturing method described above makes it possible to manufacture a cutting tool that is particularly suitable for cutting cast iron work materials and carbon steel work materials.

[5] In the second step, each of the first gas containing an aluminum halide gas and a titanium halide gas and the second gas containing an ammonia gas is heated to 650° C. or more and 850° C. or less and 0.5 kPa or more. It preferably includes jetting against the substrate under conditions of 1.5 kPa or less. By defining in this way, it becomes possible to manufacture a cutting tool having excellent heat resistance.

[6] The energetic particles in the third step are preferably gallium ions. By defining in this way, it becomes possible to manufacture a cutting tool with even better resistance to initial wear.

[Details of Embodiments of the Present Disclosure]
An embodiment of the present disclosure (hereinafter referred to as "this embodiment") will be described below. However, this embodiment is not limited to this. In the drawings used for describing the embodiments below, the same reference numerals denote the same or corresponding parts. In this specification, the notation of the form "A to Z" means the upper and lower limits of the range (that is, from A to Z), and if no unit is described at A and only a unit is described at Z, then A and the unit of Z are the same. Furthermore, in this specification, when a compound is represented by a chemical formula in which the composition ratio of constituent elements is not limited, such as "TiN", the chemical formula can be any conventionally known composition ratio (element ratio) shall include At this time, the above chemical formula includes not only stoichiometric compositions but also non-stoichiometric compositions. For example, the chemical formula of “TiN” includes not only the stoichiometric composition “Ti ₁ N ₁ ” but also non-stoichiometric compositions such as “Ti ₁ N _0.8 ”. This also applies to the description of compounds other than "TiN".

≪Cutting tool≫
The cutting tool according to this embodiment is
A cutting tool comprising a substrate and a coating layer disposed on the substrate,
The coating layer is made of cubic hard particles,
The cubic hard particles consist of a multilayer structure and a matrix-domain structure,
the multilayer structure is in contact with the matrix-domain structure on the side opposite the substrate,
The multilayer structure includes a first unit layer and a second unit layer,
the matrix-domain structure includes a matrix region and a domain region surrounded by the matrix region;
The cubic hard particles are made of nitrides or carbides containing aluminum and titanium as constituent elements,
The atomic ratio x of the aluminum is 0.7 or more and 0.96 or less based on the total of the aluminum and the titanium in the cubic hard particles,
When the coating layer is analyzed by an X-ray diffraction method, the peak intensity derived from the (220) orientation exhibits the maximum value compared to the peak intensities derived from other orientations.

A cutting tool 50 of the present embodiment includes a base material 10 and a coating layer 20 provided on the base material 10 (hereinafter sometimes simply referred to as a "cutting tool") (Fig. 2). The cutting tool 50 may further include a foundation layer 21 provided between the substrate 10 and the coating layer 20 in addition to the coating layer 20 (FIG. 3). The underlying layer 21 will be described later.
Note that the layers provided on the substrate 10 may be collectively referred to as a "coating". That is, the cutting tool 50 comprises a coating 40 provided on the substrate 10 , and the coating 40 includes the coating layer 20 . Moreover, the coating 40 may further include the underlying layer 21 . In one aspect of the present embodiment, the coating may cover the rake face of the substrate, or may cover a portion other than the rake face (for example, the flank face).

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.

<Base material>
As the substrate of this embodiment, any substrate can be used as long as it is conventionally known as this type of substrate. 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 WC). 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.

Among these various base materials, it is particularly preferable to select a WC-based cemented carbide or a cBN sintered body. The reason for this is that these base materials have an excellent balance of hardness and strength, particularly at high temperatures, and have excellent properties as base materials for cutting tools for the above applications.

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 free carbon or an abnormal phase called η phase in the structure. The surface of the substrate used in this embodiment may be modified. For example, in the case of cemented carbide, a β-free layer may be formed on the surface, or in the case of a cBN sintered body, a surface-hardened layer may be formed. Even if the surface is modified in this way, The effect of this embodiment is shown.

FIG. 1 is a perspective view illustrating one aspect of a substrate of a cutting tool. A base material having such a shape is used, for example, as a base material for an indexable cutting insert for turning. The base material 10 has a rake face 1, a flank face 2, and a cutting edge ridge line portion 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 tip of the cutting edge of the substrate 10 . Such a shape of the base material 10 can also be grasped as the shape of the cutting tool.

When the cutting tool is an indexable cutting tip, the substrate 10 may or may not have a chip breaker. The shape of the cutting edge ridge line 3 is a sharp edge (a ridge where the rake face and the flank face intersect), a honing (a shape in which the sharp edge is rounded), a negative land (a shape in which the sharp edge is chamfered), and a combination of honing and negative land. Any shape is included in the shape.

As described above, the shape of the base material 10 and the names of the respective parts have been described with reference to FIG. We will use the term That is, the cutting tool has a rake face, a flank face, and a cutting edge ridge connecting the rake face and the flank face.

<Coating>
The coating 40 according to this embodiment includes the coating layer 20 provided on the substrate 10 (see FIG. 2). The "coating" covers at least a part of the base material (for example, the rake face that comes into contact with the work material during cutting) to provide various properties such as chipping resistance, wear resistance, and peeling resistance in the cutting tool. It has the effect of improving the It is preferable that the film covers not only a part of the base material but also the entire surface of the base material. However, it does not depart from the scope of the present embodiment even if a part of the substrate is not covered with the coating or the composition of the coating is partially different.

The thickness of the coating is preferably 4 μm or more and 30 μm or less, more preferably 7 μm or more and 25 μm or less. Here, the thickness of the coating means the sum of the thicknesses of the layers constituting the coating. Examples of the "layer constituting the coating" include a coating layer and an underlying layer, which will be described later. The thickness of the coating is, for example, using a transmission electron microscope (TEM), measuring any 10 points in a cross-sectional sample parallel to the normal direction of the surface of the substrate, and the average of the thickness of the measured 10 points It can be obtained by taking the value. The same is true when measuring the thickness of each of a coating layer and an underlying layer, which will be described later. Examples of scanning transmission electron microscopes include JEM-2100F (trade name) manufactured by JEOL Ltd.

(coating layer)
The coating layer in this embodiment is arranged on the base material. Here, "arranged on the substrate" is not limited to the aspect of being arranged directly above the substrate (see FIG. 2), but is arranged on the substrate via another layer Aspects (see FIG. 3) are also included. That is, as long as the effect of the present disclosure is exhibited, the coating layer may be arranged directly above the base material, or may be arranged on the base material via another layer such as a base layer to be described later. may be Moreover, the coating layer is the outermost surface of the coating.

The coating layer 20 is composed of cubic hard particles 30 (FIG. 4). Here, the phrase “composed of cubic hard particles” is not limited to an embodiment consisting only of cubic hard particles, and as long as the effects of the present disclosure are exhibited, cubic hard particles and cubic crystals It is a concept including an embodiment composed of hard particles other than the crystal type of the type. That is, in one aspect of the present embodiment, the coating layer may be composed only of cubic hard particles. Further, the coating layer may be composed of cubic hard particles and hard particles other than the cubic crystal type. Examples of "hard particles other than cubic crystal type" include hexagonal hard particles. The cubic hard particles and the hexagonal hard particles are distinguished, for example, by diffraction peak patterns obtained by X-ray diffraction described below.

In one aspect of the present embodiment, the coating layer may contain an amorphous phase as long as the effects of the present disclosure are exhibited.

(Peak intensity derived from (220) orientation)
In this embodiment, when the coating layer is analyzed by the X-ray diffraction method, the peak intensity derived from the (220) orientation exhibits the maximum value compared to the peak intensities derived from other orientations. From this, it can be understood that most of the hard particles contained in the coating layer of the cutting tool are crystals grown in a direction inclined at 45° with respect to the normal direction of the surface of the coating. Therefore, the cutting tool can have high hardness and the effect of effectively suppressing initial wear. Furthermore, since the (220) plane exhibits the maximum peak strength, it can have a good balance of hardness and toughness, and can be more excellent in wear resistance and chipping resistance. Here, the "peak intensity derived from other orientations" includes the peak intensity derived from (111) orientation and the peak intensity derived from (200) orientation. Specifically, the following method is applied to the X-ray diffraction (XRD) method performed on the coating layer.

First, the cutting tool to be measured by the X-ray diffraction method can be analyzed from the normal direction of the surface of the coating with an X-ray diffraction device (trade name: "SmartLab (registered trademark)", manufactured by Rigaku Corporation). set in any direction.

Next, the coating layer of the cutting tool is analyzed from the normal direction of the surface of the coating under the following conditions. This makes it possible to obtain data on the X-ray diffraction peaks in the coating layer.
Measurement method: ω/2θ method Incident angle (ω): 2°
Scan angle (2θ): 30-70°
Scan speed: 1°/min
Scan step width: 0.05°
X-ray source: Cu-Kα ray Optical system attribute: medium resolution parallel beam Tube voltage: 45 kV
Tube current: 200mA
X-ray irradiation range: Using a 2.0 mm range limiting collimator, irradiate a 2 mm diameter range on the rake face (However, X-ray irradiation on the flank face under the same conditions is also permitted)
X-ray detector: Semiconductor detector (trade name: "D/teX Ultra250", manufactured by Rigaku Corporation)

The ratio of the peak intensity derived from the (220) orientation to the sum of the peak intensity derived from the (200) orientation, the peak intensity derived from the (111) orientation, and the peak intensity derived from the (220) orientation is 50. % or more and 100% or less, more preferably 55% or more and 90% or less. Here, "peak intensity" means the peak height (cps) in the X-ray spectrum.

The thickness of the coating layer is preferably 4 μm or more and 30 μm or less, more preferably 7 μm or more and 25 μm or less. The thickness of the coating layer can be confirmed by observing vertical cross sections of the substrate and the coating using a TEM in the same manner as described above. The hard particles forming the coating layer are described below.

(Cubic type hard particles)
The cubic hard particles 30 according to the present embodiment consist of a multilayer structure portion 32 and a matrix-domain structure portion 31 (FIG. 5). The multilayer structure 32 is in contact with the matrix-domain structure 31 on the side opposite the substrate 10 (FIG. 5).

The cubic hard particles are made of nitrides or carbides containing aluminum and titanium as constituent elements. Examples of nitrides containing aluminum and titanium as constituent elements include compounds represented by Al _x Ti _1-x N. Here, the composition ratio (element ratio) between “Al _x Ti _1- x ” and “N” in the chemical formula “Al _x Ti _1-x N” is the stoichiometric composition (for example, (Al _x Ti _1-x ) ₁ N ₁ ) as well as non-stoichiometric compositions (eg, (Al _x Ti _1-x ) ₁ N _0.8 ). Carbonitrides containing aluminum and titanium as constituent elements include, for example, compounds represented by Al _x Ti _1-x CN. Here, the composition ratio (element ratio) between “Al _x Ti _1- x ” and “CN” in the chemical formula “Al _x Ti _1-x CN” is the stoichiometric composition (for example, (Al _x Ti _1-x ) ₁ (CN) ₁ ) as well as non-stoichiometric compositions (eg, (Al _x Ti _1-x ) ₁ (CN) _0.8 ).

The atomic ratio x of the aluminum (Al) is 0.7 or more and 0.96 or less, and 0.75 or more and 0.9 or less based on the total amount of the aluminum and the titanium in the cubic hard particles. is preferred. The atomic ratio x is determined by an energy dispersive X-ray spectroscopy (EDX) device attached to a transmission electron microscope (TEM) for the cubic hard particles appearing in the cross-sectional sample. It is possible to obtain by analyzing using The atomic ratio x of aluminum obtained at this time is a value obtained as an average of all the cubic hard particles. Specifically, the arbitrarily selected 10 hard particles in the coating layer of the cross-sectional sample are measured to determine the atomic ratio of aluminum, and the average value of the 10 values obtained is the cubic It is the atomic ratio of aluminum in the crystal type hard particles. At this time, numerical values that seem to be abnormal values at first glance are not adopted. Here, the "arbitrarily selected 10 points" are selected from different hard particles of the coating layer. Examples of the EDX apparatus include JED-2300 (trade name) manufactured by JEOL Ltd. Note that the atomic ratio of not only aluminum but also titanium, nitrogen, etc. can be calculated by the above-described method.

(multilayer structure)
The multilayer structure includes a first unit layer and a second unit layer. The first unit layers and the second unit layers are alternately laminated. In the present embodiment, the interface between the first unit layer and the second unit layer is perpendicular or substantially perpendicular to the direction in which the first unit layer and the second unit layer are laminated. In other words, the first unit layer and the second unit layer do not form an interface that is not perpendicular to the direction in which both layers are laminated. Therefore, in the multilayer structure portion, the first unit layer is not surrounded by the second unit layer. Also, the second unit layer is not surrounded by the first unit layer. In other words, the first unit layer is surrounded by the second unit layer in the direction in which both layers are laminated, but is surrounded by the second unit layer in the direction perpendicular to the direction in which both layers are laminated. It can be grasped that it is not surrounded by a unit layer. In addition, the second unit layer is surrounded by the first unit layer in the direction in which both layers are laminated, but the first unit layer is surrounded in the direction perpendicular to the direction in which both layers are laminated. It can be understood that it is not surrounded by layers. That is, the multi-layer structure section forms a structure that is clearly different from the matrix-domain structure section described later.

(first unit layer)
The first unit layer has a higher atomic ratio of aluminum than the second unit layer, which will be described later. When the multilayer structure is observed with a TEM, the first unit layer is observed as a darker layer than the second unit layer (see FIG. 6, for example). Therefore, the first unit layer can be clearly distinguished from the second unit layer.

The thickness of the first unit layer is preferably 1 nm or more and 20 nm or less, more preferably 2 nm or more and 10 nm or less. The thickness of the first unit layer is obtained by measuring 10 arbitrarily selected points in the same layer in a cross-sectional sample parallel to the normal direction of the surface of the substrate using a TEM, and measuring the thickness of 10 points. can be obtained by taking the average value of At this time, numerical values that seem to be abnormal values at first glance are not adopted. When the multilayer structure portion includes two or more first unit layers, first, the thickness of each first unit layer is obtained by the method described above, and the average value of the obtained values is calculated as the thickness of the first unit layer in the multilayer structure portion. thickness. When the number of first unit layers contained in the multi-layer structure portion exceeds 10, the thickness of each of the 10 arbitrarily selected first unit layers is obtained by the method described above, Let the average value of the values obtained from the first unit layers be the thickness of the first unit layer in the multilayer structure.

(Second unit layer)
The second unit layer has a lower atomic ratio of aluminum than the first unit layer. When the multilayer structure is observed with a TEM, the second unit layer is observed as a brighter layer than the first unit layer (for example, see FIG. 6). Therefore, the second unit layer can be clearly distinguished from the first unit layer.

The thickness of the second unit layer is preferably 0.5 nm or more and 5 nm or less, more preferably 1 nm or more and 2.5 nm or less. The thickness of the second unit layer can be determined using a TEM in the same manner as described above.

(Repeating unit of first unit layer and second unit layer)
In the repeating unit consisting of one layer of the first unit layer and one layer of the second unit layer, the thickness of the repeating unit is preferably 1.5 nm or more and 25 nm or less, and more preferably 1.5 nm or more and 20 nm or less. is more preferable, and more preferably 5 nm or more and 15 nm or less. The present inventors believe that the coating layer has improved resistance to thermal abrasion when the repeating unit has the above structure. The multilayer structure part according to the present embodiment is formed by alternately laminating the first unit layer and the second unit layer. The unit layers are collectively referred to as "repeating unit consisting of one first unit layer and one second unit layer" or simply "repeating unit". The "thickness of the repeating unit" means the sum of the thickness of the first unit layer and the thickness of the second unit layer that constitute the repeating unit.

(matrix-domain structure)
The matrix-domain structure includes a matrix region and a domain region surrounded by the matrix region.

The thickness of the matrix-domain structure portion is preferably 0.1 μm or more and 2 μm or less, more preferably 0.2 μm or more and 1.5 μm or less. The thickness d of the matrix-domain structure part is understood as the shortest distance between the surface of the hard particle opposite to the base material and the interface between the multilayer structure part and the matrix-domain structure part. (See Fig. 5). At this time, it is considered that the surface of the hard particles on the side opposite to the substrate and the interface between the multilayer structure and the matrix-domain structure are conceptually parallel. In addition, the boundary surface described above is the unit layer farthest from the substrate side in the multilayer structure portion (that is, the first unit layer or the second unit layer) and the unit layer maintaining the layered structure. It can also be grasped as the interface farther from the substrate. Specifically, using a TEM, 10 arbitrarily selected hard particles in the coating layer in a cross-sectional sample parallel to the normal direction of the surface of the substrate are measured, and the measured 10 matrix - It can be obtained by averaging the thickness of the domain structure. At this time, numerical values that seem to be abnormal values at first glance are not adopted.

(domain area)
In the present embodiment, the term “domain region” means a region that is divided into a plurality of parts and exists in a dispersed state in a matrix region described later (for example, darkened regions in FIG. 7). The domain regions are then considered to be dispersed in the matrix region in all directions. Here, "any direction" includes the normal direction of the surface of the substrate and the direction perpendicular to the normal direction. The above-mentioned "distributed state" basically means that adjacent domain regions are not in direct contact with each other, but does not exclude cases in which some domain regions are in contact with each other.

Also, the domain region can be understood as a region divided into a plurality of regions in the matrix-domain structure. In one aspect of the present embodiment, it can also be understood that most of the plurality of regions forming the domain region are surrounded by the matrix region. At this time, the domain region is considered to be surrounded by the matrix region in all directions. Here, "any direction" includes the direction normal to the surface of the substrate and the direction perpendicular to the normal.

Thus, in the matrix-domain structure, the domain regions are dispersed in the matrix region. Therefore, the domain region and the matrix region do not form a laminate structure, and the matrix-domain structure part forms a structure clearly different from the multilayer structure part.

The domain region is a region having a higher atomic ratio of aluminum than the matrix region described later. The domain region is observed as a darker region than the matrix region when the matrix-domain structure is observed with a TEM (eg, see FIG. 7). Therefore, the domain region can be clearly distinguished from the matrix region.

The volume ratio of the domain region is not particularly limited. It may be below. The volume ratio of the domain regions can be obtained as follows. First, a predetermined field of view (for example, 0.5 μm×0.5 μm) in a cross-sectional sample parallel to the normal direction of the surface of the substrate is observed with a TEM to obtain an observed image. The magnification at this time is, for example, 2000000 times. In the observed image obtained, the area of each of the domain region and the matrix region is calculated. Next, the area ratio of the domain region is calculated based on the total area of the domain region and the matrix region. Such measurements are performed in at least 10 fields of view, and the average value of the area ratios calculated in each of the 10 fields of view is regarded as the volume ratio of the domain region.

The size of the domain region is preferably 2 nm or more and 15 nm or less, more preferably 2.5 nm or more and 10 nm or less. The size of the domain region can be obtained as follows. First, a predetermined visual field (for example, 0.05 μm×0.05 μm) in a cross-sectional sample parallel to the normal direction of the surface of the substrate is observed with a TEM to obtain an observed image. The magnification at this time is, for example, 10000000 times. In the observed image obtained, the area of each domain region is calculated, and the corresponding area circle diameter (Heywood diameter) is obtained based on the calculated area. At this time, the number of domain regions to be measured should be at least 10 or more.

(matrix area)
In the present embodiment, the “matrix region” is a region that forms the base of the matrix-domain structure (for example, the region shown brightly in FIG. 7) and means a region other than the domain region. In other words, most of the matrix region can also be understood as a region arranged so as to surround each of the plurality of regions forming the domain region. It can also be understood that most of the matrix region is arranged between a plurality of regions forming the domain region.

The matrix region is a region having a lower atomic ratio of aluminum than the domain region. The matrix region is observed as a brighter region than the domain region when the matrix-domain structure is observed with a TEM (eg, see FIG. 7). Therefore, the matrix region can be clearly distinguished from the domain region.

The volume ratio of the matrix region is not particularly limited. or less, or 10% by volume or more and 30% by volume or less. The volume ratio of the matrix region can be obtained as follows. First, a predetermined field of view (for example, 0.5 μm×0.5 μm) in a cross-sectional sample parallel to the normal direction of the surface of the substrate is observed with a TEM to obtain an observed image. The magnification at this time is, for example, 2000000 times. In the observed image obtained, the area of each of the domain region and the matrix region is calculated. Next, based on the total area of the domain region and the matrix region, the area ratio of the matrix region is calculated. Such measurements are performed in at least 10 fields of view, and the average value of the area ratios calculated in each of the 10 fields of view is regarded as the volume ratio of the matrix region.

(Hexagonal hard particles)
As long as the effects of the present disclosure are exhibited, the coating layer may contain hexagonal hard particles. The constituent elements of the hexagonal hard particles are considered to be the same as the constituent elements of the cubic hard particles. However, the elemental composition of the hexagonal hard particles may be the same as or different from the elemental composition of the cubic hard particles. When the coating layer contains hexagonal hard particles, the content ratio of the hexagonal hard particles (h / (c + h)) is the cubic hard particles (c) and the hexagonal hard particles Based on the total amount of the particles (h), it is preferably more than 0% by volume and 20% by volume or less, more preferably more than 0% by volume and 15% by volume or less, and 0% by volume. More preferably, it exceeds 10% by volume or less. In one aspect of the present embodiment, the coating layer preferably does not contain hexagonal hard particles. The content ratio can be determined, for example, by analyzing a pattern of diffraction peaks obtained by X-ray diffraction. A specific method is as follows.

Using an X-ray diffractometer (“MiniFlex 600” (trade name) manufactured by Rigaku), an X-ray spectrum of the coating layer in the above cross-sectional sample is obtained. The conditions of the X-ray diffraction device at this time are, for example, as follows.
Characteristic X-ray: Cu-Kα (wavelength 1.54 Å)
Tube voltage: 45kV
Tube current: 40mA
Filter: Multilayer mirror Optical system: Focusing method X-ray diffraction method: θ-2θ method

In the obtained X-ray spectrum, the peak intensity (Ic) of the cubic hard particles and the peak intensity (Ih) of the hexagonal hard particles are measured. Here, "peak intensity" means the peak height (cps) in the X-ray spectrum. The peaks of the cubic hard particles can be confirmed near the diffraction angles 2θ=38° and 44°. The peak of the hexagonal hard particles can be confirmed near the diffraction angle 2θ=33°. The peak intensity is the value excluding the background.

The content ratio (% by volume) of the hexagonal hard particles based on the total amount of the cubic hard particles and the hexagonal hard particles is calculated by the following formula. Here, the peak intensity (Ic) of the cubic hard particles is determined by the sum of the peak intensity near 2θ=38° and the peak intensity near 2θ=44°.
Content ratio of the hexagonal hard particles (% by volume) = 100 x {Ih/(Ih+Ic)}

(other layers)
The film may further include other layers as long as the effects of the present embodiment are not impaired. The composition of the other layer may be different from or the same as that of the coating layer. Other layers include, for example, a TiN layer, a TiCN layer, a TiBN layer, an Al ₂ O ₃ layer, and the like. For example, the other layer includes a base layer provided between the substrate and the hard coating layer. The thickness of the other layer is not particularly limited as long as the effect of the present embodiment is not impaired.

≪Manufacturing method of cutting tools≫
The method for manufacturing a cutting tool according to this embodiment includes:
A method for manufacturing the cutting tool,
a first step of preparing the substrate;
a second step of forming a precursor of the coating layer on the substrate using chemical vapor deposition;
a third step of intermittently irradiating the surface of the precursor of the coating layer with energetic particles;
including.

<First Step: Step of Preparing Base Material>
In this step, the substrate is prepared. As the base material, as described above, any conventionally known base material of this type can be used. For example, when the base material is made of a cemented carbide, raw material powders having a predetermined composition (% by mass) are uniformly mixed using a commercially available attritor, and then the mixed powder is shaped into a predetermined shape (e.g. , SEET13T3AGSN-G, CNMG120408, etc.), and then sintering in a predetermined sintering furnace at 1300 ° C to 1500 ° C for 1 to 2 hours to obtain the above base material made of cemented carbide. can. Moreover, a commercially available product may be used as it is for the base material. Commercially available products include EH520 (trade name) manufactured by Sumitomo Electric Hardmetal Co., Ltd., for example.

<Second step: step of forming a precursor of the coating layer on the base material by using a chemical vapor deposition method>
In this step, a precursor of the coating layer is formed on the substrate using chemical vapor deposition. In the second step, each of the first gas containing the aluminum halide gas and the titanium halide gas and the second gas containing the ammonia gas is heated to 650° C. or higher and 850° C. or lower and 0.5 kPa or higher and 1.5 kPa or higher. It preferably comprises jetting the substrate in the following atmosphere. This step can be performed using, for example, a CVD apparatus described below.

(CVD equipment)
FIG. 8 shows a schematic cross-sectional view of an example of a CVD apparatus used for manufacturing the cutting tool of the embodiment. As shown in FIG. 8, the CVD apparatus 70 includes a plurality of substrate setting jigs 71 for setting the substrate 10, and a reaction vessel 72 made of heat-resistant alloy steel covering the substrate setting jigs 71. ing. A temperature controller 73 for controlling the temperature inside the reaction vessel 72 is provided around the reaction vessel 72 .

In the reaction container 72, a first gas introduction pipe 74 and a second gas introduction pipe 75, which are joined adjacently, extend vertically in the space inside the reaction container 72, and are rotatable about the vertical direction. is provided in The gas introduction pipe 76 is configured such that the first gas introduced through the first gas introduction pipe 74 and the second gas introduced through the second gas introduction pipe 75 are not mixed inside the gas introduction pipe 76 . there is In addition, a part of each of the first gas introduction pipe 74 and the second gas introduction pipe 75 is supplied with the gas flowing through each of the first gas introduction pipe 74 and the second gas introduction pipe 75 . A plurality of through-holes are provided for jetting onto the base material 10 placed on the inside.

Furthermore, the reaction container 72 is provided with a gas exhaust pipe 77 for discharging the gas inside the reaction container 72 to the outside, and the gas inside the reaction container 72 passes through the gas exhaust pipe 77 to The gas is discharged to the outside of the reaction vessel 72 through the gas exhaust port 78 .

More specifically, the above-described first gas and second gas are introduced into the first gas introduction pipe 74 and the second gas introduction pipe 75, respectively. At this time, the temperatures of the first gas and the second gas in each gas introduction pipe are not particularly limited as long as they are not liquefied. Next, the first gas is introduced into the reaction vessel 72 having an atmosphere of 650° C. or higher and 850° C. or lower (preferably 730° C. or higher and 750° C. or lower) and 0.5 kPa or higher and 1.5 kPa or lower (preferably 0.5 kPa or higher and 1 kPa or lower). , the second gas is repeatedly ejected in this order. Since the gas introduction pipe 76 has a plurality of through-holes, the introduced first gas and second gas are jetted into the reaction vessel 72 through different through-holes. At this time, the gas introduction pipe 76 is rotating about its axis at a rotational speed of, for example, 2 to 10 rpm, as indicated by the rotating arrow in FIG. Thereby, the first gas and the second gas can be repeatedly jetted to the substrate 10 in this order.

(first gas)
The first gas includes an aluminum halide gas and a titanium halide gas.

Halide gases of aluminum include, for example, aluminum chloride gas (AlCl ₃ gas, Al ₂ Cl ₆ gas). Preferably AlCl ₃ gas is used. The concentration (% by volume) of the halide gas of aluminum is preferably 0.3% by volume or more and 1.5% by volume or less, based on the total volume of the first gas and the second gas, and 0.6% by volume. It is more preferable to be 0.8 volume % or less.

Titanium halide gases include, for example, titanium (IV) chloride gas ( _TiCl4 gas), titanium chloride (III) gas ( _TiCl3 gas), and the like. Titanium (IV) chloride gas is preferably used. The concentration (% by volume) of the titanium halide gas is preferably 0.1% by volume or more and 1% by volume or less, based on the total volume of the first gas and the second gas, and 0.14% by volume or more and 0 0.4% by volume or less is more preferable.

The volume ratio of the aluminum halide gas in the mixed gas of the first gas and the second gas is 0.5 or more and 0.85 or less based on the total volume of the aluminum halide gas and the titanium halide gas. , and more preferably 0.6 or more and 0.85 or less.

The first gas may contain hydrogen gas, or may contain an inert gas such as argon gas. The concentration (% by volume) of the inert gas is preferably 5% by volume or more and 50% by volume or less, and 20% by volume or more and 40% by volume or less, based on the total volume of the first gas and the second gas. is more preferred. Hydrogen gas usually accounts for the remainder of the first and second gases.

In one aspect of the present embodiment, the first gas may further contain a hydrocarbon gas. Examples of hydrocarbon gas include methane gas and ethylene gas (C ₂ H ₄ gas). The concentration (% by volume) of the hydrocarbon gas is preferably 0.1% by volume or more and 1% by volume or less, and 0.2% by volume or more and 0.4% by volume, based on the total volume of the first gas and the second gas. It is more preferably vol% or less.

It is preferable that the flow rate of the first gas when jetted onto the substrate is 20 to 30 L/min.

(second gas)
The second gas includes ammonia gas. The second gas may contain hydrogen gas, or may contain an inert gas such as argon gas. Formation of the multilayer structure is promoted by jetting the second gas onto the substrate.

The concentration (% by volume) of the ammonia gas is preferably 0.5% by volume or more and 4% by volume or less, and 1% by volume or more and 2% by volume or less, based on the total volume of the first gas and the second gas. is more preferable. Hydrogen gas usually accounts for the balance of the first gas and the second gas.

The flow rate of the second gas when it is jetted onto the substrate is preferably 10 to 20 L/min.

<Third step: Step of intermittently irradiating the surface of the precursor of the coating layer with energy particles>
In this step, the surface of the precursor of the coating layer is intermittently irradiated with energetic particles. By doing so, a part of the multilayer structure portion of the hard particles constituting the precursor of the coating layer is changed to the matrix-domain structure portion, thereby forming the coating layer. As is clear from the above steps, the multilayer structure portion of the coating layer precursor and the multilayer structure portion of the coating layer have the same layer structure and composition.

Conventionally, when attempting to convert a multilayer structure into a matrix-domain structure, it was necessary to heat-treat (anneal) the entire coating layer (ie, the entire hard particle). Such conventional heat treatment could only produce hard particles composed entirely of matrix-domain structures. In the present disclosure, as described above, by intermittently irradiating the surface of the precursor of the coating layer with energetic particles, it is possible to heat-treat only a part of the hard particles. Therefore, it is possible to produce hard particles with both a multi-layer structure and a matrix-domain structure, which reduces the initial wear when machining cast iron and carbon steel materials. And it becomes possible to provide a cutting tool having excellent resistance to thermal wear.

In addition, even in a cutting tool manufactured without performing the third step, it is considered that the surface portion of the coating layer is eventually heated by frictional heat associated with cutting. However, the inventors believe that the matrix-domain structure is not produced because the degree of heating is not strictly controlled.

Examples of the energetic particles include gallium ions (Ga ⁺ ) and xenon ions (Xe ⁺ ). In one aspect of the present embodiment, the energetic particles in the third step are preferably gallium ions.

The method of irradiating with energetic particles is not particularly limited, but examples thereof include laser processing, electron beam irradiation, focused ion beam irradiation (FIB irradiation), radiation irradiation and the like. As the device, a known device can be used, and JIB-4501 (trade name) manufactured by JEOL Ltd. can be used, for example.

The irradiation time of the energetic particles is preferably 0.01 seconds or more and 0.1 seconds or less, more preferably 0.05 seconds or more and 0.1 seconds or less.

After irradiation with energetic particles, the waiting time (interval time) until the next irradiation is preferably 0.005 seconds or more and 0.02 seconds or less, and 0.01 seconds or more and 0.02 seconds or less. It is more preferable to have By setting the irradiation time of the energetic particles and the waiting time until the next irradiation as described above, heat can be efficiently applied to the surface of the precursor of the coating layer without escaping the heat to the substrate. be possible.

The number of repetitions of the operation of irradiating with energetic particles and waiting for a predetermined time is preferably 5 times or more and 500 times or less, and more preferably 10 times or more and 50 times or less.

One aspect of this embodiment WHEREIN: When FIB irradiation using gallium ion is performed as a 3rd process, the following conditions are illustrated.
Accelerating voltage: 1-2 kV
Current density: 40-60nA
Irradiation angle: 45-90°
Irradiation time: 0.1 sec Interval: 0.02 sec Number of repetitions: 10 to 50 Processing depth: 300 to 1020 nm

<Other processes>
In the manufacturing method according to the present embodiment, in addition to the above-described steps, a step of forming other layers, a step of surface treatment, and the like may be performed as appropriate. When forming the other layers described above, the other layers may be formed by conventional methods.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these.

In this example, sample No. 1 having different film composition and formation conditions was used. 1-12 and sample no. 21-23 cutting tools were made. The performance of these cutting tools was then evaluated. Sample no. 1 to 12 correspond to examples. Sample no. 21 to 23 correspond to comparative examples.

≪Manufacturing cutting tools≫
<Preparation of base material>
Sample no. 1-12 and sample no. In order to produce the cutting tools Nos. 21 to 23, a base material A having the formulation shown in Table 1 below was prepared. Specifically, first, raw material powders having the composition shown in Table 1 were uniformly mixed. Next, the mixed raw material powder was pressure-molded into a predetermined shape. After that, by sintering the above pressure-molded raw material powder at a sintering temperature of 1300 to 1500 ° C. for a sintering time of 1 to 2 hours, a cemented carbide substrate (Sumitomo manufactured by Denko Hardmetal Co., Ltd.) was obtained (first step). SEET13T3AGSN-G is the shape of an indexable cutting insert for milling.

<Formation of film>
A coating was formed on the surface of the base material obtained above. Specifically, using the CVD apparatus 70 shown in FIG. 8, the base material 10 was set on the base material setting jig 71, and the film 40 was formed on the base material 10 using the CVD method.

(Formation of base layer)
Sample no. 1 to 12, and sample no. The conditions for forming the underlying layers in 21 and 22 are as shown in Table 2 below. Each layer of TiN, TiCN, and Al ₂ O ₃ in each sample was formed on the substrate after adjusting the injection time of the raw material gas so as to have a thickness shown in Table 6, which will be described later. Sample no. For the substrate No. 23, an AlTiN layer was formed on the substrate by PVD (physical vapor deposition) using a target composed of Al and Ti (target composition: Al:Ti=50:50).

Here, the PVD conditions for forming the AlTiN layer on the substrate of sample No. 23 are as follows.
Arc current: 150V
Bias voltage: -40A
Chamber internal pressure: 2.6×10 ⁻³ Pa
Reactive gas: Nitrogen gas Rotational speed of rotary table on which substrate is placed: 10 rpm

(Formation of coating layer)
Regarding the coating layer, the second step of forming the precursor of the coating layer on the substrate using the chemical vapor deposition method (CVD method) described above, and the energetic particles are deposited on the surface of the precursor of the coating layer. was formed by performing a third step of intermittently irradiating the

(Second step)
First, a precursor of the coating layer (a layer consisting only of the multilayer structure portion) was formed on the substrate by the second step. As shown in Table 3, the conditions for forming the precursor of the coating layer were two conditions T1 and T2. In condition T1, a first gas containing AlCl ₃ gas, TiCl ₄ gas and H ₂ gas, and a second gas containing NH ₃ gas and Ar gas were respectively injected to form a mixed gas in the reaction vessel. In condition T2, in addition to AlCl ₃ gas, TiCl ₄ gas and H ₂ gas, a first gas containing C ₂ H ₄ gas and a second gas containing NH ₃ gas and Ar gas are ejected, respectively, and to form a gas mixture. Under conditions T1 and T2, the composition of the mixed gas, the volume ratio of AlCl ₃ /(AlCl ₃ +TiCl ₄ ) in the mixed gas, and the temperature and pressure conditions in the reaction vessel 72 of the CVD apparatus 70 are as shown in Table 3, respectively. be.

Specifically, in the second step, the first gas was introduced from the introduction port 74 of the CVD apparatus 70 into the introduction pipe 76 , and the second gas was introduced into the introduction pipe 76 from the introduction port 75 . Subsequently, the introduction pipe 76 was rotated to eject the first gas and the second gas from the through holes of the introduction pipe 76 . As a result, a mixed gas in which the first gas and the second gas were homogenized was obtained, and a precursor of the coating layer was formed by jetting the obtained mixed gas onto the underlayer.

As shown in Table 3, for example, under condition T1, the first unit layer having an aluminum atomic ratio of 0.86 and the second unit layer having an aluminum atomic ratio of 0.60 are repeated periods (that is, repeated Forming a precursor of a coating layer laminated with a unit thickness of 4 nm and having an average composition of the first unit layer and the second unit layer (that is, an average composition of the multilayer structure portion) of Al _0.8 Ti _0.2 N can do.

In the second step, sample no. 1 to 7, and sample no. For substrates 21 and 22, condition T1 was used to form the precursor of the coating layer. Sample no. For substrates 8-12, condition T2 was used to form the precursor of the coating layer. Here sample no. FIG. 6 shows a transmission electron microscope image of the multilayer structure in the precursor of the coating layer No. 1. A product name: "JEM-2100F (manufactured by JEOL Ltd.)" was used for the transmission electron microscope.

(Third step)
Furthermore, sample no. For 1 to 12, the surface of the precursor of the coating layer is intermittently irradiated with gallium ions (energy particles) (FIB irradiation) in the third step to generate a matrix-domain structure. A coating layer was obtained. As is clear from the above-described steps, it is considered that the multilayer structure portion of the coating layer precursor and the multilayer structure portion of the coating layer have the same layer structure and composition. As shown in Table 4, three conditions, J1 to J3, were used to generate the matrix-domain structure.

As shown in Table 4, for example, under condition J1, the surface of the precursor of the coating layer was intermittently irradiated with gallium ions at an acceleration voltage of 1 kV, a current density of 40 nA, an irradiation angle of 45°, and a processing depth of 195 nm. At this time, a cycle of an irradiation time of 0.1 second and an interval of 0.02 second was repeated 10 times. Further, JIB-4501 (trade name) manufactured by JEOL Ltd. was used as an apparatus for irradiating gallium ions.

In the third step, as shown in Table 6 to be described later, sample No. A coating layer was obtained by using the condition J1 for the precursor of the coating layer of No. 1. Sample no. The coating layer was obtained by using condition J2 for the coating layer precursor of No. 2. Sample no. Coating layers were obtained by using condition J3 for precursors of coating layers 3-12. Sample no. The third step was not performed on the precursor of the coating layer of 21. Sample no. For the coating layer precursor No. 22, instead of performing the third step, annealing is performed under the following condition C1 to turn the entire multilayer structure of hard particles in the coating layer precursor into a domain-matrix structure. changed to obtain a coating layer. Sample no. The third step was not performed on the PVD AlTiN layer of No. 23.
Annealing condition C1
Heating rate: 10°C/min Annealing temperature: 900°C
Annealing time: 60 minutes Annealing atmosphere: Ar gas Cooling temperature: 40°C/minute Furnace pressure during cooling: 0.9 MPa

Sample no. FIG. 7 shows a transmission electron microscope image of the domain-matrix structure in the hard particles in the coating layer in Example 1. A product name: "JEM-2100F (manufactured by JEOL Ltd.)" was used for the transmission electron microscope.

(surface treatment)
Furthermore, sample no. For 4.5, 7, 9, 10 and 12, surface treatment was performed by shot blasting under the conditions shown in Table 5 to impart compressive stress to the coating.

By forming a film on each substrate as described above, sample No. 1-12 and sample no. 21-23 cutting tools were made. Table 6 shows the composition of the substrate and coating in each sample. In Table 6, sample no. 1 is a cutting tool in which a TiN layer having a thickness of 1 μm is formed as an underlayer immediately above the base material A, and a coating layer (AlTiN) having a thickness of 4.5 μm is formed on the underlayer. showing. Sample no. Cutting tool No. 1 has a coating layer obtained by treating a precursor of the coating layer formed under conditions T1 under conditions J1. "-" in the "Underlayer" column of Table 6 means that a layer with the corresponding composition does not exist. "-" in the "surface treatment" column of Table 6 means that no surface treatment was performed.

≪Evaluation of cutting tools≫
<Measurement of thickness of coating>
The thickness of the coating (that is, the thickness of the coating layer and the underlying layer) is measured using a transmission electron microscope (TEM) (manufactured by JEOL Ltd., trade name: JEM-2100F) in the normal direction of the surface of the base material. It was obtained by measuring arbitrary 10 points in a cross-sectional sample parallel to , and averaging the thickness of the measured 10 points. The observation magnification at this time was 10000 times. Table 6 shows the results.

<Observation of coating layer>
(Peak intensity derived from (220) orientation)
Sample no. 1-12, and sample no. For the cutting tools Nos. 21 to 23, the coating layer was first analyzed from the stacking direction of the coating by the X-ray diffraction method under the following measurement conditions, and it was investigated in which crystal plane the diffraction peak was maximized. Also, from the above measurement results, the ratio of peak intensity derived from (220) orientation was calculated by the method described above. Table 7 shows the results. From the results in Table 7, sample No. It was found that the coating layers on cutting tools 1 to 12 exhibited a diffraction peak maximum in the (220) plane. For example, the lower right photographs in FIGS. 6 and 7 show sample no. 1 shows the result of X-ray diffraction of the coating layer in cutting tool No. 1. FIG. As a result, the surface-coated cutting tools of Samples 1 to 12 are excellent in wear resistance and fracture resistance, and have excellent performance for applications that require cutting of work materials such as carbon steel and interrupted machining such as castings. expected to be able to demonstrate
Measurement method: ω/2θ method Incident angle (ω): 2°
Scan angle (2θ): 30-70°
Scan speed: 1°/min
Scan step width: 0.05°
X-ray source: Cu-Kα ray Optical system attribute: medium resolution parallel beam Tube voltage: 45 kV
Tube current: 200mA
X-ray irradiation range: Using a 2.0 mm range limiting collimator, irradiate a 2 mm diameter range on the rake face (However, X-ray irradiation on the flank face under the same conditions is also permitted)
X-ray detector: Semiconductor detector (trade name: "D/teX Ultra250", manufactured by Rigaku Corporation)

(Volume ratio of hexagonal hard particles)
Next, sample no. 1-12, and sample no. For the cutting tools Nos. 21 to 23, the peak intensity of the cubic hard particles and the peak intensity of the hexagonal hard particles in the coating layer were measured by the X-ray diffraction method under the following measurement conditions. Based on the measured peak intensities, the volume ratio of the hexagonal hard particles was calculated. Table 7 shows the results. In addition, according to this X-ray diffraction measurement, sample No. It was confirmed that the coating layers of cutting tools 1 to 12 contained cubic hard particles.
X-ray diffraction device: Rigaku "MiniFlex600" (trade name)
Characteristic X-ray: Cu-Kα (wavelength 1.54 Å)
Tube voltage: 45kV
Tube current: 40mA
Filter: Multilayer mirror Optical system: Focusing method X-ray diffraction method: θ-2θ method

(Elemental analysis of coating layer)
Furthermore, sample no. 1-12, and sample no. The coating layers of the cutting tools Nos. 21 to 23 were observed using the transmission microscope described above, and elemental analysis was performed using EDX attached to the transmission microscope. Thus, the atomic ratio x of Al in the hard particles forming the coating layer was obtained. Table 7 shows the results.

(Thickness of matrix-domain structure)
The thickness of the matrix-domain structure was measured using a TEM for 10 arbitrarily selected hard particles in the coating layer in a cross-sectional sample parallel to the normal direction of the surface of the substrate. It was obtained by averaging the thickness of the matrix-domain structure portion at each location. Table 7 shows the results. In the column "thickness of matrix-domain structure" in Table 7, "-" means that the matrix-domain structure is not present in the hard particles.

<Cutting test 1>
Next, sample no. 1-12, and sample no. A cutting test (wear resistance test) was performed on the cutting tools No. 21 to 23 under the following cutting conditions. Specifically, sample no. 1-12, and sample no. With respect to cutting tools No. 21 to 23 (shape SEET13T3AGSN-G), the available cutting time until the flank wear amount (Vb) reached 0.30 mm was measured under the following cutting conditions. The results are shown in Table 7. It is shown that the longer the cutting tool can cut, the longer the life of the cutting tool because the initial wear and thermal wear are suppressed.

<Cutting conditions>
Work material: S45C block material (carbon steel)
Cutter: WGC4160R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.)
Peripheral speed: 400m/min
Feeding speed: 0.4mm/sec Depth of cut: 1.0mm
Cutting fluid: none

From Table 7, sample no. The cutting tools of 1 to 12 (Examples) are sample Nos. Compared to the cutting tools of Nos. 21 to 23 (comparative examples), it was found that initial wear and thermal wear were suppressed, and the life of the cutting tools was longer.

<Cutting test 2>
Next, sample no. 3, and sample no. Cutting tools Nos. 21 to 23 were subjected to a cutting test (wear resistance test) under the following cutting conditions to investigate the correlation between the cutting time and the amount of flank wear. Specifically, sample no. 3, and sample no. Cutting tools No. 21 to 23 (shape SEET13T3AGSN-G) were subjected to cutting under the following cutting conditions, and the flank wear amount (Vb) at each cutting time was measured. The cutting test was terminated when Vb exceeded 0.31 mm. The results are shown in Table 8 and FIG. In Table 8, "-" means that the flank wear amount was not measured. In FIG. 9, the vertical axis indicates the amount of flank wear (mm), and the horizontal axis indicates the cutting time (minutes).

<Cutting conditions>
Work material: S45C block material (carbon steel)
Cutter: WGC4160R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.)
Peripheral speed: 400m/min
Feeding speed: 0.4mm/sec Depth of cut: 1.0mm
Cutting fluid: none

From the results of Table 8 and FIG. 9, sample No. having a coating layer containing hard particles consisting only of a multilayer structure portion. With the cutting tool No. 21, the amount of flank wear after 1 minute from the start of cutting was 0.08 mm, indicating large initial wear. Sample No. having a coating layer containing hard particles consisting only of a matrix-domain structure. With No. 22 cutting tools, the amount of flank wear until 7 minutes after the start of cutting was smaller than those of the other three cutting tools, suggesting that they are resistant to initial wear. However, after 9 minutes from the start of cutting, the amount of flank wear increased, indicating that thermal wear was large. Sample No. having a coating layer formed by PVD method. Twenty-three cutting tools were found to have both high initial wear and thermal wear.

On the other hand, sample No. 1 has a coating layer made of hard particles, which consists of a multilayer structure and a matrix-domain structure disposed in contact with the surface of the multilayer structure. With the cutting tool No. 3, the flank wear of sample No. 1 after 1 minute from the start of cutting. It was found to be smaller than 21 and to have excellent resistance to initial wear. In addition, the cutting tool started cutting sample No. 9 after 9 minutes. It was found that the amount of flank wear was smaller than that of the cutting tool No. 22, and the resistance to thermal wear was also excellent.

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.

REFERENCE SIGNS LIST 1 rake face 2 flank face 3 cutting edge ridge 10 substrate 20 coating layer 21 base layer 30 hard particles 31 matrix-domain structure 32 multi-layer structure 40 coating 50 cutting tool 70 CVD device 71 substrate setting jig 72 reaction vessel 73 Temperature control device 74 First gas introduction pipe 75 Second gas introduction pipe 76 Gas introduction pipe 77 Gas exhaust pipe 78 Gas exhaust port d Thickness of matrix-domain structure

Claims (6)

A cutting tool comprising a substrate and a coating layer disposed on the substrate,
The coating layer is made of cubic hard particles,
The cubic hard particles are composed of a multilayer structure and a matrix-domain structure,
the multilayer structure is in contact with the matrix-domain structure on the side opposite the substrate,
The multilayer structure includes a first unit layer and a second unit layer,
the matrix-domain structure includes a matrix region and a domain region surrounded by the matrix region;
The cubic hard particles are made of nitrides or carbides containing aluminum and titanium as constituent elements,
The atomic ratio x of the aluminum is 0.7 or more and 0.96 or less based on the total amount of the aluminum and the titanium in the cubic hard particles,
A cutting tool, wherein when the coating layer is analyzed by an X-ray diffraction method, the peak intensity derived from the (220) orientation exhibits the maximum value compared to peak intensities derived from other orientations. When the coating layer contains hexagonal hard particles, the content of the hexagonal hard particles is based on the total amount of the cubic hard particles and the hexagonal hard particles. 2. The cutting tool according to claim 1, which is more than 0% by volume and not more than 20% by volume. 3. The cutting tool according to claim 1, wherein the matrix-domain structure has a thickness of 0.1 μm or more and 2 μm or less. A method for manufacturing a cutting tool according to any one of claims 1 to 3,
a first step of preparing the substrate;
a second step of forming a precursor of the coating layer on the substrate using chemical vapor deposition;
a third step of intermittently irradiating the surface of the precursor of the coating layer with energetic particles;
A method of manufacturing a cutting tool, comprising: In the second step, each of the first gas containing the aluminum halide gas and the titanium halide gas and the second gas containing the ammonia gas is heated at 650° C. or higher and 850° C. or lower and 0.5 kPa or higher and 1.5 kPa or higher. 5. The method of manufacturing a cutting tool according to claim 4, comprising jetting against the substrate under the following conditions. 6. The method of manufacturing a cutting tool according to claim 4, wherein said energetic particles in said third step are gallium ions.

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