JP2016003368A - Hard coating, cutting tool and method for manufacturing hard coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard coating capable of manufacturing a long life cutting tool, a cutting tool and a method for manufacturing the hard coating.SOLUTION: The hard coating comprises a plurality of crystal grains and an amorphous phase between the crystal grains. The crystal grains have a structure formed by alternately laminating a TiAlN layer having a fcc structure and a TiAlN layer having a fcc structure. The Al composition ratio x of the TiAlN layer satisfies the relationship of 0≤x<1, the Al composition ratio y of the TiAlN layer satisfies the relationship of 0<y≤1, and the Al composition ratio x and the Al composition ratio y satisfy the relationship of (y-x)≥0.2. The amorphous phase is a hard coating including carbide, nitride or carbon nitride of at least one of Ti and Al.

Description

  The present invention relates to a hard coating, a cutting tool, and a method for manufacturing a hard coating.

  Conventionally, cutting of steel, castings, and the like has been performed using a cutting tool made of a cemented carbide. In such cutting tools, the cutting edge is exposed to a severe environment such as high temperature and high pressure at the time of cutting, so the problem that the cutting edge is worn or chipped often occurs. Has a challenge.

  Therefore, for the purpose of improving the cutting performance of the cutting tool, development of a coating that covers the surface of a base material such as cemented carbide is underway. In particular, a film made of a compound of titanium (Ti), aluminum (Al), and nitrogen (N) (hereinafter also referred to as “TiAlN”) can have high hardness and increase the content ratio of Al. Therefore, oxidation resistance can be improved. Since the performance of the cutting tool can be improved by coating the cutting tool with such a coating, further development of the coating is expected.

For example, Patent Document 1 discloses a hard film having at least one Ti _1-x Al _x N hard film formed by CVD (Chemical Vapor Deposition) without performing plasma excitation. Ti _1-x Al _x N hard coating is a single phase of cubic NaCl structure with a stoichiometric coefficient of x> 0.75 to x = 0.93 and a lattice constant a _{fcc of} 0.412 nm to 0.405 nm. Present as a layer, or Ti _1-x Al _x N hard coating, the major phase of which is a stoichiometric coefficient of x> 0.75 to x = 0.93 and a lattice of 0.412 nm to 0.405 nm It consists of Ti _1-x Al _x N having a cubic NaCl structure with a constant a _fcc . As another phase, Ti _1-x Al _x N is a multi-phase layer containing TiN _x having a wurtzite structure and / or NaCl structure, and the Ti _1-x Al _x N hard coating contains chlorine. The rate is in the range of 0.05 to 0.9 atomic%. Non-patent document 1 also discloses a similar technique.

Further, for example, Patent Document 2 discloses at least one hard material composite layer. The hard material composite layer contains cubic TiAlCN and hexagonal AlN as the main phase, and the cubic TiAlCN has a microcrystalline fcc-Ti _1-x Al _x C _y N _z having a crystallite size of ≧ 0.1 μm. (Where x> 0.75, y = 0 to 0.25, and z = 0.75 to 1). Further, the hard material composite layer further contains amorphous carbon in a mass ratio of 0.01% to 20% in the grain boundary region. Non-Patent Document 2 also discloses a similar technique.

Special table 2008-545063 gazette Special table 2013-510946 gazette

I. Endler et al. "Novel aluminum-rich Ti1-xAlxN coatings by LPCVD", Surface & Coatings Technology 203 (2008) 530-533. I. Endler et al. “Aluminum-rich TiAlCN coatings by Low Pressure CVD”, Surface & Coatings Technology 205 (2010) 1307-1312.

However, the Ti _1-x Al _x N hard coatings described in Patent Document 1 and Non-Patent Document 1 are not suitable as cubic crystals because _{x in} the Ti _1-x Al _x N hard coating is larger than 0.7. There is a problem that when it is stable and heated to high temperature by rubbing heat generated at the time of cutting, it transforms into a wurtzite structure and the hardness decreases. When _{x in the} Ti _1-x Al _x N hard coating is greater than 0.7, large distortion occurs in the crystal structure, so that the internal energy of the entire coating is reduced by phase transition to a more stable wurtzite type. This is for stabilization.

Further, in the Ti _1-x Al _x N hard coating described in Patent Document 1 and Non-Patent Document 1, hexagonal AlN having a low hardness precipitates due to a heat drop in the cooling process after being heated to a high temperature. The hexagonal AlN thus precipitated becomes a defect in the Ti _1-x Al _x N hard coating, hinders the improvement of the wear resistance of the coating, and reduces the chipping resistance and fracture resistance of the cutting tool. Cutting performance cannot be obtained.

  In order to solve such a problem, in Patent Document 2 and Non-Patent Document 2, by adding amorphous carbon and depositing amorphous carbon at the grain boundary, the wurtzite type is formed from cubic TiAlCN. The phase transition to is suppressed.

  However, since amorphous carbon is oxidized during cutting, a phase transition of cubic TiAlCN to a wurtzite type occurs suddenly. For this reason, the hardness of the coating film of the cutting tool is suddenly reduced, and a sudden defect occurs.

  Therefore, a long-life cutting tool has not yet been realized, and its development is desired.

The hard coating according to an aspect of the present invention includes a plurality of crystal grains and an amorphous phase between the crystal grains, and each of the crystal grains includes a Ti _1-x Al _x N layer having an fcc structure. And Ti _1-y Al _y N layers having the fcc structure are alternately stacked, and the Al composition ratio x of the Ti _1-x Al _x N layer is such that 0 ≦ x <1 The Al composition ratio y of the Ti _1-y Al _y N layer satisfies the relationship 0 <y ≦ 1, and the Al composition ratio x and the Al composition ratio y are (y−x) ≧ 0.2 The amorphous phase contains at least one carbide, nitride or carbonitride of Ti and Al.

  The cutting tool which concerns on the other one aspect | mode of this invention is equipped with the base material and said hard film provided on the said base material.

  The method for producing a hard coating according to still another aspect of the present invention includes a step of jetting a titanium halide gas, an aluminum halide gas, a tetrakisneopentyl titanium gas, and an ammonia gas to the surface of the substrate. And a step of cooling the substrate.

  According to the above, it is possible to provide a hard coating, a cutting tool, and a method for manufacturing a hard coating capable of producing a long-life cutting tool.

It is a typical sectional view of the cutting tool of an embodiment. It is a typical expanded sectional view of a hard film. It is a typical expanded sectional view of one crystal grain. It is typical sectional drawing of an example of the CVD apparatus used for preparation of the hard film of embodiment. It is typical sectional drawing of the gas introduction pipe | tube shown in FIG. It is a typical top view which shows the ejection direction of 1st gas-4th gas. It is a typical enlarged plan view illustrating the calculation method of the grain size of a crystal grain.

[Description of Embodiment of the Present Invention]
First, embodiments of the present invention will be listed and described.

(1) A hard film according to an aspect of the present invention includes a plurality of crystal grains and an amorphous phase between the crystal grains, and each of the crystal grains has a Ti _1-x Al having an fcc structure. _x N layers and Ti _1-y Al _y N layers having an fcc structure are alternately stacked, and the Al composition ratio x of the Ti _1-x Al _x N layers is 0 ≦ x < 1, the Al composition ratio y of the Ti _1-y Al _y N layer satisfies the relationship of 0 <y ≦ 1, and the Al composition ratio x and the Al composition ratio y are (y−x) ≧ The relationship of 0.2 is satisfied, and the amorphous phase includes at least one of Ti and Al carbide, nitride, or carbonitride. Thereby, since the wear resistance of the hard coating is improved, the chipping resistance and chipping resistance of the cutting tool provided with the hard coating is improved, so that a long-life cutting tool can be realized.

(2) In the hard coating film according to one aspect of the present invention, the sum of the thickness per layer of the adjacent Ti _1-x Al _x N layers and the thickness per layer of the Ti _1-y Al _y N layers The thickness is preferably 1 nm or more and 50 nm or less. When the total thickness of the adjacent Ti _1-x Al _x N layers and the thickness of the Ti _1-y Al _y N layer is 1 nm or more, Manufacture is easy. When the total thickness of the adjacent Ti _1-x Al _x N layers and the thickness of the Ti _1-y Al _y N layer adjacent to each other is 50 nm or less , Due to the relaxation of the strain at the interface between the Ti _1-x Al _x N layer and the Ti _1-y Al _y N layer and the phase transition of the Ti _1-y Al _y N layer having a high Al composition ratio A decrease in wear resistance of the coating can be suppressed. Further, in this case, it is possible to suppress the appearance of TiAlN crystal grains having a low-hardness hcp structure rather than crystal grains having a high-hardness fcc structure.

  (3) In the hard film which concerns on 1 aspect of this invention, it is preferable that the particle size of the said crystal grain is 0.01 micrometer or more and 1 micrometer or less. In this case, the crystal grains can have high hardness and the amorphous phase can have high lubricity. Thereby, since the wear resistance of the hard coating is improved, the chipping resistance and chipping resistance of the cutting tool provided with the hard coating are improved, and the life of the cutting tool can be further extended.

  (4) In the hard film which concerns on 1 aspect of this invention, it is preferable that the thickness of the said amorphous phase is 100 nm or less. In this case, the hard coating can be prevented from becoming hard and brittle, and suitable lubricity can be imparted to the hard coating, so that the wear resistance of the hard coating can be improved. Thereby, the chipping resistance and chipping resistance of the cutting tool provided with the hard coating can be further improved.

  (5) In the hard film which concerns on 1 aspect of this invention, it is preferable that the indentation hardness by the nano indentation method of the said hard film is 30 GPa or more. In this case, excellent performance can be exhibited when cutting difficult-to-cut materials such as heat-resistant alloys using a cutting tool provided with a hard coating.

  (6) The cutting tool which concerns on 1 aspect of this invention is equipped with the base material and the hard film in any one of said provided provided on the said base material. Thereby, since the wear resistance of the hard coating is improved, the chipping resistance and chipping resistance of the cutting tool provided with the hard coating is improved, so that a long-life cutting tool can be realized.

(7) The method for producing a hard coating according to one embodiment of the present invention includes a step of jetting a titanium halide gas, an aluminum halide gas, a tetrakisneopentyl titanium gas, and an ammonia gas to the surface of the substrate. And a step of cooling the substrate. Thereby, an amorphous phase made of Ti carbide, Ti nitride or Ti carbonitride can be formed, and the amorphous phase can further prevent oxidation due to heat of rubbing during cutting. Therefore, since the effect of suppressing the sudden phase transition of crystal grains to the wurtzite type can be enhanced, an amorphous phase is formed using Ti [CH ₂ C (CH ₃ ) ₃ ] ₄ gas In addition, the cutting tool can have a longer life.

(8) In the method for producing a hard coating according to an aspect of the present invention, the step of cooling the base material includes the step of cooling the base material to 400 ° C. or less at a rate of 7 ° C./min or more, In the method for producing a film, after the step of cooling to 400 ° C. or lower, the substrate is heated at a temperature of 600 ° C. or higher and 800 ° C. or lower in a flow of ammonia gas or a mixed gas of ammonia gas and hydrogen gas. It is preferable to further include a step of heating for not less than 300 minutes and not more than 300 minutes. When the substrate is cooled to 400 ° C. or less at a rate of 7 ° C./min or more, the crystal grains in which Ti _1-x Al _x N layers and Ti _1-y Al _y N layers are alternately laminated are more stable. Can be produced. In this case, since unreacted substances and defects contained in the amorphous phase between crystal grains can be removed, the lubricity of the hard coating is improved, and the chipping resistance and chipping resistance of the cutting tool are improved. Can be further improved.

[Details of the embodiment of the present invention]
Hereinafter, embodiments will be described. In the drawings used to describe the embodiments, the same reference numerals represent the same or corresponding parts. In this specification, the fcc structure means a crystal structure having a face-centered cubic structure. The hcp structure means a crystal structure of a hexagonal close packed structure.

<Coating>
In FIG. 1, typical sectional drawing of the cutting tool of embodiment is shown. As shown in FIG. 1, the cutting tool of the embodiment includes a base material 11 and a coating 50 provided on the base material 11. The coating 50 includes a base film 20 and a hard film 30 provided on the base film 20.

  In FIG. 2, the typical expanded sectional view of the hard film 30 is shown. As shown in FIG. 2, the hard coating 30 includes a plurality of crystal grains 21 and an amorphous phase 22 between the plurality of crystal grains 21.

<Crystal grains>
FIG. 3 shows a schematic enlarged cross-sectional view of one crystal grain 21. As shown in FIG. 3, the crystal grain 21 has a structure in which Ti _1-x Al _x N layers 21a having an fcc structure and Ti _1-y Al _y N layers 21b having an fcc structure are alternately stacked. doing. Here, the Al composition ratio x of the Ti _1-x Al _x N layer 21a satisfies the relationship of 0 ≦ x <1. Further, Ti _1-y Al _y N layer 21b of the Al composition ratio y satisfies the relationship of 0 <y ≦ 1. Further, the Al composition ratio x of the Ti _1-x Al _x N layer 21a and the Al composition ratio y of the Ti _1-y Al _y N layer 21b satisfy the relationship of (y−x) ≧ 0.2.

Incidentally, Ti _1-x Al _x N-layer 21a Al composition ratio x as long as satisfying the above relationship, Al composition ratios of Ti _1-x Al _x N layer 21a of the other of the at least one layer constituting the crystal grains 21 It may be different from x or may be the same. Further, Ti _1-y Al y Al composition ratio of the N layer 21b y also, as long as satisfying the above relationship, Al composition ratios of Ti _1-y Al _y N layer 21b of another of the at least one layer constituting the crystal grains 21 It may be different from y or the same.

Further, for the Ti _1-x Al x N layer 21a and Ti _1-y Al y N layer 21b of the crystal grains 21 has a fcc structure, respectively, by observation using a transmission electron microscope (TEM) Can be confirmed.

The composition (type of constituent elements and constituent ratio of constituent elements) of the Ti _1-x Al _x N layer 21a and the Ti _1-y Al _y N layer 21b of the crystal grains 21 is energy dispersive X-ray analysis (EDX). Or three-dimensional atom probe field ion microscope analysis.

<Amorphous phase>
The amorphous phase 22 contains at least one of Ti, Al carbide, nitride, or carbonitride.

  That is, the amorphous phase 22 includes Ti carbide (TiC), Ti nitride (TiN), Ti carbonitride (TiCN), Al carbide (AlC), Al nitride (AlN), Al At least one metal compound selected from the group consisting of carbonitride (AlCN), Ti and Al carbide (TiAlC), Ti and Al nitride (TiAlN) and Ti and Al carbonitride (TiAlCN) It is out.

  The presence of the amorphous phase 22 can be confirmed by observation using a TEM.

<Base material>
As the substrate 11, for example, tungsten carbide (WC) based cemented carbide, cermet, high speed steel, ceramics, cubic boron nitride sintered body or diamond sintered body can be used. It is not limited.

<Under film>
As the base film 20, a film capable of increasing the bonding strength between the base material 11 and the hard film 30 can be used, for example, a titanium nitride (TiN) film, a titanium carbonitride (TiCN) film, or a TiN film. A laminated film of TiCN film and TiCN film can be used.

<Cutting tools>
As the cutting tool of the embodiment, for example, a drill, an end mill, a cutting edge replacement type cutting tip for a drill, a cutting edge replacement type cutting tip for an end mill, a cutting edge replacement type cutting tip for milling, a cutting edge replacement type cutting tip for turning, a metal saw, A gear cutting tool, a reamer, a tap, etc. can be mentioned.

<CVD equipment>
FIG. 4 shows a schematic cross-sectional view of an example of a CVD apparatus used for producing the hard coating 30 of the embodiment. As shown in FIG. 4, the CVD apparatus 10 includes a plurality of base material setting jigs 12 for holding the base material 11 and a reaction vessel 13 made of heat-resistant alloy steel that covers the base material setting jig 12. ing. A temperature control device 14 for controlling the temperature in the reaction vessel 13 is provided around the reaction vessel 13. The reaction vessel 13 is provided with a gas introduction pipe 16 having a gas introduction port 15. The gas introduction pipe 16 is provided so as to extend in the vertical direction in the space inside the reaction vessel 13 in which the base material setting jig 12 is disposed. In addition, a plurality of through holes 17 are formed in the gas introduction pipe 16 for jetting the gas flowing inside the gas introduction pipe 16 to the surface of the base material 11 held by the base material setting jig 12. Further, the reaction vessel 13 is provided with a gas exhaust pipe 18 for exhausting the gas inside the reaction vessel 13 to the outside, and the gas inside the reaction vessel 13 passes through the gas exhaust pipe 18. Then, the gas is discharged from the gas outlet 19 to the outside of the reaction vessel 13.

  FIG. 5 is a schematic cross-sectional view of the gas introduction pipe 16 shown in FIG. FIG. 5 shows a cross section perpendicular to the axial direction of the gas introduction pipe 16 and where the through hole 17 is located. As shown in FIG. 5, four pipe lines 16 a to 16 d are provided along the axial direction of the gas introduction pipe 16, and the through-hole 17 is configured to constitute a part of the outer periphery of each of the pipe lines 16 a to 16 d. Is provided.

  In the CVD apparatus 10 shown in FIG. 4, a plurality of different types of gases introduced from the gas introduction port 15 side of the gas introduction pipe 16 pass through different pipe lines of the four pipe lines 16 a to 16 d and vertically upward. And is ejected from the through holes 17 onto the surface of the base material 11 held by the base material setting jig 12 inside the reaction vessel 13.

  FIG. 6 is a schematic plan view showing ejection directions of a plurality of different types of gases (first gas to fourth gas) introduced from the gas introduction port 15 side of the gas introduction pipe 16. The first gas is ejected from the through hole 17 in the direction of the arrow P1, the second gas is ejected from the through hole 17 in the direction of the arrow P2, the third gas is ejected from the through hole 17 in the direction of the arrow P3, and the fourth gas The gas is ejected from the through hole 17 in the direction of the arrow P4. In the present embodiment, the first gas and the second gas, the second gas and the fourth gas, the fourth gas and the third gas, and the third gas and the first gas have a phase of 90 ° with respect to the axis W, respectively. In the state where it is, it is ejected from the through hole 17. Further, since the gas introduction pipe 16 ejects the gas from the through hole 17 while rotating around the axis of the gas introduction pipe 16 as a central axis, all of the plurality of different types of gases reach the surface of each substrate 11. become.

<Manufacturing method>
Hereinafter, an example of the manufacturing method of the hard film 30 of embodiment is demonstrated using the CVD apparatus shown in FIGS. An example of the manufacturing method of the hard film 30 of the embodiment includes an ejection process and a cooling process, and the hard film 30 is manufactured by a CVD (Chemical Vapor Deposition) method.

<Ejection process>
First, prior to carrying out this process, the base material setting jig 12 inside the reaction vessel 13 of the CVD apparatus 10 has the surface of the base material 11 forming the hard coating 30 formed inside the reaction vessel 13. The base material 11 is arrange | positioned so that it may expose.

  The inside of the reaction vessel 13 is maintained in a high temperature and reduced pressure environment. Here, the temperature inside the reaction vessel 13 is preferably maintained at 700 ° C. or higher and 900 ° C. or lower. Moreover, it is preferable that the pressure inside the reaction vessel 13 is maintained at 0.1 kPa or more and 13 kPa or less.

Next, in the gas introduction pipe 16, a titanium halide gas, an aluminum halide gas, a titanium alkyl compound (tetrakisneopentyl titanium (Ti [CH ₂ C (CH ₃ ) ₃ ] ₄ )) gas, Ammonia (NH ₃ ) gas is introduced and ejected from the plurality of through holes 17 provided in the gas introduction pipe 16 onto the surface of the substrate 11.

Here, as the halide gas of titanium, for example, titanium tetrachloride (TiCl ₄ ) gas or the like can be used. Further, as the aluminum halide gas, for example, aluminum trichloride (AlCl ₃ ) gas or the like can be used.

For example, the first gas is TiCl ₄ gas, the second gas is AlCl ₃ gas, the third gas is Ti [CH ₂ C (CH ₃ ) ₃ ] ₄ gas, and the fourth gas is NH ₃ gas. In this embodiment, the first gas is introduced into the pipeline 16a, the second gas is introduced into the pipeline 16b, the third gas is introduced into the pipeline 16c, and the fourth gas is introduced into the pipeline 16d. Introduce in. Then, when the gas introduction pipe 16 is rotated by a drive unit (not shown), the first gas to the fourth gas are simultaneously ejected into the reaction vessel 13, and the first gas to the fourth gas are in turn based on the order. The surface of the material 11 is reached, and a film is formed on the surface of the base material 11 by the CVD method. Incidentally, with each gas in the first gas through fourth gas, for example hydrogen (H ₂₎ may be introduced carrier gas, such as gas and argon (Ar) gas.

  The ejection speeds of the first gas to the fourth gas are the introduction speed (L / min) of each gas introduced into the pipe lines 16a to 16d, the number and size of the through holes 17 leading to the pipe lines 16a to 16d, etc. It can be easily controlled by controlling

<Cooling process>
Next, the base material 11 is cooled. Here, the substrate 11 is preferably cooled to 400 ° C. or lower at a rate of 7 ° C./min or higher. In this case, the crystal grains 21 having a structure in which the Ti _1-x Al _x N layers 21a having the fcc structure and the Ti _1-y Al _y N layers 22a having the fcc structure are alternately laminated are stably produced. can do.

Further, after the base material 11 is cooled to 400 ° C. or less at a rate of 7 ° C./min or more, the base material 11 is kept at 600 ° C. in an NH ₃ gas stream or a mixed gas stream of NH ₃ gas and H ₂ gas. It is preferable to heat at a temperature of 800 ° C. or lower for 30 minutes to 300 minutes. In this case, since unreacted substances and defects contained in the amorphous phase 22 can be removed, the lubricity of the hard coating 30 is improved, and the chipping resistance and chipping resistance of the cutting tool of the embodiment are further improved. Can be improved.

<Effect>
The hard coating 30 of the embodiment includes a plurality of crystal grains 21 and an amorphous phase 22 between the plurality of crystal grains 21, and each of the crystal grains 21 has Ti _1-x Al _x N having an fcc structure. The layer 21a and the Ti _1-y Al _y N layer 21b having the fcc structure are alternately stacked, and the Al composition ratio x and Ti _{1-y of the} Ti _1-x Al _x N layer 21a The Al composition ratio y of the Al _y N layer 21b satisfies the relationship of 0 ≦ x <1, 0 <y ≦ 1, and (y−x) ≧ 0.2. And at least one of carbide, nitride or carbonitride of Al.

In the hard coating 30 having such a configuration, at the interface between the Ti _1-x Al _x N layer 21a and the Ti _1-y Al _y N layer 21b made of TiAlN crystals having the same crystal structure (fcc structure) and different compositions. Mismatched strain in the lattice spacing due to the difference in composition is accumulated. By forming the storage of interface resulting nano-level mismatch with Ti _1-x Al _x N layer 21a and the Ti _1-y Al _y N layer 21b, the hardness of the hard coating 30 is remarkably improved, as a result Abrasion resistance is improved.

Further, when the Al composition ratio x of the Ti _1-x Al _x N layer 21a and the Al composition ratio y of the Ti _1-y Al _y N layer 21b satisfy the relationship of (y−x) ≧ 0.2, Since the strain formed at the interface between the Ti _1-x Al _x N layer 21a and the Ti _1-y Al _y N layer 21b can be increased, the hardness of the hard coating 30 can be further increased. Thereby, the wear resistance of the hard coating 30 is further improved.

Further, an amorphous phase 22 containing at least one carbide, nitride, or carbonitride of Ti and Al is provided between the crystal grains 21. The amorphous phase 22 can improve the wear resistance of the hard coating 30 by improving the lubricity of the hard coating 30. In addition, since the amorphous phase 22 is less likely to be oxidized than conventional amorphous carbon, a sudden phase into the wurtzite type of the Ti _1-y Al _y N layer 21b in which the Al composition ratio of the crystal grains 21 is large. It is possible to suppress the occurrence of sudden breakage of the cutting tool due to the transition.

For the above reason, in the present embodiment, the crystal grains 21 and the amorphous phase 22 in which the Ti _1-x Al _x N layers 21a and the Ti _1-y Al _y N layers 21b are alternately stacked The wear resistance of the hard coating 30 having high hardness and high lubricity can be improved. Thereby, since the wear resistance of the hard coating 30 is improved, the chipping resistance and chipping resistance of the cutting tool provided with the hard coating 30 are improved, and as a result, a long-life cutting tool can be realized. In addition, the amorphous phase 22 which is less likely to be oxidized than the conventional amorphous carbon causes a sudden phase transition to the wurtzite type of the Ti _1-y Al _y N layer 21b having a large Al composition ratio of the crystal grains 21. Since this can suppress the occurrence of sudden defects, this action also contributes to extending the life of the cutting tool.

In addition, when the hard coating 30 is formed, Ti [CH ₂ C (CH ₃ ) ₃ ] ₄ gas is introduced together with titanium halide gas, aluminum halide gas, and NH ₃ gas, whereby TiC, TiN, TiCN. The amorphous phase 22 containing at least one metal compound selected from the group consisting of TiAlC, TiAlN, and TiAlCN can be formed. These Ti carbides, since Ti nitride and Ti carbonitride capable of further preventing oxidation by Kosuka heat during cutting, wurtzite large Ti _1-y Al _y N layer 21b of the Al composition ratio The effect of suppressing sudden phase transition to can be enhanced. Therefore, when the amorphous phase 22 is formed using Ti [CH ₂ C (CH ₃ ) ₃ ] ₄ gas, the cutting tool can have a longer life.

<Other preferred forms>
≪Total thickness of Ti _1-x Al _x N layer and Ti _1-y Al _y N layer≫
In the crystal grains 21, the total thickness t3 of the Ti _1-x Al x N and the thickness of each layer 21a t1 and Ti _1-y Al y N and the thickness of each layer 21b t2 Adjacent It is preferably 1 nm or more and 50 nm or less. If the total thickness t3 of the Ti _1-x Al x N and the thickness of each layer 21a t1 and Ti _1-y Al y N and the thickness of each layer 21b t2 adjacent is 1nm or more Makes it easy to produce the hard coating 30. Further, the total thickness t3 of the Ti _1-x Al x N and the thickness of each layer 21a t1 and Ti _1-y Al y N and the thickness of each layer 21b t2 adjacent is at 50nm or less In this case, the strain at the interface between the Ti _1-x Al _x N layer 21a and the Ti _1-y Al _y N layer 21b is relaxed, and the phase transition of the Ti _1-y Al _y N layer 21b having a high Al composition ratio is caused. The deterioration of the wear resistance of the resulting coating 30 can be suppressed. Further, in this case, it is possible to suppress the appearance of TiAlN crystal grains having a low-hardness hcp structure rather than crystal grains having a high-hardness fcc structure.

In addition, in the crystal grain 21, the total thickness of at least one pair of the adjacent Ti _1-x Al _x N layer 21a and the Ti _1-y Al _y N layer 21b may be 1 nm or more and 50 nm or less. Ti _1-x the Al _x N layer 21a and the Ti _1-y Al y N layer hard coating 30 having excellent wear resistance that the total thickness of all of the set is 1nm or more 50nm or less and 21b stably It is preferable from the viewpoint of manufacturing.

Further, the thickness t1 per layer of the Ti _1-x Al _x N layer 21a and the thickness t2 per layer of the Ti _1-y Al _y N layer 21b are hard on the surface of the substrate 11, respectively. The coating 30 is formed, and the cross section of the hard coating 30 formed on the surface of the substrate 11 is STEM high angle scattering dark field method (HAADF-STEM: High-Angle Angular Dark-field Scanning Transmission Electron Microscopy). It can be measured by observing.

≪Crystal grain size≫
The grain size of the crystal grains 21 is preferably 0.01 μm or more and 1 μm or less. When the grain size of the crystal grains 21 is 0.01 μm or more and 1 μm or less, the crystal grains 21 can have high hardness and the amorphous phase 22 can have high lubricity. Thereby, since the wear resistance of the hard coating 30 is improved, the chipping resistance and chipping resistance of the cutting tool according to the embodiment provided with the hard coating 30 are improved, and the life of the cutting tool can be further extended. .

  The grain size of the crystal grains 21 is calculated by the following method (hereinafter, this method is referred to as “line segment method”). First, for example, as shown in a schematic enlarged plan view of FIG. 7, the structure obtained by observing the hard coating 30 using an optical microscope is printed on a paper surface, an arbitrary line 40 is drawn, and the entire line 40 is drawn. Examine the length (L). Next, the lengths (LC1, LC2, LC3) of the crystal grains 21 crossed by the line 40 are examined. Finally, the lengths (L, LC1, LC2 and LC3) examined as described above are converted into actual lengths, and the total lengths after conversion of the crystal grains 21 crossed by the line 40 (LC1 + LC2 + LC3) Is divided by the number (three) of the crystal grains 21 crossed by the line 40, the grain size of the crystal grains 21 can be calculated.

≪Amorphous phase thickness≫
The thickness of the amorphous phase 22 is preferably 100 nm or less. When the thickness of the amorphous phase 22 is 100 nm or less, the hard coating 30 can be prevented from becoming hard and brittle, and suitable lubricity can be imparted to the hard coating 30. Abrasion resistance can be improved. Thereby, the chipping resistance and chipping resistance of the cutting tool of the embodiment provided with the hard coating 30 can be further improved.

  The thickness of the amorphous phase 22 is also calculated by the line segment method. For example, first, as shown in the schematic enlarged plan view of FIG. 7, the structure obtained by observing the hard coating 30 using an optical microscope is printed on a paper surface, an arbitrary line 40 is drawn, and the entire line 40 is drawn. Examine the length (L). Next, the lengths (LA1, LA2) of the amorphous phase 22 crossed by the line 40 are examined. Finally, the lengths (L, LA1 and LA2) examined as described above are converted into actual lengths, respectively, and divided by the number (2) of the amorphous phases 22 crossed by the line 40 to obtain an amorphous material. The thickness of the mass phase 22 can be calculated.

≪Indentation hardness≫
The indentation hardness of the hard coating 30 by the nanoindentation method is preferably 30 GPa or more. When the indentation hardness of the hard coating 30 by the nanoindentation method is 30 GPa or more, excellent performance when cutting difficult-to-cut materials such as heat-resistant alloys using a cutting tool provided with the hard coating 30 Can be demonstrated.

  The indentation hardness of the hard coating 30 by the nanoindentation method is measured in the thickness direction of the hard coating 30 using an ultra-fine indentation hardness tester (for example, manufactured by Elionix Co., Ltd.) that can use the nanoindentation method. It is calculated by dividing by the contact area between the indenter and the hard coating 30 when the indenter is pushed in at a predetermined load (for example, 25 mN) perpendicularly to.

<Other configurations>
The hard coating 30 may or may not contain at least one impurity selected from the group consisting of chlorine (Cl), oxygen (O), and carbon (C).

The film 50 of the cutting tool of the embodiment may include a film other than the base film 20 and the hard film 30. As the film other than the base film 20 and the hard coating 30, for example, at least one selected from the group consisting of Ti, Zr and Hf and from the group consisting of N, O, C, B, CN, BN, CO and NO A film composed of at least one selected compound may be included. Further, the coating 50 may include at least one of an α-Al ₂ O ₃ film and a κ-Al ₂ O ₃ film as an oxidation resistant film. For example, the film 50 may include a film other than the hard film 30 as the outermost film on the outermost surface. Further, the coating 50 may not include the base film 20.

  The total thickness T1 of the hard coating 30 is preferably 1 μm or more and 20 μm or less. When the total thickness T1 of the hard coating 30 is 1 μm or more, the characteristics of the hard coating 30 tend to be remarkably improved. When the total thickness T1 of the hard coating 30 is 20 μm or less, there is a tendency that a large change is seen in the improvement of the characteristics of the hard coating 30. From the viewpoint of improving the characteristics of the hard coating 30, the total thickness T1 of the hard coating 30 is more preferably 2 μm or more and 15 μm or less, and further preferably 3 μm or more and 10 μm or less.

  The total thickness T2 of the coating 50 is preferably 3 μm or more and 30 μm or less. When the total thickness T2 of the film 50 is 3 μm or more, the characteristics of the film 50 tend to be suitably exhibited. When the total thickness T2 of the coating 50 is 30 μm or less, peeling of the coating 50 during cutting tends to be suppressed. The total thickness T2 of the coating 50 is more preferably 5 μm or more and 20 μm or less, and preferably 7 μm or more and 15 μm or less from the viewpoint of suitably exhibiting the characteristics of the coating 50 and suppressing the peeling of the coating 50 during cutting. More preferably.

  The absolute value of the compressive residual stress of the coating 50 is preferably 0.2 GPa or less in the residual stress measurement by the X-ray diffraction method. When the absolute value of the compressive residual stress of the coating 50 is 0.2 GPa or less, since the strain of an appropriate size is maintained in the coating 50, the coating 50 tends to have high hardness. From the viewpoint of increasing the hardness of the coating 50, the absolute value of the compressive residual stress of the coating 50 is more preferably 0.2 GPa or more and 2 GPa or less, and further preferably 0.2 GPa or more and 2 GPa or less. In addition, the compressive residual stress of the film 50 can be expressed by, for example, an additional physical process (peening process).

  Here, the “compressive residual stress” is a kind of internal stress (intrinsic strain) existing in the coating 50 and is represented by a numerical value “−” (minus) (unit: “GPa” is used in the embodiment). Stress. For this reason, the concept that the compressive residual stress is large indicates that the absolute value of the numerical value is large, and the concept that the compressive residual stress is small indicates that the absolute value of the numerical value is small. That is, the absolute value of the compressive residual stress being 2 GPa or less means that the preferable compressive residual stress relating to the coating 50 is −2 GPa or more and less than 0 GPa.

The compressive residual stress of the film 50 can be measured by the sin ² ψ method using an X-ray stress measuring device. The sin ² ψ method using X-rays is widely used as a method for measuring the residual stress of a polycrystalline material. For example, “X-ray stress measurement method” (Japan Society of Materials, 1981 stock) The method described in detail on pages 54-67 of the company Yokendo) can be used.

The thickness of each film of the coating in each of the following samples was measured by observing the cross section of the coating by the STEM high angle scattering dark field method using STEM. In addition, the composition of each film of the following samples was determined by three-dimensional atom probe field ion microscope analysis. In addition, the crystal structure of the crystal grains and the presence of the amorphous phase in each film of the coatings in the following samples were confirmed by observation using a TEM. In each of the following samples, the crystal grain size and the amorphous phase thickness of each film of the coating were calculated by the line segment method. Moreover, the indentation hardness (Hv) by the nanoindentation method of the film in each of the following samples was calculated using an ultra-fine indentation hardness tester manufactured by Elionix Corporation. Furthermore, the absolute value of the compressive residual stress of the coating of each sample below was calculated by the sin ² ψ method using an X-ray stress measurement apparatus.

<Production of cutting tool>
≪Preparation of base material≫
First, the base material K and the base material L shown in the following Table 1 were prepared as the base materials to be coated. Specifically, first, raw material powders having the composition (% by mass) shown in Table 1 were uniformly mixed. “Remaining” in Table 1 indicates that WC occupies the remainder of the composition (mass%). Next, after pressing this mixed powder into a predetermined shape, sintering was performed at 1300 to 1500 ° C. for 1 to 2 hours to obtain a base material K and a base material L made of cemented carbide.

<< Preparation of coating: Sample No. 1-23 >>
A film is formed on the surface of the base material K or the base material L by forming the base film, the hard film and the outermost film shown in the column of the structure of the film in Table 2 on the surface of the base material K or the base material L. A cutting tool (Sample Nos. 1 to 23) in which was formed was prepared. Sample No. Cutting tools of 1 to 8 and 10 to 18 are examples. Cutting tools 9 and 19-23 are comparative examples.

  In Table 2, the base film is a film in direct contact with the surface of the substrate, the hard coating is a film formed on the base film, and the outermost film is a film formed on the hard coating and exposed to the outside. It is a film. Moreover, the description of the compound of Table 2 is a compound which comprises the base film, hard film, and outermost film of Table 2, and the right parenthesis of the compound means the thickness of the film. Further, when two compounds (for example, “TiN (0.5) -TiCN (2.5)”) are described in one column of Table 2, the left side (“TiN (0.5)” ") Means that the compound located on the side closer to the surface of the substrate, and the compound on the right side (" TiCN (2.5) ") is located on the side far from the surface of the substrate. The numerical value in parentheses means the thickness of each film. In addition, the column indicated by “-” in Table 2 means that no film is present.

  For example, sample no. In the cutting tool 1, a TiN film having a thickness of 0.5 μm and a TiCN film having a thickness of 2.5 μm are laminated in this order on the surface of the substrate K, and a base film is formed thereon, which will be described later. A hard film having a thickness of 5.0 μm formed under the formation condition a is formed, and has a film on which the outermost film is not formed on the hard film, and the thickness of the film is 8.0 μm. It means a certain cutting tool.

The base film and outermost film shown in Table 2 are films formed by a conventionally known CVD method, and the formation conditions are as shown in Table 3. For example, the row of “TiN (base film)” in Table 3 shows the conditions for forming a TiN film as the base film. The description of the TiN film (underlayer film) in Table 3 is that the substrate is placed in a reaction vessel of the CVD apparatus (the environment in the vessel is 6.7 kPa, 915 ° C.), and 2% by volume of TiCl ₄ gas is contained in the reaction vessel. , 39.7% by volume of N ₂ gas and the remaining 58.3% by volume of H ₂ gas were ejected at a flow rate of 63.8 L / min. Note that the thickness of each film formed under each forming condition is controlled by the time during which each reactive gas is ejected.

Moreover, the hard film shown in Table 2 was produced using the CVD apparatus 10 shown in FIGS. 4 to 6 under any one of the formation conditions a to j or m shown in Table 4. For example, the description of the formation condition a (1-A-I) in Table 4 indicates that the hard coating is No. 1 in Table 5. 1 film forming temperature (780 ° C.), furnace pressure (3 kPa), reaction gas composition (N ₂ : 10 vol%, Ar: 5 vol%, AlCl ₃ : 1.5 vol%, TiCl ₄ : 0.5 vol) %, Ti [CH ₂ C (CH ₃ ) ₃ ] ₄ : 0.01% by volume, NH ₃ : 4% by volume, H ₂ : remaining) and the total gas amount (55 L / min), and then No. in Table 6 The substrate is cooled at a cooling rate of A. Finally, the substrate is heated at the conditions of heating temperature (800 ° C.), heating time (30 minutes) and air flow composition of I in Table 7, and Table 4 indicating characteristic (Ti _1-x Al x N layer of the Al composition ratio _{x (0.50), Ti 1-} y Al y N layer of Al composition ratio y (0.80), y-x (0.3), Total thickness (15 nm) of _one adjacent Ti _1-x Al _x N layer and one Ti _1-y Al _y N layer, grain size (less than 100 nm), thickness of amorphous phase A hard coating having a hard coating Hv (30.7 GPa) and a hard coating phase transition temperature (970 ° C.) was prepared (less than 20 μm).

As described above, the sample numbers shown in Table 2 were obtained. 1 to 18 include a plurality of crystal grains and an amorphous phase between the crystal grains, and each crystal grain includes a Ti _1-x Al _x N layer having an fcc structure having the composition shown in Table 4. , Ti _1-y Al _y N layers having an fcc structure are alternately laminated one by one, and a hard film in which an amorphous phase made of TiCN is formed between crystal grains is formed. It was.

The formation condition j in Table 4 is that the single layer containing a plurality of Al _0.87 Ti _0.13 N crystal grains and amorphous carbon (a-C) between them is No. 5 in Table 5. After forming by the CVD method under the conditions shown in FIG. The substrate was cooled at a cooling rate of C. It means that the film is formed without being heated after cooling as shown in III.

The formation conditions shown in Table 4 m also a single layer of polycrystalline film of Al _0.5 Ti _0.5 N in Table 5 No. After forming by the PVD method under the conditions shown in FIG. The substrate was cooled at a cooling rate of C. It means that the film is formed without being heated after cooling as shown in III.

  Moreover, the description of aj and m of the column of the hard film of Table 2 means that it is the film | membrane formed on the conditions of aj and m of the column of the formation conditions of Table 4, respectively, The numerical values in parentheses on the right side of a to j and m in the column of hard coating in Table 2 mean the total thickness of the hard coating.

  Moreover, the grain size of the crystal grains in Table 4 means the grain size of the crystal grains of the hard coating, and the thickness of the amorphous phase in Table 4 means the thickness of the amorphous phase of the hard coating. Yes.

  Moreover, the phase transition temperature shown in Table 4 means the temperature when the film is heated and the crystal grains undergo phase transition to the wurtzite type. The phase transition to the wurtzite type was performed by observing the hard film using TEM.

<Cutting performance>
Sample No. produced as described above. Using the cutting tools 1 to 23, the following cutting tests 1 to 5 were performed to evaluate the cutting performance of each cutting tool.

<Cutting test 1: Round bar outer periphery cutting test>
Sample No. For the cutting tools 1 to 4, 9, 19 and 23, the cutting time until the flank wear amount (Vb) reaches 0.20 mm is measured according to the cutting conditions of the following cutting test 1 and the final damage form of the cutting edge is determined. Observed. The results are shown in Table 8. It shows that the larger the numerical value in the column of the cutting time in Table 8, the better the wear resistance of the coating and the longer the tool life. Moreover, description of the last damage form shown in Table 8 shows that abrasion resistance is excellent in order of normal wear, chipping, and a defect | deletion. In the final damage forms in Table 8, “normal wear” means a damage form (having a smooth wear surface) that does not cause chipping and chipping, and is composed only of wear, and “defect” means a cutting edge portion. It means a big chip that occurred.

<Cutting conditions of cutting test 1>
Work material: SUS316 round bar peripheral cutting Peripheral speed: 200 m / min
Feeding speed: 0.1mm / rev
Cutting depth: 1.0mm
Cutting fluid: Yes

  As shown in Table 8, Sample No. The cutting tools 1 to 4 are sample Nos. Compared with the cutting tools of 9, 19, and 23, it was confirmed that the wear resistance was excellent and a long life of the cutting tool could be achieved. This is the sample No. The coatings 1 to 4 are sample Nos. It shows that the film is superior in abrasion resistance as compared with the coating films of 9, 19, and 23.

<Cutting Test 2: Round Bar Perimeter Cutting Test>
Sample No. For the cutting tools 1, 3, 6, 7, 9, 19, 21, and 23, the cutting time until the flank wear amount (Vb) reaches 0.20 mm under the cutting conditions of the following cutting test 2 is measured. The final damage form of the cutting edge was observed. The results are shown in Table 9. The larger the numerical value in the column of the cutting time in Table 9, the better the wear resistance of the coating, and the longer the tool life. In the final damage form shown in Table 9, “chipping” means a minute chip generated in the cutting edge part that generates the finished surface. Other notations in Table 9 are the same as in Table 8.

<Cutting conditions of cutting test 2>
Work material: FCD700 round bar peripheral cutting Peripheral speed: 200 m / min
Feeding speed: 0.1mm / rev
Cutting depth: 1.0mm
Cutting fluid: Yes

  As shown in Table 9, sample no. The cutting tools 1, 3, 6 and 7 are respectively sample Nos. Compared to the cutting tools of 9, 19, 21 and 23, it was confirmed that the cutting tool was excellent in wear resistance and could achieve a long life of the cutting tool. This is the sample No. The coatings of 1, 3, 6 and 7 are sample No. Compared to the 9, 19, 21 and 23 coatings, it shows superior wear resistance.

<Cutting test 3: groove material chipping resistance test>
Sample No. For the cutting tools 1, 2, 3, 5, 6, 9, 19, 21, and 23, the cutting time (minutes) until a chipping or chipping occurs at the tool edge is measured according to the cutting conditions of the following cutting test 3. did. The results are shown in Table 10. The longer the cutting time shown in Table 10, the better the fatigue toughness.

<Cutting conditions of cutting test 3>
Work material: SCM435 groove peripheral speed: 200 m / min
Feeding speed: 0.2mm / s
Cutting depth: 1.0mm
Cutting fluid: Yes

As shown in Table 10, sample no. The cutting tools of 1, 2, 3, 5 and 6 are sample Nos. It was confirmed that it was excellent in fatigue resistance toughness as compared with the cutting tools of 9, 19, 21 and 23. Sample No. Have a fatigue toughness high cutting tool 1, 2, 3, 5 and 6, alternate stacked structure of Ti _1-x Al x N layer and the Ti _1-y Al y N layer with these cutting tools This is probably because a hard coating composed of crystal grains having a crystallinity and an amorphous phase between crystal grains has a high elastic recovery rate.

<Cutting test 4: Blocking chipping resistance test>
Sample No. shown in Table 11 For the cutting tools 10, 11, 14, 15, 16, 20, and 22, while measuring the cutting distance until the defect or flank wear amount (Vb) becomes 0.20 mm under the cutting conditions of the following cutting test 4 The final damage form of the cutting edge was observed. The results are shown in Table 11. It shows that it is excellent in abrasion resistance, so that the numerical value of the column of the cutting distance shown in Table 11 is large. The notation in the column of final damage form in Table 11 is the same as in Table 8 and Table 9.

<Cutting conditions of cutting test 4>
Work material: FD450 block material Peripheral speed: 150 m / min
Feeding speed: 0.3mm / s
Cutting depth: 2.0mm
Cutting fluid: Available Cutter: WGC4160R (manufactured by Sumitomo Electric Hardmetal Corp.)
Tip: SEET13T3AGSN-G1 blade (manufactured by Sumitomo Electric Hardmetal Corp.)

  As shown in Table 11, sample no. Although the final damage forms of the cutting tools 10, 11, 14, 15, 16, 20, and 22 were all missing, The cutting tools 10, 11, 14, 15 and 16 are sample Nos. Compared with 20 and 22 cutting tools, it was confirmed that the cutting distance was long and the wear resistance was excellent. This is the sample No. The coatings Nos. 10, 11, 14, 15 and 16 have sample nos. Compared to the 20 and 22 coatings, it shows superior wear resistance.

<Cutting test 5: Block material chipping resistance test>
Sample No. shown in Table 12 For the 12, 13, 16, 17, 18, 20, and 22 cutting tools, the cutting distance until the defect or flank wear amount (Vb) becomes 0.20 mm is measured according to the cutting conditions of the following cutting test 5. The final damage form of the cutting edge was observed. The results are shown in Table 12. It shows that it is excellent in abrasion resistance, so that the numerical value of the column of the cutting distance shown in Table 12 is large. The notation in the column of final damage form in Table 12 is the same as in Tables 8 and 9.

<Cutting conditions of cutting test 5>
Work material: SUS304 block material Peripheral speed: 200 m / min
Feeding speed: 0.2mm / s
Cutting depth: 1.5mm
Cutting fluid: None Cutter: WGC4160R (manufactured by Sumitomo Electric Hardmetal Corp.)
Tip: SEET13T3AGSN-G1 blade (manufactured by Sumitomo Electric Hardmetal Corp.)

  As shown in Table 12, sample no. Although the final damage forms of the cutting tools 12, 13, 16, 17, 18, 20, and 22 were all missing, The cutting tools of Nos. 12, 13, 16, 17 and 18 are sample Nos. Compared to the cutting tools 20 and 22, it was confirmed that the cutting distance was long and the wear resistance of the coating was excellent. This is the sample No. The coatings of Nos. 12, 13, 16, 17, 18, 20, and 22 are sample Nos. It shows that it is superior in wear resistance as compared with the coatings of 20 and 22.

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

  The embodiments and examples disclosed herein are illustrative in all respects and should not be construed as being restrictive. The scope of the present invention is shown not by the embodiments and examples described above but by the scope of claims, and is intended to include meanings equivalent to the scope of claims and all modifications within the scope.

10 CVD device 11 substrate 12 substrate the jig 13 reaction vessel 14 temperature controller 15 gas inlet 16 gas introduction pipe 17 through hole 18 a gas exhaust pipe 19 gas outlet 20 underlying film 21a Ti _1-x Al x N layer 21b Ti _1-y Al y N layer 22 amorphous phase 30 hard coating 40 wire 50 coating

Claims (8)

A plurality of grains,
An amorphous phase between the crystal grains,
Each of the crystal grains has a structure in which Ti _1-x Al _x N layers having an fcc structure and Ti _1-y Al _y N layers having an fcc structure are alternately stacked.
The Al composition ratio x of the Ti _1-x Al _x N layer satisfies the relationship of 0 ≦ x <1,
The Ti _1-y Al _y N layer of Al composition ratio y satisfies 0 <y ≦ 1 relationship,
The Al composition ratio x and the Al composition ratio y satisfy the relationship of (y−x) ≧ 0.2,
The hard film, wherein the amorphous phase includes at least one carbide, nitride, or carbonitride of Ti and Al. The total thickness of the thickness per layer of the adjacent Ti _1-x Al _x N layers and the thickness per layer of the Ti _1-y Al _y N layers is 1 nm or more and 50 nm or less. Hard coating as described in 4.   The hard coating film according to claim 1 or 2, wherein a grain size of the crystal grains is 0.01 µm or more and 1 µm or less.   The hard film according to claim 1, wherein the amorphous phase has a thickness of 100 nm or less.   The hard film according to any one of claims 1 to 4, wherein an indentation hardness of the hard film by a nanoindentation method is 30 GPa or more. A substrate;
The cutting tool provided with the hard film of any one of Claims 1-5 provided on the said base material. A step of jetting titanium halide gas, aluminum halide gas, tetrakisneopentyl titanium gas, and ammonia gas to the surface of the substrate;
And a step of cooling the substrate. The step of cooling the substrate includes the step of cooling the substrate to 400 ° C. or less at a rate of 7 ° C./min or more,
In the method for producing the hard coating, after the step of cooling to 400 ° C. or lower, the substrate is heated to a temperature of 600 ° C. or higher and 800 ° C. or lower in a flow of ammonia gas or a mixed gas of ammonia gas and hydrogen gas. The method for producing a hard coating film according to claim 7, further comprising a step of heating for 30 minutes to 300 minutes.

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