JP6522985B2 - Coated tools - Google Patents

Description

  The present invention relates to a coated tool having a coating layer on the surface of a substrate.

  Conventionally, a coating layer such as a titanium carbide layer, a titanium nitride layer, a titanium carbonitride layer, an aluminum oxide layer, and a titanium aluminum nitride layer is formed in a single layer or multiple layers on the surface of a base such as cemented carbide, cermet or ceramic. Coated tools such as cutting tools are known.

  Such cutting tools are increasingly used for heavy interrupted cutting or the like in which a large impact is applied to the cutting edge with the recent increase in efficiency of cutting. Under such severe cutting conditions, the coating layer is subjected to a large impact, and chipping and peeling of the coating layer are likely to occur. Therefore, it is required to improve chipping resistance of the coating layer and to suppress chipping and peeling of the coating layer.

  In the above-mentioned cutting tool, as a technique for improving the fracture resistance, in Patent Document 1, while optimizing the particle diameter and layer thickness of the aluminum oxide layer, the texture coefficient (orientation coefficient) in the (012) plane is obtained. A technology capable of forming a compact, highly fracture resistant aluminum oxide layer by setting it to 1.3 or more is disclosed. Further, in Patent Document 2, the residual stress in the aluminum oxide layer is easily released by setting the organization coefficient in the (012) plane of the aluminum oxide layer to 2.5 or more, and the fracture resistance of the aluminum oxide layer is improved. Techniques are disclosed that can be improved.

  In Patent Document 3, in the cutting tool, as a technique for improving the wear resistance, an aluminum oxide layer located immediately above the intermediate layer is formed by laminating two or more unit layers showing different X-ray diffraction patterns. By forming in, the technique which can improve the intensity | strength and toughness of a film is disclosed.

  In Patent Document 4, the (006) plane orientation coefficient of the aluminum oxide layer is increased to 1.8 or more, and the peak intensity ratio I (104) / I (110) of the (104) plane to the (110) plane is predetermined. A controlled cutting tool within the scope is disclosed.

  Furthermore, in Patent Document 5, the peak intensity ratio I (104) / I (012) of the (104) plane to the (012) plane of the aluminum oxide layer is higher than the first surface below the aluminum oxide layer. A cutting tool that has been enlarged in size has been disclosed.

Unexamined-Japanese-Patent No. 6-316758 Japanese Patent Application Laid-Open No. 2003-025114 JP 10-204639 A JP, 2013-132717, A JP, 2009-202264, A

  Coated tools are required to further improve the wear resistance and fracture resistance of the coated layer. In particular, further improvement of the chipping resistance of the aluminum oxide layer has been desired.

The coated tool according to the present invention is a coated tool in which at least a titanium carbonitride layer and an aluminum oxide layer of α-type crystal structure are sequentially laminated on a substrate surface, and the oxidation in X-ray diffraction analysis of the aluminum oxide layer The orientation coefficient Tc (134) on the surface side represented by the following general formula Tc (hkl) of the surface side peak detected by measurement from the surface side of the aluminum layer is 0.7 or more , and the orientation coefficient Tc on the surface side (006) is 2.90 or more .
Orientation coefficient Tc (hkl) = {I (hkl) / I ₀ (hkl)} / [(1/8) × Σ {I (HKL) / I ₀ (HKL)}]
Here, (HKL) is the crystal planes I (HKL) and I (hkl) of (012), (104), (110), (006), (113), (024), (116), (134). The peak intensities I ₀ (HKL) and I ₀ (hkl) of the peaks belonging to each crystal plane detected in the X-ray diffraction analysis of the aluminum oxide layer are the same as those of JCPDS card no. Standard diffraction intensity of each crystal plane described in 00-010-0173

  According to the present invention, since the orientation coefficient of the (134) plane of the aluminum oxide layer is as high as 0.7 or more, the chipping of the aluminum oxide layer is suppressed, the wear resistance is improved, and the coated tool can be used for a long time It becomes.

It is a schematic perspective view of a cutting tool which is one example of a covering tool concerning the present invention. It is a schematic sectional drawing of the cutting tool of FIG.

  A cutting tool (hereinafter simply referred to as a tool) 1 showing one embodiment of the coated tool of the present invention is, as shown in FIG. 1, one main surface of the tool 1 rake face 2 and side face flank 3 The cutting edges 4 are formed by intersecting ridges between the rake face 2 and the flank 3.

  Further, as shown in FIG. 2, the tool 1 is provided with a base 5 and a covering layer 6 provided on the surface of the base 5. The covering layer 6 is formed by laminating a base layer 7, a titanium carbonitride layer 8, an intermediate layer 9, an aluminum oxide layer 10, and a surface layer 11 in this order from the base 5 side. The aluminum oxide layer 10 has an α-type crystal structure.

In the present embodiment, in the X-ray diffraction analysis measured from the surface of the aluminum oxide layer 10, the following general formula Tc (hkl) ((hkl) of the aluminum oxide layer 10 is (012), (104), (110) The surface-side orientation coefficient Tc (134) represented by (006), (113), (024), (116), or (134), is 0.7 or more. Orientation coefficient Tc (hkl) = {I (hkl) / I ₀ (hkl)} / [(1/8) × Σ {I (HKL) / I ₀ (HKL)}]
Here, (HKL) is a crystal plane of (012), (104), (110), (006), (113), (024), (116), (134).
I (HKL) and I (hkl) are peak intensities of peaks assigned to respective crystal planes detected in X-ray diffraction analysis of the aluminum oxide layer 10.
I ₀ (HKL) and I ₀ (hkl) are JCPDS card no. It is a standard diffraction intensity of each crystal plane described in 00-010-0173.

Thereby, the wear resistance of the aluminum oxide layer 10 is improved. As a result, the tool 1 becomes a usable tool 1 for a long period of time. That is, when the orientation coefficient Tc (134) becomes high, that is, the ratio of the peak intensity I (134) of the (134) plane becomes high, from the surface side of the aluminum oxide layer 10 in the film forming direction (direction perpendicular to the surface) It is considered that the aluminum oxide crystals constituting the aluminum oxide layer 10 tend to be susceptible to such impact, and the resistance to breakage is increased. Therefore, on the surface side of aluminum oxide layer 10, by increasing the orientation coefficient Tc (134), micro chipping generated on the surface of aluminum oxide layer 10 is suppressed, and the progress of wear due to micro chipping is suppressed. It seems that you can do it. A desirable range of the surface side Tc (134) is 0.7 to 3.0, a particularly desirable range is 0.8 to 2.5, and a further desirable range is 0.9 to 1.7.

  In addition, for the other peaks than the (134) plane, Tc (012) is 0.2 to 0.7, Tc (104) is 0.5 to 1.7, and Tc (110) is 0.3 to 1 .5, Tc (006) is 2 to 7, Tc (113) is 0.05 to 0.7, and Tc (116) is 0.3 to 1.3.

  In the present embodiment, Tc (006) is higher than other organization coefficients. Thereby, the wear resistance of the aluminum oxide layer 10 can be enhanced. Then, by enhancing Tc (134) together with Tc (006), the chipping resistance of the aluminum oxide layer 10 can be enhanced, and the wear resistance of the aluminum oxide layer 10 is further improved.

  Here, according to the present embodiment, the substrate side peak detected by measurement in a state where only the substrate side portion of the aluminum oxide layer 10 is left by polishing a part of the aluminum oxide layer 10, and the aluminum oxide layer When the surface side peaks detected by measurement from the surface side of 10 are compared, the surface side Tc (134) in the surface side peak is larger than the substrate side Tc (134) in the substrate side peak. That is, the substrate side Tc (134) is smaller than the surface side Tc (134). When the orientation coefficient Tc (134) becomes higher, the thermal expansion coefficient in the direction parallel to the surface of the aluminum oxide layer 10 becomes larger, so the aluminum oxide layer 10 and the intermediate layer 9 or carbon on the substrate side than the aluminum oxide layer 10 The difference with the thermal expansion coefficient of the titanium nitride layer 8 is large, and the aluminum oxide layer 10 tends to be easily peeled off. In addition to the surface side Tc (134) becoming larger than the substrate side Tc (134), peeling of the aluminum oxide layer 10 is suppressed by the surface side Tc (134) being 0.7 or more.

  Therefore, peeling of the aluminum oxide layer 10 can be suppressed by reducing the orientation coefficient Tc (134) of the aluminum oxide layer 10 on the substrate side. The desirable range of the substrate side Tc (134) is 0.1 to 1.0, preferably 0.3 to 0.7.

  Further, a method of measuring the substrate side Tc (134) and the surface side Tc (134) of the aluminum oxide layer 10 will be described. The X-ray diffraction analysis of the aluminum oxide layer 10 is measured using a general X-ray diffraction analysis apparatus using a CuKα ray. Since the measurement is performed on a flat surface having a large area, when unevenness such as a breaker is formed on the rake surface 2, measurement is performed on the flank 3. In order to determine the peak intensity of each crystal plane of the aluminum oxide layer 10 from the X-ray diffraction chart, the No. of JCPDS card No. The diffraction angle of each crystal plane described in 00-101 to 0173 is confirmed, the crystal plane of the detected peak is identified, and the peak intensity is measured.

To measure the surface side Tc (134), the peak intensity of the aluminum oxide layer 10 is measured, including the substrate side of the aluminum oxide layer 10 from the surface side of the aluminum oxide layer 10. Specifically, X-ray diffraction analysis is performed on the covering layer 6 in a state in which the surface layer 11 is removed by polishing or in a state in which the surface layer 11 is not polished. The peak intensity of each of the obtained peaks is measured to calculate the orientation coefficient Tc (hkl). When the surface layer 11 is polished and removed, 20% or less of the thickness of the aluminum oxide layer 10 may be removed. Further, even when X-ray diffraction analysis is performed on the surface layer 11 without polishing, it is only necessary to measure nine peaks of aluminum oxide. The surface side peak is detected including the orientation of the aluminum oxide layer 10 on the substrate 5 side, but the texture at a position close to the measurement surface of the aluminum oxide layer 10 in the X-ray diffraction analysis largely affects the peak. Therefore, the influence of the orientation state on the substrate 5 side on the surface side peak is small.

  In order to measure the substrate side Tc (134), a part of the aluminum oxide layer 10 is polished, and the peak intensity is measured with only the substrate side portion of the aluminum oxide layer 10 left. Specifically, first, the aluminum oxide layer 10 of the covering layer 6 is polished to a thickness of 10 to 40% with respect to the thickness of the aluminum oxide layer 10 before polishing. Polishing is performed by brush processing using diamond abrasive grains, processing using an elastic whetstone, or blast processing. Thereafter, X-ray diffraction analysis is performed on the polished portion of the aluminum oxide layer 10 under the same conditions as the measurement on the surface side portion of the aluminum oxide layer 10 to measure the peak of the aluminum oxide layer 10, and the orientation coefficient Tc ( Calculate hkl).

  The surface side Tc (134) and the substrate side Tc (134) in the surface side peak of the aluminum oxide layer 10 measured by the above method can be compared. The orientation coefficient Tc can be obtained as a ratio to non-orientated standard data defined by the JCPDS card, and thus is an index indicating the degree of orientation of each crystal plane.

  Moreover, according to the present embodiment, in the surface side peak of the aluminum oxide layer 10, I (104) and I (116) are the first and second highest. That is, I (104) may be the highest and I (116) may be the second highest, I (116) may be the first and I (134) may be the second highest. Crater wear on the rake face 2 side is thereby suppressed. At the flank 3 side, flank wear due to micro chipping tends to be suppressed.

In the JCP DS card, Io (006) is 1, that is, 100 times smaller than the peak intensity Io (113) of the (113) plane, which is the strongest peak, being 100. In the present embodiment, Tc (006) is 2 to 7, and Tc (006) is very high compared to Tc of other peaks, so Tc of other peaks is difficult to compare. So, in this embodiment, the orientation state of another crystal plane is also evaluated by the correction orientation coefficient calculated | required by the following general formula Tc '(hkl) except the peak of (006) plane.
Orientation coefficient Tc (hkl) = {I (hkl) / I ₀ (hkl)} / [(1/7) × Σ {I (HKL) / I ₀ (HKL)}]
Here, (HKL) is a crystal plane of (012), (104), (110), (113), (024), (116), (134).
I (HKL) and I (hkl) are peak intensities of peaks assigned to respective crystal planes detected in X-ray diffraction analysis of the aluminum oxide layer 10.
I ₀ (HKL) and I ₀ (hkl) are JCPDS card no. It is a standard diffraction intensity of each crystal plane described in 00-010-0173.

  In the present embodiment, Tc '(134) is 1.1 to 2.0. That is, the (134) plane tends to be more oriented than non-oriented aluminum oxide. By this, micro chipping is suppressed and progress of wear can be suppressed. For the other peaks, Tc '(012) is 0.4 to 0.9, Tc' (104) is 0.8 to 2.0, Tc '(110) is 0.6 to 2.5, Tc' (113) is 0.1 to 0.5, and Tc '(116) is 0.7 to 1.7.

The titanium carbonitride layer 8 is a laminate in which a so-called MT-titanium carbonitride layer 8a and an HT-titanium carbonitride layer 8b are present in order from the substrate side. MT- titanium carbonitride layer 8a comprises acetonitrile _(CH 3 CN) gas as a raw material, the film forming temperature of columnar crystals formed at relatively low temperatures from 780 to 900 ° C.. The HT-titanium carbonitride layer 8 b is composed of granular crystals formed at a film forming temperature of 950 to 1100 ° C. and a high temperature. According to this embodiment, a triangular protrusion is formed on the surface of the HT-titanium carbonitride layer 8b in a cross-sectional view tapering toward the aluminum oxide layer 10, whereby the adhesion of the aluminum oxide layer 10 is enhanced. Peeling and chipping of the covering layer 6 can be suppressed.

  Further, according to the present embodiment, the intermediate layer 9 is provided on the surface of the HT-titanium carbonitride layer 8 b. The intermediate layer 9 contains titanium and oxygen, and is made of, for example, TiAlCNO, TiCNO or the like. FIG. 2 is made of a lower intermediate layer 9a and an upper intermediate layer 9b on which these are laminated. By this, the aluminum oxide particle which comprises the aluminum oxide layer 10 becomes an alpha-type crystal structure. The aluminum oxide layer 10 having an α-type crystal structure has high hardness, and can improve the wear resistance of the coating layer 6. The intermediate layer 9 has a laminated structure of the lower intermediate layer 9a made of TiAlCNO and the upper intermediate layer 9b made of TiCNO, so that the fracture resistance of the cutting tool 1 can be improved. The titanium carbonitride layer 8 has a thickness of 6.0 to 13.0 μm, and the intermediate layer 9 has a thickness of 0.05 to 0.5 μm.

  Furthermore, the underlayer 7 and the surface layer 11 are made of titanium nitride. In the other embodiment of the present invention, the lower layer 7 and the surface layer 11 may be made of other materials than titanium nitride such as titanium carbonitride, titanium carbonitride, chromium nitride and the like. Further, at least one of the underlayer 7 and the surface layer 11 may not be provided. Furthermore, the underlayer 7 is provided with a thickness of 0.1 to 1.0 μm, and the surface layer 11 is provided with a thickness of 0.1 to 3.0 μm.

  The thickness of each layer and the properties of crystals constituting each layer are measured by observing an electron micrograph (a scanning electron microscope (SEM) photograph or a transmission electron microscope (TEM) photograph) of the cross section of the tool 1. Is possible. Further, in the present invention, that the crystal form of the crystals constituting each layer of the covering layer 6 is columnar means that the ratio of the average crystal width to the length in the thickness direction of the covering layer 6 of each crystal is an average of 0. Point 3 or less. On the other hand, when the ratio of the average crystal width to the length in the thickness direction of the coating layer of each crystal exceeds 0.3 on average, the crystal form is defined as granular.

On the other hand, the substrate 5 of the tool 1 is hard made of tungsten carbide (WC) and, if desired, at least one selected from the group consisting of carbides, nitrides and carbonitrides of Group 4, 5 and 6 metals of periodic table. Phase, cemented carbide and Ti-based cermet combined with a binder phase consisting of iron group metals such as cobalt (Co) and nickel (Ni), or Si ₃ N ₄ , Al ₂ O ₃ , diamond, cubic nitriding Ceramics such as boron (cBN) may be mentioned. Among them, when used as a cutting tool such as the tool 1, the base 5 may be made of cemented carbide or cermet in terms of chipping resistance and wear resistance. Further, depending on the application, the substrate 5 may be made of metal such as carbon steel, high speed steel, alloy steel or the like.

  Furthermore, the cutting tool is for cutting with the cutting edge formed at the intersection ridge line portion between the rake face and the flank face against the object to be cut, and the above-described excellent effect can be exhibited. Moreover, the coated tool of the present invention can be applied to various uses such as sliding parts and wear-resistant parts such as molds, tools such as drilling tools, cutters, and impact-resistant parts other than cutting tools. Also have excellent mechanical reliability.

  Next, a method of manufacturing a coated tool according to the present invention will be described with reference to an example of a method of manufacturing the tool 1.

First, metal powder, carbon powder and the like are appropriately added to and mixed with an inorganic powder such as metal carbide, nitride, carbonitride or oxide which can form a hard alloy to become the substrate 5 by firing, press forming and casting After forming into a predetermined tool shape by a known forming method such as forming, extrusion forming, cold isostatic press forming, etc., the above-described substrate 5 made of hard alloy is obtained by firing in vacuum or in a non-oxidizing atmosphere. Make. Then, the surface of the substrate 5 is subjected to polishing or honing of the cutting edge as desired.

  Next, a coating layer is formed on the surface by chemical vapor deposition (CVD).

First, as a reaction gas composition, a mixed gas consisting of 0.5 to 10% by volume of titanium tetrachloride (TiCl ₄ ) gas, 10 to 60% by volume of nitrogen (N ₂ ) gas, and the rest being hydrogen (H ₂ ) gas Then, the TiN layer which is the underlayer 7 is formed at a film forming temperature of 800 to 940 ° C. and 8 to 50 kPa.

Thereafter, as a reaction gas composition, 0.5 to 10% by volume of titanium tetrachloride (TiCl ₄ ) gas, 5 to 60% by volume of nitrogen (N ₂ ) gas, and 0. 0 to 5 parts by volume of acetonitrile (CH ₃ CN) gas. A mixed gas consisting of 1 to 3.0% by volume, the balance being hydrogen (H ₂ ) gas is adjusted and introduced into the chamber, and the film forming temperature is set to 780 to 880 ° C., 5 to 25 kPa, MT-titanium carbonitride layer To form a film. At this time, by increasing the content ratio of acetonitrile (CH ₃ CN) gas later in the film formation than in the initial film formation, the average crystal width of titanium carbonitride columnar crystals constituting the titanium carbonitride layer is made surface side relative to the substrate side. Can be made larger.

Next, an HT-titanium carbonitride layer that constitutes the upper part of the titanium carbonitride layer 8 is deposited. According to this embodiment, specific film forming conditions of the HT-titanium carbonitride layer are 1 to 4% by volume of titanium tetrachloride (TiCl ₄ ) gas, and 5 to 20% by volume of nitrogen (N ₂ ) gas, A mixed gas consisting of 0.1 to 10% by volume of methane (CH ₄ ) gas and hydrogen (H ₂ ) gas as the balance is adjusted and introduced into the chamber, and the film forming temperature is set to 900 to 1050 ° C. and 5 to 40 kPa Form a film.

Furthermore, the intermediate layer 9 is produced. Specific film forming conditions for this embodiment include, as a first step, 3 to 30% by volume of titanium tetrachloride (TiCl ₄ ) gas, 3 to 15% by volume of methane (CH ₄ ) gas, and nitrogen (N ₂₎ 5.) 5 to 10% by volume of gas, 0.5 to 1% by volume of carbon monoxide (CO) gas, 0.5 to 3% by volume of aluminum trichloride (AlCl ₃ ) gas, the rest being hydrogen (H ₂ ) gas Adjust the mixed gas consisting of These mixed gases are adjusted and introduced into the chamber, and film formation temperatures are set to 900 to 1050 ° C. and 5 to 40 kPa. By this process, the intermediate layer 9 having irregularities is formed on the surface of the titanium carbonitride layer 8.

Subsequently, as the second stage of the intermediate layer 9, titanium tetrachloride (TiCl ₄₎ gas 3 to 15% by volume, methane (CH ₄₎ gas 3-10% by volume, nitrogen _{(N 2)} gas 10-25 A mixed gas consisting of vol%, 0.5 to 2.0 vol% of carbon monoxide (CO) gas and the balance of hydrogen (H ₂ ) gas is prepared. These mixed gases are adjusted and introduced into the chamber, and film formation temperatures are set to 900 to 1050 ° C. and 5 to 40 kPa. The present process may change the above nitrogen (N ₂₎ gas in argon (Ar) gas. By this process, the unevenness of the surface of the intermediate layer 9 becomes fine, and the growth state of the aluminum oxide crystal in the aluminum oxide layer 10 to be formed next can be adjusted.

Then, the aluminum oxide layer 10 is formed. First, nuclei of aluminum oxide crystals are formed. 5 to 10% by volume of aluminum trichloride (AlCl ₃ ) gas, 0.1 to 1.0% by volume of hydrogen chloride (HCl) gas, 0.1 to 5.0% by volume of carbon dioxide (CO ₂ ) gas, The balance is adjusted to 950 to 1100 ° C. and 5 to 10 kPa using a mixed gas containing hydrogen (H ₂ ) gas. By the film formation of this first step, the growth state of the aluminum oxide crystal to be formed is changed, and Tc (134) of the aluminum oxide layer 10 is controlled.

Next, 0.5 to 5.0% by volume of aluminum trichloride (AlCl ₃ ) gas, 1.5 to 5.0% by volume of hydrogen chloride (HCl) gas, and 0.5 of carbon dioxide (CO ₂ ) gas Using a mixed gas consisting of ~ 5.0% by volume, 0 to 1.0% by volume of hydrogen sulfide (H ₂ S) gas, and the rest being hydrogen (H ₂ ) gas, changing to 950 to 1100 ° C, 5 to 20 kPa Form a film. The growth state of the aluminum oxide crystal film formed on the intermediate layer side of the aluminum oxide layer 10 is adjusted by the film forming process of the second stage to control the substrate side Tc (134).

Subsequently, 5 to 15% by volume of aluminum trichloride (AlCl ₃ ) gas, 0.5 to 2.5% by volume of hydrogen chloride (HCl) gas, and 0.5 to 5.0% of carbon dioxide (CO ₂ ) gas Oxidation using the mixed gas consisting of 0.0% to 1.0% by volume of hydrogen sulfide (H ₂ S) gas and the balance of hydrogen (H ₂ ) gas, and changing to 950 to 1100 ° C., 5 to 20 kPa for oxidation An aluminum layer 10 is formed. The growth state of the aluminum oxide crystal film formed on the surface side of the aluminum oxide layer 10 is adjusted by the third film forming step to control the surface side Tc (134). The second and third steps are not independent steps, and the composition of the mixed gas may change continuously.

Then, the surface layer (TiN layer) 11 is deposited as desired. Specific film forming conditions are, as a reaction gas composition, 0.1 to 10% by volume of titanium tetrachloride (TiCl ₄ ) gas, 10 to 60% by volume of nitrogen (N ₂ ) gas, and the rest being hydrogen (H ₂ ) gas The mixed gas which consists of these is adjusted, it introduce | transduces in a chamber, and film-forming temperature is made into a film as 960-1100 degreeC and 10-85 kPa.

  Thereafter, at least the cutting edge portion of the surface of the formed coating layer 6 is polished if desired. By this grinding process, the cutting edge part is processed to be smooth, welding of the work material is suppressed, and a tool having excellent fracture resistance is obtained.

  First, 6% by mass of metallic cobalt powder having an average particle diameter of 1.2 μm, 0.5% by mass of titanium carbide powder having an average particle diameter of 2.0 μm, and 5% by mass of niobium carbide powder having an average particle diameter of 2.0 μm There were added and mixed at a ratio of tungsten carbide powder having an average particle diameter of 1.5 μm, and formed into a tool shape (CNMG 120408) by press forming. Thereafter, binder removal processing was performed, and firing was performed for 1 hour in a vacuum of 1500 ° C. and 0.01 Pa to prepare a substrate made of cemented carbide. Thereafter, the produced substrate was subjected to brush processing, and R honing was applied to a portion to be a cutting blade.

  Next, a coating layer was formed on the above-mentioned cemented carbide substrate by the chemical vapor deposition (CVD) method under the film forming conditions of Table 1 to prepare a cutting tool. In Tables 1 and 2, each compound is represented by a chemical symbol.

  With respect to the above sample, first, X-ray diffraction analysis with CuKα ray is performed on the flat surface of the flank surface without polishing the coating layer, and the surface side peak measured from the surface side of the aluminum oxide layer at three arbitrary places The identification (indicated as surface side or surface side peak in the table) and the peak intensity of each peak were measured. Further, for the surface side peak, the highest intensity peak and the second highest intensity peak were confirmed, and the orientation coefficient Tc of each crystal plane of the JCPDS card was calculated.

  Next, the aluminum oxide layer was polished to a thickness of 10 to 40% of the thickness of the aluminum oxide layer, and similarly, it was measured by X-ray diffraction analysis while a part of the aluminum oxide layer was polished to leave only the substrate side portion. The identification of the substrate side peak (in the table, described as the substrate side) and the peak intensity of each peak were measured. The orientation coefficient Tc of each crystal plane was calculated using the peak intensity of each peak obtained. Moreover, the torn surface of the said tool was observed with the scanning electron microscope (SEM), and the thickness of each layer was measured. The results are shown in Tables 2 and 3.

Next, using the obtained cutting tool, a continuous cutting test and an intermittent cutting test were performed under the following conditions to evaluate wear resistance and fracture resistance. The results are shown in Table 4.
(Continuous cutting conditions)
Work material: Chromium-molybdenum steel (SCM 435)
Tool shape: CNMG120408
Cutting speed: 300 m / min Feeding speed: 0.3 mm / rev
Cut: 1.5 mm
Cutting time: 25 minutes, etc.: Water-soluble cutting fluid usage evaluation item: Observation of the honing portion with a scanning electron microscope and flank wear width on the flank face and crater wear on the rake face in the actually worn part Measure the width. (Intermittent cutting conditions)
Work material: Chrome-molybdenum steel 4-grooved steel (SCM 440)
Tool shape: CNMG120408
Cutting speed: 300 m / min Feeding speed: 0.3 mm / rev
Cut: 1.5 mm
Other: Water-soluble cutting fluid use evaluation item: Measure the number of impacts leading to a defect.

  According to the results of Tables 1 to 5, according to the sample No. 1 in which Tc (134) of the surface side peak of the aluminum oxide layer is less than 0.7. In all of the samples 6 to 8, the wear progressed quickly, the aluminum oxide layer was easily peeled off by impact, and the number of impacts was small.

  On the other hand, sample No. 1 where Tc (134) of the surface side peak of the aluminum oxide layer is 0.7 or more. In 1 to 5, fine chipping of the aluminum oxide layer was suppressed, and peeling hardly occurred, and the number of impacts was large. Sample No. It turned out that Tc '(134) of 1-5 is 1.1-2.0 in all, and tends to orientate to (134) plane.

  In addition, sample No. 1 where the substrate side Tc (134) is smaller than the surface side Tc (134). 1 to 4 are sample Nos. The crater wear width was smaller compared to 5. Furthermore, in the surface side peak of the aluminum oxide layer, sample No. 1 in which the (104) plane and the (116) plane consist of the first and second highest peaks. 1 to 3 are sample No. The crater wear width was smaller than in the cases of 4 and 5.

DESCRIPTION OF SYMBOLS 1 ... cutting tool 2 ... rake face 3 ... flank face 4 ... cutting blade 5 ... base 6 ... covering layer 7 ... foundation layer 8 ... titanium carbonitride layer 8a ... MT-titanium carbonitride layer 8b ... HT-titanium carbonitride layer 9 ... intermediate layer 9a ... lower intermediate layer 9b ... upper intermediate layer 10 ... aluminum oxide layer 11 ... surface layer

Claims (3)

A coated tool in which at least a titanium carbonitride layer and an aluminum oxide layer having an α-type crystal structure are sequentially laminated on the surface of a substrate, and in X-ray diffraction analysis of the aluminum oxide layer, from the surface side of the aluminum oxide layer. The orientation coefficient Tc (134) on the surface side represented by the following general formula Tc (hkl) of the surface side peak detected by measurement is 0.7 or more , and the orientation coefficient Tc (006) on the surface side is 2.90 Coated tool that is more than .
Orientation coefficient Tc (hkl) = {I (hkl) / I ₀ (hkl)} / [(1/8) × Σ {I (HKL) / I ₀ (HKL)}]
Here, (HKL) is the crystal planes I (HKL) and I (hkl) of (012), (104), (110), (006), (113), (024), (116), (134). The peak intensities I ₀ (HKL) and I ₀ (hkl) of the peaks belonging to each crystal plane detected in the X-ray diffraction analysis of the aluminum oxide layer are the same as those of JCPDS card no. Standard diffraction intensity of each crystal plane described in 00-010-0173   And a substrate side peak detected by measurement in a state where only the substrate side portion of the aluminum oxide layer is left by polishing a part of the aluminum oxide layer, and by detection from the surface side of the aluminum oxide layer The alignment coefficient Tc (134) on the substrate side of the substrate side peak is smaller than the orientation coefficient Tc (134) on the surface side of the surface side peak when compared with the surface side peak. Coated tools.   The coated tool according to claim 1 or 2, wherein I (104) and I (116) are first and second highest at the surface side peak.

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