JP2007186743A - Member coated with multilayered film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a member coated with a multi-layered film, which has improved cracking resistance and abrasion resistance. <P>SOLUTION: The member coated with the multi-layered film comprises: a single-layer film made from any one compound of a carbide, a nitride, a carbonitride, an oxide, a carboxide, a nitroxide and carbonitroxide of one or more elements selected from the group consisting of metals belonging to the groups 4a, 5a and 6a of the periodic table, or a multilayer film made from two or more of the above compounds, directly formed on a substrate; and at least two or more unit layers coated on the above film, while the unit layer comprises a titanium carbonitride layer and a titanium boronitride layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multilayer coating member having excellent wear resistance and crack resistance.

  Techniques aimed at improving the wear resistance of the covering member are disclosed in Patent Documents 1 to 3. Patent Documents 1 and 2 have a multi-layered film of a titanium carbonitride layer and a titanium boronitride layer, and the orientation of the titanium carbonitride layer has an orientation index of (422) plane and (311) plane. Both are 1.3 or more and 3 or less, and Patent Document 2 discloses that titanium boronitride is TiBxNy as an intermediate layer, x and y are atomic%, and 0.001 <x / (x + y) <0.04. A titanium boronitride film having a thickness of 3 to 30 μm is disclosed, and Patent Document 3 discloses a technique related to a coated cemented carbide tool having a titanium carbonitride layer formed of a columnar crystal having an aspect ratio of 5 or more with a film thickness of 3 to 30 μm.

JP-A-11-140647 US2005 / 0042482A1 JP 2000-141107 A

  This invention is providing the multilayer film coating | coated member which improved crack resistance and abrasion resistance.

  The present invention relates to a carbide, nitride, carbonitride, oxide, carbonate, nitride oxide and carbonitride oxidation of one or more elements selected from the group 4a, 5a and 6a metals of the periodic table immediately above the substrate. A single-layer film or a multilayer film composed of two or more kinds of materials, and a layer of titanium carbonitride and titanium boronitride as a unit layer on the film and covering at least two unit layers It is the multilayer film covering member characterized by having carried out. By adopting the above configuration, a multilayer coating member having excellent crack resistance and wear resistance is realized. That is, the crack propagated along the grain boundary of titanium carbonitride is blocked by titanium boronitride, and the crack resistance is improved. Furthermore, a multilayer film-coated member having further excellent wear resistance can be obtained by forming a laminated structure of two or more units of titanium carbonitride having excellent wear resistance and titanium boronitride having a high film hardness.

  The multilayer film covering member of the present invention is characterized in that the titanium boronitride constituting the unit layer is TixByN, where x and y are% by weight, and 0.01 ≦ y / (x + y) ≦ 0.9. The multilayer film covering member. In addition, the titanium carbonitride of the unit layer has a columnar structure, and the equivalent X-ray diffraction intensity ratio PR from the (422) plane or the (311) plane is maximized, so that the multilayer film has excellent wear resistance. A covering member is obtained.

  The present invention could provide a multilayer coating member with improved crack resistance and wear resistance. When the multilayer coating member coated with the unit layer of the present invention was applied to a cutting tool, a multilayer coating tool having excellent durability characteristics could be obtained.

  In the present invention, by coating two or more unit layers of titanium carbonitride and titanium boronitride multilayer film, propagation of cracks along the crystal grain boundary of titanium carbonitride is blocked by titanium boronitride, and crack resistance is improved. To do. Further, by covering at least two unit layers or more, the effect of blocking the propagation of cracks acts effectively, realizing good crack resistance and wear resistance. Since the titanium carbonitride film grows columnar crystals in the film thickness direction, the titanium carbonitride film exhibits excellent characteristics in a balance between wear resistance and toughness. However, since the titanium carbonitride film alone is a grain boundary in a direction perpendicular to the substrate, for example, when used as a cutting tool, the mechanical impact at the time of cutting edge biting or intermittent cutting during cutting As a result, a crack is generated in the film, and the crack propagates along the crystal grain boundary of the titanium carbonitride film. For this reason, there is an inconvenience that the growth of cracks becomes easy and the chipping of the cutting edge is likely to occur. Therefore, in the present invention, by laminating with titanium boronitride having a high film hardness and covering two or more unit layers, the propagation of cracks is blocked and the crack resistance is remarkably improved.

  In the multilayer film-coated member of the present invention, the titanium boronitride constituting the unit layer is TixByN, where x and y are weight percentages 0.01 ≦ y / (x + y) ≦ 0.9, This is a preferred embodiment because the film hardness of the unit layer titanium boronitride is improved, the propagation of cracks due to mechanical impact is suppressed, and the crack resistance and wear resistance are excellent. Further, when the above relationship is established, titanium boronitride tends to have a fine grain size and a layered structure. Therefore, the titanium boronitride forming the laminated structure has an effect of blocking cracks generated at the crystal grain boundaries of titanium carbonitride. On the other hand, when y / (x + y) <0.01, the boron content of titanium boronitride is small, the crystallinity becomes high, and the film tends to grow long in the film thickness direction, so that the crack resistance may be inferior. Further, when y / (x + y)> 0.9, the titanium boronitride of the unit layer becomes brittle and the toughness may be inferior.

In the multilayer coating member of the present invention, since the titanium carbonitride constituting the unit layer has a columnar structure, the balance between wear resistance and toughness of titanium carbide is the best, so the characteristics of the multilayer coating member are It is considered the best. Here, the columnar structure means that the particle size of titanium carbonitride constituting the unit layer is one time or less than the film thickness of titanium carbonitride. The measurement of the number of unit layers of the film, the presence or absence of a columnar structure, and the measurement of the particle size were measured by a photograph of a scanning electron microscope (S-2300, manufactured by Hitachi, Ltd., hereinafter referred to as SEM). The number of unit layers was obtained by breaking the film vertically and photographing at a magnification of 30k, and counting the number of unit layers. The measurement of the particle size was similarly determined from the photograph. In the measurement method, a straight line having a length T (μm) is drawn in parallel with the substrate at the center of the film to be measured, the number of columns of the columnar structure on the straight line is measured as the number D of crystal grains, and T is divided by D. This was the average crystal grain size. When titanium carbide is not a columnar structure, the wear resistance and toughness of the multilayer film are inferior. For example, when used as a tool, it wears easily, chipping occurs, and the durability of the multilayer film is inferior.
The titanium carbonitride composing the unit layer has a finer particle size because the particle size of the titanium carbonitride becomes fine due to the maximum equivalent X-ray diffraction intensity ratio PR from the (422) plane or the (311) plane. Improves wear resistance. X-ray diffraction of titanium carbonitride was measured by the same method using data of a JCPDS file (Powder Diffraction File Published by JCPDS International Center for Diffraction Data) of a substance close to the film composition of titanium carbonitride. That is, since X-ray diffraction of titanium carbonitride is not described in the JCPDS file, X-ray diffraction data of TiC and TiN (JCPDS files No. 29-1361 and No. 38-1420) and X obtained by actually measuring the film Identification was made based on the surface index and 2θ values in Table 1 obtained from the line diffraction pattern.

Here, the X-ray diffraction pattern uses CuKα ₁ line (λ = 0.15405 nm) as the X-ray source, and the film portion of the flat part of the tool surface of the sample is measured as 2θ = 10 to 145 degrees by the 2θ-θ scanning method. It measured in the range of. The background was removed by software built in the device. Further, since the lattice constant of titanium carbonitride varies in the range of 0.42 to 0.44 nm, TiC, TiN, WC (JCPDS file) appearing in the X-ray diffraction peak measured with reference to the 2θ value in Table 1 The X-ray diffraction peak of titanium carbonitride was determined in consideration of the positional relationship with peaks such as No. 25-1047). The equivalent X-ray diffraction intensity ratio PR (hkl) was defined by Equation 1 in order to quantitatively evaluate the X-ray diffraction peak intensity from the (hkl) plane of titanium carbonitride.

  This value indicates the relative intensity of the measured X-ray diffraction peak intensity I (hkl) of the film with respect to the X-ray diffraction peak intensity I0 (hkl) of the isotropic particles described in Table 1. The larger the PR (hkl) value, the stronger the X-ray diffraction peak intensity from the (hkl) plane is than the other X-ray diffraction peak intensities, and the (hkl) plane of the coating is strongly oriented in the direction parallel to the substrate. Show. Here, Σ indicates the sum of eight (hkl) of (111), (200), (220), (311), (222), (422), (420), and (511). Yes.

  The y value, which is the boron content of the titanium carbonitride and boronitride layers of the unit layer, is determined by subjecting the measurement sample to 17 ° or 5 ° slant polishing, and determining the composition of each coating portion by an energy dispersive X-ray analyzer (hereinafter referred to as EDX). ) And measured. Since the measurement area of the EDX attached to the SEM is as large as about 2 μm or less, when the thickness of the titanium boronitride layer alone or the titanium carbonitride and titanium boronitride layers is about 2 μm or more, Although the boron content can be measured, it is difficult to measure the boron content of the film alone when the film thickness of the titanium boronitride layer alone or the titanium carbonitride and titanium boronitride layers is less than about 2 μm. At this time, an average amount of boron in the entire multilayer film region can be measured by scanning an electron beam having a spot diameter of 1 μm for a length of 10 μm substantially parallel to the surface of the substrate and obtaining an average value therebetween. Using this, the boron content of the titanium carbonitride and the titanium boronitride layer alone can be calculated by proportionally dividing by the film thickness ratio constituting the unit layer. Moreover, the said analysis was measured at three points, a film | membrane surface part, a film | membrane intermediate part, and a film | membrane lower surface part. Also in this case, the boron content of each film can be analyzed by using a transmission electron microscope (hereinafter referred to as TEM).

  The thicknesses of titanium carbonitride and titanium boronitride in the unit layer are 0.1 <b / (when the average thickness of titanium carbonitride is a (μm) and the thickness of titanium boronitride is b (μm). The relationship of a + b) <0.9 is preferable, and the relationship of 0.12 <b / (a + b) <0.7 is more preferable. The case of the relationship of 0.15 <b / (a + b) <0.5 is most preferable. In the case of 0.1 <b / (a + b) <0.9, the thickness of the titanium boronitride film that blocks cracks is sufficient, and the crack blocking effect is excellent, so that the crack resistance and wear resistance are excellent. A multilayer coating member is obtained. In the case of b / (a + b) ≦ 0.1, since the titanium boronitride film that blocks cracks is thin, the blocking effect cannot be obtained. Further, when b / (a + b) ≧ 0.9, the film thickness of the titanium boronitride film is large, so that the film becomes brittle and problems such as chipping and chipping occur. In the case of 0.12 <b / (a + b) <0.7, the crack blocking effect is further improved. In the case of 0.15 <b / (a + b) <0.5, the most effective crack blocking effect is obtained. For example, when used as a tool, a multilayer coated tool having excellent crack resistance and wear resistance can be obtained.

  In the multilayer film-coated member of the present invention, the characteristics of the film can be improved by coating aluminum oxide or zirconium oxide on the upper layer side of the multilayer film coated portion coated with two or more unit layers. As the aluminum oxide film used here, a κ-type aluminum oxide single layer film or an α-type aluminum oxide single layer film can be used. Alternatively, a mixed film of κ-type aluminum oxide and α-type aluminum oxide may be used. Alternatively, a mixed film composed of κ-type aluminum oxide and / or α-type aluminum oxide and at least one of γ-type aluminum oxide, θ-type aluminum oxide, σ-type aluminum oxide, and χ-type aluminum oxide may be used. Alternatively, a mixed film of aluminum oxide and another oxide typified by silicon oxide or the like may be used. The multilayer film-coated member of the present invention is produced using a normal film forming method such as a chemical vapor deposition (hereinafter referred to as thermal CVD) method or a chemical vapor deposition (hereinafter referred to as PACVD) method with plasma. can do. The application is not limited to cutting tools, but may be wear-resistant materials, molds or molten metal parts coated with a multilayer film.

Example 1
A cemented carbide insert tool having a composition of WC: 72%, TiC: 8%, (TaNb) C: 11%, Co: 9% by weight% is set in the CVD film forming apparatus, and heat is applied to the surface. Coating was performed by the CVD method. The TiN film and Ti (CN) film, which are films directly on the substrate, were coated by a thermal CVD method. The coating condition was that the TiN film was coated to a predetermined film thickness under a predetermined temperature condition using H2 carrier gas, N2 gas and TiCl4 gas as source gases. The Ti (CN) film was coated to a predetermined film thickness under a predetermined temperature condition using H2 carrier gas, TiCl4 gas and CH3CN gas as source gases. Tables 2 and 3 show the temperature conditions and film thicknesses of the TiN film and Ti (CN) film.

Next, when a (TiB) N film and a Ti (CN) film were used as unit layers, they were repeatedly laminated a predetermined number of times. The (TiB) N film was coated to a predetermined film thickness under a predetermined temperature condition using H2 carrier gas, TiCl4 gas, BCl3 gas, and N2 gas as source gases. The Ti (CN) film was coated to a predetermined film thickness under a predetermined temperature condition using H2 carrier gas, TiCl4 gas and CH3CN gas as source gases. Tables 2 and 3 show the temperature conditions of the (TiB) N film and Ti (CN) film, the number of repetitions of lamination, and the film thickness of the laminated structure. Invention Examples 1 to 9 were produced from the above-mentioned film directly on the substrate and a film having a laminated structure of unit layers.
Conventional examples 10 to 12 are different from the examples of the present invention in the laminated structure of the unit layers. Conventional Example 10 was a single layer of (TiB) N film, and the film thickness was 6.0 μm. In Conventional Example 11, when a Zr (CN) film and a Ti (CN) film were used as unit layers, this was repeated 10 times. The total thickness of the unit layer was 8.0 μm. In Conventional Example 12, when an AlN film and a Ti (CN) film were used as unit layers, this was repeated 10 times. The total thickness of the unit layer was 8.0 μm. In the above Invention Examples 1 to 9 and Conventional Examples 10 to 12, the upper film was not laminated.

Table 3 shows the results of measuring the boron contents of Invention Examples 1 to 9 and Conventional Example 10 by EDX. The x and y values of titanium boronitride in the unit layers of Invention Examples 1 to 9 were in a relationship of 0.01 ≦ y / (x + y) ≦ 0.9. On the other hand, Conventional Examples 11 and 12 did not contain boron. Table 3 also shows the crystal structure of the Ti (CN) film and the PR value. From Table 3, the crystal structures of the Ti (CN) films of Invention Examples 1 to 9 were columnar structures, and the strongest PR was the (311) plane or the (422) plane. On the other hand, in the conventional examples 10 to 12, the crystal structure was a columnar structure, but the strongest PR was the (220) plane.
Using 10 cutting tools of Invention Examples 1 to 9 and Conventional Examples 10 to 12, respectively, the number of impacts was set to 3000 under the conditions shown in Cutting Condition 1, and then the rake face crack of the tool was magnified 200 times. Were observed with an optical microscope. The observation results are shown in Table 4.
(Cutting condition 1)
Work material: SCM437 (A) with 4 grooves Tool shape: WNMG080412
Cutting speed: 200 m / min
Feed: 0.40mm / rotation Cut: 2.5mm
Cutting fluid: Uses water-soluble fluid

From Table 4, Examples 1 to 9 of the present invention showed no cracks on the rake face and no defects. In Invention Examples 1 to 9, since titanium carbonitride having excellent wear resistance and titanium boronitride having a high film hardness are coated at least two unit layers, cracks propagated along the crystal grain boundary of titanium carbonitride Was blocked by titanium boronitride, and the crack resistance was improved. In addition, since the x and y values of titanium boronitride constituting the unit layer are 0.01 ≦ y / (x + y) ≦ 0.9, titanium boronitride has a fine crystal grain size and a layered structure. The effect of blocking the propagation of cracks by blocking the grain boundaries of titanium carbonitride was demonstrated. In the laminated structure of titanium boronitride and titanium carbonitride, the titanium carbonitride has a columnar structure, and the equivalent X-ray diffraction intensity ratio PR from the (422) plane or the (311) plane is maximum, thereby preventing cracking. Excellent in properties.
In Conventional Example 10, cracks occurred on the rake face of all the tools, and defects that could be caused by cracks occurred in 8 of 10 samples. In Conventional Example 11, cracks occurred in 8 samples out of 10 samples, and defects that could be caused by cracks occurred in 6 samples out of 10 samples. In Conventional Example 12, cracks occurred in 4 samples out of 10 samples, and defects that could be caused by cracks occurred in 4 samples out of 10 samples.

(Example 2)
Using the same cemented carbide test substrate and cemented carbide insert tool as in Example 1, the surface was coated by the thermal CVD method to produce Invention Examples 13 to 21 shown in Tables 5 and 6. did. The film directly on the substrate was in accordance with Example 1, and the film thickness and temperature conditions are shown in Table 5. The unit layer film also conforms to Example 1, and the temperature conditions and the number of unit layers are shown in Tables 5 and 6.

Subsequently, a TiN film, a Ti (CN) film, and an α-type aluminum oxide film, which are upper layer films, were continuously coated by a thermal CVD method. The coating conditions were as follows: a TiN film was formed to a thickness of 0.5 μm with H 2 carrier gas, TiCl 4 gas and N 2 gas at 1000 ° C., and a mixed gas of CO 2 and CO was added to the Ti (NO) film. The α-type aluminum oxide film formed to a thickness of 3 μm is formed of AlCl 3 gas generated by flowing H 2 gas at a flow rate of 310 ml / min and HCl gas 130 ml / min into a small tube filled with Al metal pieces and kept at 350 ° C. And H2 gas 2 (l / min) and a mixed gas of CO2 and CO of 100 to 400 ml / min were flowed into the film forming apparatus and reacted at 1000 degrees to form a film thickness of 2 μm. Invention Examples 13 to 21 were produced by the above lower layer film, intermediate layer film and upper layer film. Comparative examples 22 and 23 were produced in order to clarify the influence of the boron content of titanium boronitride. The film directly on the substrate and the upper film of Comparative Example 22 were formed under the same conditions as in Invention Examples 13-21. The unit layer film had a temperature condition of 800 degrees. For the (TiB) N film, H2 carrier gas, TiCl4 gas, and a very small amount of BCl3 gas and N2 gas were used. The unit layer film of Comparative Example 23 had a temperature condition of 900 degrees. For the (TiB) N film, H2 carrier gas, TiCl4 gas, BCl3 gas, and NH3 gas were used.
Comparative Examples 24 and 25 were prepared in order to clarify the influence of the equivalent X-ray diffraction intensity ratio PR from the (422) plane or the (311) plane of titanium carbonitride. The temperature condition of the TiC film and the Ti (CN) film, which are the film directly on the substrate of Comparative Example 24, was 1000 degrees. The TiC film was formed by using H2 carrier gas, TiCl4 gas, and CH4 gas as raw material gas and having a thickness of 3 [mu] m. Of the TiN film and Ti (CN) film directly on the substrate of Comparative Example 25, the Ti (CN) film is formed with a film thickness of 3 μm using H2 carrier gas, TiCl4 gas, CH4 gas, and N2 gas as source gases. did. In addition, the Ti (CN) film that is a unit layer film uses H2 carrier gas, TiCl4 gas, CH4 gas, and N2 gas as source gases. In Comparative Example 26, the film directly on the substrate and the unit layer film were coated by an ion plating (hereinafter referred to as IP) method. Then, it replaced with the CVD apparatus and coat | covered the upper film. In Comparative Example 27, the coating directly on the substrate and the unit layer coating were coated by the PACVD method. For the Ti (CN) film constituting the film directly on the substrate and the unit layer film, H2 carrier gas, TiCl4 gas, CH4 gas and N2 gas were used as source gases. Then, it replaced with the CVD apparatus and coat | covered the upper film. For the Ti (CN) film constituting the coating directly on the substrate of Conventional Example 28, H2 carrier gas, TiCl4 gas, CH4 gas and N2 gas were used as source gases. The unit layer film was a (TiB) N film having a thickness of 4 μm.

  Table 5 shows the results of measuring the boron contents of Invention Examples 13 to 21, Comparative Examples 22 to 27 and Conventional Example 28 by EDX, and the results of the crystal structure and PR value of the Ti (CN) film. From Table 5, the x value and y value of the titanium boronitride constituting the unit layers of Invention Examples 13 to 21 were in a relationship of 0.01 ≦ y / (x + y) ≦ 0.9. In Comparative Example 22, the y / (x + y) value was 0.009, and Comparative Example 23 was 0.910, which was outside the specified value range of the present invention. Table 7 shows the crystal structures of titanium carbonitride constituting the unit layers of Invention Examples 13 to 21, Comparative Examples 22 to 27 and Conventional Example 28. From Table 7, Examples 13 to 21 of the present invention and Comparative Examples 26 and 27 showed columnar structures. However, the columnar structures of Comparative Examples 26 and 27 were not columnar structures long in the film thickness direction but wide in the width direction. Comparative Examples 24 and 25 and Conventional Example 28 had a granular structure. The strongest surface of the PR value in X-ray diffraction of Invention Examples 13 to 21 and Comparative Examples 22 and 23 was (422) or (311). The strongest surfaces of PR values of Comparative Examples 24 to 27 and Conventional Example 28 were (220), (111), and (200), and were not (422) or (311).

Using the cutting tools of Invention Examples 13 to 21, Comparative Examples 22 to 27, and Conventional Example 28, five continuous cuttings were performed under the conditions shown in Cutting Condition 2. The amount of wear on the flank face of the tool was observed with an optical microscope with a magnification of 200 times, and when the amount of wear reached 0.30 mm, the cutting life was determined. Table 7 shows the evaluation results.
(Cutting test 2)
Work material: SCM437 (A)
Tool shape: WNMG080412
Cutting speed: 220 m / min
Feeding: 0.3mm / rotation Cutting: 3.0mm
Cutting fluid: Uses water-soluble fluid

From Table 7, Invention Examples 13 to 21 had few cracks on the rake face side and were excellent in wear resistance. However, Comparative Examples 22 and 23 were worn quickly and the continuous cutting life was 24 minutes and 26 minutes, which was inferior as a cutting tool. In Comparative Example 22, the y / (x + y) value according to the x value and y value of titanium boronitride in the unit layer was 0.009. As a result, the boron content of the film was small, the effect of preventing the propagation of cracks and the crack resistance were inferior, and the cutting life was short. The y / (x + y) value of Comparative Example 23 was 0.910. Accordingly, since the film hardness was hard and brittle, chipping occurred in the film at the initial stage of crack generation, and the cutting life was short. In Comparative Examples 24 and 25, the wear was fast and the continuous cutting life was 22 minutes, which was inferior as a cutting tool. This is because the titanium carbonitride film has a granular structure, so that cracks generated during processing propagated quickly, the toughness was poor, and chipping was easily caused, so that the cutting life was short. In Comparative Examples 26 and 27, the wear was quicker, and the continuous cutting life was 17 minutes and 18 minutes, which were inferior as cutting tools. This is probably because the strongest surface of the X-ray diffraction PR value is not the (311) plane or the (422) plane, so that the crystal grain size is large and chipping has occurred. Conventional Example 28 was inferior as a cutting tool with a continuous cutting life of 12 minutes.

Claims (4)

Any one of carbides, nitrides, carbonitrides, oxides, carbonates, nitrides and carbonitrides of one or more elements selected from Group 4a, 5a, and 6a metals in the periodic table directly above the substrate It has one type of single-layer coating or a multilayer coating consisting of two or more types, and a layer of titanium carbonitride and titanium boronitride is used as a unit layer on the coating, and at least two unit layers are covered. A multilayer coating member characterized by the above. 2. The multilayer film-coated member according to claim 1, wherein titanium boronitride constituting the unit layer is TixByN, where x and y are% by weight, and 0.01 ≦ y / (x + y) ≦ 0.9. A multilayer coating member characterized by the above. The multilayer coating member according to claim 1, wherein the titanium carbonitride of the unit layer has a columnar structure. The multilayer coating member according to claim 3, wherein the titanium carbonitride of the unit layer has a maximum equivalent X-ray diffraction intensity ratio PR from the (422) plane or the (311) plane. Element.