JP2019131861A - Hard film, hard film-coated tool, and manufacturing method thereof - Google Patents

Abstract

To provide a high-performance hard film capable of showing excellent lubricity; and to provide a hard film-coated tool, and a manufacturing method thereof.SOLUTION: A hard film has a composition shown by (AlCrB)NO(where, x, 1-x-y, y, a and 1-a are figures each showing an atomic ratio of Al, Cr, B, N and O, and satisfying 0.35≤x≤0.75, 0.01≤y≤0.1 and 0.990≤a≤0.998), which is a hard film having a single structure in which an X-ray diffraction pattern is fcc. A hard film-coated tool obtained by forming a hard film on a substrate, and a manufacturing method thereof are also provided.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an (AlCrB) N hard film, a hard film-coated tool, and a method for producing the same, which exhibit excellent lubricity.

  Various hard coatings have been proposed in order to extend the life of tools for cutting work materials at high feed rates and high speeds, dies used for severe molding conditions, and the like.

Japanese Patent Laying-Open No. 2005-330539 (Patent Document 1) discloses that 0.35 ≦ x ≦ 0.65 in the composition formula: (Al _1-x Cr _x ) (N _1-y B _y ) _{z on} the surface of a substrate. , 0.03 ≦ y ≦ 0.3 and 0.8 ≦ z ≦ 1.2 are disclosed.

Patent No. 3640310 (Patent Document _{2), (Al x Cr 1-x} -y Si y) (N 1-α-β-γ B α C β O γ), where, x, y, α, β and γ represents an atomic ratio, and 0.45 <x <0.75, 0 <y <0.20, 0 ≦ α <0.12, 0 ≦ β <0.20, and 0 <γ <0.25. A hard film having the composition is disclosed.

Patent No. 533310 (Patent Document 3) is Al _α Cr _b X _c α _d N [where X is a BN of a hybrid orbital in which the binding state is SP2 or SP3, and a diameter of 10 to 1000 nm is in the range of 1 to 1000 nm. Is an agglomerate containing amorphous BN, or at least one crystal of cBN and hBN, and α is IVa group, Va group, VIa group (excluding Cr), B, C, Si in the periodic table , Y are one or more elements, and a, b, c, and d are atomic ratios of 0.35 ≦ a ≦ 0.76, 0.12 ≦ b ≦ 0.43, 0.02 ≦, respectively. Aluminum within the range of c ≦ 0.20, 0 ≦ d ≦ 0.20, and the ratio of atomic ratio of Cr to Al (b / a) within the range of 0.25 ≦ b / a ≦ 0.67 Rich, a + b + c + d = 1. ] Is disclosed.

Japanese Patent No. 5684929 (Patent Document 4) forms an fcc-structured AlCrBN film (paragraph 0014) by cathodic arc evaporation (arc ion plating method) in an N ₂ atmosphere at 3.5 Pa and 500 ° C.

Japanese Patent Laying-Open No. 2005-330539 Japanese Patent No. 3640310 Japanese Patent No. 5313210 Japanese Patent No. 5684929

  As described in the above prior art, a hard film with high hardness can be obtained by adding B to AlCrN. However, in order to obtain a hard coating that satisfies the recent demands for long life, not only the wear resistance by improving the hardness of the hard coating but also the chipping resistance and wear resistance by improving the lubricity of the hard coating. Need to be improved. Therefore, a new (AlCrB) N coating satisfying the above requirements and a cutting tool coated with the coating are required.

  Accordingly, an object of the present invention is to provide a (AlCrB) N hard coating that exhibits superior lubricity, has a long life, and has a long life, a hard coating tool that has the hard coating formed on a substrate, and a method for manufacturing the same. Is to provide.

The hard coating of the present invention has (Al _x Cr _1-xy B _y ) N _a O _1-a (where x, 1-xy, y, a, and 1-a are Al, Cr, B, respectively). , N and O, and a numerical value satisfying 0.35 ≦ x ≦ 0.75, 0.01 ≦ y ≦ 0.1, and 0.990 ≦ a ≦ 0.998. The X-ray diffraction pattern has a single structure of fcc.

  In the above hard coating, the peak intensity ratio (BN) / (BO) between the BN bond and the BO bond specified by the X-ray photoelectron spectroscopy is 0.4 to 1.0. Preferably there is.

  The hard film-coated tool of the present invention is characterized in that the hard film is formed on a substrate.

The manufacturing method of the hard film coated tool of the present invention is (Al _x Cr _1-xy B _y ) N _a O _1-a (where x, 1-xy, y, a and 1-a are respectively Represents the atomic ratio of Al, Cr, B, N, and O, and is a number that satisfies 0.35 ≦ x ≦ 0.75, 0.01 ≦ y ≦ 0.1, and 0.990 ≦ a ≦ 0.998 )) And a hard film coated tool having a hard film having a single structure with an X-ray diffraction pattern of fcc on a substrate, which is produced by arc ion plating. Using an AlCrB sintered body alloy having an oxygen content of 2000 to 4000 μg / g as an evaporation source (target), in a nitrogen gas atmosphere with a total pressure of 2.7 to 3.3 Pa, the temperature is set to 400 to 550 ° C. The hard coating is formed on the held substrate. The features.

  In the above production method, the peak intensity ratio (BN) / (BO) between the BN bond and the BO bond specified by X-ray photoelectron spectroscopy in the hard coating is 0.4 to 1. It is preferable that a bias voltage of −160 V to −100 V is applied to the substrate. The bias voltage is preferably a DC bias voltage or a pulse bias voltage.

In the above manufacturing method, the composition of the metal element and the metalloid element of the target is Al _α Cr _1-α-β B _β (where α, 1-α-β, and β are atomic ratios of Al, Cr, and B, respectively) And is a number satisfying 0.4 ≦ α ≦ 0.8 and 0.04 ≦ β ≦ 0.17).

  The (AlCrB) N hard coating of the present invention has a single structure with an X-ray diffraction pattern of fcc and an oxygen content (1-a) of 0.010 to 0.002, It exhibits excellent lubricity compared to AlCrB) N hard coating, and has a long life and high performance.

  In the (AlCrB) N hard coating, the peak intensity ratio (BN) / (BO) between the BN bond and the BO bond specified by the X-ray photoelectron spectroscopy is 0.4 to 0.4. If it is 1.0, it will exhibit further superior lubricity compared to the conventional (AlCrB) N hard coating, and it will be a long-life and high-performance (AlCrB) N hard coating.

  The hard-coated tool having the hard coating of the present invention exhibits significantly superior lubricity compared to the conventional (AlCrB) N hard-coated tool, and has a long life and high performance, so that it can be used as an insert, end mill, or drill. It is extremely useful as a cutting tool.

It is a front view which shows an example of the arc ion plating apparatus which can be used for formation of the hard film of this invention. 2 is a scanning electron microscope (SEM) photograph (magnification 25,000 times) showing a cross section of the hard film-coated tool of Example 1. FIG. It is a graph which shows the X-ray photoelectron spectrum which shows the coupling | bonding state of B in the cross-sectional center position of the (AlCrB) N hard film of Example 1. FIG. 3 is a graph showing an X-ray diffraction pattern of the (AlCrB) N hard coating film of Example 1. FIG. It is a photograph which shows the crystal structure analyzed from the nano beam diffraction pattern of the (AlCrB) N hard film of Example 1. It is a perspective view which shows an example of the insert base | substrate which comprises the hard film coating tool of this invention. It is the schematic which shows an example of the blade-tip-exchange-type rotary tool equipped with the insert.

  Embodiments of the present invention will be described in detail below, but the present invention is not limited thereto, and may be changed or improved as appropriate based on ordinary knowledge of those skilled in the art without departing from the technical idea of the present invention. May be added. Further, the description relating to one embodiment can be applied to other embodiments as it is unless otherwise specified.

[1] Hard film-coated tool The hard film-coated tool of the present embodiment has (Al _x Cr _1-xy B _y ) N _a O _1-a (where x, 1-xy, y, a, and 1-a represent atomic ratios of Al, Cr, B, N, and O, respectively, and 0.35 ≦ x ≦ 0.75, 0.01 ≦ y ≦ 0.1, and 0.990 ≦ a ≦ 0.998 is a hard film-coated tool in which a hard film having a composition represented by: The X-ray diffraction pattern of the hard coating has a single structure of fcc. The peak intensity ratio (BN) / (BO) between the BN bond and the BO bond specified by X-ray photoelectron spectroscopy in the hard coating is 0.4 to 1.0. Is preferred. The hard coating can be formed by an arc ion plating (AI) method.

(A) Substrate The substrate needs to be made of a material that has high heat resistance and can be applied with physical vapor deposition. Examples of the material of the substrate include cemented carbide, cermet, high speed steel, tool steel, and ceramics such as cubic boron nitride (cBN). From the viewpoints of strength, hardness, wear resistance, toughness, thermal stability, etc., a cemented carbide substrate or a ceramic substrate is preferred. The cemented carbide is composed of tungsten carbide particles and a binder phase of Co or an alloy mainly composed of Co, and the content of the binder phase is preferably 1 to 13.5% by mass, and more preferably 3 to 13% by mass. When the binder phase content is less than 1% by mass, the toughness is insufficient, and when the binder phase exceeds 13.5% by mass, the hardness (abrasion resistance) is insufficient. The (AlCrB) N hard coating of this embodiment can be formed on any of the unprocessed surface, the polished surface, and the blade edge processed surface of the sintered substrate.

(B) Modified layer of cemented carbide substrate When the substrate is a cemented carbide, the surface of the substrate is irradiated with ions generated from a TiB target described later (hereinafter also referred to as ion bombardment), and the average thickness is 1 to 10 nm. It is preferable to form a modified layer having an fcc structure. In the cemented carbide, the main component tungsten carbide has an hcp structure, but the modified layer has the same fcc structure as the (AlCrB) N hard coating, and preferably 30% of crystal lattice fringes at the boundary (interface) between them. As described above, a portion of 50% or more, more preferably 70% or more continues. The cemented carbide substrate and the (AlCrB) N hard coating are firmly adhered to each other through the modified layer.

  The modified layer has an fcc structure and is formed in a high-density thin layer, so that it is unlikely to become a starting point of destruction. If the average thickness of the modified layer is less than 1 nm, the effect of improving the adhesion of the hard coating to the substrate cannot be obtained sufficiently, and if it exceeds 10 nm, the adhesion is worsened. The average thickness of the modified layer is more preferably 2 to 9 nm.

(C) (AlCrB) N hard coating (1) Composition The (AlCrB) N hard coating of this embodiment formed on the substrate by the AI method contains Al, Cr, B, N and O as essential elements. The composition of the hard film is represented by the general formula: (Al _x Cr _1-xy B _y ) N _a O _1-a (where x, 1-xy, y, a and 1-a are Al, (It represents the atomic ratio of Cr, B, N and O, and is a number satisfying 0.35 ≦ x ≦ 0.75, 0.01 ≦ y ≦ 0.1, and 0.990 ≦ a ≦ 0.998.) It is represented by The (AlCrB) N hard coating of this embodiment has a single structure of fcc. In the (AlCrB) N hard coating of this embodiment, the peak intensity ratio (BN) / (BO) between the BN bond and the BO bond specified by the X-ray photoelectron spectroscopy spectrum is 0.00. It is preferably 4 to 1.0, more preferably 0.4 to 0.9, and particularly preferably 0.3 to 0.9.

  The total of the atomic ratios x, 1-xy and y of Al, Cr and B of the (AlCrB) N hard coating of this embodiment is 1, and the range of the atomic ratio x of Al is 0.35 to 0.75. It is. If x is less than 0.35, the Al content of the hard coating is too small, so that the oxidation resistance is impaired. On the other hand, if x exceeds 0.75, a soft hcp structure is formed in the hard coating, and the wear resistance is impaired. The lower limit of x is preferably 0.4, and the upper limit of x is preferably 0.74.

  The total of the atomic ratios x, 1-xy and y of Al, Cr and B of the (AlCrB) N hard coating of this embodiment is 1, and the range of the atomic ratio 1-xy of Cr is 0.64. ~ 0.15. If 1-xy is less than 0.15, the hard coating has too much Al content, so that a soft hcp structure is formed in the hard coating and wear resistance is impaired. On the other hand, if 1-xy exceeds 0.64, the Al content of the hard coating becomes too small, so that the oxidation resistance is impaired. The lower limit of 1-xy is preferably 0.17, and the upper limit of 1-xy is preferably 0.58.

  The total of the atomic ratios x, 1-xy and y of Al, Cr and B of the (AlCrB) N hard coating of this embodiment is 1, and the range of the atomic ratio y of B is 0.01 to 0.1. It is. If y is less than 0.01, the effect of addition cannot be obtained and the lubricity is impaired. On the other hand, if y exceeds 0.1, it becomes brittle and cannot maintain a single structure of fcc. The lower limit of y is preferably 0.02, and the upper limit of y is preferably 0.09.

The total p of each atomic ratio of the metal component AlCr and the semimetal component B and the total q of each atomic ratio of nitrogen and oxygen is 1, and the range of p is 0.4 to 0.6 (the range of q is 0.6 to 0.4). That, (AlCrB) N hard coating of the present _{embodiment, (Al x Cr 1-x} -y B y) p (N a O 1-a) q [ However, x, 1-x-y , y, a , 1-a, p and q represent atomic ratios of Al, Cr, B, N, O, AlCrB and NO, respectively, 0.35 ≦ x ≦ 0.75, 0.01 ≦ y ≦ 0.1, The numbers satisfy 0.990 ≦ a ≦ 0.998, 0.4 ≦ p ≦ 0.6, and 0.6 ≦ q ≦ 0.4. It has the composition represented by this.
If p is less than 0.4, impurities are likely to be taken into the crystal grain boundaries of the (AlCrB) N polycrystal. Impurities are derived from the internal residue of the film forming apparatus. In such a case, the strength of the (AlCrB) N hard film is reduced, and the film is easily broken by an external impact. On the other hand, if p exceeds 0.6, the ratio of the metal component AlCr and the semimetal component B becomes excessive, the crystal strain increases, the adhesion with the substrate decreases, and the (AlCrB) N hard coating peels off. It becomes easy. The lower limit of p is preferably 0.40, and the upper limit of p is preferably 0.60.

  The total of the atomic ratios of nitrogen (N) and oxygen (O) contained in the (AlCrB) N hard coating of this embodiment is 1, and the range of the atomic ratio a of N is 0.990 to 0.998. If a is less than 0.990, the oxygen content becomes excessive, and the wear resistance decreases. When a exceeds 0.998, the oxygen content becomes too low and the lubricity is lowered. The lower limit of a is preferably 0.981, and more preferably 0.982. The upper limit of a is preferably 0.997, and more preferably 0.996. The nitrogen (N) and oxygen (O) contents can be analyzed by using EPMA and TEM-EDS described later in combination.

  The (AlCrB) N hard coating of this embodiment may contain C. In that case, in order to maintain high wear resistance, the C content is preferably 0.1 or less when the total content (atomic ratio) of N, O and C of nonmetallic elements is 1. More preferably, it is 0.05 or less.

(2) Mechanism The hard-coated tool having the (AlCrB) N hard coating on the substrate of this embodiment has significantly better lubricity than the conventional (AlCrB) N hard-coated tool, and has a long life and high The mechanism of performance has not been fully clarified, but is considered as follows.
As illustrated in Conventional Example 1 to be described later, the conventional (AlCrB) N hard coating coated tool has a short life, and has not been able to sufficiently meet the recent demands for long life and high performance.

  As a result of intensive studies on the long life and high performance of the (AlCrB) N hard coating, the present inventor has (a) oxygen content of 2000 to 4000 μg / g as a target used for forming the (AlCrB) N hard coating. (B) When the total pressure of the nitrogen gas atmosphere during film formation is set to 2.7 to 3.3 Pa, the (AlCrB) N hard film formed is fcc. It was discovered that it has a single structure and the nitrogen content (atomic ratio) can be adjusted to 0.990-0.998 (oxygen content (atomic ratio) 0.010-0.002). Further, in the obtained (AlCrB) N hard coating, BN bond and BO bond coexist in the bond state specified by X-ray photoelectron spectroscopy, and the BN bond and BO bond are It was discovered that the peak intensity ratio (BN) / (BO) can be adjusted to 0.4 to 1.0. And the hard film coated tool formed by forming the (AlCrB) N hard film of the present embodiment on the tool base exhibits a remarkable excellent lubricity, so that it becomes a long-life and high-performance cutting tool. I understood.

  From the detailed examination of the present inventors, in the (AlCrB) N hard coating of this embodiment, the B—O bond portion mainly shares excellent lubricity, and the B—N bond portion mainly has excellent resistance to resistance. It is considered that the hard coating tool of the present embodiment has a long life and high performance as a result of sharing the wear characteristics and thus achieving both lubricity and wear resistance.

(3) Film thickness 0.5-8 micrometers is preferable and, as for the thickness of the (AlCrB) N hard film of this embodiment, 1-5 micrometers is more preferable. With a film thickness in this range, the (AlCrB) N hard coating is prevented from peeling from the substrate, and excellent lubricity and wear resistance are exhibited. If the thickness is less than 0.5 μm, the coating effect of the (AlCrB) N hard film cannot be sufficiently obtained, and if the thickness exceeds 8 μm, the residual stress becomes excessive, and the (AlCrB) N hard film is easily peeled off from the substrate. Become. Here, the “thickness” of the non-flat (AlCrB) N hard coating means “arithmetic average thickness”.

(4) Crystal structure The X-ray diffraction pattern of the hard coating of this embodiment has a single fcc structure.
In X-ray diffraction, even if a micro phase other than fcc is present, it does not appear in the X-ray diffraction pattern. Therefore, according to electron diffraction using a transmission electron microscope (TEM) capable of detecting a micro phase of a hard coating, The hard film of the form may have fcc as the main structure and other structures (hcp, etc.) as the substructure. From the viewpoint of practicality, the electron diffraction pattern preferably has fcc as the main structure and hcp as the substructure, and more preferably has a single structure of fcc.

(5) Peak intensity ratio (BN) / (BO)
The peak intensity ratio (BN) / (BO) between the BN bond and the BO bond specified by X-ray photoelectron spectroscopy is preferably 0.4 to 1.0, and 0 More preferably, it is from 5 to 0.9. When the peak intensity ratio (B—N) / (B—O) satisfies the above range, a long-life hard coating having both wear resistance and lubricity can be obtained. When the peak intensity ratio is less than 0.4, the BN bond is relatively lowered, so that the wear resistance is lowered. On the other hand, when the peak intensity ratio exceeds 1.0, the B—O bond is relatively lowered, so that the lubricity is lowered.

[2] Film formation apparatus (AlCrB) N An AI apparatus can be used for forming a hard film, and an AI apparatus or other physical vapor deposition apparatus (such as a sputtering apparatus) can be used for forming a laminated hard film. it can. For example, as shown in FIG. 1, the AI apparatus includes a decompression vessel 5, arc discharge evaporation sources 13 and 27 attached to the decompression vessel 5 via an insulator 14, and arc discharge evaporation sources 13 and 27. Attached targets 10, 18, arc discharge power sources 11, 12 connected to the respective arc discharge evaporation sources 13, 27, and a rotatable support column 6 penetrating to the inside of the decompression vessel 5 through the bearing portion 4. A holder 8 supported by the column 6 for holding the substrate 7, a drive unit 1 that rotates the column 6, and a bias power source 3 that applies a bias voltage to the substrate 7. The decompression vessel 5 is provided with a gas introduction part 2 and an exhaust port 17. The arc ignition mechanisms 16 and 16 are attached to the decompression vessel 5 via arc ignition mechanism bearing portions 15 and 15. A filament type electrode 20 is attached to the decompression vessel 5 via insulators 19 and 19 for ionization of a gas (argon gas, nitrogen gas, etc.) introduced into the decompression vessel 5. Between the target 10 and the base body 7, a shielding plate 23 is provided in the decompression vessel 5 via a shielding plate bearing portion 21. The shielding plate 23 is moved, for example, vertically or horizontally by the shielding plate driving unit 22, and after the shielding plate 23 is not present between the target 10 and the base body 7, the (AlCrB) N hard coating of this embodiment is used. Is formed.

(A) (AlCrB) N Hard Film Formation Target (1) Composition of Sintered Body Alloy The (AlCrB) N hard film formation target used in this embodiment uses, for example, Al powder and a CrB alloy powder having a predetermined composition. Then, the composition of the following AlCrB sintered body alloy is blended and mixed, the obtained mixed powder is molded, and the obtained molded body is sintered to obtain an AlCrB sintered body alloy target. is there. The amount of oxygen contained in the target can be adjusted, for example, by appropriately selecting the particle sizes of Al powder and CrB alloy powder.

The composition of the AlCrB sintered body alloy is Al _α Cr _1-α-β B _β (where α, 1-α-β and β represent atomic ratios of Al, Cr and B, respectively, except for inevitable impurities, 0 It is preferable to have a composition represented by the following formula: 4 ≦ α ≦ 0.8 and 0.04 ≦ β ≦ 0.17. By setting α and β within the specific ranges, the (AlCrB) N hard coating of this embodiment can be formed.

  The total of the atomic ratios of Al, Cr and B of the AlCrB sintered body alloy is 1, and the range of the atomic ratio α of Al is preferably 0.4 to 0.8. If α is less than 0.4, the Al content of the (AlCrB) N hard coating is too small, so that the oxidation resistance is impaired. On the other hand, if α exceeds 0.8, a soft hcp structure is formed in the (AlCrB) N hard coating, and the wear resistance is impaired. The lower limit of α is more preferably 0.45, and the upper limit of α is more preferably 0.78.

  The total atomic ratio of Al, Cr and B of the AlCrB sintered alloy is 1, and the range of the atomic ratio 1-α-β of Cr is preferably 0.56 to 0.03. If 1-α-β is less than 0.03, the effect of adding Cr cannot be obtained. On the other hand, if 1-α-β exceeds 0.56, the Al content becomes too low and the oxidation resistance is impaired. The lower limit of 1-α-β is more preferably 0.10, and the upper limit of 1-α-β is more preferably 0.50.

  The total atomic ratio of Al, Cr and B in the AlCrB sintered alloy is 1, and the range of the atomic ratio β of B is preferably 0.04 to 0.17. If β is less than 0.04, the effect of adding B cannot be obtained. On the other hand, if β exceeds 0.17, the single structure of fcc cannot be maintained in the (AlCrB) N hard coating. The lower limit of β is more preferably 0.05, and the upper limit of β is more preferably 0.16.

(2) Oxygen content of sintered body alloy The oxygen content of the AlCrB sintered body alloy is 2000 to 4000 μg / g. When the oxygen content is less than 2000 μg / g and more than 4000 μg / g, the oxygen content of the (AlCrB) N hard coating is less than 0.002 and more than 0.010, and the advantageous effect of the hard coating of the present embodiment Do not play. Furthermore, it does not satisfy the specific range of the peak intensity ratio (BN) / (BO). The lower limit of the oxygen content of the AlCrB sintered body alloy is preferably 2050 μg / g, more preferably 2100 μg / g. On the other hand, the upper limit of the oxygen content of the AlCrB sintered body alloy is preferably 3900 μg / g, more preferably 3800 μg / g.

(B) TiB target for modified layer formation TiB target for modified layer formation is Ti _f B _1-f (where f is the atomic ratio of Ti, 0.5 ≦ f ≦ 0.9 is satisfied). If the atomic ratio f of Ti is less than 0.5, a modified layer having an fcc structure cannot be obtained. If f exceeds 0.9, a decarburized layer is formed, and a modified layer having an fcc structure cannot be obtained. The lower limit of the atomic ratio f of Ti is more preferably 0.7, and the upper limit of the atomic ratio f of Ti is more preferably 0.88.

(C) Arc Discharge Evaporation Source and Arc Discharge Power Source As shown in FIG. 1, arc discharge evaporation sources 13 and 27 are formed of a TiB target 10 for forming a modified layer of cathode material and (AlCrB) N hard coating, respectively. The target 18 is provided. For example, a DC arc current is supplied to the target 10 from the arc discharge power supplies 11 and 12, and a pulse arc current is supplied to the target 18. Although not shown, the arc discharge evaporation sources 13 and 27 are provided with a magnetic field generating means (a structure having an electromagnet and / or a permanent magnet and a yoke) in the vicinity of the base body 7 on which the (AlCrB) N hard film is formed. It is preferable to form a magnetic field distribution with a gap magnetic flux density of several tens of G (for example, 10 to 50 G).

  The target for forming an (AlCrB) N hard coating contains Al that is liable to generate droplets. The droplets cause the division of the growth of (AlCrB) N polycrystalline grains and the starting point for the destruction of the (AlCrB) N hard coating. Therefore, excessive generation of droplets can be suppressed by supplying a direct current arc current of 150 to 250 A to the AlCrB sintered body alloy target (evaporation source).

(D) Bias power source As shown in FIG. 1, a DC voltage or a pulse bias voltage is applied to the substrate 7 from the bias power source 3.

[3] Film Formation Conditions The (AlCrB) N hard coating of the present embodiment can be formed by the AI method using the AlCrB sintered alloy target. The film forming conditions of the (AlCrB) N hard film of this embodiment will be described in detail below for each process.

(A) Substrate cleaning step After the substrate 7 is set on the holder 8 of the AI apparatus shown in FIG. 1, the inside of the decompression vessel 5 is 1 to 5 × 10 ⁻² Pa (for example, 1.5 × 10 ⁻² Pa). The substrate 7 is heated to a temperature of 250 to 650 ° C. by a heater (not shown). Although shown in FIG. 1 as a cylinder, the substrate 7 can take various shapes such as a solid type end mill or insert. Thereafter, argon gas is introduced into the decompression vessel 5 to obtain an argon gas atmosphere of 0.5 to 10 Pa (for example, 2 Pa). In this state, a DC bias voltage or pulse bias voltage of −250 to −150 V is applied to the substrate 7 from the bias power source 3 to clean the surface of the substrate 7 by bombarding with argon ions.

  If the substrate temperature is less than 250 ° C., there is no etching effect by argon ions, and if it exceeds 650 ° C., it is difficult to set the substrate temperature to a predetermined condition during the film forming process. The substrate temperature is measured by a thermocouple embedded in the substrate (the same applies to the subsequent steps). When the pressure of the argon gas in the decompression vessel 5 is outside the range of 0.5 to 10 Pa, the bombardment process using argon ions becomes unstable. When the DC bias voltage or pulse bias voltage is less than −250 V, arcing occurs in the substrate, and when it exceeds −150 V, the cleaning effect by bombard etching cannot be sufficiently obtained.

(B) Modified layer forming step The ion bombardment to the WC-based cemented carbide substrate 7 using the modified layer forming TiB target is performed in an argon gas atmosphere having a flow rate of 30 to 150 sccm after the substrate 7 is cleaned. Then, a modified layer is formed on the surface of the substrate 7. An arc current (DC current) of 50 to 100 A is supplied from the arc discharge power supply 11 to the surface of the TiB target attached to the arc discharge evaporation source 13. The substrate 7 is heated to a temperature of 450 to 750 ° C., and a DC bias voltage of −1000 to −600 V is applied from the bias power source 3 to the substrate 7. By ion bombardment using a TiB target, Ti ions and B ions are irradiated onto the WC-based cemented carbide substrate 7.

  When the temperature of the substrate 7 is outside the range of 450 to 750 ° C., the modified layer having the fcc structure is not formed, or a decarburized layer is formed on the surface of the substrate 7 and the performance is significantly lowered. If the flow rate of the argon gas in the decompression vessel 5 is less than 30 sccm, the energy of Ti ions incident on the substrate 7 is too strong, and a decarburized layer is formed on the surface of the substrate 7 and the adhesion of the hard coating is impaired. On the other hand, when the flow rate of argon gas exceeds 150 sccm, the energy of Ti ions or the like is weakened, and the modified layer is not formed.

  When the arc current is less than 50 A, the arc discharge becomes unstable, and when it exceeds 100 A, a large number of droplets are formed on the surface of the substrate 7 and the adhesion is impaired. When the DC bias voltage is less than −1000 V, energy such as Ti ions is too strong and a decarburized layer is formed on the surface of the substrate 7, and when it exceeds −600 V, a modified layer is not formed on the substrate surface.

(C) (AlCrB) N Hard Film Formation Step (AlCrB) N hard film is formed on the substrate 7 or, if a modified layer is formed, on the modified layer. At this time, nitrogen gas is used, and an arc current is applied to the surface of the target 18 attached to the arc discharge evaporation source 27 from the arc discharge power source 12. At the same time, a DC bias voltage or a unipolar pulse bias voltage is applied from the bias power source 3 to the substrate 7 controlled to the following temperature.

(1) Substrate temperature The substrate temperature during deposition of the (AlCrB) N hard coating is set to 400 to 550 ° C. Since the (AlCrB) N does not crystallize sufficiently when the substrate temperature is less than 400 ° C., the (AlCrB) N hard film does not have sufficient lubricity and wear resistance, and the increase in residual stress may cause film peeling. Become. On the other hand, if the substrate temperature exceeds 550 ° C., the refinement of crystal grains is promoted and the lubricity and wear resistance are impaired. The substrate temperature is preferably 480 to 540 ° C.

(2) Pressure of nitrogen gas Nitrogen gas is used as a film forming gas for forming the (AlCrB) N hard film of this embodiment. The pressure (total pressure) of nitrogen gas is set to 2.7 to 3.3 Pa. If the pressure of the nitrogen gas is less than 2.7 Pa, the nitriding of the (AlCrB) N hard coating (formation of BN bonds) becomes insufficient, the oxygen content becomes excessive, and there are other phases such as an AlCrB alloy phase that is not nitrided. To do. On the other hand, when the pressure of nitrogen gas exceeds 3.3 Pa, the oxygen content becomes too small. Furthermore, the peak intensity of the BN bond becomes larger than the peak intensity of the BO bond. The lower limit of the nitrogen gas pressure is preferably 2.8 Pa, and more preferably 2.9 Pa. The upper limit of the pressure of nitrogen gas is preferably 3.2 Pa, and more preferably 3.1 Pa.

(3) Flow rate of nitrogen gas The flow rate of nitrogen gas is preferably 750 to 900 sccm. If the flow rate of nitrogen gas is less than 750 sccm and more than 900 sccm, it is difficult to adjust the pressure (total pressure) of the nitrogen gas to 2.7 to 3.3 Pa. The lower limit of the flow rate of nitrogen gas is more preferably 770 sccm, and the upper limit of the flow rate of nitrogen gas is more preferably 880 sccm.

(4) Bias voltage applied to the substrate In order to form the (AlCrB) N hard coating, a DC bias voltage or a unipolar pulse bias voltage is applied to the substrate. The DC bias voltage is preferably −160 to −100V. When the DC bias voltage is less than −160 V, the B content is significantly reduced. On the other hand, when the DC bias voltage exceeds -100V, the (AlCrB) N hard coating has a short life. A more preferable range of the DC bias voltage is −150 to −110V.

  In the case of a unipolar pulse bias voltage, the negative bias voltage (a negative peak value excluding a portion with a steep rise from zero to the negative side) is preferably −160 to −100V. By setting the negative bias voltage within this range, a long-life (AlCrB) N hard coating can be obtained. A more preferable range of the negative bias voltage is −150 to −110V. The frequency of the unipolar pulse bias voltage is preferably 20 to 50 kHz, and more preferably 30 to 40 kHz.

(4) Arc current In order to suppress droplets during the formation of the (AlCrB) N hard coating, an arc current (DC current) is passed through the (AlCrB) N hard coating formation target (AlCrB sintered alloy target) 18. Is preferred. The arc current is preferably 150 to 250A. If the arc current is less than 150 A, the arc discharge becomes unstable and it becomes difficult to form an (AlCrB) N hard coating. On the other hand, when the arc current exceeds 250 A, the number of droplets increases remarkably and the wear resistance deteriorates. The arc current is more preferably 160 to 240A.

  The present invention will be described in more detail with reference to the following examples, but the present invention is of course not limited thereto. In the following examples and comparative examples, the composition of the target metal element and metalloid element is measured by the fluorescent X-ray method unless otherwise specified, and the oxygen content is determined by the carrier gas hot extraction method. It is a measured value. In the embodiments, the insert is used as the base of the hard coating. However, the present invention is of course not limited thereto, and can be applied to cutting tools other than the insert (end mill, drill, etc.) or a die. .

Example 1
(1) Substrate cleaning Finished milling insert substrate made of WC-based cemented carbide containing 8.0% by mass of Co and the balance of WC and unavoidable impurities (Mitsubishi Hitachi having the shape shown in FIG. 6) ZDFG300-SC manufactured by Tool Co., Ltd.) and an insert base for measuring physical properties (SNMN120408 manufactured by Mitsubishi Hitachi Tool Co., Ltd.) are set on the holder 8 of the AI apparatus shown in FIG. (Not shown). Thereafter, argon gas is introduced at a flow rate of 500 sccm (cc / min at 1 atm and 25 ° C.) to adjust the pressure in the vacuum vessel 5 to 2.0 Pa and to each of the substrates (hereinafter also referred to as the substrate 7). The substrate 7 was cleaned by etching with argon ion bombardment by applying a DC bias voltage of −200V.

(2) Formation of a modified layer using a TiB target A target having a composition represented by Ti _0.8 B _0.2 (atomic ratio) while maintaining the substrate temperature at 550 ° C. and setting the flow rate of argon gas to 70 sccm. 10 is disposed in an arc discharge evaporation source 13 to which an arc discharge power source 11 is connected. A DC voltage of −800 V is applied to the substrate 7 by the bias power supply 3, a 75 A DC arc current is passed from the arc discharge power supply 11 to the surface of the target 10, and a modified layer having an average thickness of 4 nm is formed on the surface of the substrate 7. Formed. The average thickness of the modified layer was measured by the method described in Japanese Patent No. 5967329.

(3) Formation of (AlCrB) N hard coating (Al) _0.59 (Cr) _0.31 (B) _0.10 (atomic ratio) composition of metal elements and metalloid elements, and oxygen content is 2250 μg / A target 18 made of an AlCrB sintered body alloy of g was placed in an arc discharge evaporation source 27 to which the arc discharge power source 12 of FIG. 1 was connected. The temperature of the substrate 7 was set to 450 ° C., the total pressure of nitrogen gas in the decompression vessel 5 in a nitrogen gas atmosphere was adjusted to 3.0 Pa, and the flow rate of nitrogen gas was adjusted to 800 sccm.

A DC power of −120 V is applied to the base 7 by the bias power source 3, and a DC arc current of 200 A is applied to the target 18 from the arc discharge power source 12, and (Al _0.54 Cr _0.42 B) is applied on the base 7. The (AlCrB) N hard coating of this example having a thickness of 3 μm and a composition of _0.04 ) N _0.994 O _0.006 (atomic ratio) was coated. Thus, a hard film coated tool (milling insert) of this example was obtained. The composition of the hard film formed was such that the center position in the thickness direction of the hard film was measured with an electron probe microanalyzer EPMA (JXA-8500F manufactured by JEOL Ltd.) at an acceleration voltage of 10 kV, an irradiation current of 0.05 A, and a beam diameter. The measurement was performed under the condition of 0.5 μm. The EPMA measurement conditions are the same in other examples. Further, the analysis values of the N and O elements contained in the (AlCrB) N hard film are energy dispersive X-rays mounted on a transmission electron microscope (JEM-2100 manufactured by JEOL Ltd.) together with the EPMA analysis. It was determined by using together with TEM-EDS analysis using a spectroscope (EDS, URAN type Si (Li) semiconductor detector manufactured by NORAN, beam diameter: about 1 μm).

  FIG. 2 is a scanning electron microscope (SEM) photograph (magnification: 25,000 times) showing a cross-sectional structure of the (AlCrB) N hard film-coated milling insert. In FIG. 2, 31 indicates a WC-based cemented carbide substrate, and 32 indicates an (AlCrB) N hard coating composed of a polycrystalline structure of columnar crystal grains. Since FIG. 2 is a low magnification, the modified layer is not visible.

(4) Bonded state of B in (AlCrB) N hard coating Using an X-ray photoelectron spectrometer (PHI-PHI-5000 Versaprobe II), the thickness of the (AlCrB) N hard coating having the above-mentioned cross-sectional structure is measured by argon ions 3 is etched to a depth half of the direction (surface side), and then irradiated with AlK _alpha rays (1486.7 eV, 25 kV, monochrome) in a range of 100 μm in diameter, and the X-ray photoelectron of FIG. A spectroscopic spectrum was obtained. In FIG. 3, the horizontal axis represents binding energy (eV), and the vertical axis represents c / s (counts per second). FIG. 3 shows the detected B1s spectrum and the B—O bond and the B—N bond obtained by performing peak separation of the B1s spectrum. From FIG. 3, the peak intensity of the BN bond is observed at 191 eV, and the peak intensity of the BO bond is observed at 193 eV, and the peak intensity ratio between the BN bond and the BO bond (B—N ) / (BO) was 0.6.

(5) X-ray diffraction pattern of (AlCrB) N hard coating In order to observe the crystal structure of (AlCrB) N hard coating on the insert substrate for measuring physical properties, an X-ray diffractometer (EMPYREAN manufactured by Panallytical) was used. The surface of the (AlCrB) N hard coating was irradiated with CuKα1 rays (wavelength λ: 0.15405 nm) under the following conditions to obtain an X-ray diffraction pattern (FIG. 4).
Tube voltage: 45kV
Tube current: 40 mA
Incident angle ω: fixed at 3 ° 2θ: 20-90 °

  In FIG. 4, the (111) plane, (200) plane, (220) plane, (311) plane, and (222) plane are all X-ray diffraction peaks of the fcc structure. Therefore, it can be seen that the (AlCrB) N hard coating of Example 1 has an fcc single structure. In FIG. 4, the X-ray diffraction peaks not indexed are X-ray diffraction peaks of the WC-based cemented carbide substrate.

(6) Microstructure of (AlCrB) N hard coating At the center position in the thickness direction of the cross section of the (AlCrB) N hard coating of the physical property measurement insert, an accelerating voltage of 200 kV and a transmission electron microscope (JEM-2100) Nanobeam diffraction was performed under the condition of a camera length of 50 cm. The obtained diffraction image is shown in FIG. In FIG. 5, since the diffraction patterns of the (111), (200), and (220) planes of the fcc structure were observed, the (AlCrB) N hard film of this example has a single electron diffraction pattern of fcc. It turned out to be a structure.

(7) Measurement of tool life As shown in FIGS. 6 and 7, the above (AlCrB) N hard coating coated milling insert (hereinafter also referred to as insert 30) is replaced with a blade-exchangeable rotary tool (manufactured by Mitsubishi Hitachi Tool Co., Ltd.) The tool body 36 of the ABPF30S32L150) 40 was mounted using a set screw 37. The blade diameter of the blade-tip-exchange-type rotary tool 40 was 30 mm. Cutting is performed under the following rolling conditions using the blade-tip-replaceable rotary tool 40, the flank of the insert 30 sampled every unit time is observed with an optical microscope (magnification: 100 times), and the wear width of the flank Alternatively, the machining time when the chipping width was 0.2 mm or more was determined as the tool life.

Cutting conditions Machining method: Continuous rolling Work material: S50C square (120 mm x 250 mm) (HB220)
Inserts used: ZDFG300-SC (for milling)
Cutting tool: ABPF30S32L150
Cutting speed: 380 m / min Feed amount per blade: 0.3 mm / blade Axial cut amount: 0.3 mm
Radial cut depth: 0.1 mm
Cutting fluid: None (dry machining)

  The composition of the used AlCrB sintered body alloy target for forming the (AlCrB) N hard coating is shown in Table 1, the film forming conditions of the used (AlCrB) N hard coating are shown in Table 2, and the obtained (AlCrB) N hard The composition of the film is shown in Table 3, the measurement result of the crystal structure of the film by X-ray diffraction and electron diffraction, the peak intensity ratio of B—O bond and B—N bond identified by X-ray photoelectron spectroscopy ( Table 4 shows BN) / (BO) and tool life.

Examples 2-9
(AlCrB) N In the same manner as in Example 1, except that the AlCrB sintered body target of each example shown in Table 1 was used, and the film forming conditions of the (AlCrB) N hard film of each example shown in Table 2 were used. Hard film coated milling inserts and hard film coated tools were produced. In Examples 2 and 3, the addition amount of Al (Cr) was changed with respect to Example 1. In Examples 4 and 5, the B addition amount was changed from that in Example 1. In Examples 6 and 9, the total pressure of nitrogen gas was changed from that in Example 1. In Example 7, the bias voltage was changed from that in Example 5. In Example 8, the amount of oxygen contained in the sintered compact target was changed from that in Example 1. The composition of the AlCrB sintered body alloy target of each example is shown in Table 1, the film formation conditions of the (AlCrB) N hard film of each example are shown in Table 2, and the obtained (AlCrB) N hard The composition of the film is shown in Table 3, and the measurement results of the crystal structure by X-ray diffraction and electron diffraction of the (AlCrB) N hard film of each of the above examples, the B− specified by the X-ray photoelectron spectroscopy of each of the above examples Table 4 shows the peak intensity ratio (BN) / (BO) of the O bond and BN bond, and the tool life of each example.

Comparative Example 1
(AlCrB) N hard as in Example 1, except that the total pressure of the nitrogen gas atmosphere in the decompression vessel 5 during the formation of the (AlCrB) N hard coating was adjusted to 2 Pa and the flow rate of the nitrogen gas to 700 sccm. Film coated milling inserts and hard film coated tools were produced.

Comparative Example 2
(AlCrB) In the same manner as in Example 1 except that the total pressure of the nitrogen gas atmosphere in the decompression vessel 5 was adjusted to 3.5 Pa and the flow rate of the nitrogen gas to 900 sccm during the formation of the N hard coating (AlCrB) N hard coating coated milling inserts and hard coating coated tools were produced.

Comparative Example 3
A (AlCrB) N hard coating coated milling insert and a hard coating coated tool were produced in the same manner as in Example 1 except that an AlCrB sintered alloy target (Table 1) with an excessive oxygen content (420 μg / g) was used. .

Comparative Example 4
A (AlCrB) N hard coating coated milling insert and a hard coating coated tool were produced in the same manner as in Example 1 except that an AlCrB sintered alloy target (Table 1) having an excessive oxygen content (5390 μg / g) was used. .

Conventional Example 1
<Trace Experiment on Film Formation Conditions of Sample No. 4 in Table 1 of Patent Document 1 (Japanese Patent Laid-Open No. 2005-330539)>
Nitrogen gas flow rate during deposition of (AlCrB) N hard coating: 200 sccm, nitrogen gas total pressure: 1 Pa, arc current: 200 A, and substrate bias voltage: −50 V (Table 2) Similarly, an (AlCrB) N hard coating coated milling insert and a hard coating coated tool were produced.

Example 10
A (AlCrB) N hard coating coated milling insert and a hard coating coated tool were produced in the same manner as in Example 1 except that a modified layer using a TiB target was not formed on the WC-based cemented carbide substrate. Table 1 shows the composition of the AlCrB sintered alloy target used, Table 2 shows the film forming conditions of the (AlCrB) N hard coating used, and Table 3 shows the composition of the obtained (AlCrB) N hard coating. And the measurement result of the crystal structure of the (AlCrB) N hard coating by X-ray diffraction and electron diffraction, the peak intensity ratio of B—O bond and B—N bond identified by X-ray photoelectron spectroscopy (B—N ) / (BO) and tool life are shown in Table 4.

Note: (1) Pressure of nitrogen gas atmosphere.
(2) Apply to the AlCrB sintered alloy target.
(3) Apply to the substrate.

Notes: (1) Single structure.
(2) Main structure.
(3) Ratio of the peak intensity of the BN bond and the peak intensity of the BO bond specified by the X-ray photoelectron spectroscopy.
(4): Not measured.
(5): B—O bond was not observed and could not be calculated.

  As shown in Table 4, from the X-ray photoelectron spectroscopy spectrum of each obtained example, in each of the (AlCrB) N hard coatings of Examples 1 to 10, the oxygen content (1-a) is 0.990 to 0 Within the range of .998. Furthermore, in each of the (AlCrB) N hard coatings of Examples 1 to 8 and 10, the B—O bond and the B—N bond are formed, and the peak intensity of the BN bond and the peak of the B—O bond are formed. It can be seen that the intensity ratio (BN / BO) is in the range of 0.4 to 1.0. In particular, the oxygen content (1-a) of the (AlCrB) N hard coating of Example 1 was 0.006, and the peak intensity ratio (BN / BO) was 0.6. Therefore, the tool life of the blade-tip-exchangeable rotary tool equipped with the (AlCrB) N hard coating-coated insert of Example 1 was 400 minutes, which was the longest. The tool life of the blade-tip-exchange-type rotary tool equipped with the (AlCrB) N hard coating-coated insert of Example 10 in which no modified layer was formed by the TiB target was 310 minutes, and Examples 1 to 1 in which the modified layer was formed The tool life was shorter than that of each of the 9 cutting edge exchange type rotary tools, but was longer than that of the respective cutting edge exchange type rotary tools of Comparative Examples and Conventional Example 1.

  The blade-tip-exchangeable rotary tools equipped with the (AlCrB) N hard coating-coated inserts of Comparative Examples 1 to 4 and Conventional Example 1 all had a short life. In the (AlCrB) N hard coating of Comparative Example 1, the oxygen content (1-a) was 0.012, and the peak intensity ratio (BN / BO) was 0.3. It is judged that good lubricity and wear resistance were not compatible. In the (AlCrB) N hard film of Comparative Example 2, the oxygen content (1-a) was 0.001, and the peak intensity ratio (BN / BO) was 2.1. It is judged that good lubricity and wear resistance were not compatible. In the (AlCrB) N hard coating film of Comparative Example 3, the oxygen content (1-a) is 0.001, and further, since no B—O bond is formed, both good lubricity and wear resistance are achieved. It is judged that it was not possible. In the (AlCrB) N hard coating of Comparative Example 4, the oxygen content (1-a) was 0.016, and the peak intensity ratio (BN / BO) was 0.1. It is judged that good lubricity and wear resistance were not compatible. Since the flow rate and pressure of nitrogen gas are low in the (AlCrB) N hard coating film of Conventional Example 1, the oxygen content (1-a) is 0.013, and further no BN bond is formed. It is judged that good lubricity and wear resistance were not compatible.

1: Drive unit 2: Gas introduction unit 3: Bias power supply 4: Bearing unit 5: Depressurization vessel 6: Lower holder (support)
7: Substrate 8: Upper holder 10, 18: Cathode material (target)
DESCRIPTION OF SYMBOLS 11, 12: Arc discharge power supply 13, 27: Arc discharge evaporation source 14: Insulator for fixing arc discharge evaporation source 15: Arc ignition mechanism bearing 16: Arc ignition mechanism 17: Exhaust port 19: Insulation for fixing electrode Material 20: Electrode 21: Shield plate bearing portion 22: Shield plate drive portion 23: Shield plate 30: Insert for milling 31: WC base cemented carbide substrate 32: (AlCrB) N hard coating 35: Rake face of insert 36: Tool Substrate 37: Insert set screw 38: Tip end of tool body 39: Blade-replaceable rotary tool 46: Tool body 47: Insert set screw 48: Tip end of tool body

Claims (6)

(Al _x Cr _1-xy B _y ) N _a O _1-a (where x, 1-xy, y, a and 1-a are atomic ratios of Al, Cr, B, N and O, respectively) Is a number satisfying 0.35 ≦ x ≦ 0.75, 0.01 ≦ y ≦ 0.1, and 0.990 ≦ a ≦ 0.998.) There,
A hard film, wherein the X-ray diffraction pattern has a single structure of fcc.   The hard film according to claim 1, wherein the peak intensity ratio (BN) / (BO) between the BN bond and the BO bond specified by X-ray photoelectron spectroscopy is 0.4 to 0.4. Hard coating characterized by being 1.0.   A hard film-coated tool, wherein the hard film according to claim 1 or 2 is formed on a substrate. (Al _x Cr _1-xy B _y ) N _a O _1-a (where x, 1-xy, y, a and 1-a are atomic ratios of Al, Cr, B, N and O, respectively) And a composition satisfying 0.35 ≦ x ≦ 0.75, 0.01 ≦ y ≦ 0.1, and 0.990 ≦ a ≦ 0.998) A method for producing a hard film-coated tool having a hard film having a single structure having a line diffraction pattern of fcc on a substrate by an arc ion plating method,
Using an AlCrB sintered alloy having an oxygen content of 2000 to 4000 μg / g as an arc discharge evaporation source (target), in a nitrogen gas atmosphere having a total pressure of 2.7 to 3.3 Pa, a temperature of 400 to 550 ° C. A method for producing a hard film-coated tool, wherein the hard film is formed on the substrate maintained at a temperature.   5. The method for manufacturing a hard film-coated tool according to claim 4, wherein a peak intensity ratio (B−N) / (B—N bond and B—O bond specified by X-ray photoelectron spectroscopy in the hard film is obtained. B-O) is 0.4 to 1.0, and a bias voltage of -160 V to -100 V is applied to the substrate. In the manufacturing method of the hard coat | cover coated tool of Claim 4 or 5, the composition of the metal element and metalloid element of the target is Al _α Cr _1-α-β B _β (where α, 1-α-β and β represents an atomic ratio of Al, Cr, and B, and is a number satisfying 0.4 ≦ α ≦ 0.8 and 0.04 ≦ β ≦ 0.17). Manufacturing method of hard coating tool.