JP2007063650A - Hard stacked film, and hard stacked film-coated tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the fusion resistance of a hard stacked film essentially composed of TiAlN. <P>SOLUTION: Excellent wear resistance and toughness can be obtained by a substrate layer 22 in which TiAlN layers 22a and mixed layers 22b of TiAlN+CrBN are alternately stacked. Further, lubricity, i.e., fusion resistance improves since the friction coefficient of a CrBN layer 26 provided at the uppermost part so as to compose the surface is low. Also, excellent film characteristics are stably maintained even in a high temperature environment since the oxidation starting temperature of the CrBN layer 26 is high about 700°C. Thus, according to a ball end mill 10 coated with such hard stacked film 20, excellent machinability and durability can be obtained over a wide range from a ferrous work or a nonferrous work of a copper alloy or the like having low hardness and easy to be fused to a high hardness material such as a refined steel having a hardness of about 50 HRC. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hard laminated film, and more particularly to a hard laminated film having high lubricity (welding resistance) in addition to excellent wear resistance and toughness.

It has been proposed to coat the surface of a tool base material such as high-speed tool steel or cemented carbide with a hard multilayer coating in which TiAlN layers and TiAlN + CrN mixed layers are alternately laminated. The rotary cutting tool described in Patent Document 1 is an example, and a high hardness TiAlN layer and a mixed layer containing CrN having a relatively low hardness are alternately laminated. While wearability is obtained, toughness is increased by the presence of a mixed layer containing CrN having a relatively low hardness, and chipping and peeling of the coating are suppressed, and the durability of the tool is substantially improved. The same document also proposes using CrBN instead of CrN.
JP 2002-275618 A

  However, since the TiAlN layer has a relatively high coefficient of friction, for example, when cutting is performed on workpieces that are easily welded, such as copper and copper alloys, welding is likely to occur due to friction, and cutting such as machining accuracy is difficult. While performance is impaired, there is a case where desired durability performance cannot be obtained due to early wear. For example, welding is likely to occur at sites that are susceptible to frictional contact, such as surfaces that are likely to be near the rotation center of a rotary cutting tool such as a ball end mill or a drill.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to improve the welding resistance of a hard multilayer coating mainly composed of TiAlN.

  In order to achieve such an object, the hard laminated film of the first invention comprises: (a) a foundation layer in which TiAlN layers and TiAlN + CrBN mixed layers are alternately laminated on the surface of a predetermined member; and (b) the foundation layer. And an intermediate layer made of a mixed layer of TiAlN + CrBN, and (c) a CrBN layer which is provided on the intermediate layer and forms a surface.

  The second invention is the hard laminated film of the first invention, wherein the film thickness of the underlayer is in the range of 2 μm to 8 μm, the film thickness of the intermediate layer is in the range of 0.1 μm to 5 μm, and the CrBN layer The film thickness is in the range of 0.1 μm to 5 μm, and the total film thickness is 10 μm or less.

  The hard laminated film of the third invention comprises: (a) an underlayer in which TiAlN layers and TiAlN + CrBN mixed layers are alternately laminated on the surface of a predetermined member; and (b) an underlayer provided on the underlayer. And a CrBN layer which is formed.

  4th invention is the hard laminated film of 3rd invention, The film thickness of the said foundation | substrate layer is in the range of 2 micrometers-8 micrometers, The film thickness of the said CrBN layer is in the range of 0.1 micrometers-8 micrometers, Total film thickness is It is 10 μm or less.

  A fifth invention is characterized in that in the hard laminated film of any one of the first to fourth inventions, the lowermost layer and the uppermost layer of the underlayer are both TiAlN layers.

  A sixth invention is characterized in that in the hard multilayer coating of any of the first to fifth inventions, the surface of the cutting tool is coated.

  7th invention is related with the hard laminated film coating tool, The surface is coat | covered with the hard laminated film in any one of 1st invention-5th invention, It is characterized by the above-mentioned.

  In the hard multilayer coatings of the first to sixth inventions, excellent wear resistance and toughness can be obtained and the top layer is provided by the underlayer in which TiAlN layers and mixed layers of TiAlN + CrBN are alternately laminated. Since the CrBN layer constituting the surface has a small friction coefficient, lubricity, that is, welding resistance is improved. Further, since the oxidation start temperature of the CrBN layer is as high as about 700 ° C., excellent film properties are stably maintained even in a high temperature environment.

  Therefore, when such a hard multilayer coating is applied to a rotary cutting tool such as a ball end mill, the hardness is about 50 HRC from a non-ferrous workpiece such as an iron-based or copper alloy that is low in hardness and easily welded. Excellent cutting performance and durability performance can be obtained over a wide range up to high-hardness materials such as tempered steel. Specifically, rake face wear is suppressed by the presence of the CrBN layer, and the rake angle is suppressed from changing to the negative side in the late stage of cutting, so that the sharpness is maintained well over a long period of time and durability is improved. Improvement and stabilization of the machined surface properties can be realized. In addition, the workpiece is easy to weld near the center of rotation of the tip of a rotary cutting tool such as a ball end mill, but the workpiece is easily welded. However, the presence of the CrBN layer suppresses welding, so the cutting performance and durability are maintained well. Is done. In addition, since excellent coating properties can be stably obtained even in a high temperature environment, processing under severe cutting conditions such as high-efficiency processing that becomes high temperature by frictional heat or the like becomes possible.

  In the first invention, since the intermediate layer made of the mixed layer of TiAlN + CrBN containing CrBN is provided between the underlayer and the CrBN layer, the CrBN layer is laminated with high adhesion, and the CrBN layer Chipping and peeling are more preferably suppressed.

  In the fifth invention, since the lowermost layer and the uppermost layer of the foundation layer are both TiAlN layers, the lowermost TiAlN layer provides excellent adhesion to a predetermined member (tool base material, etc.) and the uppermost layer. Excellent wear resistance can be obtained by the TiAlN layer. Since the CrBN layer is provided directly or via an intermediate layer on the uppermost TiAlN layer, the high-hardness TiAlN layer does not directly contact the workpiece or the like, but the TiAlN layer deforms the CrBN layer. Is suppressed, and the wear resistance of the CrBN layer is improved.

  In the seventh invention relating to the hard laminated coating-coated tool, substantially the same effects as those of the first to fifth inventions can be obtained.

  The present invention is suitably applied to a hard laminated film coated on the surface of a rotary cutting tool having a cutting edge such as an end mill, a tap, or a drill, but a non-rotary cutting tool such as a cutting tool or a rolling tool, The present invention can be similarly applied to a hard laminated film coated on the surface of a member other than a processing tool such as various processing tools or a surface protective film of an electronic component or the like. A cemented carbide is preferably used as the member provided with the hard multilayer coating such as a tool base material, but other metal materials such as high-speed tool steel may be used.

  An arc ion plating method is preferably used as the method for forming the hard laminated film of the present invention, but other physical vapor deposition methods (PVD method) such as sputtering method, chemical vapor deposition such as plasma CVD method, thermal CVD method and the like. The method (CVD method) can also be used.

  When the total thickness of the hard laminated film of the present invention exceeds 10 μm, it is easy to peel off, and when it has a cutting edge, the cutting edge becomes round and the sharpness is lowered, so that it is preferably 10 μm or less. If the film thickness of the underlayer is less than 2 μm, sufficient film performance such as wear resistance, heat resistance, toughness and film strength cannot be obtained, so 2 μm or more is desirable, and the total film thickness of the entire film is 10 μm or less. In this case, the base layer is suitably 8 μm or less.

  The film thickness of the TiAlN layer of the underlayer is suitably in the range of 160 nm to 2000 nm, for example, and the film thickness of the mixed layer of TiAlN + CrBN is suitably in the range of 10 nm to 1000 nm, while maintaining the wear resistance by the TiAlN layer, It is possible to obtain the effect of preventing chipping and peeling by the mixed layer of TiAlN + CrBN. The thicknesses of the plurality of TiAlN layers and the mixed layer of TiAlN + CrBN may be constant, but various modes are possible such as continuously changing one layer at a time. The Ti: Al mixed crystal ratio of the TiAlN layer is preferably within a range of about Ti: Al = 2: 8 to 6: 4. The same applies to TiAlN in the mixed layer of TiAlN + CrBN constituting the underlayer and intermediate layer, but the mixed crystal ratio is not necessarily the same as that of the TiAlN layer.

  The underlayer is preferably provided with an odd number of layers such that at least three TiAlN layers and a mixed layer of TiAlN + CrBN are stacked, and the lowermost layer and the uppermost layer are both TiAlN layers. However, when the thickness of the mixed layer of TiAlN + CrBN is as thin as several tens of nanometers, the uppermost layer can be a mixed layer of TiAlN + CrBN. In that case, a new intermediate layer consisting of a mixed layer of TiAlN + CrBN is also laminated. The uppermost mixed layer can be used as an intermediate layer. In the third invention, when the uppermost layer of the underlayer is a TiAlN layer, it is assumed that a CrBN layer is directly laminated on the TiAlN layer. However, the uppermost layer of the underlayer is a mixed layer of TiAlN + CrBN. In some cases, a CrBN layer is directly provided without newly providing an intermediate layer.

  If the thickness of the intermediate layer is less than 0.1 μm, a sufficient adhesion effect cannot be obtained, so that the thickness is suitably 0.1 μm or more. If the film thickness of the uppermost CrBN layer is less than 0.1 μm, the effect of lubricity cannot be sufficiently obtained, so 0.1 μm or more is appropriate, and 0.5 μm or more is desirable. When the total film thickness of the entire coating is 10 μm or less, and having an intermediate layer, it is appropriate that the intermediate layer and the CrBN layer have a film thickness of 5 μm or less, respectively, and if the intermediate layer is not provided, CrBN The layer thickness is suitably 8 μm or less. In addition, the total film thickness of the entire hard laminate film is 2.1 μm or more when there is no intermediate layer including an underlayer with a film thickness of 2 μm or more for obtaining a predetermined film strength and film performance, and when there is an intermediate layer. Is suitably 2.2 μm or more, preferably 2.5 μm or more.

  Both the mixed layer and the intermediate layer of the underlayer are composed of a mixed layer of TiAlN + CrBN, and can be formed with exactly the same film composition. However, the mixed crystal ratio of Ti and Al, the TiAlN and CrBN By changing the mixing ratio, the film formation conditions such as the arc current and the bias voltage during film formation, the composition and properties of both can be positively changed.

  The CrBN mixed crystal ratio of CrBN constituting the mixed layer of the CrBN layer, intermediate layer, and underlayer is preferably in the range of Cr: B = 75: 25 to 95: 5. The mixed crystal ratio can also be changed between the CrBN layer, the intermediate layer, and the underlayer.

  Further, in the present invention, the CrBN layer is provided on the uppermost part of the coating, but since the intermediate layer of the first invention contains CrBN, the intermediate layer can be used as the uppermost coating without providing the CrBN layer. A certain degree of improvement in lubricity can be expected.

  TiAlN layer, mixed layer of TiAlN + CrBN (including intermediate layer), and CrBN layer are within the range where predetermined effects can be obtained with respect to wear resistance, toughness, adhesion, heat resistance, welding resistance, etc. required as a hard laminate film. In other words, other elements such as carbon may be included in addition to the inevitable impurities within a range that does not greatly impair the performance. For example, CrBN can adopt carbon nitride CrBCN containing C (carbon) in addition to pure nitride of CrB, and TiAlN can use C (carbon) in addition to pure nitride of TiAlN. Carbonitride TiAlCN containing can also be adopted.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1A and 1B are views for explaining a ball end mill 10 as an example of a hard cutting film-coated rotary cutting tool to which the present invention is applied, in which FIG. It is the expanded bottom view seen from the side (right direction of a figure), and the shank and the blade part 14 are integrally provided in the tool base material 12 comprised with the cemented carbide. The blade portion 14 is provided with a pair of outer peripheral blades 16 and a ball blade 18 symmetrically with respect to the shaft center as cutting blades, and these outer peripheral blades 16 and balls are rotated around the shaft center. Cutting is performed by the blade 18, and a hard laminated film 20 is coated on the surface of the blade portion 14. 1 (a) and 1 (b) represent the hard laminated film 20, and FIG. 1 (c) is a cross-sectional view of the surface layer portion of the blade portion 14 coated with the hard laminated film 20. The ball end mill 10 corresponds to a hard multilayer coating-coated tool, and the tool base material 12 corresponds to a predetermined member on which the hard multilayer coating 20 is provided.

  As is clear from FIG. 1 (c), the hard laminated film 20 is composed of the base layer 22, the intermediate layer 24, and the uppermost CrBN layer 26 constituting the surface. The film thickness is in the range of 2.2 μm to 10 μm. The underlayer 22 is formed by alternately laminating three or more TiAlN layers 22a and TiAlN + CrBN mixed layers 22b, and the underlayer 22 has a thickness in the range of 2 to 8 μm. The average film thickness of the TiAlN layer 22a is in the range of 160 nm to 2000 nm, and the average film thickness of the mixed layer 22b is in the range of 10 nm to 1000 nm. The mixed layer 22b is a mixture of TiAlN and CrBN at a predetermined ratio, and the Ti / Al mixed crystal ratio of TiAlN in the TiAlN layer 22a and the mixed layer 22b is Ti: Al = 2: 8-6. In the present embodiment, Ti: Al = 4: 6. Further, the lowermost layer and the uppermost layer of the hard laminated film 20 are both composed of the TiAlN layer 22a, and the total number of the TiAlN layer 22a and the mixed layer 22b is an odd number of 3 or more.

  The hardness (Hv) of the TiAlN is about 2300 to 3000, whereas the hardness (Hv) of CrBN is about 2000 to 2700. Such a mixed layer 22b of CrBN and TiAlN is composed only of TiAlN. The hardness is lower than that of the TiAlN layer 22a. Therefore, the foundation layer 22 in which the high hardness TiAlN layers 22a and the mixed layers 22b having relatively low hardness are alternately laminated provides excellent wear resistance by the high hardness TiAlN layers 22a, and the low hardness mixed layer. The presence of 22b increases the toughness and makes it difficult for chipping and peeling. The average film thickness of the TiAlN layer 22a is in the range of 160 nm to 2000 nm, the average film thickness of the mixed layer 22b is in the range of 10 nm to 1000 nm, and the total film thickness of the underlayer 22 is in the range of 2 μm to 8 μm. Further, while maintaining the wear resistance by the TiAlN layer 22a, the effect of preventing chipping and peeling by the mixed layer 22b can be sufficiently obtained.

  The intermediate layer 24 is a mixed layer in which TiAlN and CrBN are mixed. In the present embodiment, the intermediate layer 24 has the same composition as the mixed layer 22b. The intermediate layer 24 is continuously provided on the underlayer 22, specifically, the TiAlN layer 22a which is the uppermost layer of the underlayer 22, and the film thickness thereof is in the range of 0.1 μm to 5 μm. It is. Thus, by providing the TiAlN + CrBN intermediate layer 24 on the underlayer 24, that is, on the uppermost TiAlN layer 22a prior to the CrBN layer 26, the adhesion of the CrBN layer 26 to the underlayer 22 is improved. The mixed crystal ratio of TiAl of TiAlN in the intermediate layer 24 is within the range of Ti: Al = 2: 8 to 6: 4, and in this embodiment, Ti: Al = 4: 6.

  The CrBN layer 26 is continuously provided on the intermediate layer 24, and its film thickness is in the range of 0.1 μm to 5 μm. The CrBN constituting the CrBN layer 26 has a smaller friction coefficient than TiAlN, and the CrBN layer 26 is provided on the uppermost portion so as to constitute the surface, so that the lubricity between the workpiece and the workpiece, Improved welding resistance. The Cr and B mixed crystal ratios of CrBN constituting the mixed layer 22b of the CrBN layer 26, the intermediate layer 24 and the underlayer 22 are all in the range of Cr: B = 75: 25 to 95: 5. In this embodiment, Cr: B = 85: 15.

  FIG. 4 is a diagram for explaining the results of examining the friction coefficient of CrBN and TiAlN by the ball-on-disk method similar to the test method defined in JIS R1613. (A) is the test condition, and (b) is the test condition. It is a result. The friction coefficient curve in (b) represents the initial change in the friction coefficient, TiAlN converges in the range of about 0.5 to 0.7, and CrBN in the range of about 0.2 to 0.3. Converge to. (C) in FIG. 4 is a coefficient of friction investigated at high temperature (400 ° C.). TiAlN is about 0.7, whereas CrBN is about 0.21, and (b) room temperature ( The results were almost the same as in the case of 25 ° C. (C) in FIG. 4 is the same as (a) except for the fact that the temperature is 400 ° C.

  In addition, although the said hard laminated film 20 is provided with the intermediate | middle layer 24, the intermediate | middle layer 24 is abbreviate | omitted and the CrBN layer 26 may be laminated | stacked directly on the base layer 22 like the hard laminated film 28 of FIG. it can. In this case, the underlayer 22 is configured in the same manner as the hard laminated film 20, but the CrBN layer 26 can be thickened by the absence of the intermediate layer 24, and the film thickness is 0.1 μm to 8 μm. It is determined within the range.

  In addition, TiAlN in the TiAlN layer 22a, the mixed layer 22b, and the intermediate layer 24 of the underlayer 22 is a pure nitride of TiAlN that does not contain carbon, but carbon is within a range that does not impair hardness, adhesion, and the like. It is also possible to introduce carbonitride TiAlCN. CrBN in the mixed layer 22b, the intermediate layer 24, and the CrBN layer 26 of the underlayer 22 is also a pure nitride of CrB, but carbon is introduced to the extent that lubricity, heat resistance, etc. are not impaired, and carbonitride CrBCN. It can be.

On the other hand, FIG. 3 is a schematic configuration diagram (schematic diagram) illustrating an arc ion plating apparatus 30 that is preferably used when such a hard laminated film 20 or 28 is formed. , 28, a workpiece holder 32 holding the tool base material 12 on which the cutting edges 16, 18, etc. are formed, and a rotating device 34 that rotates the workpiece holder 32 around a substantially vertical rotation center. , A bias power source 36 for applying a negative bias voltage to the tool base 12, a chamber 38 as a processing container containing the tool base 12 and the like, and a reactive gas supply for supplying a predetermined reactive gas into the chamber 38 An apparatus 40, an exhaust apparatus 42 that exhausts the gas in the chamber 38 with a vacuum pump or the like to reduce the pressure, a first arc power supply 44, a second arc power supply 46 and the like are provided. The workpiece holder 32 has a cylindrical shape or a polygonal column shape centered on the rotation center, and holds a large number of tool base materials 12 in a posture in which the blade portion 14 protrudes outward substantially horizontally. . Further, the reactive gas supply device 40 includes a tank of nitrogen gas (N ₂ ), and nitrides of TiAl and CrB are formed by supplying nitrogen gas into the chamber 38. In the case of forming such carbonitrides, a tank of a hydrocarbon gas (CH ₄ , C ₂ H _2, etc.) may be provided to supply the hydrocarbon gas together with the nitrogen gas.

  The first arc power source 44 supplies a predetermined arc current to the anode 50 using the first evaporation source (target) 48 made of TiAl alloy constituting the TiAlN of the TiAlN layer 22a and the mixed layer 22b as a cathode. The TiAl is evaporated from the first evaporation source 48 by arc discharge, and the evaporated TiAl becomes a positive (+) metal ion and a negative (−) bias voltage is applied to the tool base material. 12 adheres. The second arc power source 46 is connected to the anode 54 with the second evaporation source (target) 52 made of CrB alloy constituting the mixed layer 22b, the intermediate layer 24, and the CrBN layer 26 as a cathode. Is supplied with a predetermined arc current to cause arc discharge to evaporate CrB from the second evaporation source 52. The evaporated CrB becomes a positive (+) metal ion and has a negative (−) bias voltage. It adheres to the applied tool base material 12. The first evaporation source 48 and the second evaporation source 52 are disposed at symmetrical positions in the substantially horizontal direction with the work holder 32 interposed therebetween.

When the hard laminated coating 20 or 28 is formed on the surface of the blade portion 14 of the tool base material 12 using such an arc ion plating device 30, first, the inside of the chamber 38 is exhausted by the exhaust device 42. Is supplied from the reaction gas supply device 40 so as to be maintained at a predetermined pressure (for example, about 1.33 × 5 × 10 ⁻¹ Pa to 1.33 × 40 × 10 ⁻¹ Pa), A predetermined bias voltage (for example, about −50 V to −150 V) is applied to the tool base 12 by the bias power source 36. Then, the first arc power supply 44 and the second arc power supply 46 are turned on (energized) and turned off (non-energized) while rotating the workpiece holder 32 at a predetermined rotational speed (for example, about 3 min ⁻¹ ) by the rotating device 34. By doing so, the hard laminated film 20 or 28 is formed.

  That is, when the arc current is turned on (energized) by the first arc power supply 44 with the second arc power supply 46 turned off (non-energized), the TiAl metal ions are released from the first evaporation source 48, By reacting with nitrogen gas, TiAlN is formed and adheres to the surface of the tool base material 12. Thereby, the TiAlN layer 22a can be formed. The energization time and the current value of the arc current are determined according to the film thickness of the TiAlN layer 22a to be formed.

  Further, when the arc current is turned on (energized) by the second arc power supply 46 with the first arc power supply 44 turned off (non-energized) to cause arc discharge, CrB metal ions are released from the second evaporation source 52, By reacting with nitrogen gas, CrBN is formed and adheres to the surface of the tool base material 12. Thereby, the CrBN layer 26 can be formed. The energization time and the current value of the arc current are determined according to the film thickness of the CrBN layer 26 to be formed.

  Further, when the arc current is turned on (energized) by the first arc power supply 44 to cause arc discharge, and when the arc current is turned on (energized) by the second arc power supply 46 to cause arc discharge, the TiAl of the first evaporation source 48 As metal ions are released, CrB metal ions are released from the second evaporation source 52 and react with nitrogen gas to form TiAlN and CrBN, respectively, which adhere to the surface of the tool base 12. Since the first evaporation source 48 and the second evaporation source 52 are arranged on the opposite side with the workpiece holder 32 interposed therebetween, TiAlN and CrBN are alternately turned into the tool mother as the workpiece holder 32 is driven to rotate. It is attached to the surface of the material 12. Thereby, the mixed layer 22b and the intermediate layer 24 in which TiAlN and CrBN are mixed can be formed. The energizing time of each of the arc power supplies 44 and 46 is determined according to the film thickness of the mixed layer 22b and the intermediate layer 24 to be formed, and the current value of the arc current of the arc power supplies 44 and 46 is determined by the mixed layer 22b and the intermediate layer to be formed. It is determined according to the film thickness of the layer 24, the mixing ratio of TiAlN and CrBN, and the like.

  Thus, by switching the energization state (ON, OFF) of the first arc power supply 44 and the second arc power supply 46, the base layer 22 in which the TiAlN layers 22a and the TiAlN + CrBN mixed layers 22b are alternately stacked, the mixture of TiAlN + CrBN The intermediate layer 24 composed of layers and the CrBN layer 26 can be formed continuously, and the hard laminated coatings 20 and 28 can be provided on the surface of the tool base material 12. The operation of forming the hard laminated films 20 and 28 including switching of the energization states (ON and OFF) of the first arc power supply 44 and the second arc power supply 46 may be automatically performed by a control device including a computer. it can.

  Here, the hard multilayer coatings 20 and 28 of the present example are provided with excellent wear resistance and toughness by the underlayer 22 in which the TiAlN layers 22a and the TiAlN + CrBN mixed layers 22b are alternately laminated, and the topmost portion. Since the CrBN layer 26 provided on the surface and constituting the surface has a small coefficient of friction, lubricity, that is, welding resistance is improved. Moreover, since the oxidation start temperature of the CrBN layer 26 is as high as about 700 ° C., excellent film properties are stably maintained even in a high temperature environment.

  Therefore, according to the ball end mill 10 coated with such a hard multilayer coating 20 or 28, the hardness is approximately 50 HRC from a non-ferrous workpiece such as iron or copper alloy which is low in hardness and easily welded. Excellent cutting performance and durability performance can be obtained over a wide range up to high hardness materials such as tempered steel. Specifically, rake face wear is suppressed due to the presence of the CrBN layer 26, and the rake angle is suppressed from changing to the negative side in the later stage of cutting, so that the sharpness is well maintained over a long period of time, and durability is improved. And stabilization of the machined surface properties can be realized. Further, near the center of rotation of the tip of the ball end mill 10, the cutting edge of the ball blade 18 is poor and the workpiece is easily welded. However, since the welding is suppressed by the presence of the CrBN layer 26, the cutting performance and durability are good. Maintained. On the other hand, since excellent film properties can be stably obtained even in a high-temperature environment, it is possible to perform processing under severe cutting conditions such as high-efficiency processing that becomes high temperature by frictional heat or the like.

  In this embodiment, since the lowermost layer and the uppermost layer of the base layer 22 are both TiAlN layers 22a, the lowermost TiAlN layer 22a provides excellent adhesion to the tool base material 12, and the uppermost layer. Excellent wear resistance is obtained by the TiAlN layer 22a. Since the CrBN layer 26 is provided directly or via the intermediate layer 24 on the uppermost TiAlN layer 22a, the high-hardness TiAlN layer 22a does not directly contact the workpiece or the like, but the TiAlN layer 22a As a result, deformation of the CrBN layer 26 is suppressed, and the wear resistance of the CrBN layer 26 is improved.

  In the case of the hard laminated film 20 of FIG. 1, an intermediate layer 24 made of a mixed layer of TiAlN + CrBN containing CrBN is provided between the base layer 22 and the CrBN layer 26, so that the TiAlN layer is the uppermost layer. The CrBN layer 26 is laminated with high adhesion to the underlying layer 22 where the 22a is located, and chipping and peeling of the CrBN layer 26 are more preferably suppressed.

  Further, the hard laminated coatings 20 and 28 of the present example have an overall total film thickness of 10 μm or less, so that exfoliation to the tool base material 12 is suppressed and excellent adhesion can be obtained, and the outer peripheral edge 16 and the ball While it is prevented that the cutting edge of the blade 18 is rounded and the sharpness is lowered, since it is 2.2 μm or more, predetermined coating strength and coating performance can be obtained. That is, since the film thickness of the underlayer 22 is 2 μm or more, the film performance and film strength required for the underlayer 22 such as wear resistance, heat resistance, and toughness can be sufficiently obtained, and the intermediate layer 24, CrBN layer Since the film thicknesses of each film are 0.1 μm or more, sufficient film performance such as adhesion and lubrication performance can be obtained.

  Incidentally, in FIG. 5, a ball end mill 10 having a radius R of 1.5 mm of the ball blade 18 prepared by coating various coatings shown in (b) is prepared, and C1100 ( This figure shows the results of examining the VB wear width (flank wear width) after performing 400 m cutting on JIS (copper), and the VB wear width of the product of the present invention is 0.03 μm to 0.048 μm. It can be seen that the wear resistance is improved as compared with the comparative product, and excellent durability can be obtained even for workpieces that are easily welded such as copper. For example, since the VB wear width of the comparative product (conventional product) consisting only of the base layer 22 having a multilayer structure is 0.093 μm, the product of the present invention has a durability of about twice or more than that. The underlayer 22 having a multilayer structure in which the TiAlN layers 22a and the mixed layers 22b of TiAlN + CrBN are alternately laminated has the TiAlN layer 22a as the uppermost layer and the lowermost layer in both the present invention and the comparative product.

  FIG. 6 shows a ball end mill 10 having a radius R of 3 mm of the ball blade 18 coated with various coatings shown in (b). S50C (JIS: mechanical structure) under the processing conditions shown in (a). This is a figure showing the results of examining the VB wear width (flank wear width) after cutting 56 m to the carbon steel for use in the present invention. The VB wear width of the product of the present invention is 0.061 μm to 0.072 μm. It can be seen that the wear resistance is improved as compared with the comparative product, and excellent durability can be obtained even for a high-hardness workpiece such as carbon steel. For example, since the VB wear width of the comparative product (conventional product) consisting only of the base layer 22 having a multilayer structure is 0.091 μm, the product of the present invention further improves the durability by 20% or more. The underlayer 22 having a multilayer structure in which the TiAlN layers 22a and the mixed layers 22b of TiAlN + CrBN are alternately laminated has the TiAlN layer 22a as the uppermost layer and the lowermost layer in both the present invention and the comparative product.

  As mentioned above, although the Example of this invention was described in detail based on drawing, these are one embodiment to the last, and this invention is implemented in the aspect which added the various change and improvement based on the knowledge of those skilled in the art. be able to.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the end mill which is one Example of this invention, (a) is the front view seen from the direction orthogonal to an axial center, (b) is an enlarged bottom view, (c) is the blade part provided with the hard laminated film It is sectional drawing of the surface layer part. It is sectional drawing which shows another example of the hard laminated film shown to (c) of FIG. It is a schematic block diagram explaining an example of the arc ion plating apparatus which can form the hard laminated film of FIG. 1, FIG. 2 suitably. It is a figure which shows the result of having investigated the friction coefficient of CrBN by the ball-on-disk method compared with TiAlN. It is a figure explaining the result of having investigated cutting face flank wear width by cutting on C1100 (copper) on predetermined working conditions using a plurality of the present invention goods and comparative goods from which the composition of a coat differs. The figure explaining the result of having investigated cutting face flank wear width by cutting on S50C (carbon steel for machine structure) with a predetermined processing condition using a plurality of the present invention products and comparative products having different coating configurations It is.

Explanation of symbols

  10: Ball end mill (hard laminated coating coated tool) 12: Tool base material (member) 20, 28: Hard laminated coating 22: Underlayer 22a: TiAlN layer 22b: Mixed layer 24: Intermediate layer 26: CrBN layer

Claims (7)

An underlayer in which TiAlN layers and mixed layers of TiAlN + CrBN are alternately stacked on the surface of a predetermined member;
An intermediate layer made of a mixed layer of TiAlN + CrBN provided on the underlayer;
A CrBN layer provided on the intermediate layer and constituting a surface;
A hard laminated film characterized by comprising: The thickness of the underlayer is in the range of 2 μm to 8 μm, the thickness of the intermediate layer is in the range of 0.1 μm to 5 μm, and the thickness of the CrBN layer is in the range of 0.1 μm to 5 μm. The hard laminated film according to claim 1, wherein the film thickness is 10 μm or less. An underlayer in which TiAlN layers and mixed layers of TiAlN + CrBN are alternately stacked on the surface of a predetermined member;
A CrBN layer which is provided on the underlayer and forms a surface;
A hard laminated film characterized by comprising: The film thickness of the underlayer is in the range of 2 μm to 8 μm, the film thickness of the CrBN layer is in the range of 0.1 μm to 8 μm, and the total film thickness is 10 μm or less. Hard laminate coating. The hard multilayer coating according to any one of claims 1 to 4, wherein both the lowermost layer and the uppermost layer of the base layer are TiAlN layers.   The hard laminated film according to any one of claims 1 to 5, which is coated on a surface of a cutting tool.   A hard multilayer coating-coated tool, the surface of which is coated with the hard multilayer coating according to any one of claims 1 to 5.

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