JP5331210B2 - Hard coating and hard coating tool - Google Patents

Description

  The present invention relates to a hard coating, and more particularly to a hard coating excellent in wear resistance and heat resistance.

  It is widely performed to provide a hard coating on the surface of a predetermined member such as a tool base material such as high-speed tool steel or cemented carbide. For example, in high-speed machining of a high-hardness work material, the heat resistance of the coating (oxidation resistance at high temperatures) is very important and greatly affects the tool life. As such hard coatings excellent in heat resistance, for example, TiAlN-based and AlCrN-based coatings are conventionally known (see, for example, Patent Documents 1 to 5). Patent Document 6 proposes a hard coating containing cBN (cubic boron nitride) or hBN (hexagonal boron nitride).

JP 2007-15106 A JP 2007-119795 A JP 2007-2332 A JP 2006-307323 A JP 2004-130514 A JP 2004-136430 A

  However, the cutting edge may be used under severe processing conditions where the cutting edge becomes even higher due to higher speed and higher efficiency of cutting, and further improvement in heat resistance is required for hard coatings. Moreover, although reduction of the usage-amount of cutting fluid is calculated | required from the environmental problem, if the usage-amount of cutting fluid is reduced, a tool will become high temperature easily and the improvement of the heat resistance of a hard film is requested | required also from this point.

  The present invention has been made against the background described above, and an object of the present invention is to provide a hard coating film that can obtain more excellent heat resistance.

In order to achieve this object, the first invention is a hard coating having excellent wear resistance and heat resistance provided on the surface of a predetermined member, comprising: (a) Al _a Cr _b X _c α _d N [ However, X is a BN having a hybrid orbital with SP2 or SP3 in the bound state, and is a mass having a diameter of 1 nm to 1000 nm consisting of 10 or more molecules, and is an amorphous BN, or at least one crystal of cBN or hBN. Α is one or more elements of groups IVa, Va, VIa (excluding Cr), B, C, Si, Y of the periodic table of elements, and a, b, c, d Are atomic ratios of 0.35 ≦ a ≦ 0.76, 0.12 ≦ b ≦ 0.43, 0.02 ≦ c ≦ 0.20, 0 ≦ d ≦ 0.20, and The ratio b / a of the atomic ratio of Cr to Al is within the range of 0.25 ≦ b / a ≦ 0.67. And is provided with a first film provided on the outermost surface, and (b) the total film thickness Ttotal is in the range of 0.5 to 15 μm, and the first film The film thickness including the other film portion when the other film portion having the same film component as the first film or the first film is 20% or more of the total film thickness Ttotal To do.

  The second invention is the hard coating of the first invention, wherein (a) the first coating is provided directly on the surface of the predetermined member and is constituted only by the first coating; (b) the first coating One film thickness T1 is a total film thickness Ttotal.

According to a third invention, in the hard coating of the first invention, Ti _e Al _f Cr _g β _h N [provided that the surface of the predetermined member is between the predetermined member and the first coating; β is one or more elements in groups IVa, Va, VIa (excluding Ti and Cr), B, C, Si, and Y of the periodic table of elements, and e, f, g, and h are respectively The atomic ratio is within the range of 0 ≦ e ≦ 0.64, 0.32 ≦ f ≦ 0.81, 0 ≦ g ≦ 0.40, 0 ≦ h ≦ 0.20, and e and g are 0 at the same time. And e + f + g + h = 1] is provided.

  4th invention is the hard film of 3rd invention, (a) The said 1st film is directly provided on the said 2nd film, and is comprised only by those 1st films and 2nd films, (b) The film thickness T1 of the first film is 20% or more of the total film thickness Ttotal.

  According to a fifth aspect of the present invention, in the hard coating according to the third aspect of the present invention, coatings having the same coating component as those of the first coating and the second coating are alternately laminated between the first coating and the second coating. The present invention is characterized in that an intermediate layer composed of alternating layers or a mixed layer of coating components in which the first coating and the second coating are mixed is provided.

  The sixth invention relates to a hard coating coated tool, characterized in that the surface of the tool base material is coated with the hard coating of any one of the first to fifth inventions.

According to the hard coating of the first aspect of the present invention, an aluminum-rich AlCrN-based coating in which the ratio of the atomic ratio of Cr to Al (b / a) is in the range of 0.25 ≦ b / a ≦ 0.67 has a predetermined bonding state. A first film of Al _a Cr _b X _c α _d N added with an atomic ratio of 0.02 to 0.20 consisting of BN is provided on at least the outermost surface, and the film thickness of the first film When T1 or other film portions having the same film component as the first film are provided, the film thickness including the other film portions is 20% or more of the total film thickness Ttotal. (Oxidation resistance at high temperature) can be obtained. That is, the amorphous BN or cBN, hBN crystals contained in the X are all resistant to oxidation at high temperatures, and the presence of such amorphous BN, cBN, hBN causes oxygen to enter the film. Diffusion can be delayed. In addition, cBN has extremely high hardness (generally around 6000-7500 HV), so it has improved wear resistance and excellent durability, and hBN and amorphous BN have excellent lubricity and are therefore resistant to welding. Improves. This enables high-efficiency machining such as high-load cutting with a large depth of cut and cutting under severe conditions where the cutting edge is at a high temperature, such as high-speed cutting for hard materials, or such cutting. The tool life in machining is improved, and the amount of cutting fluid used can be reduced.

  Further, when α is added at an atomic ratio of 0.20 or less, more excellent heat resistance can be obtained. This makes it possible to obtain excellent wear resistance and heat resistance under conditions in which the cutting edge is exposed to high temperatures for a long time (such as drill corners) for a long period of time, such as high-speed drilling. (Lifetime) is improved. In other words, in end mills, etc., where the load acts on the cutting edge almost evenly, a clear durability improvement effect due to the addition of α was not observed, but in high-speed drilling with a drill, compared to the case without α addition. Durability is further improved.

The third aspect of the present invention, the second coating of a given _{Ti e Al f Cr g β h} N having excellent adhesion with strong on the surface of the member is provided, thereby improving the adhesion of the hard coating, first Since the film thickness of the portion having the film component of the film is 20% or more of the total film thickness Ttotal, the effect of improving the heat resistance by the film component of the first film is appropriately obtained. Thereby, for example, even when a high-hardness work material of 50 HRC or higher is subjected to high-speed cutting by dry processing (air blow), film peeling is suppressed, and excellent wear resistance and heat resistance can be appropriately obtained. In addition, even when the second coating is added at an atomic ratio of β of 0.20 or less, further excellent heat resistance can be obtained. For example, in a TiAl compound, oxidation resistance may be poor because oxidation of Ti is faster than oxidation of Al, but adding β decreases the oxygen vacancy concentration of the Ti oxide and decreases its growth rate. I can expect that. As a result, a uniform Al oxide layer can be easily formed and oxidation resistance can be obtained.

  According to a fifth aspect of the present invention, an alternating layer or a first coating and a second coating in which coatings of the same coating component as those of the first coating and the second coating are alternately laminated between the first coating and the second coating. In the case where an intermediate layer composed of a mixed layer of mixed coating components is provided, the adhesion of the first coating is further improved and the toughness of the entire coating is improved. As a result, even when difficult-to-cut materials (hard and sticky materials) are processed, surface layer peeling is suppressed, and long-term stable processing performance can be obtained, thereby improving the tool life.

  The sixth invention relates to a hard coating coated tool, which is a case where the surface of the tool base material is coated with the hard coating of any of the first invention to the fifth invention, and is substantially the first invention to the fifth invention. The same effect as that of the hard coating can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a ball end mill to which the present invention is applied, in which (a) is a front view seen from a direction perpendicular to the axis, (b) is an enlarged bottom view seen from the tip side, and (c) is provided with a hard coating. It is an expanded sectional view of the surface vicinity of the blade part. It is a conceptual diagram of the film structure of AlCr (BN) N. It is a figure which compares and shows the measurement result by XRD about an AlCr (BN) N film | membrane and an AlCrN film | membrane. It is a figure explaining the other Example of this invention, (a), (b) is sectional drawing equivalent to (c) of FIG. FIG. 6 is a diagram for explaining still another embodiment of the present invention, in which both (a) and (b) are cross-sectional views corresponding to (c) of FIG. 1. It is a figure explaining the test conditions at the time of performing a durability test about multiple types of test goods including this invention goods and a conventional product. FIG. 7 is a diagram specifically showing the coating composition and film thickness of the test product used in the durability test of FIG. 6 and explaining test results such as the durability test and heat resistance test of FIG. 6. It is a figure explaining the test conditions at the time of performing the durability test different from FIG. 6 about multiple types of test products including this invention product and a conventional product. It is a figure which illustrates concretely the film composition of the test article used in the durability test of FIG. It is a figure explaining test results, such as the film thickness of the test article of FIG. 9, and the durability test and heat resistance test of FIG. It is a figure explaining the test conditions at the time of conducting the durability test of the drill coat | covered with the same hard film as FIG.7, FIG.9, FIG.10 test article No16, No20, No27, No43, No49, No51, No53. It is a figure explaining the test result of the durability test of FIG.

  INDUSTRIAL APPLICABILITY The present invention is suitably applied to hard coatings provided on the surfaces of various processing tools such as end mills, taps, and rotary cutting tools such as drills, non-rotating cutting tools such as cutting tools, and rolling tools. However, the present invention can also be applied to a hard coating provided on the surface of a member other than a processing tool such as a surface protective film of a semiconductor device or the like. As the tool base material of the hard coating coated tool, cemented carbide, high speed tool steel, alloy tool steel, cermet, ceramics, polycrystalline diamond (PCD), single crystal diamond, polycrystalline CBN, single crystal CBN are preferably used. However, other tool materials can be employed.

As a means for forming the hard coating, a PVD method (physical vapor deposition method) such as an arc ion plating method, a sputtering method, or a PLD (Puls LASER Deposition) method is preferably used. Al, Cr, Ti, α, β, etc. constituting the hard coating can be formed using a single metal or alloy as a target, but Al _a Cr _b , Al _a Cr _{b α d, Ti e Al f} , Ti e Al f Cr g, a _{Ti e Al f β h, Ti} e Al f Cr g β h of alloy can be performed a film forming process by using as a target. Regarding X containing hybrid orbital BN of SP2 or SP3, which is a lump with a diameter of 10 nm or more in the range of 1 nm to 1000 nm and containing BN in an amorphous state, or at least one crystal of cBN and hBN Is obtained by performing a film forming process using cBN as a target. X preferably contains both cBN and hBN crystals in amorphous BN, but may contain either cBN or hBN in amorphous BN, or only amorphous BN. In this case, various bonding states can be obtained depending on the film forming conditions, for example, it may not contain any of cBN and hBN crystals. N (nitrogen) can be added by supplying the reaction gas. C (carbon), which is an option for α and β, can be added by supplying a reaction gas (hydrocarbon gas or the like) or by a solid target (C target, C-containing target).

  Hard-coated tools are suitable for use in cutting conditions where the cutting edge is at a high temperature, such as dry cutting at high speed and high load, and high-speed cutting on high-hardness workpieces, and have excellent durability ( (Tool life) can be obtained, but it is of course possible to use it under machining conditions that do not require so much wear resistance and heat resistance, for example, cutting using a cutting fluid.

Α of the first film and β of the second film both have an atomic ratio d, h of 0, and are optionally added. The first film is made of Al _a Cr _b X _c N [however, a + b + c = 1] may be a second coating Ti _e Al _f Cr _g N [however, may be e + f + g = 1]. When α or β is added, the atomic ratios a to d are determined to have a relationship of a + b + c + d = 1, and the atomic ratios e to h are determined to have a relationship of e + f + g + h = 1. When both α and β are added, α = β may be satisfied, or α ≠ β may be satisfied.

  The atomic ratios e and g of Ti and Cr in the second coating include 0, but the atomic ratios e and g do not become 0 at the same time, and include at least one of Ti and Cr. Is done. Both Ti and Cr may be contained in a predetermined atomic ratio. In other words, in addition to TiAlCrβN, TiAlβN or AlCrβN can be used as the second coating.

  The total film thickness Ttotal of the hard coating is in the range of 0.5 μm to 15 μm, but if it is less than 0.5 μm, sufficient performance as a hard coating cannot be obtained, and if it exceeds 15 μm, the cutting edge of the cutting tool becomes round. For example, the tool performance may be impaired. Further, if the film thickness including the first film and other film parts having the same film component as the first film is less than 20% with respect to the total film thickness Ttotal, the heat resistance due to the film component of the first film Since the improvement effect is not sufficiently obtained, it is set to 20% or more. The other film portion having the same film component as the first film is, for example, an alternating layer in which a film of the same film component as the first film and another film are alternately laminated, or a film component of the first film and other In order to include a mixed layer mixed with a film component, the alternate layer includes the total film thickness of the film portion of the same film component as the first film, and the mixed layer includes the total film thickness. It is more desirable that only the film thickness T1 of the first coating located on the outermost surface is 20% or more of the total film thickness Ttotal.

  In the third invention, a second film is provided between the predetermined member and the first film, and in the fifth invention, an intermediate layer is further provided between the second film and the first film. In the implementation of the above, it is sufficient that at least the first coating is provided on the outermost surface, and the hard coating can be constituted by only the first coating as in the second invention. Another different underlayer may be provided between the predetermined member and the first coating. It is also possible to provide two or more types of coatings different from the second coating and the intermediate layer between the predetermined member and the first coating, and the first coating and the total thickness Ttotal of the hard coating Various modes are possible on condition that the total film thickness of the portion having the same film component as that of the first film is 20% or more. In carrying out the third invention, a hard coating having a multilayer structure in which coatings of the same coating component as the second coating and the first coating are alternately laminated can be employed. In this case, the total film thickness of the film having the same film component as that of the first film may be set so that the film thickness T1 of the first film is 20% or more of the total film thickness Ttotal.

  The intermediate layer of the fifth invention is composed of an alternating layer in which coatings of the same coating component as the first coating and the second coating are alternately laminated or a mixed layer of coating components in which the first coating and the second coating are mixed. However, the alternating layers only need to have at least one cycle of coatings of the same coating component as the first coating and the second coating, and the thickness of both layers may be the same or different. And individual film thicknesses are set as appropriate. The mixed layer contains all the components of the first film and the second film, and can be formed by using all of the target, reaction gas, and the like used in the film formation process of the first film and the second film. The thickness of this intermediate layer is the thickness of the portion of the intermediate layer that has the coating component of the first coating (the total thickness in the case of the mixed layer, and the coating component having the same coating component as that of the first coating in the case of the alternating layer). The total film thickness) and the film thickness T1 of the first coating are appropriately set so as to be 20% or more of the total film thickness Ttotal. You may make it become 20% or more of film thickness Ttotal. An alternating layer having a multilayer structure in which coatings of the same coating component as that of the first coating and the second coating are alternately laminated for one period or more with the mixed layer or another coating interposed may be employed as the intermediate layer.

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 which is an example of a hard film coated tool to which the present invention is applied. FIG. 1A is a front view seen from a direction perpendicular to the axis, and FIG. It is an enlarged bottom view seen from the right direction of the figure of a), and the tool base material 12 made of cemented carbide or high-speed tool steel is provided with a blade 14 integrally with the shank. ing. 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 the surface of the blade portion 14 is coated with a hard coating 20. The shaded area in FIG. 1 (a) represents the hard coating 20, and FIG. 1 (c) is a cross-sectional view of the vicinity of the surface of the blade portion 14 coated with the hard coating 20. The ball end mill 10 is a rotary cutting tool, and the tool base material 12 corresponds to a predetermined member provided with a hard coating 20.

As is clear from FIG. 1 (c), the hard coating 20 is a single-layer coating consisting only of the first coating 22 provided directly on the surface of the tool base material 12. The first coating 22 is made of Al _a Cr _b X _c α _d N [where X is a BN having a hybrid orbital in which the binding state is SP2 or SP3, and is a lump having a diameter of 1 nm to 1000 nm consisting of 10 or more molecules. Yes, including amorphous BN, or at least one crystal of cBN and hBN, α is a group of elements IVa, Va, VIa (excluding Cr), B, C, Si, Y in the periodic table of elements And a, b, c, d are atomic ratios of 0.35 ≦ a ≦ 0.76, 0.12 ≦ b ≦ 0.43, 0.02 ≦ c ≦ 0, respectively. .20, 0 ≦ d ≦ 0.20, and the ratio b / a of the atomic ratio of Cr to Al is aluminum rich within the range of 0.25 ≦ b / a ≦ 0.67, and a + b + c + d = 1], and in this embodiment, the amorphous state An X containing both crystal cBN and hBN into N. Such a first film 22 can be formed with a predetermined target and reaction gas using, for example, an arc ion plating apparatus. The film thickness T1 of the first coating 22, that is, the total film thickness Ttotal of the hard coating 20 is in the range of 0.5 to 15 μm. The hard coatings of test products No01 to No17 shown in FIG. 7 are specific examples of the hard coating 20 of this embodiment.

  Here, a bonded orbital BN of SP2 or SP3 is a lump having a diameter of 10 nm or more in the range of 1 nm to 1000 nm, and an amorphous BN, or at least one of cBN and hBN crystals. Containing X can be obtained by performing a film forming process using cBN as a target. FIG. 2 is a conceptual diagram of the film structure of the first film 22 of the present embodiment, and BN in a predetermined bonding state that satisfies the requirement of X is included in the AlCrN film (when the α atomic ratio d = 0). It exists in a substantially uniformly dispersed state, and is different from simple AlCrBN in which B and N exist separately. FIG. 3 shows the results of measurement by XRD (X-ray Diffraction) after depositing the AlCr (BN) N film of the present invention and the AlCrN film of the conventional product on a cemented carbide. In the figure shown in comparison, in the product of the present invention [AlCr (BN) N film], a peak due to cBN and hBN crystals occurs at a predetermined angular position, and whether there is BN containing cBN or hBN due to the presence or absence of this peak. You can determine whether or not. FIG. 3 shows the case where both cBN and hBN crystals exist in the amorphous BN. However, the amorphous BN includes only one of cBN and hBN, or only the amorphous BN contains cBN. Various bonding states are possible depending on the film formation conditions, such as when none of the hBN crystals are included.

The hard coating 20 of the ball end mill 10 of this embodiment is an aluminum-rich AlCrN-based coating in which the ratio of the atomic ratio of Cr to Al, b / a, is in the range of 0.25 ≦ b / a ≦ 0.67. Further, since it is constituted by the first coating 22 of Al _a Cr _b X _c α _d N added with an atomic ratio of 0.02 to 0.20, which is made of BN in a predetermined bonding state, it has excellent heat resistance (Oxidation resistance at high temperature) can be obtained. That is, amorphous BN, cBN, and hBN crystals are all resistant to oxidation at high temperatures, and the presence of such amorphous BN, cBN, and hBN can delay the diffusion of oxygen into the hard coating 20. It can be done. In addition, since cBN has a very high hardness, wear resistance is improved and excellent durability can be obtained, and hBN and amorphous BN are excellent in lubricity, so that welding resistance is improved. This enables high-efficiency machining such as high-load cutting with a large depth of cut and cutting under severe conditions where the cutting edge is at a high temperature, such as high-speed cutting for hard materials, or such cutting. The tool life in machining is improved, and the amount of cutting fluid used can be reduced.

  Further, when α is added at an atomic ratio of 0.20 or less (for example, test products No. 08 to No. 11, No. 16, No. 17 in FIG. 7), further excellent heat resistance can be obtained. This makes it possible to obtain excellent wear resistance and heat resistance under conditions in which the cutting edge is exposed to high temperatures for a long time (such as drill corners) for a long period of time, such as high-speed drilling. (Lifetime) is improved. In addition, when a load acts on the ball blade 18 substantially equally as in the ball end mill 10 of this example, a clear durability improvement effect due to the addition of α was not recognized.

  Next, another embodiment of the present invention will be described. In the following embodiments, parts that are substantially the same as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

In the hard coating 30 of FIG. 4A, a second coating 32 is interposed between the tool base material 12 and the first coating 22. This second coating 32 is made of Ti _e Al _f Cr _g β _h N [where β is a group of elements IVa, Va, VIa (excluding Ti, Cr), B, C, Si, Y of the periodic table of elements. And e, f, g, and h are atomic ratios of 0 ≦ e ≦ 0.64, 0.32 ≦ f ≦ 0.81, 0 ≦ g ≦ 0.40, 0 ≦ h ≦ 0.20, and e and g are not 0 at the same time, and e + f + g + h = 1], and the arc ion plating apparatus is similar to the first coating film 22. The film is formed using a predetermined target and a reactive gas. In this case, the total film thickness Ttotal of the hard coating 30 is in the range of 0.5 to 15 μm as in the case of the hard coating 20, and the film thickness T1 of the first coating 22 is 20% or more of the total film thickness Ttotal, and the remaining Is the thickness of the second coating 32. The hard coatings of the test products Nos. 27 to 53 shown in FIGS. 9 and 10 are specific examples of the hard coating 30 of this embodiment.

In such a hard coating 30 of this embodiment, a second coating 32 made of Ti _e Al _f Cr _g β _h N is provided between the tool base 12 and the first coating 22 and is strong and has excellent adhesion. Therefore, the adhesive force of the hard coating 30 is improved, and the film thickness T1 of the first coating 22 is 20% or more of the total film thickness Ttotal. Is obtained. Thereby, for example, even when a high-hardness work material of 50 HRC or higher is subjected to high-speed cutting by dry processing (air blow), film peeling is suppressed, and excellent wear resistance and heat resistance can be appropriately obtained. In addition, even when the second coating 32 is added at an atomic ratio of β of 0.20 or less, further excellent heat resistance can be obtained.

  4 (b), a pair of coatings 23, 33 having the same coating component between the first coating 22 and the second coating 32 are alternately arranged for one period or more (a plurality of examples are used). Periodic) A multi-layered multi-layered film in which the second film 32 and the first film 22 are alternately laminated on the tool base material 12 so that the outermost surface is substantially the first film 22. The total film thickness Ttotal of the hard film 34 is within a range of 0.5 to 15 μm, and is a film obtained by adding the film thickness T1 of the first film 22 to the total film thickness of the plurality of films 23 equal to the film component of the first film 22. Each film thickness is determined so that the thickness is 20% or more of the total film thickness Ttotal. In the figure, the film thicknesses of the coating films 22, 23, 32, and 33 are substantially the same, but the film thickness T1 of the first coating film 22 is set as appropriate, for example, larger than the film thicknesses of the other coating films 23, 32, and 33. it can.

  Also in the hard coating 34 of this embodiment, since the second coating 32 is provided on the tool base material 12, the same effect as the hard coating 30 can be obtained. Further, the hard coating 34 has a multilayer structure in which a pair of coatings 23 and 33 having the same coating component as those of the first coating 22 and the second coating 32 are alternately laminated for one period or more. The adhesion of one coating 22 is further improved and the toughness of the entire hard coating 34 is improved. Since the film thickness obtained by adding the film thickness T1 of the first film 22 to the total film thickness of the plurality of films 23 equal to the film component of the first film 22 is 20% or more of the total film thickness Ttotal, The effect of improving heat resistance by the coating component can be obtained appropriately. A film portion having a multilayer structure in which a pair of coatings 23 and 33 having the same coating component as the first coating 22 and the second coating 32 are alternately laminated for one period or more corresponds to an intermediate layer (alternate layer in this embodiment).

  The hard coating 40 of FIG. 5A is a case where an intermediate layer 42 is further provided between the first coating 22 and the second coating 32 of the hard coating 30 of the second embodiment. The intermediate layer 42 is an alternating layer in which coatings of the same coating component as the first coating 22 and the second coating 32 are alternately laminated or a mixed layer of coating components in which the first coating 22 and the second coating 32 are mixed. In the embodiment, a mixed layer is provided as the intermediate layer 42. This mixed layer contains all the components of the first coating 22 and the second coating 32, and uses all of the target, reaction gas, and the like used in the film forming process of the first coating 22 and the second coating 32. Thus, the intermediate layer 42 can be formed continuously following the film formation process of the second coating 32, and further the first coating 22 can be formed continuously. The total thickness Ttotal of the hard coating 40 is in the range of 0.5 to 15 μm, and the total thickness T2 of the first coating 22 and the intermediate layer (in the case of a mixed layer) 42 is 20% or more of the total thickness Ttotal. The remainder is the film thickness of the second coating 32. The film thickness of the intermediate layer 42 is appropriately set so that the film thickness T2 is 20% or more of the total film thickness Ttotal, but only the film thickness T1 of the outermost first film 22 is 20% of the total film thickness Ttotal. You may make it above.

  Among the test products shown in FIGS. 9 and 10, test products No. 27, No. 29, No. 32, No. 35 whose numerical values (film thicknesses) are described in the “intermediate layer” item of the “film thickness (μm)” item, The hard coating of No39, No43, No45, No48, No50 is a specific example of the hard coating 40 of the present embodiment.

  In the hard film 40 of this embodiment, the same film components as those of the first film 22 and the second film 32 are alternately laminated between the first film 22 and the second film 32. In addition, the intermediate layer 42 made of the mixed layer of the coating components in which the first coating 22 and the second coating 32 are mixed is provided, so that the adhesion of the first coating 22 is further improved and the entire hard coating 40 is Toughness is improved. Further, since the total film thickness T2 of the intermediate layer (in the case of the mixed layer) 42 and the first coating 22 is 20% or more of the total film thickness Ttotal, the heat resistance is improved by the coating components of the first coating 22. The effect is obtained appropriately. When the intermediate layer 42 is an alternating layer, the film thickness obtained by adding the film thickness T1 of the first film 22 to the total film thickness of the film portions of the same film components as the first film 22 is 20% or more of the total film thickness Ttotal. Just do it. As a result, even when difficult-to-cut materials (hard and sticky materials) are processed, surface layer peeling is suppressed, and long-term stable processing performance can be obtained, thereby improving the tool life.

  The hard coating 44 in FIG. 5B has a pair of coatings 23 and 33 having the same coating component between the first coating 22 and the second coating 32 alternately in one cycle with the intermediate layer 42 interposed therebetween. The second coating 32 and the first coating 22 are alternately arranged with the intermediate layer 42 interposed so that the outermost surface is substantially the first coating 22 in the multilayered coating as described above (in the embodiment, a plurality of periods). It is laminated on the tool base material 12. The total thickness Ttotal of the hard coating 44 is in the range of 0.5 to 15 μm, and the first coating 22 has a total thickness of the plurality of coatings 23 equal to the coating components of the first coating 22 and the intermediate layer 42 composed of the mixed layers. Each film thickness is determined such that the total film thickness T1 is 20% or more of the total film thickness Ttotal. In the figure, the film thicknesses of the coating films 22, 23, 32, 33, and 42 are substantially the same, but the film thickness T1 of the first coating film 22 is larger than the film thicknesses of the other coating films 23, 32, 33, and 42. It can be set as appropriate. Also in this embodiment, since the intermediate layer 42 is provided between the pair of coatings 23 and 33, in addition to obtaining the same operational effects as the hard coating 40, the coatings 23 and 33 are used as the intermediate layer 42. Since it has a multilayer structure in which one cycle or more is alternately sandwiched between, the adhesion and toughness are further improved. A multi-layered coating in which a pair of coatings 23 and 33 having the same coating component as the first coating 22 and the second coating 32 are alternately laminated for one period or more with the intermediate layer 42 interposed therebetween is also an aspect of the alternate layer. .

Test result 1

  Next, for a two-blade square end mill whose tool base material is molten high-speed (high-speed tool steel) and whose diameter is 10 mm, the hardness of the first embodiment consisting of a single layer of the first coating 22 as shown in FIG. A plurality of types of test products No01 to No26 including the product of the present invention provided with the coating 20 are prepared, and the coating hardness (HV0.025) is measured, and the results of the heat resistance test and the durability test are described. . The film hardness is less than 3000 as NG (failed). In the heat resistance test, the thickness of the oxide layer was measured when the test product was exposed to 1000 ° C. for 1 hour in an atmospheric pressure / air atmosphere. Not only the total oxidation of all the hard coatings, but also NG when the oxide layer thickness is 0.7 μm or more. Further, the durability test is performed by performing side cutting on carbon steel (S50C defined in JIS) under the test conditions shown in FIG. 6 and measuring the cutting distance until the flank wear width of the cutting edge becomes 0.2 mm. The case where the cutting distance is less than 10 m is determined as NG.

  The test products No01 to No17 in FIG. 7 are the products of the present invention, the test products No19 to No21 are the conventional AlCrN-based hard coatings that do not contain BN, and the test products No18 and No22 to No26 are the atomic ratios of the coating composition. This is a comparative product (NG product) in which the Cr / Al ratio (= b / a) and the total film thickness Ttotal do not satisfy the requirements of the present invention. In FIG. 7, the “hard coating” and “total film thickness” items that are shaded (scattered dots) are items that are outside the requirements of the present invention, and are “film hardness” and “oxide layer thickness”. ”And“ cutting distance ”items with shaded dots indicate NG. Note that the coating composition in the column of “Hard Coating” in FIG. 7 describes the atomic ratio in%. The “first ratio” is the ratio of the portion having the coating component of the first coating, and here is a value (all 100%) obtained regardless of whether the coating component of the first coating satisfies the requirements of the present invention. It is. Moreover, although N (nitrogen) is not described, the hard coating of all the test products is a nitride containing N (nitrogen).

  As is apparent from the test results in FIG. 7, the products of the present invention (test products No01 to No17) have a coating hardness of 3000 or more, and the conventional products (test products No19 to No21) and comparative products (test product No18). , No. 26) excellent film hardness can be obtained. The oxide layer thickness according to the heat resistance test is 0.6 μm or less for all of the products of the present invention (test products No01 to No17), which satisfy the pass requirement (less than 0.7 μm), but particularly contains α. Test products No. 08 to No. 11, No. 16, and No. 17 have an oxide layer thickness of less than 0.3 μm, and more excellent heat resistance is obtained. The cutting distance with a flank wear width of 0.2 mm according to the durability test is 10 m or more for all of the products of the present invention (test products No01 to No17), while satisfying the pass requirement. No. 19 to No. 21) and comparative products (test products No. 18, No. 22, No. 24 to No. 26) are all less than 10 m, and excellent durability can be obtained according to the product of the present invention. Note that the comparative product No. 23 of the test product No. 23 having a total film thickness Ttotal of 19.0 μm could not appropriately perform the coating hardness measurement, the heat resistance test, and the durability test by peeling the coating.

Test result 2

  FIGS. 9 and 10 show a two-blade ball end mill having a diameter of 6 mm (tip R = 3 mm) made of cemented carbide and a first coating 22 and a second coating 32 according to the second embodiment. A plurality of types including the hard coating 30 or the product of the present invention in which the hard coating 40 of Example 4 in which the intermediate layer 42 of the mixed layer is provided between the first coating 22 and the second coating 32 is provided. No. 27 to No. 58 are prepared, the film hardness (HV 0.025) is measured, and the results of the heat resistance test and the durability test are described. The film hardness is less than 3000 as NG (failed). The heat resistance test was the same as in FIG. 7, and the thickness of the oxide layer was measured when the test product was exposed to 1000 ° C. for 1 hour in an atmospheric pressure / air atmosphere. Not only the total oxidation of all the hard coatings, but also NG when the oxide layer thickness is 0.7 μm or more. In addition, the durability test is performed by dry cutting (pick processing) by air blow on high hardness alloy tool steel [SKD61 (50HRC) specified by JIS] under the test conditions shown in FIG. The cutting distance until the wear width becomes 0.1 mm is obtained, and the case where the cutting distance is less than 850 m is defined as NG.

  The test products No. 27 to No. 53 in FIG. 9 are the products of the present invention, and the test products No. 28, No. 30, No. 31, No. 33, No. 34, No. 36 to No. 38, No. 40 to No. 42, No. 44, No. 46, No. 47, No. 49 and No. 51 to No. 53 are intermediate. Specific examples of the hard coating 30 that does not include the layer 42, and test samples No 27, No 29, No 32, No 35, No 39, No 43, No 45, No 48, and No 50 are specific examples of the hard coating 40 having the intermediate layer 42. The test products No. 54 and No. 55 are conventional products made of an AlCrN-based hard coating in which the first coating does not contain BN. The test samples No. 56 to No. 58 are the first coating for the total film thickness Ttotal and the total film thickness Ttotal. The ratio of the total film thickness T2 of the intermediate layer is a comparative product (NG product) that does not satisfy the requirements of the present invention. The columns with shading (scattered dots) in the items of “first film” in FIG. 9 and “film thickness” in FIG. 10 and “first + intermediate ratio” are items that are outside the requirements of the present invention. In FIG. 10, the columns with shading (scattered points) in the items of “film hardness”, “oxide layer thickness”, and “cutting distance” represent NG. The “first + intermediate ratio” is a ratio of the total film thickness T2 of the first film and the intermediate layer to the total film thickness Ttotal, and here, regardless of whether the film component of the first film satisfies the requirements of the present invention. This is the calculated value. Note that the coating composition in the column “Hard Coating” in FIG. 9 is an atomic ratio described in%. Moreover, although N (nitrogen) is not described, the hard coating of all the test products is a nitride containing N (nitrogen).

  As is clear from the test results in FIG. 10, the products of the present invention (test products No. 27 to No. 53) have a coating hardness of 3000 or more, and are conventional products (test product No. 55) and comparative products (test product No. 57). In comparison, excellent film hardness can be obtained. The oxide layer thickness according to the heat resistance test is 0.4 μm or less for all of the products of the present invention (test products No. 27 to No. 53), which sufficiently satisfy the pass requirement (less than 0.7 μm). The test products No. 42 to No. 47 and No. 49 to No. 53 containing α have an oxide layer thickness of less than 0.3 μm, so that even better heat resistance can be obtained. The cutting distance with a flank wear width of 0.1 mm according to the durability test is 850 m or more for all of the products of the present invention (test products No. 27 to No. 53), while satisfying the pass requirement. No. 54, No. 55) and comparative products (test products No. 56, No. 57) are both less than 850 m, and according to the product of the present invention, excellent durability can be obtained. In addition, from this test result, the remarkable difference by the presence or absence of the intermediate | middle layer 42 was not recognized. Further, the comparative product No. 58 of the test product No. 58 having a total film thickness Ttotal of 18.5 μm could not appropriately perform the coating hardness measurement, the heat resistance test, and the durability test by peeling the coating.

Test result 3

  FIG. 12 shows a hard drill whose tool base material is made of cemented carbide and has a diameter of 6 mm, which is the same hardness as the test products No. 16, No. 20, No. 27, No. 43, No. 49, No. 51 and No. 53 in FIGS. Seven test products provided with a coating were prepared, and a high-speed cutting drilling process was performed on carbon steel (S50C specified by JIS) with mist lubrication under the test conditions shown in FIG. It is a figure explaining a result. In the durability test, the number of processed holes until the flank wear width of the cutting edge becomes 0.2 mm is obtained, and the case where the number of processed holes is less than 4000 is determined as NG. The test product No. 20 in FIG. 12 is a conventional product in which the first coating does not contain BN, and the other test products No. 16, No. 27, No. 43, No. 49, No. 51 and No. 53 are the products of the present invention. In FIG. 12, the column with shading (scattered dots) in the “number of holes to be processed” item represents NG.

  As is clear from the test results in FIG. 12, the products of the present invention (test products No. 16, No. 27, No. 43, No. 49, No. 51, No. 53) were all capable of drilling more than 5000 holes. The conventional product No. 20 has 2110 holes, and according to the product of the present invention, the durability is greatly improved. In particular, test products No. 16, No. 43, No. 49, No. 51 and No. 53 in which the first coating contains α have a number of processed holes of 5980 or more, whereas the test product No. 27 in which the first coating does not contain α. The number of processed holes was significantly increased by adding α to the first coating.

  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.

  10: Ball end mill (hard coating coated tool) 12: Tool base material (predetermined member) 20, 30, 34, 40, 44: Hard coating 22: First coating 23: Coating having the same coating component as the first coating 32: Second coating 34: Coating having the same coating component as the second coating 42: Intermediate layer Ttotal: Total film thickness T1: Film thickness of first coating T2: Film thickness of first coating + intermediate layer

Claims (6)

A hard coating with excellent wear resistance and heat resistance provided on the surface of a predetermined member,
Al _a Cr _b X _c α _d N [wherein X is a BN of a hybrid orbital of SP2 or SP3, and is a lump with a diameter of 10 nm or more in the range of 1 nm to 1000 nm, BN in an amorphous state, Or a crystal containing at least one of cBN and hBN, where α is one or more elements of groups IVa, Va, VIa (excluding Cr), B, C, Si, Y of the periodic table of elements A, b, c, and d are atomic ratios of 0.35 ≦ a ≦ 0.76, 0.12 ≦ b ≦ 0.43, 0.02 ≦ c ≦ 0.20, and 0 ≦ d ≦, respectively. The ratio b / a of the atomic ratio of Cr to Al within the range of 0.20 is aluminum-rich within the range of 0.25 ≦ b / a ≦ 0.67, and a + b + c + d = 1. And having a first coating provided on the outermost surface,
The total film thickness Ttotal is within the range of 0.5 to 15 μm, and when the film thickness T1 of the first film or other film part having the same film component as the first film is provided, the other film part The hard film characterized by having a film thickness including 20% or more of the total film thickness Ttotal. The first coating is provided directly on the surface of the predetermined member, and is composed only of the first coating,
The hard coating according to claim 1, wherein the first coating has a total thickness T1. Between the predetermined member and the first coating and on the surface of the predetermined member, Ti _e Al _f Cr _g β _h N [where β is a group IVa, Va of the periodic table of elements, One or more elements of group VIa (excluding Ti and Cr), B, C, Si, and Y, and e, f, g, and h are atomic ratios, respectively 0 ≦ e ≦ 0.64, 0 .32 ≦ f ≦ 0.81, 0 ≦ g ≦ 0.40, 0 ≦ h ≦ 0.20, and e and g are not 0 simultaneously, and e + f + g + h = 1. The hard film according to claim 1, wherein a second film is provided. The first coating is provided directly on the second coating, and is composed of only the first coating and the second coating,
The hard coating film according to claim 3, wherein a film thickness T1 of the first coating film is 20% or more of a total film thickness Ttotal. Between the first film and the second film, alternating layers in which films of the same film component as the first film and the second film are alternately laminated, or the first film and the second film are mixed. The hard film according to claim 3, wherein an intermediate layer composed of a mixed layer of the film components is provided.   A hard coating-coated tool, wherein the surface of the tool base material is coated with the hard coating according to any one of claims 1 to 5.

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