JP2008254145A - Hard film and hard film coated tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard film of a longer life span that is excellent in heat resistivity, anti-abrasion and welding resistivity as well as in adhesive strength. <P>SOLUTION: The hard film 24 provided on a body 16 of a drill 10 is arranged such that a compound layer 26 is overlaid on a surface of a tool based material 22 and a CN layer 28 containing 3 to 40 at% of Nitrogen is overlaid on the topmost surface of the material 22 and a compound/CN gradient layer 27 of an intermediary composition between those layers 26 and 28 is provided between them with the whole thickness D of the film 24 ranging from 0.05 to 20 μm. The provision of the CN layer 28 makes the film 24 excellent in heat resistivity, anti-abrasion and welding resistivity whereas that of the compound layer 26 enhances the adhesive strength of the film 24 so as to restrain peeling and the like from occurring and make it highly endurable. Moreover, the interposition of the compound/CN gradient layer 27 between them makes the CN layer 28 very firmly adhered on the compound layer 26 so as to enhance the adhesive strength of the hard film 24 as a whole, with the result that the anti-peeling property of the film 24 highly improves. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hard coating, and more particularly to a hard coating that is excellent in heat resistance, wear resistance, and welding resistance, and that has high adhesion strength and is suitably used for tools, wear-resistant parts, and the like. is there.

Various tools such as cutting tools such as drills, end mills, milling tools, cutting tools, build-up taps, rolling tools, non-cutting tools such as press dies, or friction parts that require wear resistance It has been proposed to improve wear resistance and durability by coating a hard film on the surface of a substrate. Patent Document 1 describes a tool provided with DLC (Diamond Like Carbon) as a hard coating. DLC has a dense amorphous structure and is crystallographically different from diamond, but has a higher hardness than compound coatings such as TiAlN and CrN. Patent Documents 2 and 3 describe the use of carbon nitride as a hard coating and a method for producing the carbon nitride film. Carbon nitride has a low friction coefficient, a smooth surface and high hardness, and provides excellent wear resistance, welding resistance, and heat resistance.
JP 2005-22073 A JP 2002-38269 A JP 2006-69856 A

  However, the DLC is not always satisfactory in terms of heat resistance and wear resistance, and the C (carbon) dangling bonds are easily bonded to the work material to cause welding. It was unsuitable for. Although it has been proposed to add H (hydrogen) to the C dangling bonds to prevent bonding with the work material, other problems such as a reduction in toughness occur. Carbon nitride, on the other hand, has a structure in which N (nitrogen) is bonded to the unbonded hands of C, which is a problem of the DLC, and provides excellent welding resistance. There is a problem that sufficient durability cannot always be obtained in a cutting tool or the like.

  The present invention has been made against the background of the above circumstances, and the object thereof is excellent in heat resistance, wear resistance, and welding resistance, and high adhesion strength is obtained. Another object of the present invention is to provide a long-life hard coating that can provide excellent durability.

  In order to achieve this object, the first invention is a hard coating provided on the surface of a predetermined substrate, comprising: (a) a group IIIb, IVa, Va, VIa group metal of the periodic table of elements and It is composed of any carbide, nitride, carbonitride, or mutual solid solution of Si, and a compound layer provided on the surface of the base material; and (b) a nitrogen content of 3 to 40 at% ( A carbon nitride layer provided on the uppermost layer so as to constitute the outer surface, and (c) an intermediate in which the carbon nitride layer and the compound layer are mixed. And an intermediate layer provided so as to be in contact with the compound layer and the carbon nitride layer between the compound layer and the carbon nitride layer, and (d) a total average film thickness D of 0.05 to It is in the range of 20 μm.

  The second invention is the hard coating of the first invention, wherein the intermediate layer has a mixing ratio from a composition close to the compound layer to a composition close to the carbon nitride layer as it goes from the compound layer to the carbon nitride layer. It is characterized by being changed continuously or stepwise.

  A third invention is characterized in that in the hard coating of the first invention or the second invention, the nanoindentation hardness of the carbon nitride layer is in a range of 15 to 55 GPa.

  According to a fourth invention, in the hard coating film according to any one of the first to third inventions, the carbon nitride layer contains both single bond and double bond carbon nitride.

  A fifth invention is characterized in that, in the hard coating film of any one of the first invention to the fourth invention, the thickness of the carbon nitride layer is in the range of 0.005 to 3 μm.

  A sixth invention is a hard film-coated tool in which a hard film is provided on the surface of a substrate, and the hard film is any one of the hard films of the first to fifth inventions. .

  In the hard coating of the first invention, a compound comprising a group IIIb, group IVa, group Va, group VIa of the periodic table of elements and a carbide, nitride, carbonitride of Si, or a mutual solid solution thereof. A layer is provided on the surface of the substrate, a carbon nitride layer having a nitrogen content of 3 to 40 at% is provided on the uppermost layer so as to constitute the outer surface, and an intermediate layer having an intermediate composition thereof is provided. Since it is provided between the compound layer and the carbon nitride layer, and the overall average film thickness D is in the range of 0.05 to 20 μm, the uppermost carbon nitride layer has better heat resistance and resistance. Abrasion and welding resistance can be obtained. On the other hand, a compound layer is provided on the surface of the base material, so that high adhesion strength is obtained and peeling is suppressed. Even when used as a hard coating for cutting tools, etc. Excellent durability is obtained. As a result, for example, it is suitably used as a hard coating of a hard coating coated tool as in the sixth invention, and the welding resistance of processing in an environment where welding is likely to occur (such as in a vacuum) is improved, and stainless steel, heat resistant While it is possible to process ferrous materials such as alloy steel and provide excellent tool life and stability, non-ferrous materials such as aluminum alloys can be expected to develop into dry and semi-dry processes. .

  In addition, since an intermediate layer having an intermediate composition is provided between the compound layer and the carbon nitride layer, the carbon nitride layer is attached to the compound layer with high adhesion strength through the intermediate layer. Further, the adhesion strength of the entire hard coating is increased, and the peel resistance is further improved.

  In addition, since the hardness of the carbon nitride layer can be easily adjusted by changing the film formation conditions, film properties such as hardness and toughness are appropriately set according to the object and purpose of providing the hard film. it can. If the nanoindentation hardness of the carbon nitride layer is in the range of 15 to 55 GPa as in the third invention, excellent wear resistance is obtained, and the carbon nitride layer is suitably applied to a hard film of a cutting tool.

  In the intermediate layer according to the second aspect of the invention, the mixing ratio is changed continuously or stepwise from the compound layer to the carbon nitride layer as it goes from the compound layer to the carbon nitride layer. The carbon nitride layer is attached to the compound layer with higher adhesion strength through the intermediate layer, and the peel resistance is further improved.

  In the fourth invention, since the carbon nitride layer is configured to include both single bond and double bond carbon nitride, the carbon nitride layer is hardened by changing the film formation conditions and changing their ratio. Can be adjusted. That is, single bond carbon nitride is harder than double bond carbon nitride, so if the film formation conditions are set so that the proportion of the single bond carbon nitride is higher, the hardness of the entire carbon nitride layer On the other hand, toughness can be improved by increasing the proportion of double-bonded carbon nitride. Carbon nitride has a triple bond, but it only serves as a terminal end of the bond and is not related to mechanical properties.

  In the fifth invention, since the thickness of the carbon nitride layer is in the range of 0.005 to 3 μm, the carbon nitride layer is more excellent while improving the adhesion strength of the carbon nitride layer in the presence of the compound layer and the intermediate layer. Heat resistance, wear resistance, and welding resistance can be obtained.

  Since the hard film-coated tool of the sixth invention is coated with the hard film of any of the first to fifth inventions, substantially the same effects as the first to fifth inventions can be obtained.

  The present invention is suitably applied to various hard coating coated tools such as rotary cutting tools such as drills and milling cutters, non-rotating cutting tools such as cutting tools, or non-cutting tools such as raised taps, rolling tools, and press dies. However, it can be applied to hard coatings of various members that require wear resistance and durability, such as bearing members, other than such processing tools.

  The group IIIb, IVa, Va, VIa group metals of the periodic table of elements are, for example, Al, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, etc. It is comprised by the carbide | carbonized_material, nitride, carbonitride, or these mutual solid solution of a metal and Si. Specifically, TiAlN, TiCN, TiCrN, TiSiN, TiAlCrN, TiN, CrN, ZrN, AlN, AlCrN, CrSiN, etc. The average film thickness of the compound layer varies depending on the member to be coated and the composition of the film, For example, a range of about 0.1 to 10 μm is appropriate.

  The compound layer is suitably provided by a PVD method such as an arc ion plating method, an ion beam evaporation method, a sputtering method, a PLD (Pulse Laser Deposition) method, or an IBAD (Ion Beam Assisted Deposition) method. However, other film forming methods can be employed.

  The carbon nitride layer can be suitably formed by a PVD method such as an arc ion plating method, a sputtering method, or an IBAD method, but other film forming methods can also be adopted.

  The nitrogen content of the carbon nitride layer can be adjusted by changing the film forming conditions. For example, the arc ion plating method can be adjusted by controlling the nitrogen gas flow rate, and in the case of the IBAD method, the plasma concentration is controlled. Can be adjusted. If the nitrogen content is less than 3 at%, the effect of improving the welding resistance by binding nitrogen to C (carbon) dangling bonds cannot be sufficiently obtained. On the other hand, if the nitrogen content exceeds 40 at%, single bond carbon nitride is not obtained. Therefore, it is desirable to set within a range of 3 to 40 at%, and particularly within a range of 5 to 35 at%.

  If the overall average film thickness D is less than 0.05 μm, the function as a hard film cannot be obtained sufficiently, but if it exceeds 20 μm, it tends to peel off or chip, so that it is in the range of 0.05 to 20 μm. It is desirable to set with.

  In the intermediate layer of the second invention, the mixing ratio thereof is changed continuously or stepwise so as to change from a composition close to the compound layer to a composition close to the carbon nitride layer. An intermediate layer having a constant composition at a constant mixing ratio (for example, 50% each) can also be employed. The intermediate layer of the second invention is configured so as to change smoothly and continuously from the same composition as the compound layer to the same composition as the carbon nitride layer, for example, but the mixing ratio is two or more than three. The intermediate layer can also be constituted by a plurality of layers that change in stages. The mixing ratio can be adjusted, for example, by alternately forming the compound and carbon nitride at short time intervals and changing the film forming time ratio. Both the film formation process can be performed simultaneously, and the mixing ratio can be adjusted by changing the film formation conditions, or only one of them can be formed continuously and the other can be formed intermittently. Various film forming methods can be employed.

  In the third invention, the nanoindentation hardness of the carbon nitride layer is in the range of 15 to 55 GPa, and is suitably applied to the hard coating of the cutting tool, but nitriding according to the object or purpose of providing the hard coating. The hardness of the carbon layer can be changed as appropriate.

  In the fourth invention, the carbon nitride layer is configured to include both single bond (sp3 bond) and double bond (sp2 bond) carbon nitride, but it may also include triple bond carbon nitride. Absent. Such a carbon nitride layer is amorphous having no regular crystal structure. In carrying out other inventions, a carbon nitride layer having another structure such as a carbon nitride layer composed of a single bond and a triple bond, or a carbon nitride layer composed of a double bond and a triple bond may be employed. .

  In the fifth invention, the thickness of the carbon nitride layer is in the range of 0.005 to 3 μm. However, in the practice of other inventions, the thickness of the carbon nitride layer is less than 0.005 μm or more than 3 μm. You may do it. The film thickness of the intermediate layer varies depending on whether the composition is changing continuously or stepwise, or whether it is a constant intermediate composition. is there.

  As the base material of the hard film-coated tool of the sixth invention, cemented carbide or high-speed tool steel is preferably used. Cermet, ceramics, polycrystalline diamond, single crystal diamond, polycrystalline CBN, single crystal CBN, etc. Various tool materials can be employed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a view showing a drill 10 which is an example of a hard film coated tool of the present invention, where (a) is a front view seen from a direction perpendicular to the axis O, and (b) is provided with a cutting edge 12. It is an enlarged bottom view seen from the front end side. This drill 10 is a two-blade twist drill, and is integrally provided with a shank 14 and a body 16 in the axial direction. . A pair of cutting edges 12 are provided at the tip of the body 16 corresponding to the grooves 18, and holes are cut by the cutting edges 12 by being driven to rotate clockwise around the axis O as viewed from the shank 14 side. While processing, chips are discharged through the groove 18 to the shank 14 side.

  FIG. 1C is an enlarged cross-sectional view of the vicinity of the surface of the body 16, and a hard coating 24 is coated on the surface of a tool base material 22 made of high speed tool steel (His). The hard coating 24 includes a compound layer 26 provided on the surface of the tool base 22, a compound / CN (carbon nitride) gradient layer 27 provided directly on the compound layer 26, and a compound / CN gradient layer 27. In this case, the outer surface is constituted by the CN layer 28. The compound layer 26 is a group IIIb, IVa, Va, VIa group metal or Si carbide, nitride, carbonitride, or a mutual solid solution thereof, specifically TiAlN. TiCN, TiCrN, TiSiN, TiAlCrN, TiN, CrN, ZrN, AlN, AlCrN, CrSiN, and the like. The CN layer 28 is configured to include both single bond (sp3) and double bond (sp2) CN in a nitrogen content range of 3 to 40 at%, and its nanoindentation hardness is 15 to It is within the range of 55 GPa. The compound / CN gradient layer 27 provided between the compound layer 26 and the CN layer 28 is an intermediate layer having an intermediate composition in which the compound layer 26 and the CN layer 28 are mixed. Then, as it goes from the compound layer 26 to the CN layer 28, the mixing ratio of the compound and CN changes linearly and continuously so that the same composition as the compound layer 26 and the same composition as the CN layer 28 change smoothly and continuously. It has been made. Further, the entire film thickness D of the hard coating 24 is in the range of 0.05 to 20 μm, and the average film thickness of the CN layer 28 alone is, for example, in the range of 0.005 to 3 μm. In addition, the hatched area in FIG. 1A represents the coating range of the hard coating 24.

  2A is a schematic diagram of the bonding structure of the CN layer 28. C represents a carbon atom, N represents a nitrogen atom, and is represented by a single bond (sp3) shown in (b) and (c). It is an amorphous structure in which double bonds (sp2) are randomly distributed. FIG. 3 shows an example of the Raman spectrum of the CN layer 28, where “D-peak” is due to single-bonded CN and “G-peak” is due to double-bonded CN, and has both peaks. This indicates that both single bonds and double bonds are included. The film characteristics such as hardness can be controlled by the ratio of the bonds. For example, if the ratio of the single bond of high hardness is increased, the hardness of the CN layer 28 is increased and the double bond is increased. If the ratio is increased, the toughness of the CN layer 28 is improved.

In addition, a test piece coated with three types of hard coatings of CN (single bond + double bond), DLC, and TiN was prepared, and friction was performed under the following test conditions using the pin-on-disk test apparatus shown in FIG. When the abrasion test was performed, the results shown in FIGS. 5 and 6 were obtained. In this case, the CN has a nitrogen content of about 20 at%, a nanoindentation hardness of about 29 GPa, and is directly coated on the test piece base (hard metal).
(Test conditions)
-Partner material: SUS304 (stainless steel)
・ Load: 0.5N
・ Linear speed: 25mm / s
-Time: 500 seconds-Test environment: Air-Room temperature: 25 ° C
・ Humidity: 60%

  FIG. 5 is a result of obtaining the friction coefficient from the above test. CN is about 0.09, DLC is about 0.08, TiN is about 0.27, and CN has a very small friction coefficient like DLC. Since the values of DLC and CN are very close, these graphs are substantially overlapped in FIG. FIG. 6 is a photograph showing wear marks at the tips of CN and DLC test pieces, where (a) shows wear marks generated on CN and (b) shows wear marks generated on DLC. Welding of the counterpart material was observed in each. The ratio of the amount of Fe deposited on CN and the amount of Fe deposited on DLC is about 3:10, and CN has much better welding resistance to iron than DLC.

On the other hand, the compound layer 26, the compound / CN gradient layer 27, and the CN layer 28 are suitably formed by PVD methods such as arc ion plating, IBAD (ion beam assisted deposition), and sputtering. FIG. 7 is a schematic configuration diagram (schematic diagram) for explaining the arc ion plating apparatus 30. The tool base 22 on which a plurality of workpieces, that is, the cutting edges 12, grooves 18 and the like before coating the hard coating 24 is formed. A workpiece holder 32 that is held, a rotating device 34 that rotationally drives the workpiece holder 32 around a substantially vertical rotation center, a bias power source 36 that applies a negative bias voltage to the tool base 22, and a tool base 22 A chamber 38 serving as a processing container, a reaction gas supply device 40 for supplying a predetermined reaction gas into the chamber 38, an exhaust device 42 for discharging the gas in the chamber 38 with a vacuum pump or the like, and reducing 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 bases 22 in a radial manner with the tip projecting outward substantially horizontally. The reactive gas supply device 40 includes a tank of argon gas (Ar), nitrogen gas (N ₂ ), and hydrocarbon gas (CH ₄ , C ₂ H _2, etc.), and includes the compound layer 26 and the compound / CN. When the compound of the gradient layer 27 is formed, depending on the composition, that is, carbide, nitride, or carbonitride, hydrocarbon gas is supplied in the case of carbide, nitrogen gas is supplied in the case of nitride, and carbonitriding is performed. In the case of goods, both hydrocarbon gas and nitrogen gas are supplied. When the CN of the CN layer 28 and the compound / CN gradient layer 27 is formed, argon gas and nitrogen gas are supplied at a predetermined ratio.

  The first arc power source 44 is a group IIIb, IVa group, Va group, VIa group metal and Si in the periodic table of elements that are constituents of the compound layer 26, or mutual solid solutions (alloys) thereof. Specifically, a first arc source 48 made of TiAl, TiCr, TiSi, TiAlCr, Ti, Cr, Zr, Al, AlCr, CrSi or the like is used as a cathode, and a predetermined arc current is passed between the anode 50 and an arc. By discharging, such metal or alloy is evaporated from the first evaporation source 48. The evaporated metal or alloy becomes a positive (+) metal ion and a negative (-) bias voltage is applied. It adheres to the tool substrate 22 that is present. Then, according to the reaction gas supplied from the reaction gas supply device 40, a compound layer 26 made of carbide, nitride, or carbonitride of such metal or alloy is formed. The second arc power source 46 uses the second evaporation source 52 made of carbon (C) as a cathode and applies a predetermined arc current to the anode 54 to cause arc discharge. The carbon is evaporated, and the evaporated carbon becomes positive ions and is attached to the tool base 22 to which a negative (−) bias voltage is applied. The CN layer 28 is formed by supplying argon gas and nitrogen gas from the reaction gas supply device 40. In that case, film-forming conditions such as arc current and bias voltage are determined so that CN having a predetermined hardness and composition can be obtained. The film thickness can be adjusted by the film formation time, for example. The arc power sources 44 and 46, the evaporation sources 48 and 52, etc. may be provided only at two substantially symmetrical positions as shown in FIG. 7, but may be provided alternately at a total of four places at intervals of 90 °, for example. it can.

  When the CN layer 28 is formed, film formation conditions are determined so as to include both single bonds (sp3) and double bonds (sp2), and the processing temperature is in the range of 20 to 250 ° C., for example, about 150 ° C. The bias voltage is set to, for example, about 100 V within the range of 15 to 300 V. The supply flow rate of the nitrogen gas is determined so that the nitrogen content in the CN layer 28 is in the range of 3 to 40 at%.

  On the other hand, the compound / CN gradient layer 27 in which the same compound as the constituent material of the compound layer 26 and CN which is the constituent material of the CN layer 28 are mixed and the mixing ratio is continuously changed, For example, these compounds and CN can be alternately formed at short time intervals, and the film forming time ratio can be continuously changed. The individual film forming conditions may be the same as those for forming the compound layer 26 and the CN layer 28.

FIG. 8 shows the result of examining the durability by performing drilling under the following processing conditions using the products of the present invention (No. 10 to No. 20) and comparative products (No. 1 to No. 9) configured as described above. It is a figure explaining. In the comparative product, the shaded columns are items that are out of the requirements of the present invention (Claim 1).
(Processing conditions)
・ Tool shape: φ6 high twist drill ・ Work material: SUS304 (stainless steel)
・ Cutting speed: 20 m / min
・ Feeding speed: 0.16mm / rev
・ Processing depth: 24mm through hole ・ Cutting oil: Water-soluble ・ Step amount: Non-step

  As is clear from the test results of FIG. 8, the comparative product No1 in which only the DLC layer was directly provided on the tool base material 22 generated abnormal noise due to welding or the like at the time of 250 hole processing, and was unable to be processed. Comparative products No. 2 and No. 3 in which the DLC layer is provided on the compound layer 26 via the compound / DLC inclined layer, and the comparative product No. 4 in which only the CN layer 28 is provided directly on the tool substrate 22 without providing the compound layer 26 are The flank wear width of the cutting edge 12 when drilling 1000 holes is 0.42 mm, 0.39 mm, and 0.38 mm, respectively, whereas the present invention product is smaller than 0.3 mm, which is a pass criterion. . In addition, as for the comparative products No5 to No9 having a three-layer structure including the compound layer 26, the compound / CN inclined layer 27, and the CN layer 28 as in the present invention, the nitrogen content of the CN layer 28 exceeds 40 at%. In the case of the comparative products No5 and No8, the CN layer 28 has a coating hardness (nanoindentation hardness) that is too high and becomes brittle. In the comparative product No5, a defect occurs in the 200 holes due to chipping or peeling. In No. 8, wear is promoted, whereas in Comparative product No. 6 in which the nitrogen content is less than 3 at%, the film hardness (nanoindentation hardness) is low and wear is promoted. In the case of comparative products No. 7 and No. 9 in which the average film thickness D of the entire hard coating 24 exceeds 20 μm, wear is accelerated by peeling or the like, and the effect of improving the wear resistance by the hard coating 24 is not sufficiently obtained.

  As described above, the hard coating 24 of the drill 10 of the present embodiment is such that the compound layer 26 is provided on the surface of the tool base 22 and the CN layer 28 having a nitrogen content of 3 to 40 at% constitutes the outer surface. In addition, a compound / CN gradient layer 27 having an intermediate composition between them is provided between the compound layer 26 and the CN layer 28, and the average film thickness D is 0. Since the uppermost CN layer 28 is in the range of 05 to 20 μm, excellent heat resistance, wear resistance, and welding resistance can be obtained. Moreover, since the compound layer 26 is provided on the surface of the tool base 22, high adhesion strength is obtained, peeling and the like are suppressed, and excellent durability is obtained. Further, since the compound / CN gradient layer 27 having an intermediate composition is provided between the compound layer 26 and the CN layer 28, the CN layer 28 is interposed via the compound / CN gradient layer 27. It adheres to the compound layer 26 with high adhesion strength, and the adhesion strength of the entire hard coating 24 is increased to further improve the peel resistance.

  This improves the welding resistance of processing in an environment where welding is likely to occur (such as in a vacuum) and enables processing of ferrous materials such as stainless steel and heat-resistant alloy steel, resulting in excellent tool life and processing. On the other hand, non-ferrous materials such as aluminum alloys can be expected to develop into dry processing and semi-dry processing.

  Further, the CN layer 28 can be easily adjusted in hardness by changing the film forming conditions. In this embodiment, the CN layer 28 has a nanoindentation hardness in the range of 15 to 55 GPa. Therefore, excellent wear resistance is obtained, and the durability of the drill 10 is improved.

  Further, in this example, the mixing ratio of the compound and CN changes continuously from the compound layer 26 toward the CN layer 28 so that the composition close to the compound layer 26 becomes the composition close to the CN layer 28. Since the compound / CN gradient layer 27 is provided as an intermediate layer, the CN layer 28 is attached to the compound layer 26 with higher adhesion strength through the compound / CN gradient layer 27, and the peel resistance is further improved. To do.

  Further, in this embodiment, the CN layer 28 includes both single bond and double bond CNs. Therefore, by changing the film formation conditions and changing their ratio, the CN layer 28 is hardened. Can be adjusted. That is, the single bond CN is harder than the double bond CN. Therefore, if the film forming conditions such as the bias voltage and the arc current are set so that the ratio of the single bond CN is increased, the CN layer 28 While the overall hardness can be increased, toughness can be improved by increasing the proportion of CN of double bonds.

  In this embodiment, the CN layer 28 has a thickness in the range of 0.005 to 3 μm. Therefore, the presence of the compound layer 26 and the compound / CN gradient layer 27 improves the adhesion strength, and is superior to the CN layer 28. Heat resistance, wear resistance, and welding resistance can be obtained.

  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 drill provided with the hard film of this invention, (a) is a front view, (b) is an enlarged bottom view seen from the front end side, (c) is an expanded sectional view of the surface vicinity of a body. 1 is a schematic diagram for explaining the structure of CN (carbon nitride), in which (a) has a single bond and a double bond similarly to the CN layer of the hard coating in FIG. 1, (b) has a single bond, and (c ) Is for a double bond. It is an example of the Raman spectrum of CN which has a single bond and a double bond. It is a conceptual diagram explaining a pin-on-disk friction test apparatus when performing a frictional wear test using a test piece provided with a predetermined hard coating. It is a figure which shows an example of the result of having measured the friction coefficient of CN, DLC, and TiN using the apparatus of FIG. It is a figure which shows the wear trace (welding) of CN and DLC after performing a friction abrasion test using the apparatus of FIG. It is the schematic explaining the arc ion plating apparatus which can form suitably the hard film of FIG. It is a figure explaining the item of this invention used when performing a durability test, the specification of a comparative product, and the result of a durability test.

Explanation of symbols

  10: Drill (hard film coated tool) 22: Tool substrate (base material) 24: Hard film 26: Compound layer 27: Compound / CN gradient layer (intermediate layer) 28: CN layer (carbon nitride layer) D: Average film Thickness

Claims (6)

A hard coating provided on the surface of a predetermined substrate,
It is composed of a group IIIb, IVa, Va, VIa group metal and Si carbide, nitride, carbonitride, or a mutual solid solution thereof, and the surface of the base material. A compound layer provided in
A carbon nitride layer composed of carbon nitride having a nitrogen content in the range of 3 to 40 at%, and a carbon nitride layer provided on the uppermost layer so as to constitute the outer surface;
An intermediate layer in which the carbon nitride layer and the compound layer are mixed, and an intermediate layer provided between and in contact with the compound layer and the carbon nitride layer;
And a total film thickness D in the range of 0.05 to 20 μm. The mixing ratio of the intermediate layer is changed continuously or stepwise so that the intermediate layer changes from a composition close to the compound layer to a composition close to the carbon nitride layer as it goes from the compound layer to the carbon nitride layer. The hard coating film according to claim 1. The hard coating according to claim 1 or 2, wherein the nanoindentation hardness of the carbon nitride layer is in a range of 15 to 55 GPa. The hard film according to any one of claims 1 to 3, wherein the carbon nitride layer includes both single bond and double bond carbon nitride. The thickness of the said carbon nitride layer exists in the range of 0.005-3 micrometers. The hard film in any one of Claims 1-4 characterized by the above-mentioned. A hard film coated tool in which a hard film is provided on the surface of a substrate,
The hard film-coated tool according to any one of claims 1 to 5, wherein the hard film is the hard film according to any one of claims 1 to 5.