JP4627201B2 - Hard coating - Google Patents

Description

The present invention belongs to the technical field concerning the hard skin layer, in particular, chip, drill, cutting tool or forging dies such as an end mill, hard coating for improving the wear resistance of the tools, such as punch Belongs to the technical field.

  Conventionally, a hard film such as TiN, TiCN, TiAlN or the like has been coated for the purpose of improving the wear resistance of a cutting tool based on cemented carbide, cermet or high-speed tool steel. In particular, since the composite nitride film of Ti and Al (hereinafter also referred to as TiAlN film) as disclosed in Japanese Patent No. 2644710 shows excellent wear resistance, the titanium nitride, carbide, carbonitride Instead of coatings made of materials, etc., it is being applied to cutting tools for cutting high-hardness materials such as high-speed cutting and hardened steel. However, with the recent increase in the hardness of the work material and the increase in the cutting speed, a hard coating with further improved wear resistance is required.

In addition, a film has also been proposed in which Cr or V is added to TiAlN to increase the Al concentration and improve the oxidation resistance while keeping the crystal structure in a hard cubic structure (Japanese Patent Laid-Open No. 2003-71610). Publication, Unexamined-Japanese-Patent No. 2003-34858). A film made of CrAlVN not containing Ti has also been proposed. However, the appearance of a hard coating having further excellent oxidation resistance and wear resistance is desired.
Japanese Patent No.26444710 JP 2003-71610 A JP 2003-34858 JP

The present invention was made in view of such circumstances, and its object is excellent in oxidation resistance than TiAlN film or TiCrAlN film is a conventional hard coating, and, providing a high hardness hard skin layer It is something to try.

  As a result of intensive studies to achieve the above object, the present inventors have completed the present invention. According to the present invention, the above object can be achieved.

Thus it is completed the present invention which can achieve the above object relates to a hard skin layer, a hard film of claim 1, wherein it is obtained by the following configuration.

That is, the hard film of claim 1, wherein _{the, (Cr a Ta b Al C} ) a hard film consisting of N, the following equation (1), (5), (6), that satisfy (9) It is a characteristic hard film.
a + b + c = 1 --------------------------------------- Formula (1)
0.05 ≦ b -------------------------- Equation (5)
0.5 ≦ c ≦ 0.73 ------------------- Equation (6)
0.05 ≦ a -------------------------- Formula (9)
In the above formulas (1), (5), (6) and (9) , a represents the atomic ratio of Cr, b represents the atomic ratio of Ta, and c represents the atomic ratio of Al.

According to the present invention, it is possible to obtain a hard film having superior oxidation resistance and higher hardness than TiAlN film and TiCrAlN film, which are conventional hard films. That is, the hard skin layer according to the present invention, than conventional TiAlN coating and TiCrAlN film is hard film excellent in oxidation resistance and a high hardness, suitably used as a hard coating tools and dies, etc. And the durability of those can be improved .

  In order to achieve the above-mentioned object, the present inventors have conducted intensive studies focusing on TiAlN, TiCrAlN, TiVAlN, CrAlN, and CrAlVN Ti, Cr, V in order to achieve both the hardness and oxidation resistance of the film. It has been found that by adding Nb and Ta to these films in a form that substitutes a part of any one of Ti, Cr, and V, the film has higher hardness and excellent oxidation resistance. Further, it has been found that by replacing a part of Al with Si, B or both, the hardness is higher and the oxidation resistance is improved.

Based on this knowledge, a technology (hereinafter referred to as basic technology) and reference technologies 1 to 3 as a basis of the present invention were created, and the present invention was completed. Hard film according to the basic technique is a hard film comprising _{[(Cr, V) a (Nb} , Ta) b (Al, Si, B) C ] _{(C 1-x N x)} , the following equation (1) Ru the hard coating der characterized by satisfying to (8). Hard film according to the reference technique 1 is a hard film comprising _{[(Ti, Cr, V) a} (Nb, Ta) b (Al, Si, B) C ] _{(C 1-x N x)} , the following hard coating der characterized by satisfying the formula (1A) ~ (10A) Ru. These hard coatings, both those related to the basic technology and those related to Reference Technology 1 , have superior oxidation resistance and higher hardness than conventional hard coatings such as TiAlN coatings and TiCrAlN coatings. It can be suitably used as a hard film such as a mold, and their durability can be improved.
a + b + c = 1 --------------------------------------- Formula (1)
a _Cr + a _V = a ------------------------- Formula (2)
b _Nb + b _Ta = b -------------------------- Equation (3)
c _Al + c _Si + c _B = c ------------------- Equation (4)
0.05 ≦ b -------------------------- Equation (5)
0.5 ≦ c ≦ 0.73 ------------------- Equation (6)
0 ≦ c _Si + c _B ≦ 0.15 ---------------- Equation (7)
0.4 ≦ x ≦ 1.0 ------------------- Equation (8)
In the above formulas (1) to (8), _aCr is the atomic ratio of Cr, _aV is the atomic ratio of _V , _bNb is the atomic ratio of Nb, _bTa is the atomic ratio of _Ta , and _cAl is Al. The atomic ratio, c _Si represents the atomic ratio of Si, c _B represents the atomic ratio of B, and x represents the atomic ratio of N.
a + b + c = 1 ---------------------- Formula (1A)
a _Ti + a _Cr + a _V = a -------------------- Formula (2A)
b _Nb + b _Ta = b -------------------------- Formula (3A)
c _Al + c _Si + c _B = c ------------------- Equation (4A)
0.05 ≦ b -------------------------- Formula (5A)
0.5 ≦ c ≦ 0.73 ------------------- Equation (6A)
0 ≦ c _Si + c _B ≦ 0.15 ---------------- Equation (7A)
a _Ti > 0 -----------------------------------------------------------------
a _Cr + a _V + c _Si + c _B > 0 -------------- Formula (9A)
0.4 ≦ x ≦ 1.0 ------------------- Equation (10A)
In the above formulas (1A) to (10A), a _Ti is an atomic ratio of Ti, a _Cr is an atomic ratio of Cr, a _V is an atomic ratio of V, b _Nb is an atomic ratio of Nb, and b _Ta is Ta. The atomic ratio, c _Al is the atomic ratio of Al, c _Si is the atomic ratio of Si, c _B is the atomic ratio of B, and x is the atomic ratio of N.

About the hard film which concerns on a basic technique and the reference technique 1 , the effect of a component, the reason for numerical limitation, etc. are demonstrated below.

  The reason why the TiAlN film exhibits high oxidation resistance is that Al is preferentially oxidized in a high-temperature oxidation atmosphere to form a highly protective Al oxide film on the resurface. However, when the temperature is further increased, formation of Ti oxide with low protection preferentially occurs, and oxidation starts abruptly. Addition of Cr improves this property, but is still insufficient. For further improvement, Ta or Nb may be added in place of the element (Ti), thereby improving the oxidation resistance.

  V is an element that deteriorates oxidation characteristics. The reason why V deteriorates the oxidation characteristic is that the formed oxide of V has a low melting point, and thus lowers the protective property of the oxide film. The oxidation resistance can be improved by adding Nb and Ta also to the V-containing film. Moreover, film hardness can also be increased by adding Nb and Ta. The reason is as follows. That is, a nitride film such as TiAlN, TiCrAlN, TiVAlN, CrAlN, and CrAlVN is a composite nitride of TiN, VN, CrN, and AlN having a lattice constant of 0.41 to 0.42 nm, and its lattice constant is also 0.41. It takes a value between ˜0.42 nm. On the other hand, since the lattice constant of nitrides of Ta and Nb is 0.44 nm, which is larger than the above nitride, it is possible to increase the hardness by lattice distortion by adding Nb and Ta. is there.

The added amount b (= b _Nb + b _Ta ) of _{Ta and Nb} needs to be 0.05 (atomic ratio) or more in order to increase the hardness by sufficient lattice distortion and improve the oxidation resistance. That is, it is necessary to satisfy the expressions (5) and (5A). However, if Nb and Ta are added exceeding the total amount of addition of Ti, Cr and V, hardening due to lattice strain is reduced, so b is the amount of Ti, Cr and V added a (= a _Ti + a _Cr + a _V ) (if not including Ti, it is preferably not more than 1.2 times the _{a = a Cr + a V)} . Ti, Cr, and V are such that these nitrides are close to cubic AlN. Therefore, by adding these elements, it is possible to add Al to a high concentration to improve oxidation resistance while maintaining a high hardness cubic structure. it can. In particular, the nitrides of Cr and V have substantially the same lattice constant as AlN, and the effect is remarkable. Therefore, the total addition amount of these elements is preferably 0.05 (atomic ratio) or more, more preferably 0.15 (atomic ratio) or more.

Further, the total amount c (= c _Al + c _Si + c _B ) of Al, Si, and B needs to be 0.5 (atomic ratio) or more. If it is less than 0.5 (atomic ratio), both oxidation resistance and hardness are insufficient. However, if c exceeds 0.73, the hexagonal crystal, which is a low hardness phase, has a dominant crystal structure in the film, so that c needs to be 0.73 or less. That is, it is necessary to satisfy Expression (6) and Expression (6A).

As described above, it has been found that a part of Al is preferably substituted with Si and B in order to further improve the oxidation resistance. In addition, the addition of Si and B has the effect of reducing the crystal grains of the film and increasing the hardness. However, when the amount of addition of Si and B (c _Si + c _B ) exceeds 0.15 (atomic ratio), the film becomes amorphous and a decrease in hardness is observed, so this addition amount is 0.15 ( Atomic ratio) or less. That is, it is a requirement to satisfy Expression (7) and Expression (7A). If the addition amount is less than 0.01 (atomic ratio), the effect of addition is small, and therefore the addition amount is desirably 0.01 (atomic ratio) or more. That is, the addition amount of Si and B is preferably 0.01 to 0.15 (atomic ratio). More preferably, it is the range of 0.03-0.1 (atomic ratio).

  When Ti is contained, it is necessary to contain Cr or V having a higher hardness due to insufficient hardness, or Si or B to form a high hardness compound such as TiSiN or TiBN. That is, it is necessary to satisfy the formula (9A).

Next, it is the ratio of C and N in the film. By adding C, a high hardness VC compound can be formed and the hardness of the entire film can be increased, but excessive addition of C is unstable. Therefore, the amount of C added is approximately the same as V. From such a point, the lower limit value of the N amount x (atomic ratio) was set to 0.4. In other words, the requirement is to satisfy Equation (8) and Equation (10A). This x (atomic ratio) is desirably 0.6 or more, and more desirably 0.8 or more.
Hard film according to the present invention is a hard film of claim 1, wherein it (Cr _a Ta _b Al _C) a hard film consisting of N, the following equation (1), (5), (6) (9) A hard film characterized by satisfying (9) .
a + b + c = 1 --------------------------------------- Formula (1)
0.05 ≦ b -------------------------- Equation (5)
0.5 ≦ c ≦ 0.73 ------------------- Equation (6)
0.05 ≦ a -------------------------- Formula (9)
In the above formulas (1), (5), (6) and (9) , a represents the atomic ratio of Cr, b represents the atomic ratio of Ta, and c represents the atomic ratio of Al.

Hard film according to the reference technique 2 _{[(Ti, Cr, V) a} (Nb, Ta) b (Al, Si, B) C ] (C _1-x N x) from comprising a hard film below A hard film A satisfying the formulas (1B) to (8B) and a hard film composed of [(Ti, Cr, V) _a (Nb, Ta) _b (Al, Si, B) _C ] (C _1-x N _x ) a hard film B a film that satisfies the following formula (1C) ~ (8C), a hard coating, characterized in that alternately laminated two or more layers in total.
a + b + c = 1 -------------------------- Formula (1B)
a _Ti + a _Cr + a _V = a -------------------- Formula (2B)
b _Nb + b _Ta = b -------------------------------------------- Formula (3B)
c _Al + c _Si + c _B = c ------------------- Equation (4B)
0.05 ≦ b -------------------------- Formula (5B)
0.5 ≦ c ≦ 0.73 ------------------- Equation (6B)
0 ≦ c _Si + c _B ≦ 0.15 ---------------- Equation (7B)
0.4 ≦ x ≦ 1.0 ------------------- Equation (8B)
a + b + c = 1 -------------------------- Formula (1C)
a _Ti + a _Cr + a _V = a -------------------- Formula (2C)
b _Nb + b _Ta = b -------------------------- Formula (3C)
c _Al + c _Si + c _B = c ------------------- Equation (4C)
0.05 ≦ b -------------------------- Formula (5C)
0.5 ≦ c ≦ 0.8 ------------------- Equation (6C)
0.15 ≦ c _Si + c _B ≦ 0.5 ------------ Formula (7C)
0.4 ≦ x ≦ 1.0 ------------------- Equation (8C)
However, in the above formulas (1B) to (8B) and (1C) to (8C), a _Ti is an atomic ratio of Ti, a _Cr is an atomic ratio of Cr, a _V is an atomic ratio of V, and b _Nb is Nb. The atomic ratio, b _Ta is the atomic ratio of Ta, c _Al is the atomic ratio of Al, c _Si is the atomic ratio of Si, c _B is the atomic ratio of B, and x is the atomic ratio of N.

In this hard coating, the hard coating A itself has the same composition as the hard coating according to Reference Technique 1 . C = c _Al + c _Si + c _B (atomic ratio) of the hard coating A is 0.5 ≦ c ≦ 0.73, and c _Si + c _B (atomic ratio) is expressed by the formula: 6A As shown in (7A), 0 ≦ c _Si + c _B ≦ 0.15, whereas c = c _Al + c _Si + c _B (atomic ratio) of the hard coating B is as shown in the formula (6C). 0.5 ≦ c ≦ 0.8, and c _Si + c _B (atomic ratio) is 0.15 ≦ c _Si + c _B ≦ 0.5, as shown in Formula (7C).

Thus, the hard coating B has a larger amount of Si + B (c _Si + c _B ) and Al + Si amount + B (c _Al + c _Si + c _B ) than the hard coating A. For this reason, the hard coating B has a hexagonal or amorphous structure, and the hardness is lower than that of the hard coating A. However, the hard coating B has higher oxidation resistance than the hard coating A because the Si amount + B amount and the Al amount + Si amount + B amount are increased. Therefore, a hard film having both hardness and oxidation resistance can be obtained by alternately laminating two or more layers of the hard film A and the hard film B in total. Therefore, the hard film according to the reference technique 2 has a higher level when the hardness and oxidation resistance are combined as compared with the hard film according to the reference technique 1 , and is excellent in overall characteristics. That is, when the hard coating according to Reference Technology 2 and the hard coating according to Reference Technology 1 are made to have the same hardness, for example, the hard coating according to Reference Technology 2 can have better oxidation resistance, For example, in the case of the same level of oxidation resistance, the hard coating according to Reference Technique 2 can have a higher hardness.

In the hard coating according to Reference Technology 2 , in order to maintain high hardness, the film thickness ratio of the hard coating A layer and the hard coating B layer is 2/1 or more (the thickness of the hard coating A layer is 2 of the thickness of the hard coating B layer). It is desirable to be more than twice. Further, in order to exert the effect of lamination, it is desirable that the lamination cycle thickness (the sum of the thickness of the arbitrary hard coating A layer and the thickness of the hard coating B layer adjacent to the layer)> 10 nm, It is desirable that the thickness of the coating A layer is 5 nm or more and the thickness of the hard coating B layer is 1 nm or more. In order to exhibit the effect of lamination more highly, it is more desirable that the thickness of the hard coating A layer is 10 nm or more and the thickness of the hard coating B layer is 2 nm or more. However, if the thickness of each layer is too large, the effect of lamination is greatly reduced and almost lost, and therefore the thickness of the hard coating A layer: 100 nm or less and the thickness of the hard coating B layer: 10 nm or less are preferable. . More preferably, the thickness of the hard coating A layer is 50 nm or less, and the thickness of the hard coating B layer is 5 nm or less. The total film thickness is about 1 to 10 μm in the case of a cutting tool, although it depends on the application.

Reference technique 3 is a method of forming a hard coating according to reference technique 2, and uses a film forming apparatus having an arc evaporation source and a sputtering evaporation source, and the object to be processed is placed in front of the arc evaporation source and the sputtering evaporation source. alternately passed, to form a hard film a by cathode discharge type arc ion plating, Ru forming method der of hard film and forming a hard film B by sputtering. This forming method can be suitably used when forming the hard film according to Reference Technique 2 .

That is, since the film of the hard film B layer is high Si and B (the amount of Si + B is large), the target for forming the hard film B has a low mechanical strength. If an ion plating method is used to form the target, the target may be damaged during arc discharge. Further, the preferable range of the hard coating B layer is 10 nm or less, and particularly between 1 and 10 nm. However, since the arc evaporation source has a very high film forming rate, it is difficult to precisely control the film thickness. On the other hand, if the hard coating B is formed by a sputtering method, there is no problem of target damage as described above, and precise control of the film thickness as described above is easy. Therefore, the hard coating A is preferably formed by a cathode discharge arc ion plating method, and the hard coating B is formed by a sputtering method. And if this is performed alternately and continuously, the hard film which concerns on the reference technique 2 can be formed simply.

In the method of forming a hard film according to Reference Technology 3 , a film forming apparatus having an arc evaporation source and a sputter evaporation source is used, and the object to be processed is passed alternately in front of the arc evaporation source and the sputter evaporation source, thereby forming a hard film. Since the coating A is formed by the cathode discharge arc ion plating method and the hard coating B is formed by the sputtering method, the formation of the hard coating A by the arc ion plating method and the hard coating B by the sputtering method. Can be performed alternately and continuously, and the hard film according to the reference technique 2 can be easily formed. At this time, there is no problem of target damage as described above, and precise control of the film thickness can be facilitated. Therefore, the method for forming the hard film according to Reference Technology 3 can be suitably used when the hard film according to Reference Technology 2 is formed.

An example of an apparatus for performing the method of forming a hard film according to Reference Technology 3 is shown in FIG. This apparatus is a film forming apparatus having two arc evaporation sources and two sputtering evaporation sources in the same vacuum container. In this apparatus, four substrates 1 are symmetrically arranged on a rotating disk 9 in a chamber 8 and are formed in a circumferential shape (circumferentially) around the sputtering evaporation sources 2 and 3 and arc evaporation sources 5 and 6. Are arranged opposite to each other, and the sputtering evaporation sources 2 and 3 and the arc evaporation sources 5 and 6 are opposed to each other. The sputtering evaporation source and the arc evaporation source are alternately arranged so as to be adjacent to each other.

  Then, each substrate 1 is rotated by the rotation of the turntable 9 so that the substrates 1 alternately pass in front of the arc evaporation sources 5 and 6 and the sputtering evaporation sources 2 and 3. In this case, the arc evaporation sources 5 and 6 and the sputtering evaporation sources 2 and 3 may be rotated around the substrate 1 without rotating the turntable 9 or the substrate 1. Further, as another aspect, the sputtering evaporation sources 2 and 3 and the arc evaporation sources 5 and 6 are not arranged circumferentially in the chamber 8 but are alternately arranged in series such as a straight line to form a film. The substrate to be moved may be sequentially moved between the arc evaporation source and the sputtering evaporation source.

A target having the same composition as the hard film A is mounted as the arc evaporation sources 5 and 6, a target having the same composition as the hard film B is mounted as the sputtering evaporation sources 2 and 3, and an atmosphere containing a reactive gas (for example, argon-nitrogen) In the atmosphere or argon-nitrogen-methane atmosphere). Then, the components of the hard coating A layer are vaporized using the arc evaporation sources 5 and 6 and the components of the hard coating B layer are vaporized using the sputtering evaporation sources 2 and 3, respectively, and are laminated on the substrate 1 alternately and sequentially. Thus, the hard film according to the reference technique 2 can be formed.

  In the film forming apparatus shown in FIG. 1, both the arc evaporation source and the sputtering evaporation source use the magnetic field 10 generated and controlled by the magnetic field applying mechanism 11 provided therein. That is, the film forming apparatus shown in FIG. 1 has a mode in which the magnetic fields 10 of both evaporation sources generated and controlled by the magnetic field applying mechanism 11 are formed so as to be connected to each other.

  In this way, when the magnetic fields 10 of both evaporation sources are connected to each other, the directivity of ions from both evaporation sources is improved, the ion irradiation to the substrate is increased, and a film with better characteristics is formed. It becomes possible. That is, the magnetic field 10 (lines of magnetic force) in the same film forming chamber 8 is closed (closed magnetic field structure). For this reason, the emitted electrons from the evaporation source are trapped in the closed magnetic field structure and are not easily guided to the chamber 8 serving as the anode like the substrate 1. As a result, the concentration of emitted electrons increases, collisions with sputtering gas and reactive gas increase, and gas ionization can be performed with high efficiency.

  On the other hand, when the magnetic fields 10 of both evaporation sources are not connected to each other and are independent, the magnetic field 10 (lines of magnetic force) in the same film forming chamber 8 is in an open state (open magnetic field structure). The emitted electrons from the evaporation source are easily and easily guided to the chamber 8 quickly (easily) along the direction of each magnetic field 10 (lines of magnetic force). As a result, the concentration of emitted electrons is reduced, collision with the sputtering gas or reactive gas is reduced, and the ionization efficiency of the gas is reduced. That is, the directivity of ions from both evaporation sources becomes slow, the amount of ion irradiation to the substrate is reduced, and the possibility of hindering film properties or film formation efficiency increases.

  Examples of the present invention and comparative examples will be described below. The present invention is not limited to this embodiment, and can be implemented with appropriate modifications within a range that can be adapted to the gist of the present invention, all of which are within the technical scope of the present invention. include.

[Example A]
An alloy target made of (Ti, Cr, V) _a (Nb, Ta) _b (Al, Si, B) _C is attached to the arc evaporation sources 5 and 6 of the film forming apparatus shown in FIG. Board) As an object to be processed (substrate) 1, a cemented carbide chip, a cemented carbide ball end mill (diameter 10 mm, two blades) or an oxidation test platinum foil (30 × 5 × 0.1 mmt) After the attachment, the chamber 8 was evacuated. Thereafter, the object to be processed 1 is heated to a temperature of 500 ° C. with a heater in the chamber 8, nitrogen gas is introduced, the pressure in the chamber is set to 2.7 Pa, and arc discharge is started, and the substrate (object to be processed) 1 A film having a thickness of 3 μm was formed on the surface of the film. Note that a bias voltage of 20 to 100 V was applied to the substrate (object to be processed) 1 so that the substrate (object to be processed) 1 had a negative potential with respect to the ground potential during film formation. The turntable 9 was not rotated and remained fixed.

  After film formation, the metal component composition in the film, the crystal structure of the film, and Vickers hardness were examined. The component composition of the metal element in the film was measured by EPMA. The crystal structure of the film was identified by X-ray diffraction. The amount of impurity elements other than metal elements and nitrogen in the film was at a level of 5 at% or less for oxygen and carbon.

  Further, in order to evaluate the wear resistance, a wear test was performed under the following conditions using an end mill on which a hard film was formed, and the wear width of the middle part of the blade was measured.

[Cutting test conditions]
-Work material: SKD11 (HRC60)
・ Cutting speed: 150 m / min ・ Blade feed: 0.04 mm / blade ・ Shaft cutting: 4.5 mm
・ Diameter cut: 0.2mm
・ Cutting length: 10m
・ Others: Down cut, air blow only

  The results of the above test (investigation, measurement) are shown in Table 1. As can be seen from Table 1, the films No. 4, 7, 12, 16, and 20 (comparative examples) have higher oxidation resistance or hardness and smaller wear width than the conventional examples, but are not sufficient. .

  Compared with this, the films of Nos. 5, 6, 8 to 11, 13 to 15, 17 to 19 and 21 have high oxidation resistance and hardness, and a small wear width.

[Example B]
Targets composed of the metal components of layer A shown in Table 2 in the arc evaporation sources 5 and 6 of the film forming apparatus shown in FIG. 1 [No. 4 to 13 composition of layer A: (Ti _0.27 Nb _0.15 Al _0.56 Si _0.02 ) N], an alloy target made of the metal component of layer B shown in Table 2 is attached to the sputter evaporation sources 2 and 3, and a cemented carbide as the object to be processed (substrate) 1 on the support base (rotary disc) 9 A chip 8, a cemented carbide ball end mill (diameter 10 mm, 2 blades) or an oxidation test platinum foil (30 × 5 × 0.1 mmt) was attached, and the chamber 8 was evacuated. Thereafter, the workpiece 1 is heated to a temperature of 500 ° C. with a heater in the chamber 8, and a nitrogen-argon mixed gas (mixing ratio 1: 1) is introduced into the chamber 8 to bring the pressure in the chamber to 2.7 Pa. Then, arc discharge and sputter discharge were started simultaneously, and a film having a thickness of 3 μm was formed on the surface of the substrate (target object) 1 while rotating the target object (substrate) 1 by rotation of the turntable 9. Note that a bias voltage of 20 to 100 V was applied to the substrate (object to be processed) 1 so that the substrate (object to be processed) 1 had a negative potential with respect to the ground potential during film formation.

  After the film formation was completed, the metal component composition in the film, the crystal structure of the film, and the Vickers hardness were examined by the same method as in Example A above. Further, in order to evaluate the wear resistance, an end mill having a hard film formed thereon was used, and a cutting test was performed under the same conditions as in Example A to measure the wear width of the middle part of the blade.

  The results of the above test (investigation, measurement) are shown in Table 2. As can be seen from Table 2, the film of No. 7 has higher oxidation resistance and hardness and smaller wear width than the conventional example, but is not sufficient.

  Compared with this, the films of Nos. 4 to 6 and 8 to 14 have higher oxidation resistance and hardness, and a smaller wear width.

In addition, the films Nos. 4 to 6 and 8 to 14 have higher hardness and oxidation resistance than the basic technique examples and one reference technique example in Table 1, and the wear width is also small.

  The hard coating according to the present invention is more suitable as a coating film (hard coating) for tools, dies, etc., because it has better oxidation resistance and higher hardness than TiAlN and TiCrAlN coatings, which are conventional hard coatings. They can be used and are useful in improving their durability.

It is a schematic diagram which shows the example of the apparatus for performing the formation method of the hard film which concerns on the reference technique 3 .

  1--substrate, 2--sputtering evaporation source, 3--sputtering evaporation source, 5--arc evaporation source, 6--arc evaporation source, 8--chamber, 9--turn table, 10--magnetic field, 11 -Magnetic field application mechanism.

Claims (1)

A (Cr _a Ta _b Al _C) consisting of N hard film, the following equation (1), (5), (6), the hard film and satisfies the (9).
a + b + c = 1 ---------------------------------------
0.05 ≦ b -------------------------- Equation (5)
0.5 ≦ c ≦ 0.73 ------------------- Equation (6)
0.05 ≦ a -------------------------- Formula (9)
In the above formulas (1), (5), (6) and (9) , a represents the atomic ratio of Cr, b represents the atomic ratio of Ta, and c represents the atomic ratio of Al.

Images