JP6308298B2 - Manufacturing method of coated tool - Google Patents

Description

  The present invention is a coated tool used for, for example, a die for press working or forging, a cutting tool such as a saw blade, and a cutting tool such as a drill, and includes a diamond-like carbon film (hereinafter referred to as “DLC film”). It is related with the manufacturing method of the coated tool in which it was also formed.

When a workpiece such as aluminum, copper, or resin is molded with a mold, product abnormalities such as galling or scratching may occur due to part of the workpiece adhering to the surface of the mold. In order to solve this problem, a coated mold in which a DLC film is formed on the surface of the mold has been put into practical use. A DLC film substantially free of hydrogen (Tetrahedral amorphous carbon film: ta-C film) is widely applied to coating dies because it has high hardness and excellent wear resistance.
However, a high-hardness DLC film that does not substantially contain hydrogen is formed by an arc ion plating method using a graphite target, and particles (graphite spheres) having a size of several micrometers, called droplets, are formed. Inevitably mixed into the DLC film, the surface roughness of the DLC film deteriorates.

  For such a problem, Patent Document 1 applies a filtered arc ion plating method having a mechanism for collecting droplets to provide a smooth, high-hardness DLC substantially free of hydrogen. It is disclosed that a film can be formed.

JP 2008-297171 A

When formed by the filtered arc ion plating method as in Patent Document 1, a DLC film having a high hardness and a smooth surface state can be achieved. However, high hardness DLC films tend to have poor adhesion, and satisfactory adhesion tends to be difficult to achieve by simply applying the filtered arc ion plating method.
In addition, in order to further increase the durability of the coated tool under harsh usage environments, it is required to make the DLC film having a high hardness thicker. However, if the film formation time is lengthened to form a thick DLC film, arc discharge tends to become unstable, and it is difficult to make a high-hardness DLC film thick while ensuring excellent adhesion. It was.

  The present invention has been made in view of the circumstances as described above, and relates to a method for manufacturing a coated tool capable of forming a high-hardness DLC film in a thick film while ensuring excellent adhesion. .

The present invention is a method for manufacturing a coated tool for forming a diamond-like carbon film on the surface of a substrate by a filtered arc ion plating method, and a negative bias voltage applied to a substrate installed in a furnace is − and 2500V than -1500V less, introducing a mixed gas containing hydrogen gas into the furnace, the first step of the gas bombardment of the surface of the substrate, a nitrogen gas into the furnace after the gas bombardment And introducing a current to the graphite target to form a diamond-like carbon film on the surface of the substrate,
The second step is a method of manufacturing a coated tool including a step of decreasing the flow rate of the nitrogen gas and a step of increasing the current input to the graphite target.

The film thickness of the diamond-like carbon film is preferably 2.0 μm or more.
In the step of increasing the current input to the graphite target, the current input to the graphite target is preferably increased by 40 A or more in total.

  According to the present invention, a high-hardness DLC film having excellent adhesion can be formed in a thick film. Moreover, the film formation is stable and the coated tool which is excellent in durability can be manufactured stably.

It is a cross-sectional observation photograph (* 17,340 times) of the DLC film coat | covered with this invention example 4 with the scanning electron microscope. It is the schematic of the T-shaped filtered arc ion plating apparatus used in the Example.

  The present inventor has studied a technique for increasing the film thickness of a high-hardness DLC film having excellent adhesion. In the filtered arc ion plating method, it is important to control the gas bombardment of the base material before forming the DLC film, the atmosphere in the furnace when the DLC film is formed, and the current supplied to the graphite target. The headline, the method for producing the coated tool of the present invention has been reached. Details of the present invention will be described below.

  In the present invention, a conventionally known filtered arc ion plating apparatus can be used. By applying the filtered arc ion plating method, the droplets contained in the coating are reduced to a smooth surface state, and the nanoindentation hardness substantially containing no hydrogen is 50 GPa or more. A DLC film can be formed. In particular, it is preferable to use a T-shaped filtered arc ion plating apparatus because a smoother and harder DLC film can be formed.

  The DLC film of the present invention preferably has a nanoindentation hardness of 50 GPa or more in order to improve the wear resistance of the coated tool. Furthermore, 55 GPa or more is preferable, and 60 GPa or more is more preferable. Furthermore, 70 GPa or more is preferable. On the other hand, if the hardness of the DLC film becomes too high, the residual compressive stress becomes too high, and the adhesion to the substrate may be reduced. Therefore, the nanoindentation hardness is preferably 100 GPa or less. Furthermore, the nanoindentation hardness of the DLC film is preferably 95 GPa or less.

  Nanoindentation hardness is the plastic hardness when a probe is pressed into a sample (DLC film) and plastically deformed. A load-displacement curve is obtained from the indentation load and indentation depth (displacement). Calculate the hardness. Specifically, using a nanoindentation device manufactured by Elionix Co., Ltd., the hardness of the coating surface was measured under the measurement conditions of an indentation load of 9.8 mN, a maximum load holding time of 1 second, and a removal rate after loading of 0.49 mN / second. Ten points are measured and obtained from an average value of six points excluding two points having a large value and two points having a small value.

  A high-hardness DLC film having a nanoindentation hardness of 50 GPa or more tends to have extremely high internal stress and poor adhesion to a substrate. As a technique for improving adhesion, a technique for providing an intermediate film having a hardness lower than that of a DLC film has been proposed. However, according to the study of the present inventor, when an intermediate film such as a metal, carbide or nitride is interposed between the base material and the DLC film, the DLC film is preferentially started from the surface defect of the intermediate film. In order to peel, it confirmed that it was not enough to improve adhesiveness. Therefore, in the present invention, the gas bombarding treatment to the base material before forming the DLC film was examined so that the adhesion is not impaired even if the DLC film is directly formed on the base material.

In the present invention, as a first step, a mixed gas containing hydrogen gas is introduced into the furnace, and the surface of the substrate is subjected to gas bombardment treatment.
According to the study of the present inventor, it was confirmed that when gas bombardment treatment with a conventional argon gas was performed, a large amount of oxygen was present at the interface between the film and the substrate, resulting in a decrease in adhesion. Oxygen present at the interface originates from the oxide film formed on the substrate surface from the beginning, and is a residual element that has not been removed by the gas bombardment with argon gas.
Therefore, in the present invention, a mixed gas containing hydrogen gas is introduced into the furnace (vacuum chamber), and the surface of the substrate is subjected to gas bombardment. By gas bombarding the surface of the substrate using a mixed gas containing hydrogen gas, the oxide film on the surface of the substrate reacts with hydrogen ions to be reduced, and the oxide film and surface contamination are sufficiently removed. Thus, the adhesion of the DLC film formed directly on the substrate is improved.

  The mixed gas containing hydrogen gas is preferably a mixed gas containing 4% by mass or more of hydrogen gas with respect to the total mass of argon gas and hydrogen gas. If the amount of hydrogen gas is less than 4% by mass, it may be difficult to remove the oxide film by gas bombardment with a mixed gas. Furthermore, it is preferable to use a mixed gas containing 5% by mass or more of hydrogen gas, and it is preferable to use a mixed gas containing 7% by mass or more of hydrogen gas. Furthermore, it is preferable to use a mixed gas containing 10% by mass or more of hydrogen gas. However, in the case of a mixed gas in which the hydrogen gas exceeds 30% by mass, the effect of removing the oxide film and the surface contamination by the gas bombardment treatment tends to be constant (the effect does not increase even if the concentration of the hydrogen gas is further increased). is there. Therefore, it is preferable to use a mixed gas whose hydrogen gas is 30% by mass or less. Furthermore, it is preferable to use a mixed gas containing 25% by mass or less of hydrogen gas. Furthermore, it is preferable to use a mixed gas containing 15% by mass or less of hydrogen gas.

In the gas bombardment process using the above-described mixed gas, the negative bias voltage applied to the substrate is set to −2500V to −1500V. When the negative bias voltage applied to the substrate is larger than −1500 V (positive side from −1500 V), the impact energy of gas ions is low, so the effect of removing the oxide film and the surface contamination is reduced. The adhesion between the substrate and the high-hardness DLC film tends to decrease. In addition, when the negative bias voltage applied to the substrate is smaller than −2500V (minus side of −2500V), the plasma tends to become unstable and abnormal discharge may occur. When abnormal discharge occurs, abnormal discharge (arcing) traces are formed on the tool surface, and unevenness may occur on the tool surface. Furthermore, the negative bias voltage applied to the substrate is preferably −2400 V or higher, and more preferably −2300 V or higher. Moreover, it is preferable that the negative bias voltage applied to a base material is -1600V or less, Furthermore, it is preferable that it is -1700V or less.
In order to sufficiently remove the oxide on the substrate surface, it is preferable to perform gas bombardment treatment with a mixed gas for 60 minutes or more. Furthermore, it is preferable to carry out for 70 minutes or more. It is preferable to appropriately adjust the upper limit of the gas bombardment treatment time according to the shape and material of the substrate. However, when the gas bombardment time with the mixed gas is 180 minutes or more, the effect of removing the oxide film and the surface contamination by the gas bombardment tends to be constant (the effect is not improved any more). Therefore, it is preferable that the gas bombardment treatment with the mixed gas is performed for 180 minutes or less.

In the present invention, as the second step, nitrogen gas is introduced into the furnace after the gas bombardment treatment, current is supplied to the graphite target, and a DLC film is formed on the surface of the substrate subjected to the gas bombardment treatment.
By forming a DLC film containing nitrogen in a state where the oxide film on the surface of the substrate is sufficiently removed by gas bombardment treatment, the residual compressive stress of the DLC film on the surface of the substrate is reduced. And the adhesion of the DLC film can be further increased. In order to reduce the residual compressive stress of the DLC film on the substrate side and further improve the adhesion, the flow rate of the nitrogen gas introduced into the furnace after the gas bombardment treatment is preferably 5 sccm or more. If the flow rate of nitrogen gas is less than 5 sccm, it may be difficult to obtain a sufficient effect of improving adhesion. Furthermore, it is preferable to set it as 10 sccm or more.
On the other hand, if the flow rate of nitrogen gas introduced into the furnace after the gas bombardment process becomes too large, the content of nitrogen contained in the DLC film increases, the film hardness decreases, wear resistance decreases, and non-ferrous materials When this is processed, welding is likely to occur. Therefore, the flow rate of nitrogen gas is preferably 60 sccm or less. Furthermore, it is preferable to set it as 50 sccm or less. Furthermore, it is preferable to set it as 40 sccm or less.
If the flow rate of nitrogen gas introduced into the furnace becomes too small with respect to the volume of the furnace (vacuum chamber), it may be difficult to obtain a sufficient effect of improving the adhesion of the DLC film. Therefore, the volume in the furnace (m ³ ) / the flow rate of nitrogen gas introduced into the furnace (sccm) is preferably 10 × 10 ⁻² (m ³ / sccm) or less. Furthermore, it is preferable to set it as 5.0 * 10 ^<-2 > (m ^{< 3} > / sccm) or less. Further, if the flow rate of the nitrogen gas introduced into the furnace becomes too large with respect to the volume in the furnace, excessive nitrogen is easily included in the DLC film. Therefore, the volume in the furnace (m ³ ) / the flow rate of nitrogen gas introduced into the furnace (sccm) is preferably 0.1 × 10 ⁻² (m ³ / sccm) or more. Furthermore, it is preferable to set it as 1.0 * 10 ^<-2 > (m ^{< 3} > / sccm) or more.

In the present invention, in the second step, a step of reducing the flow rate of nitrogen gas and supplying a current to the graphite target to form a DLC film is provided.
In order to improve the adhesion to the substrate, it is effective to introduce a nitrogen gas to form a DLC film. However, if excessive nitrogen atoms are contained in the entire DLC film, the hardness decreases. Further, when non-ferrous materials are processed, welding is likely to occur. Therefore, in the present invention, the DLC film is formed by reducing the flow rate of the nitrogen gas and supplying a current to the graphite target so that the entire DLC film does not contain excessive nitrogen gas. By providing a step of forming a DLC film by reducing the flow rate of nitrogen gas at the time of film formation, the DLC film on the substrate side contains a lot of nitrogen atoms, the residual compressive stress is reduced, and the adhesion to the substrate is improved. As a result, the DLC film on the surface side has a low content of nitrogen atoms and improves wear resistance and welding resistance.
In the second step, it is preferable to form the DLC film while gradually reducing the flow rate of the nitrogen gas introduced into the furnace. And finally, it is preferable to stop the introduction of nitrogen gas and to apply a current to the graphite target to form a DLC film. By stopping the introduction of nitrogen gas and forming the DLC film, it is preferable because a DLC film having high hardness and less welding of the workpiece can be formed on the surface in contact with the other material. In order to achieve a DLC film with higher hardness and less welding of the work material, the introduction of nitrogen gas is finally stopped and the furnace pressure is set to 5 × 10 ⁻³ Pa or less to form the DLC film. It is preferable.
In the second step, a hydrocarbon gas such as acetylene may be introduced into the furnace to increase the hydrogen content of the DLC film on the substrate side. In addition, after the first step, a hydrocarbon gas such as acetylene may be introduced into the furnace, and then the second step may be performed.

In the present invention, in the second step, a step of forming a DLC film by increasing the current input to the graphite target is provided.
The present inventor has confirmed that in the formation of the DLC film by the filtered arc ion plating method, large irregularities are generated on the surface of the graphite target as the DLC film is formed, and the arc discharge becomes unstable. And even if large unevenness | corrugation generate | occur | produced on the surface of the target, it turned out that an arc discharge tends to become stable by supplying a higher electric current to a graphite target. However, even if the current supplied to the graphite target is set high, if the input power is constant, the arc discharge gradually becomes unstable with the progress of the DLC film formation, and the DLC film with high hardness and excellent adhesion It is difficult to form a thick film. In particular, in the initial stage of DLC film formation, if a high current value is applied to the target surface in a flat state, the discharge becomes unstable, a large amount of droplets are generated, and large irregularities occur on the film surface. There is a problem with the smoothness of the film surface. The present inventor has formed a DLC film for a certain period of time with a constant current supplied to the graphite target, and increased the current supplied to the graphite target before the arc current becomes unstable, thereby stabilizing the arc discharge. It has been found that a DLC film can be continuously formed. Therefore, in the present invention, a step of forming a DLC film by increasing the current input to the graphite target during film formation is provided. As a result, a DLC film having a high hardness can be formed in a thicker film with less load on the apparatus and stably.
The current supplied to the graphite target may be increased stepwise or continuously. In order to form a thicker DLC film, it is preferable to increase the current input to the graphite target stepwise. Further, it is preferable to increase the current supplied to the graphite target by 40 A or more in total. Furthermore, the total is preferably 55A or more, and more preferably 60A or more in total. By forming in this way, a thick DLC film having a high hardness can be stably formed.
The input current value varies depending on the surface state of the graphite target, and a smaller current value (30A to 50A) is more preferable in the initial flat state. Thereafter, it is desirable to increase the current value stepwise.
In the second step, the step of decreasing the flow rate of nitrogen gas and the step of increasing the current input to the graphite target may be performed simultaneously or separately. For example, the timing for decreasing the flow rate of nitrogen gas and the timing for increasing the current input to the graphite target may be the same, or may be separate, and the timing for decreasing the flow rate of nitrogen gas and the current input to the graphite target may be The timing to increase may be provided alternately. Moreover, it is preferable to finally stop the introduction of nitrogen gas and increase the electric power supplied to the graphite target to form the DLC film. By forming in this way, it becomes possible to make the DLC film of higher hardness thicker.

  If the current supplied to the graphite target becomes too large, the arc discharge tends to become unstable. In the second step of the present invention, a step of increasing the current input to the graphite target is provided. However, in order to maintain stable film formation, the current input to the graphite target is preferably 150 A or less. . Furthermore, it is preferable to set it as 120 A or less. However, if the current supplied to the graphite target becomes too small, the DLC film may not be sufficiently formed. Therefore, the current input to the graphite target is preferably 20 A or more. More preferably, it is 30 A or more.

Even if the DLC film has high hardness, if the film thickness is thin, it may be difficult to obtain excellent durability. In order to impart excellent durability to the coated tool in a harsher use environment, the film thickness of the DLC film is preferably 1.0 μm or more, and more preferably 1.5 μm or more. Furthermore, the film thickness of the DLC film is preferably 2.0 μm or more.
However, if the film thickness of the DLC film becomes too thick, the surface roughness of the film surface may deteriorate. Moreover, if the film thickness of a high-hardness DLC film becomes too thick, the risk that the DLC film partially peels increases. Therefore, the thickness of the DLC film is preferably 5.0 μm or less. Furthermore, the thickness of the DLC film is more preferably 4.0 μm or less.

  When forming the DLC film, the substrate temperature is preferably 200 ° C. or lower. When the substrate temperature is higher than 200 ° C., the DLC film is graphitized, so that the hardness tends to decrease. In forming the DLC film, it is preferable that the negative bias voltage applied to the substrate is −300 V or more and −50 V or less. When the negative bias voltage applied to the base material is larger than −50 V (positive side than −50 V), the collision energy of carbon ions becomes small, and defects such as voids are likely to occur in the DLC film. Further, when the negative bias voltage applied to the substrate is smaller than −300 V (minus side than −300 V), abnormal discharge is likely to occur during film formation. When the DLC film is formed, the negative bias voltage applied to the substrate is more preferably −200 V or more and −100 V or less.

  In the present invention, the substrate on which the DLC film is formed (the substrate of the coated tool) is not particularly limited, and can be appropriately selected depending on the application, purpose, and the like. For example, cemented carbide, cold tool steel, high speed tool steel, plastic mold steel, hot tool steel, etc. can be applied. Among the base materials, a high carbon steel having a carbon content of 1% or more, or a cemented carbide, in which the base material has a large amount of carbide and easily peels off, is preferable because of its high adhesion improvement effect. Examples of the high carbon steel include JIS-SKD11.

  Even with a DLC film formed by the filtered arc ion plating method, the surface roughness may decrease as the film thickness increases. In that case, it is preferable that after the DLC film is formed, the surface is polished and smoothed. In this invention, you may adjust so that it may become a more preferable smooth surface state by grind | polishing the surface of a DLC film.

<Deposition system>
As a film forming apparatus, a T-shaped filtered arc ion plating apparatus (vacuum chamber volume in the furnace was 0.49 m ³ ) was used.
A schematic diagram of the apparatus is shown in FIG. A deposition chamber (6), an arc discharge evaporation source on which a carbon cathode (cathode) (1) on which a graphite target is installed, and a substrate holder (7) for mounting the substrate are included. Under the substrate holder is a rotation mechanism (8), and the substrate rotates and revolves via the substrate holder (7). Reference numeral (2) indicates a carbon film-forming beam, and reference numeral (3) indicates spherical graphite (droplet) neutral particles.
When an arc discharge is generated on the surface of the graphite target, only the charged carbon is bent by the magnetic coil (4) and reaches the film forming chamber (6) to cover the substrate with the film. The droplets without charge are collected in the duct (5) without being bent by the magnetic coil.

<Base material>
As a base material for evaluating the peeled state and weldability of the formed DLC film, a base material made of JIS-SKD11 equivalent steel material tempered to 60 HRC with a dimension of φ20 × 5 mm was used.
The base material for measuring the nanoindentation hardness of the formed DLC film, film analysis, and film thickness by fracture surface is from tungsten carbide (WC-10 mass% Co) having a cobalt content of 10 mass%. A base material made of cemented carbide (dimensions: 4 mm × 8 mm × 25 mm, average particle size: 0.8 μm, hardness: 91.2 HRA) was used.
In addition, as a base material for evaluating the adhesion of the formed DLC film by a scratch test and a Rockwell hardness tester, a base material of a JIS-SKH51 equivalent steel material having dimensions of 21 mm × 17 mm × 2 mm was used.
Before any DLC film is formed on any of the above substrates, the arithmetic average roughness Ra (based on JIS-B-0601-2001) is 0.01 μm or less, and the maximum height roughness Rz (JIS-B-0601). -2001) was polished so as to have a surface roughness of 0.07 μm or less. And after grinding | polishing, it degreased and washed and it fixed to the base-material holder in a chamber. For each substrate, a DLC film was formed under the following conditions.

<Invention Example 1>
The inside of the furnace (vacuum chamber) was evacuated to 5 × 10 ⁻³ Pa, the substrate was heated to around 150 ° C. with a heater for heating, and held for 90 minutes. Thereafter, a negative bias voltage applied to the substrate was set to −2000 V, and a gas bombardment treatment with a mixed gas containing 5 mass% hydrogen gas in argon gas was performed for 90 minutes. The flow rate of the mixed gas was 50 sccm to 100 sccm.
After the gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of −150 V was applied to the base material to make the base material temperature 100 ° C. or lower. Then, the current applied to the graphite target was gradually increased from 40 A to 90 A as described below, and the flow rate of nitrogen gas was gradually decreased from 20 sccm to 0 to form a DLC film.
First, the flow rate of nitrogen gas introduced into the furnace was 20 sccm, the current supplied to the graphite target was 40 A, and a DLC film was formed for about 30 minutes.
Next, the flow rate of nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 50 A, and a DLC film was formed for about 30 minutes.
Next, the flow rate of nitrogen gas was reduced to 5 sccm, the current applied to the graphite target was increased to 60 A, and a DLC film was formed for about 40 minutes.
Next, the introduction of nitrogen gas was stopped, the pressure in the furnace was reduced to 5 × 10 ⁻³ Pa or less, the current supplied to the graphite target was increased to 70 A, and a DLC film was formed for about 40 minutes.
Next, the current applied to the graphite target was increased to 80 A, and a DLC film was formed for about 40 minutes.
Next, the current applied to the graphite target was increased to 90 A, and a DLC film was formed for about 60 minutes.

<Invention Example 2>
The gas bombardment treatment was performed in the same manner as Example 1 of the present invention. After the gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of −150 V was applied to the substrate to make the substrate temperature 100 ° C. or lower. Then, the current applied to the graphite target was gradually increased from 35 A to 95 A as described below, and the flow rate of nitrogen gas was gradually decreased from 25 sccm to 0 to form a DLC film.
First, the flow rate of nitrogen gas introduced into the furnace was 25 sccm, the current supplied to the graphite target was 35 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 20 sccm, the current applied to the graphite target was increased to 40 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 15 sccm, the current applied to the graphite target was increased to 45 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 50 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 7 sccm, the current applied to the graphite target was increased to 55 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 5 sccm, the current applied to the graphite target was increased to 60 A, and a DLC film was formed for about 20 minutes.
Next, the introduction of nitrogen gas was stopped, the pressure in the furnace was reduced to 5 × 10 ⁻³ Pa or less, the current supplied to the graphite target was increased to 65 A, and a DLC film was formed for about 20 minutes.
Next, the current supplied to the graphite target was increased stepwise to 70A, 75A, 80A, 85A, and 90A, and a DLC film was formed at each current value for about 20 minutes.

<Invention Example 3>
The gas bombardment treatment was performed in the same manner as Example 1 of the present invention. After the gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of −150 V was applied to the base material to make the base material temperature 100 ° C. or lower. Then, the current applied to the graphite target was increased stepwise from 30 A to 95 A as described below, and the flow rate of nitrogen gas was decreased stepwise from 20 sccm to 0 to form a DLC film.
First, the flow rate of nitrogen gas introduced into the furnace was set to 20 sccm, the current supplied to the graphite target was set to 30 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 15 sccm, the current applied to the graphite target was increased to 35 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 40 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 5 sccm, the current applied to the graphite target was increased to 45 A, and a DLC film was formed for about 20 minutes.
Next, the introduction of nitrogen gas was stopped, the pressure in the furnace was reduced to 5 × 10 ⁻³ Pa or less, the current supplied to the graphite target was increased to 50 A, and a DLC film was formed for about 20 minutes.
Next, the current supplied to the graphite target was increased stepwise to 55A, 60A, 65A, 70A, 75A, 80A, 85A, and 90A, and a DLC film was formed for about 20 minutes at each current value.

<Invention Example 4>
The gas bombardment treatment was performed in the same manner as Example 1 of the present invention. After the gas bombardment treatment, C ₂ H ₂ gas and nitrogen gas were introduced into the furnace, and a bias voltage of −150 V was applied to the substrate to make the substrate temperature 100 ° C. or lower. Then, the current applied to the graphite target was gradually increased from 35 A to 95 A as described below, and the flow rate of nitrogen gas was gradually decreased from 25 sccm to 0 to form a DLC film.
First, the current supplied to the graphite target was 35 A, the flow rate of nitrogen gas introduced into the furnace was 25 sccm, the flow rate of C ₂ H ₂ gas was 25 sccm, and a DLC film was formed for about 10 minutes.
Next, the current applied to the graphite target was increased to 40 A, the flow rate of C ₂ H ₂ gas was decreased to 20 sccm, and the flow rate of nitrogen gas was decreased to 20 sccm, and a DLC film was formed for about 10 minutes.
Next, the current applied to the graphite target was increased to 45 A, the flow rate of C ₂ H ₂ gas was decreased to 15 sccm, and the flow rate of nitrogen gas was decreased to 15 sccm, and a DLC film was formed for about 10 minutes.
Next, the current applied to the graphite target was increased to 50 A, the flow rate of C ₂ H ₂ gas was decreased to 10 sccm, and the flow rate of nitrogen gas was decreased to 10 sccm, and a DLC film was formed for about 10 minutes.
Next, the current applied to the graphite target was increased to 55 A, the flow rate of C ₂ H ₂ gas was decreased to 7 sccm, and the flow rate of nitrogen gas was decreased to 7 sccm, and a DLC film was formed for about 10 minutes.
Next, the current applied to the graphite target was increased to 60 A, the flow rate of C ₂ H ₂ gas was decreased to 5 sccm, and the flow rate of nitrogen gas was decreased to 5 sccm, and a DLC film was formed for about 10 minutes.
Next, the introduction of C ₂ H ₂ gas and nitrogen gas was stopped, the pressure in the furnace was reduced to 5 × 10 ⁻³ Pa or less, the current supplied to the graphite target was increased to 65 A, and a DLC film was formed for about 25 minutes. .
Next, the current supplied to the graphite target was increased stepwise to 70 A, 75 A, and 80 A, and a DLC film was formed for about 20 minutes at each current value.

<Invention Example 5>
The gas bombardment treatment was performed in the same manner as Example 1 of the present invention. After the gas bombardment treatment, C ₂ H ₂ gas and nitrogen gas were introduced into the furnace, and a bias voltage of −150 V was applied to the substrate to make the substrate temperature 100 ° C. or lower. Then, the current applied to the graphite target was gradually increased from 50 A to 80 A as described below, and the flow rate of nitrogen gas was gradually decreased from 15 sccm to 0 to form a DLC film.
First, the flow rate of nitrogen gas introduced into the furnace was set to 15 sccm, the flow rate of C ₂ H ₂ gas was set to 10 sccm, the current supplied to the graphite target was set to 50 A, and a DLC film was formed for about 6 minutes.
Next, the introduction of C ₂ H ₂ gas was stopped, the flow rate of nitrogen gas was set to 15 sccm, the current supplied to the graphite target was increased to 60 A, and a DLC film was formed for about 45 minutes.
Next, the flow rate of nitrogen gas was reduced to 5 sccm, the current applied to the graphite target was increased to 70 A, and a DLC film was formed for about 45 minutes.
Next, the introduction of nitrogen gas was stopped, the pressure in the furnace was reduced to 5 × 10 ⁻³ Pa or less, the current to be supplied to the graphite target was increased to 80 A, and a DLC film was formed for about 100 minutes.

<Invention Example 6>
The gas bombardment treatment was performed in the same manner as Example 1 of the present invention. After the gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of −150 V was applied to the substrate to make the substrate temperature 100 ° C. or lower. Then, the current applied to the graphite target was gradually increased from 25 A to 95 A as described below, and the flow rate of nitrogen gas was gradually decreased from 15 sccm to 0 to form a DLC film.
First, the flow of nitrogen gas introduced into the furnace was set to 15 sccm, the current supplied to the graphite target was set to 25 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 30 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 5 sccm, the current applied to the graphite target was increased to 35 A, and a DLC film was formed for about 20 minutes.
Next, the introduction of nitrogen gas was stopped, the pressure in the furnace was reduced to 5 × 10 ⁻³ Pa or less, the current supplied to the graphite target was increased to 40 A, and a DLC film was formed for about 20 minutes.
Next, the current supplied to the graphite target was increased stepwise to 45A, 50A, 55A, 60A, 65A, 70A, 75A, 80A, 85A, 90A, and 95A, and a DLC film was formed for about 20 minutes at each current value. .

<Invention Example 7>
In the gas bombardment treatment, a negative bias voltage applied to the substrate was set to −2000 V, and a gas bombardment treatment with a mixed gas containing 10 mass% hydrogen gas in argon gas was performed for 90 minutes. After the gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of −150 V was applied to the substrate to make the substrate temperature 100 ° C. or lower. Then, the current applied to the graphite target was gradually increased from 35 A to 95 A as described below, and the flow rate of nitrogen gas was gradually decreased from 25 sccm to 0 to form a DLC film.
First, the flow rate of nitrogen gas introduced into the furnace was 25 sccm, the current supplied to the graphite target was 35 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 20 sccm, the current applied to the graphite target was increased to 40 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 15 sccm, the current applied to the graphite target was increased to 45 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 50 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 5 sccm, the current applied to the graphite target was increased to 55 A, and a DLC film was formed for about 20 minutes.
Next, the introduction of nitrogen gas was stopped, the pressure in the furnace was reduced to 5 × 10 ⁻³ Pa or less, the current supplied to the graphite target was increased to 60 A, and a DLC film was formed for about 20 minutes.
Next, the current supplied to the graphite target was increased stepwise to 65A, 70A, 75A, 80A, 85A, 90A, and 95A, and a DLC film was formed for about 20 minutes at each current value.

<Invention Example 8>
In the gas bombardment treatment, a negative bias voltage applied to the substrate was set to −2000 V, and a gas bombardment treatment with a mixed gas containing 20 mass% hydrogen gas in argon gas was performed for 90 minutes. After the gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of −150 V was applied to the substrate to make the substrate temperature 100 ° C. or lower. Then, the current applied to the graphite target was gradually increased from 35 A to 95 A as described below, and the flow rate of nitrogen gas was gradually decreased from 25 sccm to 0 to form a DLC film.
First, the flow rate of nitrogen gas introduced into the furnace was 25 sccm, the current supplied to the graphite target was 35 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 20 sccm, the current applied to the graphite target was increased to 40 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 15 sccm, the current applied to the graphite target was increased to 45 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 50 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 5 sccm, the current applied to the graphite target was increased to 55 A, and a DLC film was formed for about 20 minutes.
Next, the introduction of nitrogen gas was stopped, the pressure in the furnace was reduced to 5 × 10 ⁻³ Pa or less, the current supplied to the graphite target was increased to 60 A, and a DLC film was formed for about 20 minutes.
Next, the current supplied to the graphite target was increased stepwise to 65A, 70A, 75A, 80A, 85A, 90A, and 95A, and a DLC film was formed for about 20 minutes at each current value.

<Invention Example 9>
The gas bombardment treatment was performed in the same manner as Example 1 of the present invention. After the gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of −150 V was applied to the base material to make the base material temperature 100 ° C. or lower. Then, the current applied to the graphite target was gradually increased from 35 A to 95 A as described below, and the flow rate of nitrogen gas was gradually decreased from 40 sccm to 0 to form a DLC film.
First, the flow rate of nitrogen gas introduced into the furnace was set to 40 sccm, the current supplied to the graphite target was set to 35 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 30 sccm, the current applied to the graphite target was increased to 40 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 20 sccm, the current applied to the graphite target was increased to 45 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 50 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 5 sccm, the current applied to the graphite target was increased to 55 A, and a DLC film was formed for about 20 minutes.
Next, the introduction of nitrogen gas was stopped, the pressure in the furnace was reduced to 5 × 10 ⁻³ Pa or less, the current supplied to the graphite target was increased to 60 A, and a DLC film was formed for about 20 minutes.
Next, the current supplied to the graphite target was increased stepwise to 65A, 70A, 75A, 80A, 85A, 90A, and 95A, and a DLC film was formed for about 20 minutes at each current value.

<Invention Example 10>
The gas bombardment treatment was performed in the same manner as Example 1 of the present invention. After the gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of −350 V was applied to the base material to make the base material temperature 100 ° C. or lower. Then, the current applied to the graphite target was gradually increased from 35 A to 95 A as described below, and the flow rate of nitrogen gas was gradually decreased from 25 sccm to 0 to form a DLC film.
First, the flow rate of nitrogen gas introduced into the furnace was 25 sccm, the current supplied to the graphite target was 35 A, and a DLC film was formed for about 20 minutes.
Next, the negative bias voltage applied to the substrate was set to −300 V, the flow rate of nitrogen gas was reduced to 20 sccm, the current applied to the graphite target was increased to 40 A, and a DLC film was formed for about 20 minutes.
Next, the negative bias voltage applied to the substrate was set to −250 V, the flow rate of nitrogen gas was reduced to 15 sccm, the current applied to the graphite target was increased to 45 A, and a DLC film was formed for about 20 minutes.
Next, the negative bias voltage applied to the substrate was set to -200 V, the flow rate of nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 50 A, and a DLC film was formed for about 20 minutes.
Next, the negative bias voltage applied to the substrate was set to −150 V, the flow rate of nitrogen gas was reduced to 7 sccm, the current applied to the graphite target was increased to 55 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 5 sccm, the current applied to the graphite target was increased to 60 A, and a DLC film was formed for about 20 minutes.
Next, the introduction of nitrogen gas was stopped, the pressure in the furnace was reduced to 5 × 10 ⁻³ Pa or less, the current supplied to the graphite target was increased to 65 A, and a DLC film was formed for about 20 minutes.
Next, the current applied to the graphite target was increased stepwise to 70A, 75A, 80A, 85A, 90A, and 95A, and a DLC film was formed for about 20 minutes at each current value.

<Invention Example 11>
In the gas bombardment treatment, the negative bias voltage applied to the substrate was set to −2500 V, and the gas bombardment treatment with a mixed gas containing 5 mass% hydrogen gas in argon gas was performed for 90 minutes. After the gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of −150 V was applied to the substrate to make the substrate temperature 100 ° C. or lower. Then, the current applied to the graphite target was gradually increased from 35 A to 95 A as described below, and the flow rate of nitrogen gas was gradually decreased from 25 sccm to 0 to form a DLC film.
First, the flow rate of nitrogen gas introduced into the furnace was 25 sccm, the current supplied to the graphite target was 35 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 20 sccm, the current applied to the graphite target was increased to 40 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 15 sccm, the current applied to the graphite target was increased to 45 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 50 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 7 sccm, the current applied to the graphite target was increased to 55 A, and a DLC film was formed for about 20 minutes.
Next, the flow rate of nitrogen gas was reduced to 5 sccm, the current applied to the graphite target was increased to 60 A, and a DLC film was formed for about 20 minutes.
Next, the introduction of nitrogen gas was stopped, the pressure in the furnace was reduced to 5 × 10 ⁻³ Pa or less, the current supplied to the graphite target was increased to 65 A, and a DLC film was formed for about 20 minutes.
Next, the current applied to the graphite target was increased stepwise to 70A, 75A, 80A, 85A, 90A, and 95A, and a DLC film was formed for about 20 minutes at each current value.

<Comparative Example 1>
The process up to gas bombardment was performed in the same manner as in Example 1. After the gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of −150 V was applied to the base material to make the base material temperature 100 ° C. or lower. Then, the current applied to the graphite target was 50 A, and the flow rate of nitrogen gas was decreased stepwise from 10 sccm to 0 to form a DLC film.
First, the flow rate of nitrogen gas introduced into the furnace was 10 sccm, and a DLC film was formed for about 10 minutes.
Next, the flow rate of nitrogen gas was reduced to 5 sccm, and a DLC film was formed for about 10 minutes.
Next, the introduction of nitrogen gas was stopped, the pressure in the furnace was reduced to 5 × 10 ⁻³ Pa or less, and a DLC film was formed for 30 minutes.

<Comparative example 2>
The process up to gas bombardment was performed in the same manner as in Example 1. After the gas bombardment treatment, a nitrogen gas was not introduced into the furnace, and a bias voltage of −150 V was applied to the substrate to make the substrate temperature 100 ° C. or lower. Then, the DLC film was formed for about 50 minutes by setting the pressure in the furnace to 5 × 10 ⁻³ Pa or less and the current to be supplied to the graphite target to be 50 A.

<Comparative Example 3>
In the gas bombardment treatment, the negative bias voltage applied to the substrate was set to −2000 V, and the gas bombardment treatment with argon gas was performed for 90 minutes.
After the gas bombardment treatment, nitrogen gas was introduced into the furnace, a bias voltage of −150 V was applied to the substrate, and the substrate temperature was set to 100 ° C. or lower. Then, the current applied to the graphite target was 50 A, and the flow rate of nitrogen gas was decreased stepwise from 10 sccm to 0 to form a DLC film.
First, the flow rate of nitrogen gas introduced into the furnace was 10 sccm, and a DLC film was formed for about 10 minutes.
Next, the flow rate of nitrogen gas was reduced to 5 sccm, and a DLC film was formed for about 10 minutes.
Next, the introduction of nitrogen gas was stopped, the pressure in the furnace was reduced to 5 × 10 ⁻³ Pa or less, and a DLC film was formed for about 30 minutes.

<Comparative Example 4>
Gas bombardment treatment was performed with only argon gas under the same conditions as in Comparative Example 3, and then about 3 μm of CrN was formed as an intermediate film. After the formation of the intermediate coating, a nitrogen gas was not introduced, and a bias voltage of −150 V was applied to the base material so that the base material temperature was 100 ° C. or lower.
Then, the DLC film was formed for about 50 minutes with the pressure in the furnace being 5 × 10 ⁻³ Pa or less and the current supplied to the graphite target being constant at 50A.

<Comparative Example 5>
The process up to gas bombardment was performed in the same manner as in Example 1. After the gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of −150 V was applied to the base material to make the base material temperature 100 ° C. or lower. Then, the current applied to the graphite target was set to 80 A, and the flow rate of nitrogen gas was gradually reduced from 10 sccm to 0 to form a DLC film.
First, the flow rate of nitrogen gas introduced into the furnace was 10 sccm, and a DLC film was formed for about 25 minutes.
Next, the flow rate of nitrogen gas was reduced to 5 sccm, and a DLC film was formed for about 25 minutes.
Next, the introduction of nitrogen gas was stopped, the pressure in the furnace was reduced to 5 × 10 ⁻³ Pa or less, and a DLC film was formed for 70 minutes.

<Comparative Example 6>
In the gas bombardment treatment, a negative bias voltage applied to the substrate was set to -1300 V, and a gas bombardment treatment with a mixed gas containing 5 mass% hydrogen gas in argon gas was performed for 90 minutes. After the gas bombardment treatment, a bias voltage of −150 V was applied to the base material so that the base material temperature was 100 ° C. or lower. And the electric current thrown into a graphite target was 50 A, and the DLC film was formed for about 50 minutes.

<Comparative Example 7>
In the gas bombardment treatment, a negative bias voltage applied to the substrate was set to −1000 V, and a gas bombardment treatment with a mixed gas containing 5 mass% hydrogen gas in argon gas was performed for 90 minutes. After the gas bombardment treatment, a bias voltage of −150 V was applied to the base material so that the base material temperature was 100 ° C. or lower. And the electric current thrown into a graphite target was 50 A, and the DLC film was formed for about 50 minutes.

In all the samples described above, the DLC film was formed while repeating the film formation and cooling so that the temperature of the base material was 200 ° C. or lower.
About each sample which formed the DLC film, hardness measurement, surface roughness measurement, adhesion evaluation, and weldability evaluation were performed. Hereinafter, the measurement conditions will be described.

<Measurement and evaluation>
-Measurement of nanoindentation hardness-
The hardness of the coating surface was measured using a nanoindentation device manufactured by Elionix Co., Ltd. 10 points were measured under the measurement conditions of indentation load of 9.8 mN, maximum load holding time of 1 second, and removal speed after load loading of 0.49 mN / second. 6 points were excluded except 2 points with large values and 2 points with small values. Obtained from the average value. It was confirmed that the hardness of the fused quartz as the standard sample was 15 GPa and the hardness of the CVD diamond film was 100 GPa.

-Measurement of surface roughness-
Arithmetic average roughness Ra and maximum height roughness Rz were measured according to JIS-B-0601-2001 using a contact surface roughness measuring device SURFCOM 480A manufactured by Tokyo Seimitsu Co., Ltd. The measurement conditions were as follows: evaluation length: 4.0 mm, measurement speed: 0.3 mm / s, cut-off value: 0.8 mm.

-Evaluation of adhesion-
The formed DLC film surface was observed at a magnification of about 800 times using an optical microscope manufactured by Mitutoyo Corporation to evaluate the peeling state. The evaluation criteria for the surface peeling of the DLC film were as follows.
<Evaluation criteria for surface peeling>
A: No surface peeling B: Micro peeling C: Coarse peeling

  The peel load (scratch load) was measured using a CSM scratch tester (REVETEST). The measurement conditions are: measurement load: 0 to 100 N, load speed: 99.25 N / min, scratch speed: 10 mm / min, scratch distance: 10 mm, AE sensitivity: 5, indenter: Rockwell, diamond, tip radius: 200 μm, hard Wear setting: Fn contact 0.9N, Fn speed: 5 N / s, Fn removal speed: 10 N / s, approach speed: 2% / s. The load when the substrate at the bottom of the scratch mark was completely exposed was evaluated.

An indentation was made on the DLC film of each sample using a C-scale diamond indenter with a Rockwell hardness tester (AR-10 manufactured by Mitutoyo Corporation). And it observed by the magnification of about 800 times using the optical microscope made from Mitutoyo Corporation, and the peeling condition of the film | membrane of an indentation periphery was evaluated. The evaluation criteria for adhesion by the Rockwell hardness (HRC) indentation test were as follows.
<Evaluation criteria for HRC impression test (HRC adhesion)>
A: No peeling or peeling with equivalent circle diameter less than 5 μm B: With fine peeling (peeling with equivalent circle diameter of 5 μm or more and less than 10 μm)
C: Coarse peeling (peeling with an equivalent circle diameter of 10 μm or more)

-Weldability test-
In order to evaluate the weldability, a ball-on-disk tester (Tribometer manufactured by CSM Instruments) was used. The disc-shaped test piece was rotated at a speed of 100 mm / sec while pressing aluminum A5052 balls (diameter 6 mm) with a load of 5 N against the substrate on which the DLC film was formed. The test distance was 100 m.

Table 1 summarizes the manufacturing conditions and evaluation results. Invention Examples 1 to 11 are DLC films having a high film hardness of 1.0 μm or more, almost no film peeling in evaluation of surface peeling and HRC indentation test, and scratch load is 50 N or more. Even in the evaluation, it has excellent adhesion. Further, it was confirmed that neither welding nor film peeling occurred in the welding test. Further, in Examples 1 to 11 of the present invention, arc discharge during film formation was stable, and stable film formation could be continuously performed.
As a representative example of a cross-sectional observation photograph of the DLC film coated with the present invention example, FIG. 1 shows an example of a cross-sectional observation photograph of the DLC film coated with the present invention example 4. In FIG. 1, it is confirmed that the DLC film which is smooth and does not contain droplets is coated with about 3.0 μm. As described above, by applying the manufacturing method of the present invention example, a coated tool having excellent adhesion, capable of coating a DLC film having a thick film, high hardness and few film defects, and having excellent durability. Can be manufactured stably.
Comparative Example 1 was a DLC film having excellent adhesion and weldability as in the inventive examples. However, since the current supplied to the graphite target is constant, the arc discharge becomes unstable, and it is difficult to coat a thicker DLC film.
Since the comparative example 2 coat | covered the DLC film | membrane, without introduce | transducing nitrogen gas, there existed a tendency for surface peeling to generate | occur | produce easily compared with the example of this invention. Moreover, welding and peeling were confirmed in the weldability evaluation.
Since the comparative example 3 performed the gas bombardment process only with argon gas, adhesiveness fell compared with the example of this invention, and welding and peeling were confirmed in weldability evaluation.
In Comparative Example 4, since the intermediate film of CrN was coated after the gas bombardment treatment only with argon gas, the adhesion was lower than that of the present invention example, and the weldability and peeling were confirmed in the weldability evaluation.
Comparative Example 5 was a DLC film having excellent adhesion and weldability as in the inventive examples. However, since the current supplied to the graphite target was constant, the arc discharge became unstable, and the arc discharge was misfired on the way, so that the film formation was not stable. Further, the scratch load tended to decrease as compared with the present invention.
In Comparative Examples 6 and 7, since the negative bias voltage applied to the base material during gas bombardment was -1300 V and -1000 V, the residual oxygen on the surface of the base material was not sufficiently removed. Compared with the adhesiveness, weldability and peeling were confirmed in the weldability evaluation.

Claims (3)

A method of manufacturing a coated tool for forming a diamond-like carbon film on the surface of a substrate by a filtered arc ion plating method,
The negative bias voltage applied to the installed base into the furnace and -2500V than -1500V less, introducing a mixed gas containing hydrogen gas into the furnace, to the gas bombardment of the surface of the substrate 1 And the process of
A second step of introducing a nitrogen gas into the furnace after the gas bombardment treatment and supplying a current to a graphite target to form a diamond-like carbon film on the surface of the substrate;
The method of manufacturing a coated tool, wherein the second step includes a step of reducing the flow rate of the nitrogen gas and a step of increasing a current input to the graphite target.   The method for producing a coated tool according to claim 1, wherein the diamond-like carbon film has a thickness of 2.0 µm or more. Wherein in the step of increasing the current to be introduced into the graphite target, method for producing a coated tool according to claim 1 or claim 2, characterized in that increasing the graphite target current introducing total at 40A or more.

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