KR20190016147A - Method for manufacturing a coated tool - Google Patents

Abstract

To a method for manufacturing a coated tool capable of forming a thick film after a high-hardness DLC film is secured with excellent adhesion.
A method of manufacturing a coated tool for forming a diamond like carbon film on a surface of a substrate by a filtered arc ion plating method, wherein a negative bias voltage applied to the substrate is set to -2500 V or more and -1500 V or less, A first step of introducing a mixed gas into the surface of the base material and subjecting the surface of the base material to gas-plasma bombardment; and a step of introducing a nitrogen gas into the furnace after the gas-bombardment treatment to apply a current to the graphite target, And a second step of forming a diamond-like carbon coating film. In the second step, a step of reducing the flow rate of the nitrogen gas and a step of increasing the current applied to the graphite target are included Method of making a coated tool.

Description

[0001] METHOD FOR MANUFACTURING A COATED TOOL [0002]

The present invention is a coating tool for use in, for example, a pressing tool, a forging tool, a cutting tool such as a saw blade, a cutting tool such as a drill, and the like, and a diamond-like carbon coating (hereinafter also referred to as a "DLC coating" And to a method for manufacturing a formed coated tool.

In the case of molding a material to be processed such as aluminum, copper and resin into a mold, a part of the material to be processed adheres to the surface of the mold, thereby causing product anomalies such as scuffing and scratches. In order to solve this problem, a coated mold having a DLC coating formed on the surface of a mold has been practically used. A DLC film (Tetrahedral amorphous carbon film: ta-C film) substantially not containing hydrogen is widely applied to a coated metal mold because of its high hardness and excellent abrasion resistance.

However, a high-hardness DLC coating substantially containing no hydrogen is formed by an arc ion plating method using a graphite target, and a particle (graphite spheres) having a size of several micrometers, which is called a droplet, It is mixed with the DLC film, and the surface roughness of the DLC film is deteriorated.

To solve this problem, Patent Document 1 discloses that it is possible to form a smooth and hard-to-form DLC coating substantially containing no hydrogen by applying a filtered arc ion plating method having a mechanism for collecting droplets. .

Japanese Patent Application Laid-Open No. 2008-297171

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 obtained. However, the high-hardness DLC film tends to be insufficient in adhesion, so that the adhesiveness that can be satisfied only by applying the filtered arc ion plating method tends to be difficult to achieve.

Further, in order to further improve the durability of the coated tool under a severe use environment, it is required to further form a thick DLC film with a high hardness. However, if the film formation time is elongated in order to form the DLC film of the thick film, the arc discharge tends to become unstable, and it is difficult to make the DLC film of high hardness as a thick film after securing good adhesion.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for producing a coated tool capable of forming a thick film after securing a high adhesion DLC film with good adhesion.

The present invention relates to a method of manufacturing a coated tool for forming a diamond like carbon film on a surface of a substrate by a filtered arc ion plating method, wherein a negative bias voltage applied to the substrate is set to -2500 V or more and -1500 V or less, The method comprising: a first step of introducing a mixed gas containing a gas into the furnace and introducing a nitrogen gas into the furnace after the gas bombardment treatment; And a second step of forming a diamond like carbon film on the surface of the substrate,

In the second step, the flow rate of the nitrogen gas is decreased, and the current applied to the graphite target is increased.

It is preferable that the thickness of the diamond-like carbon coating film is 2.0 占 퐉 or more.

In the step of increasing the current applied to the graphite target, it is preferable that the total amount of current injected into the graphite target is increased by 40 A or more.

According to the present invention, it is possible to form a high-hardness DLC coating film having excellent adhesion property as a thick film. In addition, since the film formation is stable, a coated tool having excellent durability can be stably manufactured.

1 is a cross-sectional photograph (× 17,340 times) of a DLC coating film coated in Example 4 with a scanning electron microscope.
2 is a schematic diagram of a T-shaped filtered arc ion plating apparatus used in the examples.

The inventors of the present invention have studied a method of further thickening the film thickness of a high hardness DLC coating excellent in adhesion. In the filtered arc ion plating method, it has been found that it is important to control the gas atmosphere in the furnace before forming the DLC coating, the furnace atmosphere in forming the DLC coating, and the current injected into the graphite target, A method for manufacturing the coated tool of the present invention has been reached. Hereinafter, the details of the present invention will be described.

The present invention can use a conventionally known filtered arc ion plating apparatus. By applying the filtered arc ion plating method, the droplets contained in the coating film are reduced to a smooth surface state, and a hardness DLC coating film having a nanoindentation hardness substantially not containing hydrogen of not less than 50 kPa Can be formed. Particularly, it is preferable to use a T-shaped filtered arc ion plating apparatus because a more smooth and high-hardness DLC film can be formed.

In order to improve the abrasion resistance of the coated tool, the DLC coating of the present invention preferably has a nanoindentation hardness of 50 kPa or more. Further, it is preferably not less than 55., More preferably not less than 60.. Further, it is preferable that the value is 70. Or more. On the other hand, if the hardness of the DLC coating is too high, the residual compressive stress becomes excessively high, and the adhesion with the substrate may be deteriorated. Therefore, it is preferable that the nanoindentation hardness is 100. Or less. Furthermore, the nanoindentation hardness of the DLC coating is preferably 95. Or less.

The nanoindentation hardness refers to the hardness at which the probe is plastically deformed by press-fitting the probe (DLC coating) into a specimen (DLC coating). The load-displacement curve is calculated from the indentation load and the indentation depth (displacement) to calculate the hardness. Specifically, the hardness of the surface of the coating film was set to 10 mm by using a nanoindentation device manufactured by Elyonics, Ltd. under the measurement conditions of a press-in load of 9.8 mN, a maximum load holding time of 1 second, and a removal rate of 0.49 mN / The point is measured and the average value of six points except for two points with large values and two points with small values is obtained.

A high-hardness DLC film having a nanoindentation hardness of 50 kPa or more tends to have a very low internal stress and a poor adhesion to a substrate. As a method for improving the adhesion property, a technique of forming an intermediate coat having a hardness lower than that of the DLC coating has been proposed. However, according to the study by the present inventors, when an intermediate coating such as a metal, a carbide, or a nitride is interposed between the substrate and the DLC coating, the DLC coating is preferentially peeled from the surface defect of the intermediate coating as a starting point, . Therefore, in the present invention, the gas spring pad treatment on the substrate before the formation of the DLC coating was studied so that even if the DLC coating was formed directly on the substrate, the adhesion was not impaired.

In the present invention, as the first step, a mixed gas containing a hydrogen gas is introduced into the furnace, and the surface of the substrate is subjected to gas sputtering.

According to the study of the present inventors, it was confirmed that when the conventional gas plasma bombardment treatment with argon gas was carried out, oxygen was abundantly present at the interface between the film and the substrate, and the adhesion was lowered. Oxygen existing at this interface is due to the oxide film formed on the surface of the substrate only from the beginning, and is a residual element which can not be completely removed by the gas-plasma bombardment treatment 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 sputtering. The oxide film on the surface of the substrate reacts with the hydrogen ions to be reduced and the contamination of the oxide film and the surface is sufficiently removed by the gas sputtering treatment of the surface of the substrate using a mixed gas containing hydrogen gas, The adhesion of the formed DLC film is improved.

It is preferable that the mixed gas containing hydrogen gas is a mixed gas containing hydrogen gas of 4 mass% or more with respect to the total mass of argon gas and hydrogen gas. When the amount of the hydrogen gas is less than 4 mass%, it may be difficult to remove the oxide film by the gas spring pad treatment with the mixed gas. Further, it is preferable to use a mixed gas having a hydrogen gas content of 5% by mass or more, and more preferably a mixed gas having a hydrogen gas content of 7% by mass or more. Further, it is preferable to use a mixed gas having a hydrogen gas content of 10 mass% or more. However, in the case of the mixed gas in which the hydrogen gas is more than 30 mass%, the effect of removing the contamination of the oxide film and the surface by the gas explosive treatment becomes constant (the effect does not rise even if the concentration of the hydrogen gas is increased further) There is a tendency. Therefore, it is preferable to use a mixed gas containing hydrogen gas at 30 mass% or less. Further, it is preferable to use a mixed gas having a hydrogen gas content of 25 mass% or less. Further, it is preferable to use a mixed gas containing 15 mass% or less of hydrogen gas.

In the gas spring pad treatment using the above-described mixed gas, the negative bias voltage to be applied to the substrate is set to -2500 V or more and -1500 V or less. Since the impinging energy of the gas ions is low when the negative bias voltage applied to the substrate is larger than -1500 V (on the positive side than -1500 V), the effect of removing contamination of the oxide film and the surface is reduced, The adhesiveness of the adhesive layer tends to be lowered. Further, if the negative bias voltage applied to the substrate becomes smaller than -2500 V (on the minus side of -2500 V), the plasma tends to become unstable, which may cause an abnormal discharge. If an abnormal discharge occurs, an abnormal discharge (arcing) trace is formed on the tool surface, so that irregularities may be generated on the tool surface. Further, the negative bias voltage to be applied to the substrate is preferably -2400 V or more, more preferably -2300 V or more. It is also preferable that the negative bias voltage applied to the substrate is -1600 V or less, and more preferably -1700 V or less.

In order to sufficiently remove the oxide on the surface of the substrate, it is preferable to carry out gas-gas bombardment treatment with a mixed gas for 60 minutes or more. Further, it is preferable to conduct it for 70 minutes or more. It is preferable to adjust the upper limit of the time of the gas-plasma bombardment treatment appropriately in accordance with the shape and material of the substrate. However, when the time of the gas-plasma bombardment treatment by the mixed gas is 180 minutes or more, the effect of removing the contamination of the oxide film and the surface by the gas-plasma bombardment treatment becomes constant (the effect is not improved) have. For this reason, it is preferable to perform the gas spring pad treatment with the mixed gas for 180 minutes or less.

In the present invention, as the second step, a nitrogen gas is introduced into the furnace after the gas-plasma-bombardment treatment, and a current is applied to the graphite target to form a DLC coating on the surface of the substrate subjected to gas-

The residual compressive stress of the DLC coating on the surface of the substrate is lowered by forming the nitrogen containing DLC coating in a state where the oxide film on the surface of the substrate is sufficiently removed by the gas plasma bombardment treatment and the adhesion between the substrate and the DLC coating Can be further increased. It is preferable that the flow rate of the nitrogen gas introduced into the furnace after the gas-plasma-bombardment treatment is 5 sccm or more in order to further reduce the residual compressive stress of the DLC film on the substrate side to further improve the adhesion. If the flow rate of the nitrogen gas is less than 5 sccm, the effect of improving the adhesion may not be sufficiently obtained. Furthermore, it is preferable to set it to 10 sccm or more.

On the other hand, if the flow rate of the nitrogen gas introduced into the furnace after the gas-plasma bombardment treatment becomes too large, the content of nitrogen contained in the DLC film increases to lower the hardness of the film and deteriorate the abrasion resistance, . Therefore, the flow rate of the nitrogen gas is preferably 60 sccm or less. Further, it is preferable to set it to 50 sccm or less. Further, it is preferable to set it to 40 sccm or less.

If the flow rate of the nitrogen gas introduced into the furnace is excessively small with respect to the volume of the furnace (vacuum chamber), the effect of improving the adhesion of the DLC film may not be sufficiently obtained. Therefore, the flow rate (sccm) of the nitrogen gas to be introduced into the volume (m 3) / of the furnace is preferably 10 × 10 ^-2 (m 3 / sccm) or less. Further, it is preferable to set it to 5.0 x 10 ^-2 (m 3 / sccm) or less. Further, when 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 likely to be contained in the DLC film. Therefore, it is preferable that the flow rate (sccm) of the nitrogen gas introduced into the volume (m 3) / of the furnace is 0.1 × 10 ^-2 (m 3 / sccm) or more. Furthermore, it is preferable to set it to 1.0 x 10 ^-2 (m 3 / sccm) or more.

In the present invention, in the second step, a flow rate of the nitrogen gas is reduced, and a current is applied to the graphite target to form a DLC film.

Although it is effective to form a DLC film by introducing a nitrogen gas in order to improve the adhesion with a base material, when the DLC film contains an excessive amount of nitrogen atoms, the hardness is lowered. In addition, when the non-ferrous material is processed, deposition tends to occur. Therefore, in the present invention, the flow rate of the nitrogen gas is reduced so as not to contain an excessive amount of nitrogen gas in the entire DLC coating, and a current is applied to the graphite target to form a DLC coating. The DLC film on the substrate side contains a large amount of nitrogen atoms and the residual compressive stress is lowered so that the adhesion with the substrate is enhanced and the DLC film on the surface side The content of nitrogen atoms is small and the wear resistance and the wear resistance are improved.

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. Finally, it is preferable that the introduction of the nitrogen gas is stopped and a current is applied to the graphite target to form the DLC film. By stopping the introduction of the nitrogen gas and forming the DLC film, it is possible to form a DLC film having a higher hardness on the surface in contact with the other material and less fusion of the material to be processed. In order to achieve a DLC film having a higher hardness and less fusion of the material to be processed, it is preferable that the introduction of the nitrogen gas is stopped finally and the pressure inside the furnace is set to 5 × 10 ^-3 Pa or less to form the DLC film.

In the second step, a hydrogen gas such as acetylene may be introduced into the furnace to increase the hydrogen content of the DLC coating on the substrate side. After the first step, a hydrocarbon gas such as acetylene may be introduced into the furnace, and then the second step may be performed.

According to the present invention, in the second step, a step of forming a DLC film by increasing a current applied to the graphite target is provided.

The inventors of the present invention have confirmed that large irregularities are generated on the surface of the graphite target with the progress of the formation of the DLC coating in the formation of the DLC coating by the filtered arc ion plating method and the arc discharge becomes unstable. It has also been found that arc discharge tends to be stabilized by applying a higher current to the graphite target even when large unevenness is generated on the surface of the target. However, if the applied electric power is constant even if the current applied to the graphite target is set high, the arc discharge becomes unstable gradually with the progress of the DLC film formation, and it becomes difficult to form the DLC film with high hardness and high adhesion with the thick film. Particularly, in the initial stage of the formation of the DLC film, when a high current value is applied to the target surface in a flat state, the discharge becomes unstable and a large amount of droplets are generated to cause large irregularities on the film surface. There is a problem with. The present inventors have found that by forming a DLC film for a predetermined time with constant current applied to a graphite target and increasing the current injected into the graphite target before the arc current becomes unstable, the arc discharge is stabilized to form a DLC film continuously It became possible to do. Therefore, in the present invention, a step of forming a DLC film by increasing a current applied to a graphite target at the time of film formation is provided. As a result, it is possible to form a DLC film having a stable and high hardness with a small load on the apparatus as a thick film.

The current injected into the graphite target may be increased stepwise or continuously. In order to further form a DLC film of a thick film, it is preferable to gradually increase the current injected into the graphite target. In addition, it is preferable to increase the total amount of current injected into the graphite target by 40 A or more. Furthermore, the total amount is preferably 55 A or more, and more preferably 60 A or more in total. By forming in this manner, a DLC coating having a thick film and a high hardness can be stably formed.

It is preferable that the applied current value is different depending on the surface state of the graphite target and the smaller current value (30A to 50A) when the initial is flat. Then, it is preferable to gradually increase the current value.

In the second step, the step of decreasing the flow rate of the nitrogen gas and the step of increasing the amount of the current applied to the graphite target may be performed at the same time or may be performed respectively. For example, the timing at which the flow rate of the nitrogen gas is decreased and the timing at which the current supplied to the graphite target is increased may be made to coincide with each other, or the timing at which the flow rate of the nitrogen gas is decreased and the current at the graphite target are increased May be alternately set. In addition, it is preferable to stop the introduction of the nitrogen gas finally and to increase the electric power applied to the graphite target to form the DLC film. By forming in this way, it becomes possible to make the DLC film having a higher hardness to be a thicker film.

If the current injected into 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 applied to the graphite target is provided. However, in order to continue the stable film formation, it is preferable that the current applied to the graphite target is 150 A or less. Furthermore, it is preferable to set it to 120 A or less. However, if the current injected into the graphite target becomes too small, the film formation of the DLC film may not be sufficiently performed. Therefore, it is preferable that the current applied to the graphite target is 20 A or more. More preferably 30 A or more.

Even if a high-hardness DLC coating film is thin, excellent durability may not be obtained in some cases. In order to impart excellent durability to the coated tool in a more severe use environment, the film thickness of the DLC coating is preferably 1.0 mu m or more, more preferably 1.5 mu m or more. Furthermore, it is preferable that the film thickness of the DLC coating is 2.0 m or more.

However, if the film thickness of the DLC film is excessively increased, the surface roughness of the film surface may be deteriorated. Also, if the film thickness of the high-hardness DLC film becomes too thick, the risk of partial peeling of the DLC film increases. Therefore, it is preferable that the film thickness of the DLC coating is 5.0 탆 or less. Furthermore, it is more preferable that the film thickness of the DLC coating is 4.0 m or less.

At the time of forming the DLC film, it is preferable to set the substrate temperature at 200 캜 or lower. When the base temperature becomes higher than 200 deg. C, graphitization of the DLC coating proceeds, and the hardness tends to decrease. In forming the DLC film, it is preferable to set the negative bias voltage applied to the substrate to -300 V or more and -50 V or less. When the negative bias voltage applied to the substrate is larger than -50 V (on the positive side than -50 V), the collision energy of the 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 becomes smaller than -300 V (on the negative side from -300 V), an abnormal discharge easily occurs in the film. In forming the DLC film, it is more preferable that the negative bias voltage to be applied to the substrate is -200 V or more and -100 V or less.

In the present invention, the base material (substrate of the coated tool) on which the DLC coating is formed is not particularly limited, and can be appropriately selected in accordance with the application and purpose. For example, cemented carbide, cold tool steel, high-speed tool steel, steel for plastic mold, hot tool steel and the like can be applied. Among the substrates, a high carbon steel or a cemented carbide having a carbon content of 1% or more, which easily causes film peeling due to a large amount of carbides in the base material, is preferable from the viewpoint of high adhesiveness. Examples of the high carbon steel include, for example, JIS-SKD11.

Even if the DLC coating formed by the filtered arc ion plating method is thickened, the surface roughness may be lowered. In this case, it is preferable that after the DLC film is formed, it is polished and smoothed. In the present invention, the surface of the DLC coating may be polished so as to obtain a more preferable smooth surface state.

Example

≪

The film forming apparatus used was a T-shaped filtered arc ion plating apparatus (the volume of the vacuum chamber in the furnace was 0.49 m 3).

A schematic view of the device is shown in Fig. A deposition chamber 6, an arc evaporation evaporation source for mounting a carbon anode (cathode) 1 provided with a graphite target, and a substrate holder 7 for mounting the substrate. Below the substrate holder is a rotating mechanism 8, which rotates and revolves through the substrate holder 7. Reference numeral 2 denotes a carbon film forming beam, and 3 denotes spherical graphite (droplet) neutral particles.

When an arc discharge is generated on the graphite target surface, only carbon having a charge is bent by the magnetic coil 4 to reach the film forming chamber 6 to coat the substrate with the film. The droplet having no electric charge is trapped in the duct 5 without being bent by the magnetic coil.

<Description>

A substrate of JIS-SKD11 equivalent steel material which was tempered at 60 HRC with dimensions of? 20 × 5 mm was used for evaluation of the peeling state of the formed DLC film and evaluation of the weldability.

The substrate for measuring the nanoindentation hardness of the formed DLC coating film, the coating film analysis and the film thickness by the fracture surface was made of cemented carbide made of tungsten carbide (WC-10 mass% Co) having a cobalt content of 10 mass% Substrate (dimensions: 4 mm x 8 mm x 25 mm, average particle size: 0.8 m, hardness: 91.2HRA) was used.

A substrate of JIS-SKH51 equivalent steel having a size of 21 mm x 17 mm x 2 mm was used as a substrate for evaluating the scratch test of the formed DLC coating and the adhesion by the Rockwell hardness tester.

In any of the above-mentioned inventions, before forming the DLC film, the arithmetic mean roughness Ra (in accordance with JIS-B-0601-2001) is 0.01 占 퐉 or less and the maximum height roughness Rz (in accordance with JIS-B-0601-2001) Mu m or less. Then, after polishing, degreasing and cleaning were performed and fixed to the substrate holder in the chamber. For each substrate, a DLC coating was formed under the following conditions.

<Inventive Example 1>

(Vacuum chamber) was evacuated to 5 x 10 &lt; ^-3 &gt; Pa. The substrate was heated to about 150 DEG C by a heating heater and held for 90 minutes. Thereafter, the negative bias voltage to be applied to the substrate was set to -2000 V, and a gas spring treatment with a mixed gas containing 5% by mass of hydrogen gas in argon gas was performed for 90 minutes. The flow rate of the mixed gas was set to 50 sccm to 100 sccm.

After gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of -150 V was applied to the substrate to set the substrate temperature at 100 캜 or lower. Then, the current injected into the graphite target was gradually increased from 40 A to 90 A, and the flow rate of the nitrogen gas was gradually decreased from 20 sccm to zero to form a DLC film as follows.

First, a flow rate of nitrogen gas introduced into the furnace was set to 20 sccm, and a current to be supplied to the graphite target was set to 40 A to form a DLC film for about 30 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 10 sccm, and the current applied to the graphite target was increased to 50 A to form a DLC coating film for about 30 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 5 sccm, the current applied to the graphite target was increased to 60 A, and the DLC film was formed for about 40 minutes.

Subsequently, introduction of nitrogen gas was stopped, the furnace pressure was set to 5 × 10 ^-3 Pa or less, the current applied to the graphite target was increased to 70 A, and the DLC film was formed for about 40 minutes.

Subsequently, the current injected into the graphite target was increased to 80 A, and the DLC coating was formed for about 40 minutes.

Subsequently, the current injected into the graphite target was increased to 90 A, and the DLC coating was formed for about 60 minutes.

<Inventive Example 2>

The gas spring boding treatment was performed in the same manner as in the first embodiment. After gas bombardment treatment, nitrogen gas was introduced into the furnace, and a base voltage of -150 V was applied to the substrate to set the substrate temperature at 100 캜 or lower. Then, the current injected into the graphite target was gradually increased from 35 A to 95 A as follows, and the flow rate of the nitrogen gas was gradually decreased from 25 sccm to zero to form a DLC film.

First, a flow rate of nitrogen gas introduced into the furnace was set to 25 sccm, and a current to be supplied to the graphite target was set to 35 A to form a DLC coating film for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 20 sccm, the current applied to the graphite target was increased to 40 A, and the DLC coating was formed for about 20 minutes.

Then, the flow rate of the nitrogen gas was reduced to 15 sccm, the current applied to the graphite target was increased to 45 A, and the DLC film was formed for about 20 minutes.

Then, the flow rate of the nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 50 A, and the DLC coating was formed for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 7 sccm, and the current applied to the graphite target was increased to 55 A to form the DLC coating film for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 5 sccm, and the current applied to the graphite target was increased to 60 A to form the DLC coating film for about 20 minutes.

Subsequently, the introduction of nitrogen gas was stopped, the furnace pressure was set to 5 × 10 ^-3 Pa or less, the current applied to the graphite target was increased to 65 A, and the DLC film was formed for about 20 minutes.

Subsequently, the current injected into the graphite target was gradually increased to 70A, 75A, 80A, 85A, and 90A, and DLC coatings were formed for about 20 minutes at each current value.

<Inventive Example 3>

The gas spring boding treatment was performed in the same manner as in the first embodiment. After gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of -150 V was applied to the substrate to set the substrate temperature at 100 캜 or lower. Then, the current injected into the graphite target was gradually increased from 30 A to 95 A, and the flow rate of the nitrogen gas was gradually decreased from 20 sccm to zero to form a DLC film as follows.

First, the flow rate of the nitrogen gas introduced into the furnace was set to 20 sccm, and the current applied to the graphite target was set to 30 A to form the DLC film for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 15 sccm, the current to be supplied to the graphite target was increased to 35 A, and the DLC film was formed for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 40 A, and the DLC film was formed for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 5 sccm, and the current applied to the graphite target was increased to 45 A to form the DLC coating film for about 20 minutes.

Subsequently, introduction of nitrogen gas was stopped, the furnace pressure was set to 5 × 10 ^-3 Pa or less, the current applied to the graphite target was increased to 50 A, and the DLC film was formed for about 20 minutes.

Subsequently, the current injected into the graphite target was gradually increased to 55A, 60A, 65A, 70A, 75A, 80A, 85A and 90A to form a DLC film at each current value for about 20 minutes.

<Inventive Example 4>

The gas spring boding treatment was performed in the same manner as in the first embodiment. After the gas-plasma 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 set the substrate temperature at 100 ° C or lower. Then, the current injected into the graphite target was gradually increased from 35 A to 95 A as follows, and the flow rate of the nitrogen gas was gradually decreased from 25 sccm to zero to form a DLC film.

First, the DLC film was formed for about 10 minutes by setting the current to be supplied to the graphite target to 35 A, the flow rate of the nitrogen gas introduced into the furnace to be 25 sccm, and the flow rate of the C ₂ H ₂ gas to 25 sccm.

Subsequently, the current injected into the graphite target was increased to 40 A, the flow rate of the C ₂ H ₂ gas was reduced to 20 sccm, the flow rate of the nitrogen gas was reduced to 20 sccm, and the DLC film was formed for about 10 minutes.

Subsequently, the current injected into the graphite target was increased to 45 A, the flow rate of the C ₂ H ₂ gas was reduced to 15 sccm, the flow rate of the nitrogen gas was reduced to 15 sccm, and the DLC film was formed for about 10 minutes.

Subsequently, the current injected into the graphite target was increased to 50 A, the flow rate of the C ₂ H ₂ gas was reduced to 10 sccm, the flow rate of the nitrogen gas was reduced to 10 sccm, and the DLC film was formed for about 10 minutes.

Subsequently, the current injected into the graphite target was increased to 55 A, the flow rate of the C ₂ H ₂ gas was reduced to 7 sccm, the flow rate of the nitrogen gas was reduced to 7 sccm, and the DLC film was formed for about 10 minutes.

Subsequently, the current injected into the graphite target was increased to 60 A, the flow rate of the C ₂ H ₂ gas was reduced to 5 sccm, the flow rate of the nitrogen gas was reduced to 5 sccm, and the DLC film was formed for about 10 minutes.

Subsequently, introduction of C ₂ H ₂ gas and nitrogen gas was stopped, the furnace pressure was set to 5 × 10 ^-3 Pa or less, the current applied to the graphite target was increased to 65 A, and the DLC film was formed for about 25 minutes.

Subsequently, the current injected into the graphite target was gradually increased to 70 A, 75 A, and 80 A, and DLC coatings were formed for about 20 minutes at each current value.

<Inventive Example 5>

The gas spring boding treatment was performed in the same manner as in the first embodiment. After the gas-plasma 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 set the substrate temperature at 100 ° C or lower. Then, the current injected into the graphite target was gradually increased from 50 A to 80 A, and the flow rate of the nitrogen gas was gradually decreased from 15 sccm to 0 to form a DLC film as follows.

First, a DLC film was formed for about 6 minutes at a flow rate of 15 sccm of the nitrogen gas introduced into the furnace, a flow rate of the C ₂ H ₂ gas of 10 sccm, and a current of 50 A applied to the graphite target.

Subsequently, the introduction of the C ₂ H ₂ gas was stopped, the flow rate of the nitrogen gas was set to 15 sccm, the current applied to the graphite target was increased to 60 A, and the DLC film was formed for about 45 minutes.

Then, the flow rate of the nitrogen gas was reduced to 5 sccm, the current applied to the graphite target was increased to 70 A, and the DLC coating was formed for about 45 minutes.

Subsequently, introduction of the nitrogen gas was stopped, the internal pressure was set to 5 × 10 ^-3 Pa or less, the current applied to the graphite target was increased to 80 A, and the DLC film was formed for about 100 minutes.

&Lt; Example 6 >

The gas spring boding treatment was performed in the same manner as in the first embodiment. After gas bombardment treatment, nitrogen gas was introduced into the furnace, and a base voltage of -150 V was applied to the substrate to set the substrate temperature at 100 캜 or lower. Then, the current injected into the graphite target was gradually increased from 25 A to 95 A, and the flow rate of the nitrogen gas was gradually decreased from 15 sccm to zero to form a DLC film as follows.

First, a flow rate of nitrogen gas introduced into the furnace was set to 15 sccm, and a current to be supplied to the graphite target was set to 25 A to form a DLC coating film for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 30 A, and the DLC coating was formed for about 20 minutes.

Then, the flow rate of the nitrogen gas was reduced to 5 sccm, and the current applied to the graphite target was increased to 35 A to form the DLC coating film for about 20 minutes.

Subsequently, the introduction of nitrogen gas was stopped, the pressure inside the furnace was set to 5 × 10 ^-3 Pa or less, the current applied to the graphite target was increased to 40 A, and the DLC film was formed for about 20 minutes.

Subsequently, the current injected into the graphite target was stepwise increased to 45A, 50A, 55A, 60A, 65A, 70A, 75A, 80A, 85A, 90A and 95A to form a DLC film in each current value for about 20 minutes .

&Lt; Inventive Example 7 >

The gas-plasma bombardment treatment was carried out for 90 minutes by gas-bombardment treatment with a mixed gas containing 10% by mass of hydrogen gas in argon gas at a negative bias voltage of -2000 V applied to the substrate. After gas bombardment treatment, nitrogen gas was introduced into the furnace, and a base voltage of -150 V was applied to the substrate to set the substrate temperature at 100 캜 or lower. Then, the current injected into the graphite target was gradually increased from 35 A to 95 A as follows, and the flow rate of the nitrogen gas was gradually decreased from 25 sccm to zero to form a DLC film.

First, a flow rate of nitrogen gas introduced into the furnace was set to 25 sccm, and a current to be supplied to the graphite target was set to 35 A to form a DLC coating film for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 20 sccm, the current applied to the graphite target was increased to 40 A, and the DLC coating was formed for about 20 minutes.

Then, the flow rate of the nitrogen gas was reduced to 15 sccm, the current applied to the graphite target was increased to 45 A, and the DLC film was formed for about 20 minutes.

Then, the flow rate of the nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 50 A, and the DLC coating was formed for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 5 sccm, and the current applied to the graphite target was increased to 55 A to form the DLC coating film for about 20 minutes.

Subsequently, the introduction of nitrogen gas was stopped, the furnace pressure was set to 5 × 10 ^-3 Pa or less, the current to be supplied to the graphite target was increased to 60 A, and the DLC film was formed for about 20 minutes.

Subsequently, the current injected into the graphite target was gradually increased to 65 A, 70 A, 75 A, 80 A, 85 A, 90 A, and 95 A, and a DLC film was formed at each current value for about 20 minutes.

<Inventive Example 8>

The gas-plasma bombardment treatment was carried out for 90 minutes by gas sputtering with a mixed gas containing 20% by mass of hydrogen gas in argon gas at a negative bias voltage of -2000 V applied to the substrate. After gas bombardment treatment, nitrogen gas was introduced into the furnace, and a base voltage of -150 V was applied to the substrate to set the substrate temperature at 100 캜 or lower. Then, the current injected into the graphite target was gradually increased from 35 A to 95 A as follows, and the flow rate of the nitrogen gas was gradually decreased from 25 sccm to zero to form a DLC film.

First, a flow rate of nitrogen gas introduced into the furnace was set to 25 sccm, and a current to be supplied to the graphite target was set to 35 A to form a DLC coating film for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 20 sccm, the current applied to the graphite target was increased to 40 A, and the DLC coating was formed for about 20 minutes.

Then, the flow rate of the nitrogen gas was reduced to 15 sccm, the current applied to the graphite target was increased to 45 A, and the DLC film was formed for about 20 minutes.

Then, the flow rate of the nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 50 A, and the DLC coating was formed for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 5 sccm, and the current applied to the graphite target was increased to 55 A to form the DLC coating film for about 20 minutes.

Subsequently, the introduction of nitrogen gas was stopped, the furnace pressure was set to 5 × 10 ^-3 Pa or less, the current to be supplied to the graphite target was increased to 60 A, and the DLC film was formed for about 20 minutes.

Subsequently, the current injected into the graphite target was gradually increased to 65 A, 70 A, 75 A, 80 A, 85 A, 90 A, and 95 A, and a DLC film was formed at each current value for about 20 minutes.

<Inventive Example 9>

The gas spring boding treatment was performed in the same manner as in the first embodiment. After gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of -150 V was applied to the substrate to set the substrate temperature at 100 캜 or lower. Then, the current injected into the graphite target was gradually increased from 35 A to 95 A as follows, and the flow rate of the nitrogen gas was gradually decreased from 40 sccm to zero to form a DLC film.

First, the flow rate of the nitrogen gas introduced into the furnace was set to 40 sccm, and the current to be supplied to the graphite target was set to 35 A to form a DLC coating film for about 20 minutes.

Then, the flow rate of the nitrogen gas was reduced to 30 sccm, and the current applied to the graphite target was increased to 40 A to form the DLC coating film for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 20 sccm, and the current applied to the graphite target was increased to 45 A to form a DLC coating film for about 20 minutes.

Then, the flow rate of the nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 50 A, and the DLC coating was formed for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 5 sccm, and the current applied to the graphite target was increased to 55 A to form the DLC coating film for about 20 minutes.

Subsequently, the introduction of nitrogen gas was stopped, the furnace pressure was set to 5 × 10 ^-3 Pa or less, the current to be supplied to the graphite target was increased to 60 A, and the DLC film was formed for about 20 minutes.

Subsequently, the current injected into the graphite target was gradually increased to 65 A, 70 A, 75 A, 80 A, 85 A, 90 A, and 95 A, and a DLC film was formed at each current value for about 20 minutes.

<Inventive Example 10>

The gas spring boding treatment was performed in the same manner as in the first embodiment. After gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of -350 V was applied to the substrate to set the substrate temperature at 100 占 폚 or lower. Then, the current injected into the graphite target was gradually increased from 35 A to 95 A as follows, and the flow rate of the nitrogen gas was gradually decreased from 25 sccm to zero to form a DLC film.

First, a flow rate of nitrogen gas introduced into the furnace was set to 25 sccm, and a current to be supplied to the graphite target was set to 35 A to form a DLC coating film for about 20 minutes.

Subsequently, the negative bias voltage applied to the substrate was set to -300 V, the flow rate of the nitrogen gas was reduced to 20 sccm, and the current applied to the graphite target was increased to 40 A to form the DLC coating film for about 20 minutes.

Subsequently, the negative bias voltage applied to the substrate was set to -250 V, the flow rate of the nitrogen gas was reduced to 15 sccm, and the current applied to the graphite target was increased to 45 A to form the DLC coating film for about 20 minutes.

Subsequently, the negative bias voltage applied to the substrate was set to -200 V, the flow rate of the nitrogen gas was reduced to 10 sccm, and the current applied to the graphite target was increased to 50 A to form the DLC coating film for about 20 minutes.

Subsequently, the negative bias voltage applied to the substrate was set to -150 V, the flow rate of the nitrogen gas was reduced to 7 sccm, and the current applied to the graphite target was increased to 55 A to form the DLC coating film for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 5 sccm, and the current applied to the graphite target was increased to 60 A to form the DLC coating film for about 20 minutes.

Subsequently, the introduction of nitrogen gas was stopped, the furnace pressure was set to 5 × 10 ^-3 Pa or less, the current applied to the graphite target was increased to 65 A, and the DLC film was formed for about 20 minutes.

Subsequently, the current injected into the graphite target was gradually increased to 70 A, 75 A, 80 A, 85 A, 90 A, and 95 A, and a DLC film was formed at each current value for about 20 minutes.

<Inventive Example 11>

The gas-plasma bombardment treatment was carried out for 90 minutes by gas-bombardment treatment with a mixed gas containing 5% by mass of hydrogen gas in argon gas at a negative bias voltage of -2500 V applied to the substrate. After gas bombardment treatment, nitrogen gas was introduced into the furnace, and a base voltage of -150 V was applied to the substrate to set the substrate temperature to 100 캜 or lower. Then, the current injected into the graphite target was gradually increased from 35 A to 95 A as follows, and the flow rate of the nitrogen gas was gradually decreased from 25 sccm to zero to form a DLC film.

First, a flow rate of nitrogen gas introduced into the furnace was set to 25 sccm, and a current to be supplied to the graphite target was set to 35 A to form a DLC coating film for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 20 sccm, the current applied to the graphite target was increased to 40 A, and the DLC coating was formed for about 20 minutes.

Then, the flow rate of the nitrogen gas was reduced to 15 sccm, the current applied to the graphite target was increased to 45 A, and the DLC film was formed for about 20 minutes.

Then, the flow rate of the nitrogen gas was reduced to 10 sccm, the current applied to the graphite target was increased to 50 A, and the DLC coating was formed for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 7 sccm, and the current applied to the graphite target was increased to 55 A to form the DLC coating film for about 20 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 5 sccm, and the current applied to the graphite target was increased to 60 A to form the DLC coating film for about 20 minutes.

Subsequently, the introduction of nitrogen gas was stopped, the furnace pressure was set to 5 × 10 ^-3 Pa or less, the current applied to the graphite target was increased to 65 A, and the DLC film was formed for about 20 minutes.

Subsequently, the current injected into the graphite target was gradually increased to 70 A, 75 A, 80 A, 85 A, 90 A, and 95 A, and a DLC film was formed at each current value for about 20 minutes.

&Lt; Comparative Example 1 &

The steps up to the gas spring-wetting treatment were carried out in the same manner as in Example 1. After gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of -150 V was applied to the substrate to set the substrate temperature at 100 캜 or lower. The flow rate of the nitrogen gas was gradually decreased from 10 sccm to 0 to form a DLC film, with the current injected into the graphite target being 50A.

First, the flow rate of the nitrogen gas introduced into the furnace was set to 10 sccm, and the DLC film was formed for about 10 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 5 sccm, and the DLC film was formed for about 10 minutes.

Subsequently, introduction of the nitrogen gas was stopped, the pressure inside the furnace was set to 5 x 10 &lt; ^-3 &gt; Pa or less, and the DLC film was formed for 30 minutes.

&Lt; Comparative Example 2 &

The steps up to the gas spring-wetting treatment were carried out in the same manner as in Example 1. After the gas-plasma bombardment treatment, a bias voltage of -150 V was applied to the substrate without introducing nitrogen gas into the furnace to set the substrate temperature at 100 占 폚 or lower. Then, the DLC film was formed for about 50 minutes by setting the internal pressure to 5 × 10 ^-3 Pa or less and the current to be applied to the graphite target to be 50 A.

&Lt; Comparative Example 3 &

In the gas-plasma-bombardment treatment, the negative bias voltage applied to the substrate was -2000 V, and the gas-plasma bombardment treatment with argon gas was performed for 90 minutes.

After gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of -150 V was applied to the substrate to set the substrate temperature at 100 캜 or lower. The flow rate of the nitrogen gas was gradually decreased from 10 sccm to 0 to form a DLC film, with the current injected into the graphite target being 50A.

First, the flow rate of the nitrogen gas introduced into the furnace was set to 10 sccm, and the DLC film was formed for about 10 minutes.

Subsequently, the flow rate of the nitrogen gas was reduced to 5 sccm, and the DLC film was formed for about 10 minutes.

Subsequently, introduction of nitrogen gas was stopped, and the pressure inside the furnace was set to 5 x 10 &lt; ^-3 &gt; Pa or below to form a DLC coating film for about 30 minutes.

&Lt; Comparative Example 4 &

And then subjected to gas-plasma bombardment with argon gas under the same conditions as in Comparative Example 3. Thereafter, CrN of about 3 m was formed as an intermediate coating film. After the formation of the intermediate coating film, a bias voltage of -150 V was applied to the substrate without introducing nitrogen gas to set the substrate temperature at 100 占 폚 or lower.

Then, the DLC film was formed for about 50 minutes by setting the internal pressure to 5 x 10 &lt; ^-3 &gt; Pa or less and the current applied to the graphite target to be constant at 50A.

&Lt; Comparative Example 5 &

The steps up to the gas spring-wetting treatment were carried out in the same manner as in Example 1. After gas bombardment treatment, nitrogen gas was introduced into the furnace, and a bias voltage of -150 V was applied to the substrate to set the substrate temperature at 100 캜 or lower. The flow rate of the nitrogen gas was gradually decreased from 10 sccm to 0 to form a DLC film, with the current injected into the graphite target being 80A.

First, the flow rate of the nitrogen gas introduced into the furnace was set to 10 sccm, and the DLC film was formed for about 25 minutes.

Then, the flow rate of the nitrogen gas was reduced to 5 sccm, and the DLC film was formed for about 25 minutes.

Subsequently, the introduction of nitrogen gas was stopped, the pressure inside the furnace was set to 5 × 10 ^-3 Pa or less, and the DLC coating film was formed for 70 minutes.

&Lt; Comparative Example 6 >

The gas-plasma bombardment treatment was carried out for 90 minutes by gas-bombardment treatment with a mixed gas containing 5% by mass of hydrogen gas in argon gas at a negative bias voltage of -1300 V applied to the substrate. After the gas-plasma bombardment treatment, a bias voltage of -150 V was applied to the substrate to set the substrate temperature at 100 캜 or lower. The current to be applied to the graphite target was 50 A, and the DLC coating was formed for about 50 minutes.

&Lt; Comparative Example 7 &

The gas-plasma bombardment treatment was carried out for 90 minutes by gas sputtering with a mixed gas containing 5% by mass of hydrogen gas in argon gas at a negative bias voltage of -1000 V applied to the substrate. After the gas-plasma bombardment treatment, a bias voltage of -150 V was applied to the substrate to set the substrate temperature at 100 캜 or lower. The current to be applied to the graphite target was 50 A, and the DLC coating was formed for about 50 minutes.

In all of the samples described above, the DLC film was formed while repeating the film formation and the cooling so that the temperature of the substrate became 200 DEG C or lower.

Hardness, surface roughness, adhesion, and weldability were evaluated for each of the samples on which the DLC film was formed. Hereinafter, the measurement conditions will be described.

<Measurement and Evaluation>

- Measurement of hardness of nanoindentation -

The hardness of the coating surface was measured using a nanoindentation device manufactured by Elionics. 10 points were measured under the measurement conditions of the indentation load of 9.8 mN, the maximum load holding time of 1 second, and the removal rate after load loading of 0.49 mN / sec, and from the average of 6 points except for two points with large values and two points with small values . It was confirmed that the hardness of the fused quartz as a standard sample was 15 ㎬ and the hardness of the CVD diamond coating was 100..

- Measurement of surface roughness -

The arithmetic average roughness Ra and the maximum height roughness Rz were measured in accordance with JIS-B-0601-2001 by using a contact surface roughness meter SURFCOM480A manufactured by Tokyo Seimitsu Co., Ltd. The measurement conditions were an evaluation length of 4.0 mm, a measurement speed of 0.3 mm / s, and a cut-off value of 0.8 mm.

- Evaluation of adhesion -

The surface of the formed DLC coating film was observed at a magnification of about 800 times using an optical microscope manufactured by Mitsutoyo Corporation to evaluate the peeling state. The evaluation criteria of the surface peeling of the DLC coating were as follows.

<Evaluation Criteria of Surface Peel>

A: No surface peeling

B: Smear is peeled

C: In coarse peeling

The peel load (scratch load) was measured using a scratch tester (REVETEST) manufactured by CSM. The measurement conditions were as follows: measurement load: 0 to 100 N, load rate: 99.25 N / min, scratch speed: 10 mm / min, scratch distance: 10 mm, AE sensitivity: 5, indenter: Rockwell, diamond, Hardware setting: Fn contact 0.9N, Fn speed: 5N / s, Fn removal speed: 10N / s, and approach speed: 2% / s. The load at the time when the base material of the scratch trace bottom was completely exposed was evaluated.

A C-scale diamond indenter was used with a Rockwell hardness tester (AR-10 manufactured by Mitsutoyo) to impregnate the DLC film of each sample. Then, the film was observed at a magnification of about 800 times using an optical microscope manufactured by Mitsutoyo Corporation, and the peeling state of the film around the indentation was evaluated. Rockwell hardness (HRC) Evaluation criteria of the adhesion by the indentation test were as follows.

<Evaluation Criteria of HRC Indentation Test (HRC Adhesion)>

A: No peeling or peeling with a circle-equivalent diameter of less than 5 占 퐉

B: Smear peeling (peeling with a circle-equivalent diameter of 5 탆 or more and less than 10 탆)

C: coarse peeling (peeling with a circle equivalent diameter of 10 탆 or more)

- Test of weldability -

In order to evaluate the weldability, a ball-on-disk tester (Tribometer manufactured by CSM Instruments) was used. The circular disk-shaped test piece was rotated at a speed of 100 mm / sec while pressing a 5 A load of aluminum A5052 sphere (diameter 6 mm) onto the base material on which the DLC film was formed. The test distance was set at 100 m.

Table 1 summarizes the manufacturing conditions and evaluation results. Examples 1 to 11 of the present invention are DLC films having a high film hardness of 1.0 탆 or more and have almost no peel-off in the evaluation of the surface delamination and the HRC indentation test, and the scratch load is 50 N or more, And has excellent adhesion. Further, it was confirmed that neither deposition nor film peeling occurred in the welding test. In Inventive Examples 1 to 11, since arc discharge during film formation was stable, it was possible to continuously perform stable film formation.

FIG. 1 shows an example of a photograph of a cross-sectional observation of a DLC coating film coated in Inventive Example 4, as a typical example of a cross-sectional observation photograph of a DLC coating film coated in the present invention. In Fig. 1, it is confirmed that the DLC film which is smooth and does not contain droplets is coated with about 3.0 mu m. As described above, by applying the manufacturing method of the present invention, it is possible to coat a DLC film having excellent adhesion, a thick film, a high hardness, and a small coating defect, thereby stably producing a coated tool having excellent durability.

Comparative Example 1 was a DLC film excellent in adhesion and weldability as in the case of the present invention. However, since the current injected into the graphite target is constant, arc discharge becomes unstable, and it is difficult to coat the above-mentioned thick film DLC coating.

In Comparative Example 2, since the DLC coating was coated without introducing nitrogen gas, surface peeling tended to occur more easily than in the case of the present invention. Further, adhesion and peeling were confirmed in the evaluation of the weldability.

In Comparative Example 3, since the gas barrier rib treatment was performed with only argon gas, adhesion was lowered than in the case of the present invention, and adhesion and peeling were confirmed in the evaluation of the weldability.

In Comparative Example 4, since the intermediate film of CrN was covered with gas after the gas explosion treatment with only argon gas, the adhesion was lowered than in the case of the present invention, and the weldability and peeling were confirmed in the evaluation of the weldability.

Comparative Example 5 was a DLC film excellent in adhesion and weldability as in the case of the present invention. However, since the current injected into the graphite target was constant, the arc discharge became unstable, and the arc discharge was failed on the way, so that the film formation was not stabilized. In addition, as compared with the present invention, the scratch load also tends to decrease.

In Comparative Examples 6 and 7, since the negative bias voltage applied to the substrate was -1300 V and -1000 V during the gas-plasma bombardment treatment, the removal of the residual oxygen on the substrate surface was insufficient and the adhesion was lowered And the weldability and peeling were confirmed in the evaluation of the weldability.

Claims (1)

A method for producing a coated tool for forming a diamond like carbon film on a surface of a base material by a filtered arc ion plating method,
A first step of introducing a mixed gas containing hydrogen gas into the furnace at a negative bias voltage of -2500 V or more and -1500 V or less applied to a substrate provided in a furnace to perform gas-
And a second step of introducing a nitrogen gas into the furnace after the gas spring bombardment treatment and applying a current to the graphite target to form a diamond like carbon film on the surface of the substrate,
And the second step includes a step of reducing the flow rate of the nitrogen gas and a step of increasing a current applied to the graphite target.

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