JP6528936B2 - Method of manufacturing coated tool - Google Patents

Description

  The present invention is a coated tool used for, for example, a die for pressing or forging, a cutting tool such as a saw blade, and a cutting tool such as a drill, etc. “Also relates to a method for producing a coated tool coated with

When a workpiece such as aluminum, copper, or resin is molded with a mold, a part of the workpiece may adhere to the surface of the mold to cause product abnormalities such as galling and flaws. In order to solve this problem, a coated mold coated with a DLC film on the surface of the mold has been put to practical use. DLC coatings (Tetrahedral amorphous carbon coatings: ta-C coatings) substantially free of hydrogen are widely applied to coated molds because they have high hardness and excellent abrasion resistance.
However, since a highly hard DLC film substantially free of hydrogen is coated by arc ion plating using a graphite target, particles (graphite spheres) with a size of several micrometers are called droplets. Unavoidably mixed in the DLC film, the surface roughness of the DLC film is deteriorated.

  For such problems, Patent Document 1 discloses a smooth, high-hardness DLC film substantially free of hydrogen and coated by a filtered arc ion plating method having a mechanism for collecting droplets. doing.

JP, 2008-297171, A

  By applying a DLC film having a high hardness and a smooth surface state as in Patent Document 1, improvement of the tool life is expected. However, high hardness DLC films tend to have poor adhesion to the substrate.

  According to the study of the inventor of the present invention, it was confirmed that, particularly when a cold-tool steel such as SKD11 containing a large amount of carbide is used as a base material, peeling of a highly hard DLC film tends to easily occur. Also, in the case where conventional adhesion improvement methods such as providing an intermediate film such as nitride between the substrate and the DLC film, or metal bombarding the surface of the substrate, sufficient adhesion may not be obtained. I confirmed that there is.

  The present invention has been made in view of the circumstances as described above, and relates to a method of manufacturing a coated tool coated with a DLC film having excellent adhesion.

The present inventors have found that there is an effective coating method that can improve the adhesion of a DLC film, and reached the present invention. The specific means for achieving the said subject are as follows.
That is, the present invention is a method for producing a coated tool in which a diamondlike carbon film is coated on the surface of a substrate by a filtered arc ion plating method, and the arithmetic average roughness Ra is 0.06 μm or less, and the maximum height roughness is A base material having a surface with a height Rz of 1.0 μm or less is placed in a furnace, a mixed gas containing hydrogen gas is introduced into the furnace, and a bias voltage of -2500 V or more and -1500 V or less is applied to the base material. And a step of performing a gas bombardment treatment for 60 minutes or more, and a step of coating a diamond-like carbon film on the surface of the substrate using a graphite target.

  The mixed gas is preferably a mixed gas containing 4% by mass or more of hydrogen gas. Furthermore, the mixed gas is preferably a mixed gas containing 7% by mass or more of hydrogen gas.

  According to the present invention, a coated tool coated with a DLC film excellent in adhesion can be obtained.

It is an example of the surface observation photograph by the optical microscope of the DLC film which concerns on the example of this invention. It is an example of the surface observation photograph by the optical microscope of the DLC film concerning a comparative example. It is an example of the surface observation photograph by the optical microscope after the Rockwell test of the DLC film concerning the example of the present invention. It is an example of the surface observation photograph by the optical microscope after the Rockwell test of the DLC film concerning a comparative example. It is the schematic of T-shaped filtered arc film-forming apparatus used in the Example.

The manufacturing method of the coated tool of this invention is demonstrated. In the present invention, it is important to prepare a substrate having a smooth surface condition for the substrate before the DLC film is coated. That is, in the present invention, measurement of arithmetic average roughness Ra (based on JIS-B-0601-2001) and maximum height roughness Rz (based on JIS-B-0601-2001) which are general surface roughness is measured. In this case, a substrate having a surface with an Ra of 0.06 μm or less and an Rz of 1.0 μm or less is used. When the surface of the substrate before coating has Ra of 0.06 μm or less and Rz of 1.0 μm or less, it becomes a smooth surface state with few irregularities, and adhesion with the substrate even if it is a DLC film with high hardness Improves the quality. More preferably, Ra is 0.05 μm or less and Rz is 0.8 μm or less. Furthermore, it is preferable to set Ra to 0.04 μm or less and Rz to 0.6 μm or less.
In order to achieve such surface roughness, for example, it is preferable to polish the surface of the substrate using a diamond paste of 1 μm or less.

  The base material to be applied in the present invention is not particularly limited as long as the above-described surface roughness is satisfied, and can be appropriately selected according to 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, high carbon steel having a carbon content of 1% by mass or more and a cemented carbide are preferable because they have a large amount of carbides of the base material and easily exfoliate from the viewpoint of high adhesion improvement effect. As an example of high carbon steel, JIS-SKD11 etc. are mentioned, for example.

  In the present invention, in addition to using a substrate having a smooth surface state, gas bombardment treatment before coating a DLC film is important. When a conventional gas bombardment treatment with argon gas is performed on the base material before coating the DLC film, a large amount of oxygen is present at the interface between the film and the base material, resulting in poor adhesion. The oxygen present at this interface is attributed solely to the oxide film initially formed on the surface of the substrate, and is a residual element that can not be completely removed by gas bombardment treatment with argon gas. On the other hand, the surface of the substrate is subjected to gas bombardment using a mixed gas containing hydrogen gas, whereby the oxide film on the surface of the substrate is reacted with hydrogen ions to be reduced and oxidized by the gas bombardment treatment. It is possible to remove dirt on membranes and surfaces.

In order to enhance the adhesion of a high hardness DLC film, it is important to control the bias voltage applied to the substrate and the gas bombardment processing time when performing gas bombardment processing using a mixed gas containing hydrogen gas. In the present invention, a bias voltage of −2500 V or more and −1500 V or less is applied to the base material, and gas bombardment processing is performed using a mixed gas containing hydrogen gas. When the bias voltage applied to the substrate is higher than -1500 V (plus side than -1500 V), the collision energy of gas ions is low, so the effect of removing the dirt on the oxide film and the surface becomes small, and the base The adhesion between the material and the high hardness DLC film tends to decrease. In addition, when the bias voltage applied to the base material is smaller than -2500 V (on the negative side of -2500 V), the plasma is likely to be unstable, which may cause abnormal discharge. When abnormal discharge occurs, an abnormal discharge (arching) mark is formed on the surface of the tool, so that unevenness may occur on the surface of the tool.
Furthermore, in the gas bombardment process, the bias voltage applied to the substrate is preferably -2300 V or more and -1700 V or less. Furthermore, in the gas bombardment process, the bias voltage applied to the substrate is preferably -2200 V or more and -1700 V or less.

Even if the bias voltage applied to the substrate is properly controlled, if the gas bombardment time is short, the adhesion between the substrate and the high hardness DLC film is reduced because the etching effect to remove the oxide film is not sufficient. Do. In order to uniformly remove the oxide on the surface of the substrate, it is necessary to perform gas bombardment treatment with a mixed gas containing hydrogen gas for 60 minutes or more. Furthermore, it is preferable to perform the gas bombardment treatment with the mixed gas for 70 minutes or more, and more preferably for 80 minutes or more.
It is preferable to adjust the upper limit of the time of gas bombardment processing appropriately according to a base material. However, when the time of the gas bombardment treatment with the mixed gas is 180 minutes or more, the effect of removing the dirt on the oxide film and the surface by the gas bombardment treatment tends to be constant. Therefore, it is preferable to make the gas bombardment process with mixed gas 180 minutes or less.

  For example, a mixed gas of a rare gas such as argon and hydrogen gas may be used as the mixed gas used for the gas bombardment process. The mixed gas is preferably a mixed gas containing 4% by mass or more of hydrogen gas. If the mixed gas contains less than 4% by mass of hydrogen gas, the oxide film on the surface of the substrate may not be sufficiently removed by gas bombardment. Furthermore, it is preferable to use a mixed gas of 5% by mass or more of hydrogen gas, and it is more preferable to use a mixed gas of 7% by mass or more of hydrogen gas. Furthermore, it is preferable to use a mixed gas of 10 mass% or more of hydrogen gas. However, in the case of a mixed gas of 30% by mass or more of hydrogen gas, the effect of removing dirt on the oxide film and the surface by gas bombardment tends to be constant. Therefore, it is preferable to use a mixed gas of 30 mass% or less of hydrogen gas. Furthermore, it is preferable to use a mixed gas of 25 mass% or less of hydrogen gas.

After the above-described gas bombardment process, a DLC film is coated using a graphite target. By performing gas bombardment processing under the conditions described above, the oxide film on the surface of the base material is sufficiently removed, so that excellent adhesion is ensured even when coating a high hardness DLC film directly on the base material. Can.
By coating a DLC film using a graphite target, impurities other than carbon atoms contained in the film are reduced, and carbon atoms having a diamond structure are increased, whereby a DLC film with higher hardness can be achieved. When coating the DLC film, the substrate temperature is preferably 200 ° C. or less. If the temperature is higher than 200 ° C., the graphitization of the DLC film proceeds, and the hardness tends to decrease.
In addition, when the DLC film is coated, it is preferable to set the bias voltage applied to the substrate to -300 V or more and -50 V or less. When the bias voltage applied to the base material is larger than -50 V (plus side than -50 V), the collision energy of carbon ions is reduced, and defects such as voids are easily generated in the DLC film. In addition, when the bias voltage applied to the base material is smaller than -300 V (is more negative than -300 V), abnormal discharge is likely to occur during film formation. When the DLC film is coated, the bias voltage applied to the substrate is more preferably -200 V or more and -100 V or less.
In order to obtain a higher hardness DLC film, it is preferable to set the pressure in the furnace to 5 × 10 ⁻³ Pa or less at the time of coating the DLC film.

  The diamond like carbon film coated in the present invention preferably has a nanoindentation hardness of 50 GPa or more and 100 GPa or less measured from the film surface. If the nanoindentation hardness is lower than 50 GPa, the wear resistance tends to be low because the wear resistance is lowered. On the other hand, when the hardness of the film is higher than 100 GPa, the residual stress tends to be too high, and the adhesion to the substrate tends to be lowered.

  The DLC film coated according to the present invention has a nanoindentation hardness of 55 GPa or more, more preferably 60 GPa or more, in terms of good wear resistance and excellent adhesion to a substrate. The nanoindentation hardness of the DLC film is more preferably 95 GPa or less, still more preferably 90 GPa or less.

  The nanoindentation hardness is the plastic hardness when the probe is pressed into a sample (DLC film) for plastic deformation, and the load-displacement curve is determined from the pressing load and the pressing depth (displacement). , To calculate the hardness. Specifically, using a nanoindentation device manufactured by Elionix Co., Ltd., the hardness of the film surface is measured under the following conditions: indentation load: 9.8 mN, maximum load holding time: 1 second, removal rate after load: 0.49 mN / sec Ten points are measured, and it is obtained from the average value of six points excluding two large points and two small points.

  When droplets, impurities, and the like are present on the surface of the DLC film, the work material is welded from these as a starting point to cause galling and the like. The DLC film coated by the present invention has a general surface roughness, arithmetic average roughness Ra (based on JIS-B-0601-2001), maximum height roughness Rz (JIS-B-0601-2001). In the measurement of conformity), Ra having a smoothness of 0.05 μm or less and Rz of 0.5 μm or less is preferable because surface defects as a starting point of welding of the workpiece are reduced. More preferably, Ra is 0.03 μm or less. More preferably, Rz is 0.3 μm or less.

  In the present invention, in order to achieve the above-described smooth DLC film, the surface of the substrate is coated with a diamond-like carbon film by a filtered arc ion plating method. In addition, by using the filtered arc ion plating method, not only a smooth DLC film can be obtained, but since droplets are not contained inside the film, a dense film is obtained, and a DLC film having high hardness and excellent toughness is achieved. can do. In particular, if a T-shaped filtered arc ion plating apparatus is used, it is possible to coat a DLC film with extremely few droplets contained in the film in a smoother surface state, so the durability of the coated tool is further improved. Preferred.

If the film thickness of the DLC film becomes too thin, the durability as a tool may be insufficient. If the film thickness is too thick, the surface roughness of the film surface may be deteriorated. If the film thickness is too thick, the DLC film may be partially peeled off. Therefore, the film thickness of the DLC film is preferably 0.1 μm or more and 1.5 μm or less. Furthermore, the film thickness of the DLC film is more preferably 0.1 μm or more and 1.2 μm or less. In order to provide the coated tool with sufficient wear resistance, the film thickness of the DLC film is preferably 0.2 μm or more. In order to simultaneously achieve smooth surface roughness and excellent wear resistance, the thickness of the DLC film is more preferably 0.5 μm or more and 1.2 μm or less.
Even in the case of the DLC film coated by the filtered arc ion plating method, the surface roughness may be reduced when the film thickness is increased. In that case, it is preferable to polish the surface of the coated DLC film to make it smooth.

<Deposition apparatus>
As a film forming apparatus, a T-shaped filtered arc ion plating apparatus was used. A schematic of the device is shown in FIG. The film forming chamber (6) has an arc discharge type evaporation source for mounting a carbon cathode (cathode) (1) on which a graphite target is installed, and a substrate holder (7) for mounting a substrate. Below the substrate holder, there is a rotation mechanism (8), and the substrate rotates and revolves via the substrate holder.
When an arc discharge is generated on the surface of the graphite target, only the carbon having electric charge is bent by the magnetic coil (4) to reach the film forming chamber and coat the film on the substrate. Non-charged droplets are collected in the duct (5) without being bent by the magnetic coil. The symbol (2) indicates a carbon film deposition beam, and the symbol (3) indicates spherical graphite (droplet) neutral particles.

<Base material>
As a base material for evaluating the peeling state of the coated DLC film, a base material of a JIS-SKD11 equivalent steel material having a size of 60 HRC with a diameter of 20 mm × 5 mm was used.
In addition, a base material for measuring the nanoindenter hardness of the coated DLC film includes a base material made of cemented carbide made of tungsten carbide (WC-10 mass% Co) having a cobalt content of 10 mass%. (Dimension: 12.7 mm × 12.7 mm × 5 mm, average particle size: 0.8 μm, hardness: 91.2 HRA) was used.
Further, as a base material for evaluating adhesion of the coated DLC film by a scratch test and a Rockwell hardness tester, a base material of a JIS-SKH51 equivalent steel material having a size of 21 mm × 17 mm × 2 mm was used.
For each substrate, the surface roughness was measured, and a DLC film was coated under the following conditions.

<Invention Example 1>
The film forming chamber was evacuated to 5 × 10 ⁻³ Pa, and the substrate was heated to about 150 ° C. by 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 process was performed for 90 minutes using a mixed gas containing 5 mass% hydrogen gas in argon gas. The flow rate of the mixed gas was 50 sccm to 100 sccm.
After the gas bombardment process, a bias voltage of -150 V was applied to the substrate to make the substrate temperature 100 ° C. or less. Then, the pressure in the furnace was set to 5 × 10 ⁻³ Pa or less, the current applied to the graphite target was set to 50 A, and a DLC film was formed for about 50 minutes.

<Invention Example 2>
The conditions of the invention example 1 were the same except that a mixed gas containing 10 mass% hydrogen gas as argon gas was used in the gas bombardment process.

<Invention Example 3>
The conditions of the invention example 1 were the same except that a mixed gas containing 20 mass% hydrogen gas as argon gas was used in the gas bombardment process.

<Invention Example 4>
The conditions were the same as those of Example 1 of the present invention except that the negative bias voltage applied to the base material during gas bombardment processing was set to -1700V.

<Invention Example 5>
The conditions of the invention example 1 were the same except that the gas bombardment treatment time was 70 minutes.

Comparative Example 1 (Conventional Example)
The film forming chamber was evacuated to 5 × 10 ⁻³ Pa, and the substrate was heated to about 150 ° C. by a heater for heating and held for 90 minutes. Thereafter, the negative bias voltage applied to the substrate was set to −2000 V, and the gas bombardment was performed only with argon gas. After the gas bombardment process, a bias voltage of -150 V was applied to the substrate, and the substrate temperature was adjusted to 100 ° C. or less. Then, the pressure in the furnace was set to 5 × 10 ⁻³ Pa or less, the current supplied to the graphite target was set to 50 A, and the DLC film was coated for about 50 minutes.

Comparative Example 2 (Conventional Example)
Under the same conditions as Comparative Example 1, the substrate surface was subjected to gas bombardment with only argon gas. Thereafter, about 3 μm of CrN was coated as an intermediate film. After the intermediate coating was applied, a bias voltage of -150 V was applied to the substrate to make the substrate temperature 100 ° C. or less. Then, the pressure in the furnace was set to 5 × 10 ⁻³ Pa or less, the current applied to the graphite target was set to 50 A, and a DLC film was formed for about 50 minutes.

Comparative Example 3 (Conventional Example)
Under the same conditions as Comparative Example 1, the substrate surface was subjected to gas bombardment with only argon gas. Then, the negative bias voltage applied to the base material was -1000 V, and the Ti bombardment process was performed for 5 minutes. After that, a bias voltage of -150 V was applied to the substrate to set the substrate temperature to 100 ° C. or less. Then, the pressure in the furnace was set to 5 × 10 ⁻³ Pa or less, the current applied to the graphite target was set to 50 A, and a DLC film was formed for about 50 minutes.

Comparative Example 4 (Comparative Example)>
The film forming chamber was evacuated to 5 × 10 ⁻³ Pa, and the substrate was heated to about 150 ° C. by a heater for heating and held for 90 minutes. After that, a negative bias voltage applied to the substrate was set to −1000 V, and a gas bombardment process was performed for 90 minutes using a mixed gas containing 5 mass% hydrogen gas in argon gas. The flow rate of the mixed gas was 50 sccm to 100 sccm.
After the gas bombardment process, a bias voltage of -150 V was applied to the substrate to make the substrate temperature 100 ° C. or less. Then, the pressure in the furnace was set to 5 × 10 ⁻³ Pa or less, the current applied to the graphite target was set to 50 A, and a DLC film was formed for about 50 minutes.

Comparative Example 5 (Comparative Example)>
The film forming chamber was evacuated to 5 × 10 ⁻³ Pa, and the substrate was heated to about 150 ° C. by 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 process was performed for 30 minutes using a mixed gas containing 5 mass% hydrogen gas in argon gas. The flow rate of the mixed gas was 50 sccm to 100 sccm.
After the gas bombardment process, a bias voltage of -150 V was applied to the substrate to make the substrate temperature 100 ° C. or less. Then, the pressure in the furnace was set to 5 × 10 ⁻³ Pa or less, the current applied to the graphite target was set to 50 A, and a DLC film was formed for about 50 minutes.

Comparative Example 6 (Comparative Example)>
The surface of the base material was shot-blasted (projectile: iron-based media) and then polished with a grindstone (sandpaper) of grain size # 600. Thereafter, the gas bombardment treatment and the coating of the DLC film were made to be the same conditions as Example 1 of the present invention.

Comparative Example 7 (Comparative Example)>
The surface of the substrate was ground with a diamond wheel. Thereafter, the gas bombardment treatment and the coating of the DLC film were made to be the same conditions as Example 1 of the present invention.

Comparative Example 8 (Comparative Example)>
The surface of the substrate was polished with a grindstone (sandpaper) of grain size # 400. Thereafter, the gas bombardment treatment and the coating of the DLC film were made to be the same conditions as Example 1 of the present invention.

Comparative Example 9 (Comparative Example)>
The gas bombarding conditions including the surface state of the base material and the film forming conditions were the same as Example 1 of the present invention except that the negative bias voltage applied to the base material during gas bombardment processing was changed to -1300V.

Comparative Example 10 (Comparative Example)>
The gas bombarding conditions and the film forming conditions including the surface state of the substrate except that the gas bombardment treatment time was 50 minutes were the same as the invention example 1.

In all of the above-described samples, the DLC film was coated while repeating film formation and cooling so that the temperature of the substrate was 200 ° C. or less. The film thickness of the DLC film was about 0.5 μm in all the samples.
The hardness, surface roughness and adhesion were evaluated for each of the samples coated with the DLC film. The measurement conditions will be described below.

<Measurement and evaluation>
-Measurement of nanoindentation hardness-
The hardness of the film surface was measured using a nanoindentation apparatus manufactured by Elionix Co., Ltd. Measured at 10 points under the following conditions: indentation load: 9.8 mN, maximum load holding time: 1 sec, removal speed after load: 0.49 mN / sec, and 6 points except for 2 large values and 2 small values It calculated from the average value. It was confirmed that the hardness of the fused quartz which is a standard sample is 15 GPa and the hardness of the CVD diamond film is 100 GPa.

-Measurement of surface roughness-
Arithmetic mean roughness Ra and maximum height roughness Rz from a roughness curve according to JIS-B-0601-2001 using a contact type surface roughness measuring device SURFCOM 480A manufactured by Tokyo Seimitsu Co., Ltd. Was measured. The measurement conditions were an evaluation length of 4.0 mm, a measurement speed of 0.3 mm / s, and a cutoff value of 0.8 mm.

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

The DLC film of each sample was indented using a Rockwell hardness tester (AR-10 manufactured by Mitutoyo) using a C-scaled diamond indenter. And it observed at about 800 times the magnification using a light microscope made by Mitutoyo Co., Ltd., and evaluated the exfoliation situation of the film around an impression. The evaluation criteria of the adhesiveness by a Rockwell hardness (HRC) indentation test were as follows.
<Evaluation criteria for HRC indentation test>
A: no peeling or peeling with a major axis of less than 20 μm B: peeling with a major axis of 20 μm to less than 50 μm C: peeling with a major axis of 50 μm or more

Peeling load was measured using a CSM scratch tester (REVETEST). Measurement conditions: 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 0.9 N, Fn speed: 5 N / s, Fn removal speed: 10 N / s, approach speed: 2% / s.
The load at which initial chipping occurred was evaluated as A load, and the load when the substrate was completely exposed was evaluated as B load.

An example of the surface observation photograph (800 times) by the optical microscope of the DLC film concerning the example of the present invention is shown in FIG. Even in the case where a substrate with a large amount of carbides was used, it was confirmed that in the example of the present invention, peeling of the film on the surface hardly occurred. Among the inventive examples, in the inventive examples 2 and 3 in which the gas bombardment process was performed with a high concentration of hydrogen gas, the peeling of the film was slight, and the adhesion tended to be more excellent.
An example of the surface observation photograph (800x) by the optical microscope of the DLC film concerning a comparative example is shown in FIG. In Comparative Examples 1 to 3, although the conventional adhesion improving methods such as Ar bombardment treatment, Ti bombardment treatment, and nitride intermediate coatings were coated, extremely large film peeling occurred.
In Comparative Examples 6 to 8, the gas bombardment was performed using a mixed gas containing hydrogen gas, but large surface peeling occurred because the surface roughness of the substrate before coating was not appropriate.
In Comparative Examples 4, 5, 9, and 10, the base was smooth-polished and the gas bombardment treatment was performed using a mixed gas containing hydrogen gas, and the state of surface peeling was approximately the same as that of Example 1 of the present invention. there were.

An example of the surface observation photograph (800 times) by the optical microscope after the Rockwell test of the DLC film concerning the example of the present invention is shown in FIG. In the example of the present invention, since the gas bombardment process was performed using a mixed gas containing hydrogen gas under appropriate conditions, the oxides on the surface of the substrate were sufficiently removed, the adhesion between the substrate and the DLC film was enhanced, and the high hardness was achieved. DLC film sufficiently follows the plastic deformation of the substrate, so that coarse film peeling does not occur even in the Rockwell hardness indentation test, and slight peeling is observed in part even when film peeling is observed Was about to In the invention examples 2 and 3 of the invention examples 2 and 3 in which the hydrogen gas concentration is high among the invention examples, peeling of the film was hardly confirmed, and the adhesion tended to be excellent.
An example of the surface observation photograph (800x) by the optical microscope after the Rockwell test of the DLC film concerning a comparative example is shown in FIG. Comparative Examples 1 to 3 are the conventional adhesion improving methods such as Ar bombardment treatment, Ti bombardment treatment, and an intermediate coating of nitride, but in each case, the high hardness DLC film is the plasticity of the base material Large film peeling occurred because the film could not sufficiently follow the deformation.
In Comparative Examples 6 to 8, the gas bombardment was performed with a mixed gas containing hydrogen gas, but the adhesion between the substrate and the DLC film was not sufficient because the surface roughness of the substrate before coating was not appropriate. Occurred.
In Comparative Examples 4, 5, 9 and 10, since the bias voltage or the processing time of the gas bombardment process was not appropriate, the film peeling tended to occur more frequently than the inventive example.

  The test results are summarized and shown in Table 1. In the comparative example, the B load, which is the load when the substrate was completely exposed in the scratch test, sometimes exhibited a value similar to that of the inventive example. However, in the comparative example, there is a problem that the A load at which initial chipping occurs is low, a problem that coarse peeling is present in observation of surface peeling with an optical microscope, and a problem that coarse peeling is present in Rockwell hardness indentation test At least one of the above problems existed, and the adhesion of the inventive example tended to decrease. In the examples of the present invention, it was confirmed that the adhesion is excellent.

Claims (3)

A method for producing a coated tool for coating a diamond like carbon film on a surface of a substrate by a filtered arc ion plating method, comprising:
A base material having a surface with an arithmetic average roughness Ra of 0.06 μm or less and a maximum height roughness Rz of 1.0 μm or less is placed in a furnace, and a mixed gas containing 4 to 30% of hydrogen gas in the furnace was introduced, the to a substrate by applying a -2 3 00V or -1 7 00V or less of the bias voltage, and performing gas bombardment 70 minutes or more,
Coating a diamond like carbon film on the surface of the substrate using a graphite target;
A method of manufacturing a coated tool comprising: The method for manufacturing a coated tool according to claim 1 , wherein the mixed gas is a mixed gas containing 7% by mass or more of hydrogen gas. The method according to claim 1, wherein the flow rate of the mixed gas is 50 sccm to 100 sccm.