JPH06220637A - Production of rigid carbon film coated member - Google Patents

Abstract

PURPOSE:To produce the rigid carbon coated member excellent in hardness and adhesion by introducing a specified gaseous material into a vacuum vessel to form a rigid carbon film on the surface of the intermediate layer formed on a base material. CONSTITUTION:The base material to be coated 4 is disposed in the vacuum vessel 1 provided with an evacuating device. Gaseous nitrogen is introduced from a gas introducing pipe 6 and gaseous silane is introduced from a gas introducing pipe 7 into the vacuum vessel 1, and an intermediate layer is formed on the surface of the base material 4 by an electron cyclotron resonance plasma CVD method using these gases. Then, the vacuum vessel is exhausted, and gaseous methane and gaseous hydrogen are introduced from the gas introducing pipe 6 into the vacuum vessel 1 without taking out the base material to the atmosphere, and the rigid carbon film is formed on the surface of the intermediate layer formed on the base material 4 by the electron cyclotron resonance plasma CVD method. In this way, the cutting tools long in lifetime and excellent in cutting property can be produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a hard carbon film coated member such as a cutting tool.

[0002]

2. Description of the Related Art In the prior art, when a cutting tool or the like is coated with a hard carbon film, a single layer of hard carbon is directly formed on the surface of the base material without forming an intermediate layer between the base material and the hard carbon film. A hard carbon film-coated tool was manufactured by forming a carbon film.

[0003]

In the conventional cutting tool having the above-mentioned structure, the adhesion between the base material and the hard carbon film is poor. For example, in the cutting tool, the hard carbon film of the cutting tool is not formed during cutting. It was easy to peel off and could not be put to practical use. In particular, when a hard carbon film is formed on a cutting tool made of a cobalt-containing tungsten carbide material called a super hard material, the hardness and adhesion of the hard carbon film are deteriorated and many problems such as peeling occur.

[0004]

[Means for Solving the Problems] In order to improve the adhesion between a base material and a hard carbon film, an aluminum nitride layer, a silicon nitride layer as an intermediate layer between the base material and the hard carbon film,
Any of the silicon carbide layers may be formed.

In order to form these intermediate layers, a method generally called plasma CVD method may be used, and trimethylaluminum, silane, disilane and reactive gas such as nitrogen or hydrocarbon are subjected to electron cyclotron resonance plasma. By decomposing and activating with (ECR plasma), any intermediate layer of the aluminum nitride layer, the silicon nitride layer, and the silicon carbide layer can be formed.

Further, after the formation of the intermediate layer, the hard carbon film is continuously formed without taking out the substrate from the vacuum container into the atmosphere, thereby preventing the surface of the intermediate layer from being oxidized and contaminated to further improve the adhesion. Can be improved. To form a hard carbon film, hydrocarbons and hydrogen are decomposed and activated by electron cyclotron resonance plasma or a hot filament, or hydrogen is decomposed and activated by electron cyclotron resonance plasma in a hydrogen atmosphere, and graphite is sputtered.

[0007]

[Function] A tungsten carbide sintered body used as a material for a cutting tool contains cobalt as a binder, and when a hard carbon film is to be formed on the surface of the tungsten carbide sintered body, the carbon film is affected by cobalt. A graphite component is deposited inside, which deteriorates hardness and adhesion. Therefore, if any of aluminum nitride, silicon nitride, or silicon carbide is formed as an intermediate layer between the tungsten carbide sintered body and the hard carbon film, and the hard carbon film is formed on the surface of the intermediate layer, the cobalt on the surface of the material is The effect due to disappears, and a hard carbon film coated member having excellent hardness and adhesion can be produced. In addition, the formation of the intermediate layer has the effect of relaxing the residual stress of the film.

[0008]

EXAMPLES The formation of an intermediate layer made of silicon nitride will be described below as the first example of the present invention. FIG. 1 is a sectional view showing an outline of a thin film forming apparatus used for carrying out the present invention.

The vacuum container 1 has a cylindrical shape, and a waveguide 2 is connected to one end of the vacuum container 1 to allow a microwave of 2.45 GHz to enter. At this time, by energizing the coil 3, a magnetic field of 875 Gauss is generated near the center, and the electron cyclotron resonance (EC
R) Discharge becomes possible.

Explaining the actual work, first, an end mill having a diameter of about 4 mm and made of a tungsten carbide sintered body to which cobalt is added is installed as a base material 4 on a jig 5 provided in the vacuum container 1. After evacuating the inside of the vacuum container to a pressure of 0.001 Pa or less by a turbo molecular pump, nitrogen gas is introduced into the vacuum container 1 through the gas introduction pipe 6.
Further, silane gas is simultaneously introduced from the gas introduction pipe 7. Next, the coils 3 are energized, microwaves are made incident on the vacuum vessel 1 through the waveguide 2, and electron cyclotron resonance discharge is started. As a result, plasma is generated by microwave energy, the introduced gas is decomposed and activated, and a silicon nitride layer is formed on the surface of the base material 4.

The respective conditions at this time are as follows. Silane gas flow rate 20 SCCM Nitrogen gas flow rate 30 SCCM Microwave power 500 W After about 30 minutes, introduction of silane gas and nitrogen gas is stopped, and formation of the intermediate layer is completed.

Subsequently, while the substrate 4 is held in the vacuum container as it is, hydrogen gas and methane gas are introduced from the gas introduction pipe 6 to form a hard carbon film on the surface of the intermediate layer formed in the previous step. Then, energization of the coil 3 is started. Next, when microwaves are incident from the waveguide 2, electron cyclotron resonance discharge is started in the vacuum container. At this time, plasma is generated by the microwave energy, the gas in the vacuum container is decomposed and activated, and a hard carbon film is formed on the surface of the intermediate layer already formed in the previous step.

The respective conditions at this time are as follows. Hydrogen gas flow rate 200 SCCM Methane gas flow rate 2 SCCM Microwave power 500 W After about 20 hours, gas introduction, coil 3 energization and microwave incidence are stopped, and formation of the hard carbon film is completed. After that, the substrate 4 is sufficiently cooled and the substrate 4 is taken out of the vacuum container 1.

An end mill coated with a hard carbon film was attached to an NC milling machine by the above method, and a cutting test was conducted to cut an aluminum alloy. As a result, the relationship between flank wear and cutting distance as shown in FIG. The result of the surface roughness of the cutting surface with respect to the cutting distance as shown in FIG. 4 was obtained. Each of these figures shows a state of comparison with an end mill not coated with a hard carbon film.

The end mill manufactured by the method of the present invention has no peeling of the hard carbon film and, as shown in FIGS. 3 and 4, has less wear and a longer life than the uncoated end mill. Next, a second embodiment of the present invention will be described.

The second embodiment is one in which an intermediate layer made of silicon carbide is formed, and the thin film forming apparatus is the same as that used in the first embodiment. FIG. 1 is a schematic sectional view of the apparatus. Show. First, an end mill having a diameter of about 4 mm and made of a tungsten carbide sintered body to which cobalt is added is used as a base material 4.
Is installed in a jig 5 provided in the vacuum container 1, the vacuum container 1 is evacuated to a pressure of 0.001 Pa or less by a turbo molecular pump, and then the vacuum container 1 is introduced from the gas introduction pipe 6.
Acetylene gas is introduced into the interior, and silane gas is introduced from the gas introduction pipe 7. Next, the coils 3 are energized, and microwaves are made incident on the vacuum vessel 1 from the waveguide 2 to start electron cyclotron resonance discharge. As a result, plasma is generated by the energy of microwaves, the gas introduced into the vacuum container is decomposed and activated,
A silicon carbide layer is formed on the surface of the base material 4.

The various conditions at this time are as follows. Silane gas flow rate 20 SCCM Acetylene gas flow rate 20 SCCM Microwave power 500 W After about 30 minutes, the introduction of silane gas and acetylene gas from each gas introduction pipe is stopped, and the formation of the intermediate layer is completed.

Subsequently, with the substrate 4 held in the vacuum container as it is, a hydrogen gas and a methane gas are evacuated from the gas introduction pipe 6 to form a hard carbon film on the surface of the intermediate layer formed in the previous step. It is introduced into the container 1, a hard carbon film is formed by the same method as in Example 1, and after cooling, the substrate 4 is taken out from the vacuum container 1.

When a cutting test was conducted using the hard carbon film-coated end mill obtained by the above method, the same characteristics as those of the hard carbon film-coated end mill in Example 1 were obtained. Next, a third embodiment of the present invention will be described. In this example, an example in which an intermediate layer made of aluminum nitride is formed will be described.

The thin film forming apparatus used in the present invention is the same as that used in the above embodiment. First, an end mill having a diameter of about 4 mm and made of a tungsten carbide sintered body is installed as a base material 4 on a jig 5 provided in the container 1, and the vacuum container 1 is operated by a turbo molecular pump up to a pressure of 0.001 Pa or less. After evacuation, aluminum bromide gas, argon gas and nitrogen gas are introduced into the vacuum container 1 through the gas introduction pipe 6. Next, the coil 3 is energized and microwaves are made incident on the vacuum container 1 from the waveguide 2 to start electron cyclotron resonance discharge. At this time, plasma is generated by the energy of microwaves, the gas is decomposed and activated, and an aluminum nitride layer is formed on the surface of the base material 4.

The respective conditions at this time are as follows. Nitrogen gas flow rate 30 SCCM Argon gas flow rate 30 SCCM Aluminum bromide gas flow rate 20 SCCM After about 30 minutes, introduction of aluminum bromide gas, argon gas, and nitrogen gas is stopped, and formation of the intermediate layer is completed.

Subsequently, hydrogen gas and methane gas are introduced into the vacuum container 1, a hard carbon film is formed on the surface of the substrate 4 in the same manner as in Example 1, and after cooling, taken out from the vacuum container 1. When a cutting test was performed on the hard carbon film-coated end mill obtained by the above method, the same characteristics as those of the hard carbon film-coated end mill in Example 1 were obtained.

Even when trimethylaluminum gas was used instead of aluminum bromide gas, a similar hard carbon film-coated end mill could be obtained. Next, a fourth embodiment of the present invention will be described. FIG. 2 is a sectional view showing the outline of a thin film forming apparatus used for implementing the present invention.

An annular target 8 coaxial with the vacuum container 1 is installed in the vacuum container 1, and a DC power supply 9 is connected to the target 8. The apparatus shown in FIG. 2 has the same configuration as the apparatus shown in FIG. 1 except that a target 8 is added. First, by any one of the methods described in Examples 1, 2 and 3, aluminum nitride, silicon nitride,
An intermediate layer made of any one of silicon carbide is formed. After the formation of the intermediate layer, the vacuum container 1 is evacuated again to form a hard carbon film on the surface of the intermediate layer formed on the base material 4. Therefore, hydrogen gas is supplied to the vacuum container 1 through the gas introduction pipe 6. Then, the coil 3 is energized and the waveguide 2 is introduced.
A microwave is further incident to generate electron cyclotron resonance plasma. When a voltage is applied to the target 8 in this state, the target 8 is sputtered by the ions in the plasma and a hard carbon film is formed on the surface of the base material 4.

The conditions at this time are as follows. Hydrogen gas flow rate 200 SCCM Microwave power 500 W Target applied voltage -300 V Approximately 20 hours later, the voltage was applied to the target 8 and the gas was introduced, the coil 3 was not energized, and the microwave was stopped. Finish the formation. Then, after sufficient cooling, the substrate 4 is taken out from the vacuum container 1.

When the cutting test of the hard carbon film-coated end mill obtained by the above method was performed, the same characteristics as those of the hard carbon film-coated end mill in Example 1 were obtained.

[0027]

According to the present invention, a hard carbon film coated member having excellent hardness and adhesion can be manufactured, and as a result, a cutting tool having a long life and excellent machinability can be manufactured. And so on.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing a thin film forming apparatus used in first, second and third embodiments of the present invention.

FIG. 2 is a sectional view schematically showing a thin film forming apparatus used in a fourth embodiment of the present invention.

FIG. 3 is an explanatory diagram showing the relationship between flank wear and cutting distance when the end mill obtained according to the present invention is used.

FIG. 4 is an explanatory diagram showing the relationship between the cutting distance and the surface roughness of the cutting surface when the end mill obtained according to the present invention is used.

[Explanation of symbols]

 1 Vacuum Container 2 Waveguide 3 Coil 4 Base Material 5 Jig 6 Gas Introducing Tube 7 Gas Introducing Tube 8 Target 9 DC Power Supply

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jun Tsuneyoshi 6-31-1, Kameido, Koto-ku, Tokyo Seiko Denshi Kogyo Co., Ltd.

Claims (5)

[Claims] 1. A method for producing a hard carbon film-coated member having an intermediate layer made of silicon nitride on the surface of the substrate and a hard carbon film formed on the surface of the intermediate layer, wherein the substrate is coated in a vacuum container equipped with a vacuum exhaust device. With the installation, after forming an intermediate layer on the substrate surface by electron cyclotron resonance plasma CVD method using silane gas and nitrogen gas as the material gas, the vacuum container is evacuated, the substrate from the vacuum container to the atmosphere. Methane gas and hydrogen gas are introduced as material gases into the vacuum container without taking out, and a hard carbon film is formed on the surface of the intermediate layer formed on the base material by the electron cyclotron resonance plasma CVD method. A method for manufacturing a carbon film coated member. 2. A method for producing a hard carbon film-coated member having an intermediate layer made of silicon carbide on the surface of the substrate and a hard carbon film formed on the surface of the intermediate layer, wherein the substrate is coated in a vacuum container equipped with a vacuum exhaust device. With the installation, after forming an intermediate layer on the substrate surface by electron cyclotron resonance plasma CVD method using silane gas and acetylene gas as the material gas, the vacuum container is evacuated, the substrate from the vacuum container to the atmosphere. Methane gas and hydrogen gas are introduced into the vacuum container as material gas without taking out, and a hard carbon film is formed on the surface of the intermediate layer formed on the base material by the electron cyclotron CVD method. A method for manufacturing a covering member. 3. A method for producing a hard carbon film-coated member having an intermediate layer made of aluminum nitride and a hard carbon film formed on a surface of a base material, wherein the coated base material is placed in a vacuum container equipped with a vacuum exhaust device. After forming an intermediate layer on the surface of the substrate by an electron cyclotron resonance plasma CVD method using aluminum bromide gas or trimethylaluminum gas and nitrogen gas as a gas, the vacuum container is evacuated, and then the substrate is removed from the vacuum container. It is characterized in that methane gas and hydrogen gas are introduced into the vacuum container as material gases without being taken out into the atmosphere, and a hard carbon film is formed on the surface of the intermediate layer formed on the base material by the electron cyclotron CVD method. A method for manufacturing a hard carbon film coated member. 4. A hard carbon film formed by decomposing and activating a mixed gas of hydrocarbon and hydrogen by electron cyclotron resonance plasma on the surface of an intermediate layer of a substrate having an intermediate layer of silicon nitride, silicon carbide or aluminum nitride. The method for producing a hard carbon film-coated member according to claim 1, 2, or 3, characterized in that. 5. A hard carbon film is formed on the surface of the intermediate layer of a substrate having an intermediate layer of silicon nitride, silicon carbide, aluminum nitride or the like by sputtering a target made of graphite with electron cyclotron resonance plasma in a hydrogen atmosphere. It forms, The manufacturing method of the hard carbon film coating member of Claim 1, 2 or 3 characterized by the above-mentioned.