JP6103644B2 - Carbon-based film forming method and forming apparatus - Google Patents

Description

  The present invention relates to a carbon-based film forming method and a carbon-based film forming apparatus. More specifically, without using a high energy and high cost process such as CVD (Chemical Vapor Deposition) method or PVD (Physical Vapor Deposition) method, balls and the like can be used in the presence of hydrocarbon gas in the container. The present invention relates to a carbon-based film forming technique in which a carbon-based film is formed on the surface of a metal body by a simple operation of causing a granular body to collide with the surface of the metal body.

Carbon-based coatings such as DLC (Diamond-Like Carbon) coatings have excellent characteristics such as extremely hard, low friction coefficient, and high wear resistance, depending on the type, and expectations for industrial applications are growing. Yes.
To form a carbon-based film such as a DLC film on the surface of a metal material, etc., (1) ionize hydrocarbon gases such as acetylene and methane by plasma discharge in a low vacuum and apply hydrocarbon ions to the substrate. CVD method to synthesize by accelerated collision with negative bias voltage, (2) PVD method to synthesize from solid carbon source in high vacuum using sputtering (eg magnetron sputtering), ion beam evaporation, laser ablation, etc. (For example, refer to Patent Documents 1 and 2 and Non-Patent Document 1).
However, in these processes, the apparatus itself used is expensive, and high energy is required for the carbon-based film forming process. Therefore, not only the initial cost of the apparatus but also the running cost of the apparatus is high.

JP 2008-101271 A JP 2004-099963 A JP 2007-197767 A

Aisenberg and Chabot: Journal of Applied Physics, 42 (1971), 2953-2958.

From the background as described above, there is a demand for a technique for forming a carbon-based film at a low cost with energy saving by a simple apparatus.
Therefore, the present invention provides a carbon-based film forming method and a carbon-based film forming method that can form a carbon-based film with low energy and low cost without using a high-energy and high-cost process such as a CVD method or a PVD method. It is an object to provide an apparatus.

  The present inventors have previously developed a coating apparatus and a processing method for forming a coating film of a metal, a metal compound, and a ceramic in a short processing time using a ball impact method (see Patent Document 3).

In the ball impact method, a ball made of ceramic such as ZrO ₂ or stainless steel and a powder for film formation are placed in a cup-shaped chamber, etc., and a metal substrate to be coated is covered so as to cover the chamber. As appropriate, a load or weight (or a magnetic load or weight if necessary when a magnetic powder is used) is placed on the metal substrate, and a high-speed mechanical vibration is applied to the chamber to provide the metal substrate. This is a process in which a ball impact is repeatedly given to the inner surface and a dense and highly adherent particle film is rapidly formed (see FIG. 1).

This film formation treatment is basically performed at normal temperature, normal pressure, and air atmosphere. Thus, the ball impact method has a simple process principle, and energy consumption and cost at the time of introduction and operation are very low. So far, we have succeeded in the rapid formation of LaPO ₄ particle film, TiN nanoparticle film, hydroxyapatite (HAp) particle film, etc. on the metal substrate surface using ultrasonic resonance vibration and vertical mechanical vibration.

  The present inventor has found in a further research process related to Patent Document 3 that a carbon-based film such as a DLC film can be directly formed on the surface of a metal substrate by developing a mechanochemical reaction by a ball impact method in a hydrocarbon gas atmosphere. Thus, the present invention has been completed.

That is, the present invention is based on the knowledge as described above, and the present invention provides the following.
(1) The metal body is held so that the surface of the metal body faces the internal space of the container, and the container is vibrated in a state in which the hydrocarbon-based gas and the plurality of granular materials are present in the internal space. A method of forming a carbon-based film, wherein the granular body is collided with the surface of the metal body to form a carbon-based film on the surface of the metal body.
(2) The method for forming a carbon-based film according to (1), wherein the container has a vibration frequency of 5 to 200 Hz.
(3) The carbon-based film according to (1) or (2), wherein the hydrocarbon-based gas is one or more selected from alkane, alkene, cycloalkane, and cycloalkene having 1 to 4 carbon atoms. Forming method.
(4) The method for forming a carbon-based film according to any one of (1) to (3), wherein the granular material is a ceramic ball.
(5) A container having an internal space, a hydrocarbon-based gas supply device that supplies a hydrocarbon-based gas to the internal space, and a holding that holds the metal body so that the surface of the metal body faces the internal space of the container A carbon-based film forming apparatus comprising: a portion; a plurality of granular bodies that are present in the internal space; and a vibration device that vibrates the container.

The present invention can include the following aspects.
(6) The method for forming a carbon-based film according to any one of (1) to (4), wherein the metal body is a metal substrate.
(7) The method for forming a carbon-based film according to (4), wherein the ceramic ball ceramic is zirconia.
(8) Any one of (1) to (4), (6), and (7), wherein the metal body is held so that a surface of the metal body is horizontal, and a vibration direction of the container is a vertical direction. 2. A method for forming a carbon-based film according to item 1.
(9) The carbon-based film forming apparatus according to (5), wherein the container is made of ceramic.
(10) The carbon-based film forming apparatus according to (9), wherein the ceramic constituting the container is zirconia.
(11) The carbon-based film forming apparatus according to any one of (5), (9), and (10), wherein a vibration frequency of the vibration device is 5 to 200 Hz.
(12) The hydrocarbon-based supply device according to any one of (5) and (9) to (11), wherein the hydrocarbon-based supply device intermittently supplies a hydrocarbon-based gas. .

  According to the present invention, carbon such as a DLC film can be obtained with a simple operation using a relatively simple low-cost apparatus and a low running cost without using a high-energy and high-cost process such as a CVD method or a PVD method. A system film can be formed.

The figure which shows the well-known ball impact method typically. The optical microscope photograph which shows the carbon-type membrane | film | coat formed in the metal body surface when the vibration processing time is 1 min, 5 min, 10 min, and 20 min, respectively, according to Example 1 of the present invention. The figure which shows the Raman spectrum of the carbon-type membrane | film | coat formed in the metal body surface when vibration processing time is set to 1min, 5min, 10min, and 20min, respectively according to Example 1 of this invention. The optical micrograph which shows the formation state of the carbon-type membrane | film | coat in the metal body surface when vibration processing is (Initial) according to Example 2 of this invention, and a vibration frequency is 3 Hz, 5 Hz, 10 Hz, 15 Hz, and 20 Hz, respectively.

  To carry out the method for forming a carbon-based film of the present invention, a container having an internal space, a hydrocarbon-based gas supply device that supplies a hydrocarbon-based gas to the internal space, and the surface of a metal body that is a target for film formation A carbon-based film forming apparatus comprising: a holding portion that holds a metal body so that the surface faces the internal space of the container; a plurality of granular bodies that are present in the internal space; and a vibration device that vibrates the container Is used.

  As such a carbon-based film forming apparatus, any known apparatus (see FIG. 1) used for carrying out the ball impact method can be used, and supply of hydrocarbon-based gas to the known apparatus. By attaching the apparatus, the carbon-based film forming apparatus of the present invention can be obtained.

The container may be made of a ceramic (for example, made of zirconia) having an internal space such as a cubic shape, a rectangular parallelepiped shape, a cylindrical shape, or a polygonal column shape.
The container may be one having at least one opening (for example, a cup shape or the like) so that the surface of the metal body that is the target for film formation can easily face the internal space of the container. In such an opening, a ring-shaped cover serving as a holding portion can be fixed so as to contact the surface of the metal body on which the film is formed and prevent particulates (balls and the like) from being discharged out of the container. The cover is not limited, but may be made of a porous flexible material (for example, foam rubber).

The metal body that is the target of film formation may be held by a suitable mechanical fixing means on the container opening or ring-shaped cover as a holding part, but if the opening is formed on the top of the container, the metal body The metal body may be held on the opening due to the gravity of the load or the gravity of another load or weight placed on the metal body.
The container may have a lid body that opens and closes the opening. In this case, the metal body that is a target for film formation is held on the inner surface of the lid body or other container inner surface by an appropriate fixing means. Can do.

The metal body is preferably plate-shaped, but is not necessarily limited to a plate shape, and may be any three-dimensional shape. Further, the surface of the metal body on which the film is to be formed may be a flat surface, an inclined surface, a curved surface, an uneven surface, a composite surface thereof, or the like.
When the surface of the metal body where the film is to be formed is a plane perpendicular to the vibration direction of the container, it is desirable because the film is formed most efficiently and relatively evenly, but it is formed when the surface is uneven or curved. The film can also have a predetermined distribution according to the unevenness or curved surface.
The material of the metal body is not limited at all, and examples thereof include steels such as stainless steel, bearing steel, tool steel, and simple metals such as copper, aluminum, nickel, chromium, titanium, and various alloys. It may be plated.

  As the granular material present in the internal space of the container, a ceramic ball (for example, zirconia) or a stainless steel ball can be preferably used. Although the diameter thru | or average diameter (average of a major axis and a minor axis) of a granular material are not limited, It can be set to 1-10 mm, More preferably, it is 2-7 mm.

The hydrocarbon-based gas supply device supplies a hydrocarbon-based gas to the internal space of the container, and may be a temporary supply before starting the vibration of the container, or continuously when the container vibrates. It may be supplied periodically or intermittently.
Examples of the hydrocarbon-based gas to be supplied include alkanes having 1 to 4 carbon atoms, alkenes, cycloalkanes, and cycloalkenes. More specifically, methane, ethane, propane, butane, isobutane, ethylene, cyclopropane and the like can be mentioned.
The container and the vibration device of the present invention can be provided in the atmosphere control box so that the hydrocarbon-based gas supplied to the internal space of the container does not flow out.

Various mechanical devices can be used as the vibration device for vibrating the container. If it has an amplitude of about 30-50 mm and a frequency of about 5-100 Hz, it can be used sufficiently, and a wider range of amplitude (for example, 20-70 mm, 10-100 mm, 5-150 mm, etc.) Naturally, those capable of a wide range of frequencies (for example, 3 to 200 Hz, 2 to 500 Hz, 1 to 1000 Hz, etc.) can also be used.
The vibration direction of the vibration device may be any direction as long as the collision of the granular material occurs on the surface of the metal body, but usually the vibration direction is a direction perpendicular to the surface of the metal body. It is preferable to set so that. Further, during one vibration treatment step, the vibration direction can be changed within a range where the collision of the granular material occurs on the surface of the metal body.

  In the formation of the carbon-based film using the ball impact method of the present invention, the coverage of the carbon-based film on the surface of the metal body, the carbon, depending on the vibration frequency applied to the container, the vibration treatment time, the number of granular materials, the size of the container, etc. Since the type and state of the system coating are slightly different, it is desirable to adjust the vibration frequency and the vibration processing time applied to the container according to the required carbon-based coating.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to these Examples.

(Example 1) <Carbon-based film formation experiment 1: Influence of vibration treatment time>
A carbon film forming apparatus according to an embodiment of the present invention is provided with a hydrocarbon gas supply device (not shown) attached to an apparatus (but not using coating powder) used in the mechanical vibration ball impact method similar to that shown in FIG. It was. The surface of a stainless steel substrate (SUS304, after pickling, length and width 50 mm, thickness 2 mm) faces the internal space of a zirconia vibration chamber (outer diameter 40 mm, height 40 mm, internal space volume 45 mL). As described above, the load was placed on a fixed cover made of foamed rubber around the opening end of the vibration chamber, and a load or weight was placed on the stainless steel substrate.
Place 30g of zirconia balls (diameter 5mm) in the vibration chamber, fill the chamber with methane gas (purity 99.99%) at room temperature and 1atm (no coating powder), then vibration amplitude of the chamber 40mm, frequency 20Hz Vibration treatment was performed for 1, 5, 10, and 20 minutes.

An example in which the surface of each substrate after vibration treatment is observed with an optical microscope is shown in FIG. FIG. 3 shows a Raman spectrum obtained using a microscopic laser Raman spectroscopic analyzer (manufactured by Thermo Scientific, DXR Raman Microscope).
In the treatment time of 1 minute, a small amount of both an interference color film having a size of several to 20 μm and a small black spot film at the crystal grain boundary were formed. Film nuclei are formed at the grain boundaries, and the film undergoes repeated ball collisions and grows into an interference color film. The Raman spectrum of the interference color film has peaks in both the D band (near 1330 cm ^-1 ) indicating the diamond structure of carbon (sp3) and the G band (near 1580 cm ^-1 ) indicating the graphite structure (sp2). The DLC (Diamond-Like Carbon) film was formed. Although the carbon structure cannot be specified, a fine spectrum was also observed at a Raman shift of 700 cm ^-1 or less.
In the processing time of 5 minutes, the relatively large interference color film (DLC film) once formed begins to break down due to physical destruction by ball collision or thermal decomposition by mechanochemical reaction, and it does not have a DLC structure. It changes to a carbon film. The Raman spectrum is the same as when the processing time is 1 minute.
With a treatment time of 10 minutes, the coverage of the film (the area where the carbon-based film is formed / the area of the metal surface facing the inner space of the container) has improved, but physical destruction by ball collision and thermal decomposition by mechanochemical reaction In response, the proportion of the carbon film that has turned black is increased. In the Raman spectrum, the peaks in the D and G bands are small, and the spectrum intensity is relatively large at a Raman shift of 700 cm ⁻¹ or less.
In the treatment time of 20 minutes, almost no interference color film was observed, and the film changed to a black powder film. Coverage reaches 70%. In the Raman spectrum, the peaks disappear in the D and G bands, and only the spectrum at about 700 cm ⁻¹ or less is obtained.

(Example 2) <Carbon-based film formation experiment 2: Influence of vibration frequency>
Using a carbon film forming apparatus holding the same stainless steel substrate as in Example 1 above, 30 g of a zirconia ball (diameter 5 mm) is placed in a vibration chamber, and the inside of the chamber is methane gas (purity 99.99%) at 1 atm. After filling (no coating powder), vibration treatment was performed for 20 minutes at a chamber vibration amplitude of 40 mm and frequencies of 3, 5, 10, 15, and 20 Hz.
An example in which the surface of each substrate after vibration treatment is observed with an optical microscope is shown in FIG. In addition, the photograph before processing (Initial) is also added.
The photographs before processing and at the time of 3 Hz processing are very similar, and the existence of grain boundaries can be clearly seen. However, when the frequency is 5 Hz or higher, the formed interference color film and black film can be confirmed. Under the present experimental conditions, it can be said that the frequency threshold for forming the carbon film is about 5 Hz. Here, the maximum excitation force F [N] when an object of mass m [kg] is vibrated is calculated using amplitude A [m] and frequency f [Hz].
F = m × A × (2πf) ²
Therefore, it increases in proportion to the amplitude and in proportion to the square of the frequency. Therefore, when calculating the portion corresponding to the maximum vibration acceleration,
A × (2πf) ² = 0.040 × (2π × 5) ² = 39 [m / s ² ]
Thus, when using the vibration chamber of this time, it can be said that the maximum value of acceleration applied to the chamber is 39 m / s ² or more as a condition for forming the carbon film. However, since the acceleration time of the ball changes when the chamber height changes, the maximum vibration acceleration condition changes.
As the frequency increased, the chamber vibration acceleration was proportional to the square of the frequency, so the collision energy of the ball increased and the number of collisions increased, and the coating coverage improved. However, the formation of the carbon film and the physical destruction or thermal decomposition of the film once formed simultaneously occur. At the time of 20Hz treatment, the ratio of the black film considered to have changed from the interference color film was large, and the coverage was clearly improved compared to the case of 15Hz or less.

  According to the present invention, a carbon-based film can be formed at a low energy and at a low cost using a relatively simple apparatus without using a high energy and high cost process such as a CVD method or a PVD method. The present invention can be applied to the formation of a carbon-based film on various surfaces that require a carbon-based film, such as a lubrication surface and a sliding surface of a machine part.

Claims (5)

A carbon-based film forming method for forming a carbon-based film without using a CVD method or a PVD method , wherein the metal body is held so that the surface of the metal body faces the internal space of the container, and a hydrocarbon-based gas The container is vibrated in a state where a plurality of granular bodies are present in the internal space, and a plurality of granular bodies collide with the surface of the metal body to form a carbon-based film on the surface of the metal body. A method for forming a coating film.   The method for forming a carbon-based film according to claim 1, wherein the container has a vibration frequency of 5 to 200 Hz.   The method for forming a carbon-based film according to claim 1 or 2, wherein the hydrocarbon-based gas is one or more selected from alkanes having 1 to 4 carbon atoms, alkenes, cycloalkanes, and cycloalkenes.   The method for forming a carbon-based film according to any one of claims 1 to 3, wherein the granular material is a ceramic ball. A carbon-based film forming apparatus that forms a carbon-based film without using a CVD method or a PVD method, a container having an internal space, and a hydrocarbon-based gas supply device that supplies a hydrocarbon-based gas to the internal space A holding unit that holds the metal body so that the surface of the metal body faces the internal space of the container, a plurality of granular bodies that exist in the internal space, and a vibration device that vibrates the container. An apparatus for forming a carbon-based film.

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