JP4750896B1 - Diamond-like carbon film coated article - Google Patents

Abstract

Disclosed is a diamond-like carbon film-coated article, which is excellent in adhesion of a diamond-like carbon film to an article body.
A diamond-like carbon film-coated article W that is at least partially coated with a diamond-like carbon (DLC) film formed through an intermediate layer made of an amorphous silicon carbide film. Amorphous silicon carbide film is a film showing a peak in the range of the spectral intensity of Raman shift 1400cm ^-1 ~1600cm ^-1 in a laser Raman spectroscopic analysis using a laser with a wavelength of 532 nm.
[Selection] Figure 3

Description

The present invention relates to an article that is at least partially coated with a diamond-like carbon film.
The present invention also relates to a method for forming such a diamond-like carbon film.

  A diamond-like carbon film is known as a film having high hardness, high wear resistance, and excellent slidability and electrical insulation. Therefore, at least a part of various mechanical parts, tools, electric appliance parts, ornaments, etc. that require one or more of high hardness, wear resistance, slidability, electrical insulation, etc. are made of diamond. Coating with a carbon-like carbon film has been proposed and implemented.

In many cases, the diamond-like carbon film is formed by a plasma CVD method.
For example, in Japanese Patent Application Laid-Open No. 2000-119853, an article intended to form a diamond-like hard carbon film is placed in a vacuum chamber, a carbon-containing gas is introduced into the chamber, and plasma is generated therefrom. The formation of a hard carbon film on an article is described.

  In this publication, an auxiliary electrode is disposed at the center of the film-forming article having an opening, the auxiliary electrode is set to a ground potential, and a high-frequency voltage or a negative DC voltage is applied to the article. It is also described that plasma is generated from a carbon-containing gas in a vacuum chamber including an opening, and a film is formed on the inner surface of the opening under the plasma.

  Japanese Patent Application Laid-Open No. 2006-199980 discloses an inner surface coating of an article to be treated (film formation target article) by plasma CVD, particularly an inner surface of a hollow part of the article to be treated, for example, an inner surface of a hollow part of a cylindrical article to be treated. The coating process by the plasma CVD method is described.

  Furthermore, in this publication, the article to be coated on the inner surface is placed in a vacuum chamber, a discharge gas (such as argon gas and hydrogen gas) is introduced into the chamber, and a coating material gas [carbon-containing gas] (E.g., tetramethylsilane gas (TMS), acetylene gas, etc.)] and asymmetric pulse power (positive voltage value and negative voltage value are symmetrical as discharge power to the article to be processed while controlling the gas pressure in the chamber Non-pulse power) is applied, thereby generating a uniform hollow discharge from the discharge gas in the hollow portion of the cylindrical article to be processed, and the material gas is also turned into a plasma to form a diamond shape on the inner surface of the article to be processed. It describes the formation of a carbon (Diamond Like Carbon: DLC) film.

  Further, in order to improve the adhesion of the diamond-like carbon film to the article to be processed, an intermediate layer forming gas (tetramethyl) is formed together with a discharge gas (argon gas and hydrogen gas) in the chamber prior to the formation of the diamond-like carbon film. Silane (TMS) gas) is introduced, these gases are turned into plasma while maintaining the gas pressure in the chamber at a predetermined pressure, and a silicon carbide film is formed as an intermediate layer on the inner surface of the article to be processed under the plasma, Instead of hydrogen gas, a coating material gas (acetylene gas) is introduced, and TMS gas is introduced, but the amount is reduced, and an intermediate layer (silicon carbide film) is placed on the inner surface of the article to be treated under the plasma of these gases Thus, it is described that a diamond-like carbon (DLC) film is formed with good adhesion.

JP 2000-119853 A Japanese Patent Laid-Open No. 2006-199980

  However, the DLC film having the silicon carbide film described in JP-A-2006-199980 as an intermediate layer depends on the DLC film formation target article, but is still insufficient in terms of adhesion to the film formation target article. I can not say.

  Therefore, the present invention provides a diamond-like carbon film-coated article, at least a part of which is coated with a diamond-like carbon film formed through an intermediate layer made of an amorphous silicon carbide film, and the article body of the diamond-like carbon film It is an object of the present invention to provide a diamond-like carbon film-coated article having excellent adhesion to the surface.

  The present inventor researched to solve the above problems, and when the hardness, Young's modulus, etc. of the silicon carbide film as an intermediate layer is low, the silicon carbide film is easily collapsed by an external force applied through the DLC film. It has been found that when disintegrated, the adhesion of the DLC film to the article body is impaired.

Based on this knowledge, the present invention is a diamond-like carbon film-coated article in which at least a part is covered with a diamond-like carbon film formed through an intermediate layer made of an amorphous silicon carbide film in order to solve the above-mentioned problems. The amorphous silicon carbide film and the diamond-like carbon film are films formed by plasma CVD using asymmetric pulse power as discharge power, and the amorphous silicon carbide film is obtained by laser Raman spectroscopy using a laser having a wavelength of 532 nm. Raman shift 1400cm a peak of spectral intensity in the range of ^{-1 ~1600cm -1,} indentation hardness than 15 GPa 17 GPa or less, a Young's modulus to provide a diamond-like carbon film-coated article is 147.5GPa less film than 130GPa .

Here, the “diamond-like carbon film-coated article” may be any of various kinds of articles such as various machine parts, tools, electric appliance parts, and ornaments.
An intermediate layer made of the amorphous silicon carbide as the intermediate layer in the diamond-like carbon film-coated article according to the present invention, the spectral intensity in the range of the Raman shift 1400cm ^-1 ~1600cm ^-1 in a laser Raman spectroscopic analysis using a laser with a wavelength of 532nm It is a film | membrane which shows no peak.

This means that the amorphous silicon carbide film as the intermediate layer is richer in Si—C bonds and C—C bonds than in C—H bonds and is strong.
Amorphous silicon carbide film as an intermediate layer indentation hardness than 15 GPa (at the lowest 15 GPa) 17 GPa or less, a Young's modulus of more than 130 GPa (also smaller 130GPa) 147.5GPa or less.

  Thus, the diamond-like carbon film-coated article according to the present invention is less likely to collapse even when the amorphous silicon carbide film as the intermediate layer is subjected to external force, and the adhesion of the diamond-like carbon film to the article body is maintained well.

  In the diamond-like carbon film-coated article according to the present invention, the intermediate layer and the diamond-like carbon film may be formed only on the outer surface of the article body, or may be formed on the inner surface of the recessed portion. Examples of such a recessed portion include an inner surface portion of a cylindrical article, an inner peripheral surface of a ring-shaped article, a hollow inner surface of a bowl-shaped article, a gap inner surface of a gap portion, etc., but generally speaking, an aspect ratio One or more recessed portions can be exemplified.

  A recessed portion with an aspect ratio of 1 or more is, for example, a recessed portion such as a recessed hole, the length (or depth) of the recessed portion / opening inner diameter is 1 or more, and a recessed portion such as a gap portion is its depth. / If the gap dimension is 1 or more and the inner surface of the cylindrical or ring-shaped article, the cylindrical length (ring thickness) / opening inner diameter is 1 or more.

  As described above, according to the present invention, at least a part is a diamond-like carbon film-coated article coated with a diamond-like carbon film formed through an intermediate layer made of an amorphous silicon carbide film, A diamond-like carbon film-coated article having excellent adhesion of the carbon film to the article body can be provided.

It is a figure which shows roughly the example of a film | membrane formation apparatus for forming an intermediate | middle layer and a diamond-like carbon film. It is a top view of the example of a film formation object article. It is a figure which shows typically the cross section of a part of carbon film covering article example. It is a figure which shows the laser Raman spectroscopy analysis result of an Example intermediate | middle layer. It is a figure which shows the laser Raman spectroscopy analysis result of a comparative example intermediate | middle layer.

FIG. 1 shows a film forming apparatus 10 for forming an intermediate layer and a diamond-like carbon film.
The diamond-like carbon film may be hereinafter referred to as a DLC film.
A film forming apparatus 10 in FIG. 1 applies asymmetric pulse power to a vacuum chamber 1, a columnar article holder 2 standing from the outside of the chamber 1 into the chamber 1, an article holder 2, and an article W to be formed supported by the article holder 2. A pulse power supply device 3 for supplying, an exhaust device 4 for exhausting from the chamber 1 and setting the interior of the chamber 1 at a predetermined pressure, argon (Ar) gas, hydrogen gas (H ₂ ), tetramethyl into the chamber 1 A gas supply device 5 capable of supplying one or more of silane (TMS: Si (CH ₃ ) ₄ ) gas and acetylene gas (C ₂ H ₂ ) at a predetermined timing is included.

The vacuum chamber 1 is set to the ground potential. The article holder 2 is electrically conductive stainless steel, a conductive holder made of aluminum alloy or the like, rises into the chamber 1 through the electrically insulating member 11 provided in the bottom wall of the chamber 1 airtight. The film formation target article W is supported by the holder 2 using a conductive article holding member 21 corresponding to the article.

  An example in which a DLC film is formed with good adhesion using a silicon carbide film as an intermediate layer on a film forming object using the film forming apparatus 10 and a DLC with a silicon carbide film as an intermediate layer according to the conditions described in JP-A-2006-199980 A comparative example for forming a film will be described.

  The film forming target article W is the same in both the example and the comparative example, and is a disk having a circular hole h in the center as shown in FIG. As shown in FIG. 1, ten disks W are stacked with a spacer ring r between adjacent disks, and a circular hole h and a central hole of the spacer ring r are formed in the columnar article holder 2 of the film forming apparatus 10. It is mounted on the article holding member 21 that is fitted in the part and attached to the holder 2 in advance.

The disk W is made of JIS SKH51, and has an outer diameter D = 100 mm, a central hole diameter d = 20 mm, and a thickness t = 2 mm.
The spacer ring r is made of SUS304, and has an outer diameter of 30 mm, a central hole diameter of 20 mm, and a thickness of 10 mm.
As shown in FIG. 1, in each adjacent disk W, a concave portion in the form of a gap g having a depth α = 35 mm and a gap dimension β = 10 mm is formed between the mutually facing disk surfaces.

  The columnar article holder 2 of the film forming apparatus 10 is a holder having a circular cross section, and its outer diameter is slightly smaller than the center hole diameter of the disk and the center hole diameter of the spacer ring. In the state of being mounted on the article holding member 21, the article holder 2 is placed in an electrically conductive state.

(1) Example 1
An intermediate layer and a DLC film are also formed on the exposed surface of each article W, and thus on the disk surface forming the gap g.

(1-1) Formation of an intermediate layer made of a silicon carbide film <Interlayer formation conditions>
Discharge gas Argon gas 100sccm
Hydrogen gas 0sccm
Intermediate layer material gas TMS 20sccm
Chamber internal pressure 100Pa
Asymmetric pulse power supplied from power supply 3 100W

Under these conditions, a 0.2 μm silicon carbide film was formed on the exposed surface of the article W as an intermediate layer.
The intermediate silicon carbide film was analyzed under the following analysis conditions using a Raman spectroscopic analyzer (U-1000) manufactured by HORIBA, Ltd. As shown in FIG. 4, the Raman shift was 1400 cm ^{−1 to} 1600 cm ⁻¹ . Spectral intensity peaks were observed in the range, and it was confirmed that the film was a strong amorphous silicon carbide film richer in Si—C bonds and C—C bonds than in C—H bonds.

Analysis conditions by Raman spectroscopy analyzer Analysis mode: Macro mode measurement Laser wavelength: 532nm
Laser power: Set to 100 mW immediately after the bandpass filter Laser beam diameter: 100 μm
Spectrometer: Focal length 1m Double monochromator,
1800 gr / mm diffraction grating Spectroscopic slit width: 500 μm
Detector: photomultiplier measuring range: 800cm ^-1 ~2000cm ^-1 measurement interval: 1 cm ^-1
Data acquisition time: 1 sec

When the indentation hardness of the intermediate silicon carbide film was measured with an indentation hardness meter (Nanoindenter ENT-1100a) manufactured by Elionix Co., Ltd. with a measurement load of 100 mg, it was 17.0 GPa. The Young's modulus was 147.5 GPa.
This intermediate silicon carbide film contains hydrogen, carbon, and silicon (a-SiC: H), but the atomic ratio (atom ratio) of carbon (C) and silicon (Si) is determined by EDS (energy dispersion). C: Si = 67: 33 as measured by an X-ray spectrometer.

(1-2) DLC film formation on intermediate layer <DLC film formation conditions>
Working gas Argon gas 50sccm
TMS 5sccm
Acetylene gas 50sccm
Chamber internal pressure 5Pa
Asymmetric pulse power supplied from power supply 3 150W

Under these conditions, a DLC film having a thickness of 3.0 μm was formed on the intermediate layer (see FIG. 3).
When the peel load of the DLC film was measured by a ball-on-disk test already known per se, it was 3500 [N], and it was confirmed that the adhesion of the DLC film was good.
The ball-on-disk test is performed by placing JIS SUJ2 balls (3/8 inch in diameter) on the lower surface of a JIS SKH51 disk at an equal central angular interval of 120 degrees and the distance from the disk center to the ball center (ball rotation Radius) 3 pieces fixed at 18mm, in the engine oil SM5W30 at room temperature, while the balls are pressed evenly against the DLC film through the disk, the disk is rotated at 30rpm, and the pressing load is gradually increased by the load cell This is a test for grasping when the frictional force suddenly increases due to peeling of the DLC film or the like, and setting the pressing load at that time as the peeling load.

(2) Example 2
As in the first embodiment, the intermediate layer and the DLC film are formed on the exposed surface of each article W, and thus on the disk surface forming the gap g.

(2-1) Formation of intermediate layer made of silicon carbide film <Intermediate layer formation conditions>
Discharge gas Argon gas 100sccm
Hydrogen gas 10sccm
Intermediate layer material gas Monomethylsilane gas 20sccm
Chamber internal pressure 100Pa
Asymmetric pulse power supplied from power supply 3 100W

Under these conditions, a 0.2 μm silicon carbide film was formed on the exposed surface of the article W as an intermediate layer.
When this intermediate silicon carbide film was analyzed under the same analysis conditions using the same Raman spectroscopic analyzer (U-1000) as in Example 1, a peak of spectral intensity was found in the range of Raman shifts from 1400 cm ^{−1 to} 1600 cm ^−1. As a result, it was confirmed that the film was a strong amorphous silicon carbide film richer in Si—C bonds and C—C bonds than in C—H bonds.

Further, when the indentation hardness of the intermediate silicon carbide film was measured with a measurement load of 100 mg using the same hardness meter (ENT-1100a) as in Example 1, it was 15.8 GPa. The Young's modulus was 138.0 GPa.
With respect to this intermediate silicon carbide film, the atomic ratio (atom ratio) of carbon (C) and silicon (Si) was measured by EDS, and C: Si = 65: 35.

(2-2) DLC film formation on intermediate layer <DLC film formation conditions>
Working gas Argon gas 50sccm
TMS 5sccm
Acetylene gas 50sccm
Chamber internal pressure 5Pa
Asymmetric pulse power supplied from power supply 3 150W

Under these conditions, a DLC film having a thickness of 3.0 μm was formed on the intermediate layer.
When the peel load of the DLC film was measured by the same ball-on-disk test as in Example 1, it was 3000 [N], and it was confirmed that the adhesion of the DLC film was good.

(3) Comparative Example An intermediate layer and a DLC film are formed on the exposed surface of each article W, and thus also on the disk surface forming the gap g.

(3-1) Formation of intermediate layer made of silicon carbide film <Intermediate layer formation conditions>
Discharge gas Argon gas 50sccm
Hydrogen gas 100sccm
Intermediate layer material gas TMS 30sccm
Chamber internal pressure 8Pa
Asymmetric pulse power supplied from power supply 3 100W

Under these conditions, a silicon carbide film having a thickness of 0.2 μm was formed on the exposed surface of the article W as an intermediate layer.
The intermediate silicon carbide film was analyzed under the same analysis conditions using the same Raman spectroscopic analyzer (U-1000) as in Example 1. As shown in FIG. 5, the Raman shift was 1200 cm ^{−1 to} 1800 cm ⁻¹ . No spectral intensity peak was observed in the range. That is, it was found that the intermediate layer in the comparative example is rich in C—H bonds and is not as strong as the intermediate layer in the example.

Further, when the indentation hardness of the intermediate silicon carbide film was measured with a measurement load of 100 mg using the same hardness meter as in the example, it was 13.5 GPa. The Young's modulus was 116.8 GPa.
Thus, the intermediate layer silicon carbide film of the comparative example was inferior in hardness and the like to the intermediate layer silicon carbide film of the example.

(3-2) DLC film formation on the intermediate layer A DLC film having a thickness of 3.0 μm was formed on the intermediate layer under the same DLC film formation conditions as in Example 1. When the peel load of the DLC film was measured by the same ball-on-disk test as in Example 1, it was 1000 [N], and the adhesion of the DLC film was inferior to the Example.

  Conventionally, when argon gas is used as the discharge gas, it is known that the discharge is more stable when diluted with hydrogen gas as in the comparative example, and when the gas pressure in the chamber is increased, the discharge is performed. It has been known that discharge is more likely to occur when the pressure is less than about 8 Pa, for example, as in the comparative example. In forming a silicon carbide film as an intermediate layer using an intermediate layer material gas such as TMS gas, the concept of forming the intermediate layer by introducing the intermediate layer material gas into a strong and stable discharge state in accordance with such technical common sense Was dominant.

  However, as can be seen from the comparative example, the intermediate silicon carbide film formed in accordance with this concept has a structure close to a polymer because no peak in the Raman waveform is observed as in the above examples, and Since the film has a low hardness, the surface DLC film and the article main body could not be firmly adhered.

The present inventor repeated thoughts and errors, and from the conventional viewpoint, hydrogen gas is not used as the discharge gas, or even if it is used, the amount thereof is significantly reduced compared to the conventional one. reduced, discharge becomes dark by dare adopt a condition that a strong intermediate layer exhibiting a peak of spectral intensity in the range of the Raman shift 1400cm ^-1 ~1600cm ^-1 in a laser Raman spectroscopic analysis using a laser with a wavelength of 532nm The inventors have found that a silicon carbide film can be obtained and have completed the present invention.

Here, H ₂ and SiH _x (CH ₃ ) in the introduced gas component at the time of forming the intermediate layer in relation to “does not use hydrogen gas for the discharge gas, or even if it is used, the amount is significantly reduced compared to the conventional gas”. _{An example in which} the flow rate ratio [H ₂ flow rate / SiH _x (CH ₃ ) _y flow rate] of _y is 2 or less can be given.
The flow rate ratio is 0 in Example 1, 0.5 in Example 2, and 3.3 in the comparative example.

  INDUSTRIAL APPLICABILITY The present invention can be used to provide a diamond-like carbon film-coated article that has excellent adhesion of the diamond-like carbon film to the article body.

DESCRIPTION OF SYMBOLS 10 Film forming apparatus 1 Vacuum chamber 2 Support | pillar-shaped article holder 3 Pulse power supply apparatus 4 Exhaust apparatus 5 Gas supply apparatus W

Claims (2)

A diamond-like carbon film-coated article, at least a part of which is coated with a diamond-like carbon film formed through an intermediate layer made of an amorphous silicon carbide film, wherein the amorphous silicon carbide film and the diamond-like carbon film are discharged a film formed by plasma CVD using an asymmetric pulsed power as the power, the amorphous silicon carbide film, the spectral intensity in the range of the Raman shift 1400cm ^-1 ~1600cm ^-1 in a laser Raman spectroscopic analysis using a laser with a wavelength of 532nm a peak, indentation hardness than 15 GPa 17 GPa or less, diamond-like carbon film-coated article, wherein the Young's modulus of 147.5GPa less film than 130 GPa.   2. The diamond-like carbon film coating according to claim 1, wherein at least a part of the article portion covered with the diamond-like carbon film formed through the intermediate layer made of the amorphous silicon carbide film is a recessed portion having an aspect ratio of 1 or more. Goods.

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