JP5585954B2 - Composite hard film member and method for producing the same - Google Patents

Description

  The present invention relates to a composite hard coating member in which a diamond-like carbon (DLC) film is formed on a film-forming member made of a non-ferrous metal material via an intermediate layer, and a method for manufacturing the same.

  As a method of painting on the surface of parts made of non-ferrous metal materials such as aluminum wheels for automobiles, magnesium alloy casings for mobile phones, etc., the parts are usually sprayed and dried by spraying paints dissolved in organic solvents. A method of forming a coating film on the surface is taken. Since such a coating film is comparatively soft, there is a problem that the part is easily damaged when the part is used, and the part is easily corroded by the damage. Furthermore, since organic solvents are used in large quantities, they have many problems such as environmental problems. For this reason, there is a need for a method of forming a film on the part surface in place of the above-described coating method.

  On the other hand, a technique for forming a DLC film by a PVD method (physical vapor deposition method) such as an ionization vapor deposition method or an arc discharge method is known. This technique has a problem that the cost is high due to the high cost of the apparatus and poor productivity, and can only be used for high value-added products.

  On the other hand, the present inventors have developed a new plasma CVD method (chemical vapor deposition method) capable of forming a DLC film at high speed and low cost, and this method has a large area and is a three-dimensional object. Patent Document 1 discloses that a DLC film can be formed on a low-cost system and at a low running cost.

JP 2008-038217 A

  It is conceivable to use a DLC film produced by physical vapor deposition or chemical vapor deposition as an effective means for solving the problems of the coating method as described above. The DLC film has high hardness, low friction, low wear, chemical stability, and surface smoothness. The DLC film is translucent when the film thickness is small, but is black with an interference color when the film thickness is large. For this reason, the nonferrous metal material member which formed the DLC film can have the decoration property and design which were excellent compared with the case where other hard membrane | film | coats were formed.

  However, when a DLC film is formed on the surface of a nonferrous metal material member such as aluminum or magnesium, many microcracks are generated in the DLC film due to the compressive residual stress of the DLC film. There is a problem that the member is significantly corroded.

  One aspect of the present invention is to provide a composite hard coating member capable of suppressing corrosion of a non-ferrous metal material member having a DLC film formed thereon and a method for manufacturing the same.

  Since the DLC film is produced by a film-forming method that does not use an organic solvent such as a sputtering method or a plasma CVD method and has a low environmental load, the use of the DLC film for a member made of a non-ferrous metal material will be dramatically improved if the above problems can be solved. It is thought that it will be accelerated.

  When only a DLC film is formed on a member made of a non-ferrous metal material, a carbon-containing silicon film is formed as an intermediate layer on a member made of a non-ferrous metal material, and when a DLC film is formed on the carbon-containing silicon film, The above problem cannot be solved.

  Therefore, the present inventor pays attention to a silicon oxide film that is transparent, high in hardness, excellent in chemical stability and gas barrier property, and if the silicon oxide film and the carbon-containing silicon film are combined into a DLC film as an intermediate layer. It has been found that a hard film having excellent corrosion resistance can be produced.

One embodiment of the present invention is a film-forming member made of a non-ferrous metal material;
A silicon oxide film formed on the surface of the film-forming member;
A carbon-containing silicon film formed on the silicon oxide film;
A diamond-like carbon film formed on the carbon-containing silicon film;
It is a composite hard-film member characterized by comprising.

  According to one embodiment of the present invention, a silicon oxide film and a carbon-containing silicon film are formed between the surface of the film forming member and the diamond-like carbon film, thereby corroding the film forming member made of a non-ferrous metal material. Can be effectively suppressed.

  Further, in the composite hard film member according to one aspect of the present invention, the non-ferrous metal material includes aluminum, an aluminum alloy mainly containing aluminum, magnesium, a magnesium alloy mainly containing magnesium, titanium, and titanium as main ingredients. Preferably, the material is selected from the group consisting of a titanium alloy, zinc, and a zinc alloy containing zinc as a main component. Note that an aluminum alloy containing aluminum as a main component is an alloy containing 65% by weight or more of aluminum, and a magnesium alloy containing magnesium as a main component is an alloy containing 80% by weight or more of magnesium. The titanium alloy containing the main component is an alloy containing 70% by weight or more of titanium, and the zinc alloy containing zinc as the main component is an alloy containing 90% by weight or more of zinc.

  Further, in the composite hard film member according to an aspect of the present invention, the film-forming member includes an aluminum wheel for an automobile, an aluminum iron, an aluminum alloy door knob for an automobile, a magnesium alloy casing of a laptop computer, and a camera. Preferably, the member is one member selected from the group consisting of a magnesium alloy casing and a magnesium alloy casing of a mobile phone. Thereby, while being able to give the outstanding decorating property and designability, corrosion of a film-forming member can be suppressed effectively.

In the composite hard coating member according to one embodiment of the present invention, the silicon oxide film preferably has a thickness of 0.01 to 5 μm. The reason for setting the range of 0.01 to 5 μm is that if the film thickness of the silicon oxide film is less than 0.01 μm, the film forming member is easily corroded, and if the film thickness of the silicon oxide film is thicker than 5 μm, the composite hard This is because the film member is easily peeled off.
In the composite hard coating member according to one embodiment of the present invention, the carbon-containing silicon film preferably has a thickness of 0.01 to 5 μm. The reason why the range of 0.01 to 5 μm is used is that the carbon-containing silicon film is too thick or too thin (ie, less than 0.01 μm or thicker than 5 μm), or the composite hard coating member is in close contact. This is because the strength decreases.

In one embodiment of the present invention, a silicon oxide film is formed on a surface of a deposition target member made of a non-ferrous metal material by a plasma CVD method using a first silicon compound gas and an oxygen gas,
A carbon-containing silicon film using a second silicon compound gas is formed on the silicon oxide film by a plasma CVD method,
A method for producing a composite hard coating member, comprising forming a diamond-like carbon film on the carbon-containing silicon film by a plasma CVD method.

In the method for manufacturing a composite hard film member according to one aspect of the present invention, each of the first and second silicon compound gases includes hexamethyldisilazane (C ₆ H ₁₉ NSi ₂ ), hexamethyldisiloxane (C ₆ H ₁₈ OSi ₂ ) or tetramethylsilane (C ₄ H ₁₂ Si).

  ADVANTAGE OF THE INVENTION According to this invention, the composite hard-film member which can suppress the corrosion of the nonferrous metal material member which formed the DLC film, and its manufacturing method can be provided.

It is a block diagram which shows schematically the plasma CVD apparatus by Embodiment 1 of this invention. (A) is sectional drawing which shows the composite hard film of Embodiment 1, (B), (C) is sectional drawing which shows the composite hard film of a comparative example. (A)-(C) are figures which show a combined cycle test result. (A) is the photograph which shows the aluminum wheel for motor vehicles before forming a composite hard film, (B) is a photograph which shows the state which formed the composite hard film on the surface of the aluminum wheel. It is a photograph which shows the state which mounted | wore the tire on the aluminum wheel for motor vehicles shown in FIG.4 (B). It is a photograph which shows the state which formed the composite hard film into the aluminum alloy door knob for motor vehicles by the method similar to Embodiment 1. FIG.

  Hereinafter, embodiments and examples of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments and examples below.

  In order to coat a large amount of large product with a hard film, it is necessary to mass-produce using a large reaction tank, and the chemical structure is simpler than the physical vapor deposition method (PVD method), which makes the structure of the device complicated. Vapor deposition (CVD) is advantageous. The advantage of the CVD method is that plasma can be formed with a simple structure such as a vacuum exhaust system, plasma power supply, and source gas supply device, and it is possible to form a film with good circulation even with large and complex shapes, and maintenance is also possible. Compared with the PVD method, it is much simpler.

  Among the CVD methods, the plasma CVD method is very advantageous for processing a film-forming member made of a non-ferrous metal material having a low melting point such as aluminum or magnesium because there is no need to increase the processing temperature. . Therefore, it is considered that the plasma CVD method is most suitable for coating a large amount of non-ferrous metal material with a DLC film.

(Embodiment 1)
FIG. 1 is a block diagram schematically showing a plasma CVD apparatus according to Embodiment 1 of the present invention. This plasma CVD apparatus is an apparatus for forming a composite hard film using a high frequency power source of 100 kHz.

  The plasma CVD apparatus has a vacuum chamber (chamber) 1, and a work holder (not shown) for holding a work 2 is disposed in the vacuum chamber 1. The work 2 is a film-forming member made of a non-ferrous metal material. For example, an aluminum wheel, an aluminum iron, an aluminum alloy door knob for automobiles, a magnesium alloy casing of a laptop computer, a magnesium alloy casing of a camera, and a mobile phone. It is one member selected from the group consisting of magnesium alloy casings for telephones. Non-ferrous metal materials are made of aluminum, aluminum alloy mainly composed of aluminum, magnesium, magnesium alloy composed mainly of magnesium, titanium, titanium alloy composed mainly of titanium, zinc and zinc alloy composed mainly of zinc. One material selected from the group, an aluminum alloy is an alloy containing 65% by weight or more of aluminum, a magnesium alloy is an alloy containing 80% by weight or more of magnesium, and a titanium alloy is 70% by weight. An alloy containing titanium in an amount of not less than wt%, and a zinc alloy is an alloy containing not less than 90 wt% of zinc.

  A substrate bias power supply system 4 is electrically connected to the work 2 via a work holder, and this substrate bias power supply system 4 has a substrate matching unit and a 100 kHz high frequency power supply (RF power supply). The work holder also acts as an RF electrode. The substrate bias power supply system 4 applies high-frequency power to the workpiece 2 via a workpiece holder. That is, in this plasma CVD apparatus, the substrate bias power supply system 4 supplies a high-frequency current of 100 kHz to the work holder to generate plasma of the source gas in the vicinity of the work 2.

  In the present embodiment, a frequency of 100 kHz is used. However, other frequencies may be used as long as they are within a range of 50 to 500 kHz, and more preferably, a frequency of 300 kHz or less is used. Is to use a frequency of 250 kHz or less. When a high frequency power source of 300 kHz or less is used, there is an advantage that matching can be performed with a low-cost matching device using a matching transformer or the like. Further, when the frequency of the high-frequency power source is lower than 50 kHz, a problem that induction heating occurs in the work 2 occurs. Further, when the frequency of the high-frequency power source exceeds 500 kHz, the bias applied to the work 2 is lowered, and there is a problem that a hard film is difficult to be formed.

A gas system 5 is connected to the vacuum chamber 1, and the source gas is supplied into the vacuum chamber 1 from the introduction port by the gas system 5. The source gas is argon gas, oxygen gas, silicon compound gas, and toluene. The silicon compound gas is, for example, hexamethyldisilazane (C ₆ H ₁₉ NSi ₂ ) or hexamethyldisiloxane (C ₆ H ₁₈ OSi ₂ ) (hereinafter collectively referred to as HMDS) or tetramethylsilane (C ₄ H ₁₂ Si). The gas system 5 has a gas introduction path for introducing a raw material gas into the vacuum chamber 1, and the gas introduction path has a gas pipe. The gas pipe is provided with a flow meter for measuring the gas flow rate and a gas flow controller for controlling the gas flow rate. Appropriate amounts of argon gas, oxygen gas, HMDS, and toluene are supplied into the vacuum chamber 1 from the gas inlet by the flow meter. The vacuum chamber 1 is connected to an exhaust system 6 that evacuates the inside thereof. The exhaust system 6 has a vacuum pump. This vacuum pump is composed of a mechanical booster pump and an oil rotary pump that are inexpensive and easy to maintain, without using a turbo molecular pump or a diffusion pump that is expensive and complicated to maintain. Yes. With such a simple pump, only a vacuum degree of about 0.5 to 1 Pa can be obtained, but with the method according to the present embodiment, a high-quality film can be produced even with such a low vacuum.

  Next, a method for forming a composite hard film on the workpiece surface as shown in FIG. 2A using the plasma CVD apparatus of FIG. 1 will be described.

  First, for example, an aluminum plate (size: 60 mm × 20 mm × 1 mm) 2 is prepared as a workpiece (material to be coated), and this aluminum plate 2 is subjected to ultrasonic cleaning for 30 minutes in acetone, and then in the vacuum chamber 1. Attach to the work holder.

  Next, the inside of the vacuum chamber 1 is exhausted to 0.7 Pa or less by the exhaust system 6, and then argon gas is introduced into the vacuum chamber 1. Next, an argon plasma is formed in the vicinity of the aluminum plate 2 by supplying a high frequency current of 100 kHz to the work holder using a high frequency power source with an output of 250 W, and ion etching is performed for 20 minutes to clean the surface of the aluminum plate 2. . Thereby, the surface of the aluminum plate 2 is cleaned.

Thereafter, the pressure in the vacuum chamber 1 is maintained at 0.6 Pa or less by the exhaust system 6, and hexamethyldisilazane as the source gas is flowed into the vacuum chamber 1 at a flow rate of 5 cc / min and oxygen gas at a flow rate of 50 cc / min. Introduce. Next, a high frequency current of 100 kHz is supplied to the work holder using a high frequency power source with an output of 300 W, whereby a silicon oxide film (SiO ₂ film) 7 having a thickness of 0.7 μm is formed on the surface of the aluminum plate 2. Is done.

  Next, the oxygen gas of the raw material gas is stopped, and hexamethyldisilazane is introduced into the vacuum chamber 1 at a flow rate of 8 cc / min. Next, a carbon-containing silicon film 8 having a thickness of 1.3 μm is formed on the silicon oxide film 7 by supplying a high-frequency current of 100 kHz to the work holder using a high-frequency power source with an output of 200 W. The carbon-containing silicon film 8 preferably contains 10 to 50 at% carbon, 20 to 50 at% silicon, and 10 to 40 at% hydrogen, and may further contain nitrogen and oxygen. Note that the composition of the carbon-containing silicon film 8 is considered to vary depending on the film forming conditions and the like.

  Next, the source gas hexamethyldisilazane is stopped, and toluene is introduced into the vacuum chamber 1 at a flow rate of 10 cc / min. Next, a DLC film 9 having a thickness of 2.4 μm is formed on the carbon-containing silicon film 8 by supplying a high frequency current of 100 kHz to the work holder using a high frequency power source with an output of 300 W.

  Next, as a comparative example, the DLC composite film shown in FIGS. 2B and 2C is produced using the plasma CVD apparatus of FIG. 1, and the DLC composite film corrosion test shown in FIGS. This is explained.

  First, a method for forming the DLC composite film shown in FIG. 2B using the plasma CVD apparatus in FIG. 1 will be described.

  The aluminum plate 2 is ultrasonically cleaned by the same method as the DLC composite film shown in FIG. 2A, mounted on a work holder in the vacuum chamber 1, and ion-etched for 20 minutes. Thereafter, hexamethyldisilazane is introduced into the vacuum chamber 1 in the same manner as the DLC composite film shown in FIG. Next, a carbon-containing silicon film (Si film) 8 is formed on the surface of the aluminum plate 2 by supplying a high-frequency current of 100 kHz to the work holder using a high-frequency power source. This carbon-containing silicon film 8 is the same as the carbon-containing silicon film 8 shown in FIG.

  Next, the source gas hexamethyldisilazane is stopped and toluene is introduced into the vacuum chamber 1 by the same method as the DLC composite film shown in FIG. Next, a DLC film 9 is formed on the carbon-containing silicon film 8 by supplying a high frequency current of 100 kHz to the work holder using a high frequency power source. This DLC film 9 is the same as the DLC film 9 shown in FIG.

  Next, a method for forming the DLC composite film shown in FIG. 2C using the plasma CVD apparatus in FIG. 1 will be described.

The aluminum plate 2 is ultrasonically cleaned by the same method as the DLC composite film shown in FIG. 2A, mounted on a work holder in the vacuum chamber 1, and ion-etched for 20 minutes. Thereafter, hexamethyldisilazane and oxygen gas are introduced into the vacuum chamber 1 as source gases by the same method as the DLC composite film shown in FIG. Next, a silicon oxide film (SiO ₂ film) 7 is formed on the surface of the aluminum plate 2 by supplying a high frequency current of 100 kHz to the work holder using a high frequency power source. This silicon oxide film 7 is similar to the silicon oxide film 7 shown in FIG.

  Next, the raw material gases hexamethyldisilazane and oxygen gas are stopped and toluene is introduced into the vacuum chamber 1 by the same method as the DLC composite film shown in FIG. Next, a DLC film 9 is formed on the silicon oxide film 7 by supplying a high frequency current of 100 kHz to the work holder using a high frequency power source. This DLC film 9 is the same as the DLC film 9 shown in FIG.

Next, the corrosion test of the DLC composite film shown in FIGS. 2 (A) to (C) was performed by the following method.
2A to 2C were subjected to a combined cycle test in which a cycle of salt spray (2 hours) → drying (4 hours) → wetting (2 hours) was repeated for 30 days. When the corrosion resistance of the DLC composite film was evaluated by this combined cycle test, the results shown in FIG. 3 were obtained.

  FIG. 3B shows a surface state after a combined cycle test is performed on a test piece in which a carbon-containing silicon film 8 is formed as an intermediate layer between the aluminum plate 2 and the DLC film 9. From this figure, it can be seen that the entire surface is corroded in the 30-day combined cycle test.

  FIG. 3C shows the surface state after a combined cycle test is performed on a test piece in which a silicon oxide film 7 is formed as an intermediate layer between the aluminum plate 2 and the DLC film 9. From this figure, it can be seen that the silicon oxide film 7 is partially peeled off in the 30-day combined cycle test.

  On the other hand, FIG. 3A shows the surface after performing a combined cycle test on a test piece in which a silicon oxide film 7 and a carbon-containing silicon film 8 are formed as intermediate layers between the aluminum plate 2 and the DLC film 9. Indicates the state. From this figure, it can be seen that no corrosion or delamination is observed even after the 30-day combined cycle test.

  From the above results, it has been clarified that when a DLC film is formed on an aluminum plate with the silicon oxide film 7 and the carbon-containing silicon film 8 as an intermediate layer, the corrosion resistance is dramatically improved.

  It is also known that a sufficient corrosion resistance effect cannot be obtained unless the order of forming the intermediate layer is the silicon oxide film 7 and the carbon-containing silicon film 8 from the aluminum plate 2 side. That is, when the order of forming the intermediate layer is the carbon-containing silicon film 8 and the silicon oxide film 7 from the aluminum plate 2 side, the corrosion resistance effect as shown in FIG. 3A cannot be obtained. This is because the adhesion between the DLC film and the silicon oxide film is poor, and peeling is likely to occur when salt water that has entered through the pinholes in the DLC film reaches this interface. If an intermediate layer is formed from an aluminum plate, such as a silicon oxide film and a carbon-containing silicon film, the adhesion between the interfaces is all good, so that the intrusion of salt water can be prevented.

(Embodiment 2)
FIG. 4A is a photograph showing an automotive aluminum wheel before forming a composite hard coating. FIG. 4B is a photograph showing a state in which a composite hard film is formed on the surface of the automobile aluminum wheel shown in FIG. 4A using the plasma CVD apparatus of FIG. 1 in the same manner as in the first embodiment. It is. This composite hard film is a silicon oxide film, a carbon-containing silicon film, or a DLC film formed on an aluminum wheel.
FIG. 5 is a photograph showing a state where tires are mounted on the automobile aluminum wheel shown in FIG. 4 (B).

  The aluminum wheel shown in FIGS. 4B and 5 has excellent corrosion resistance as described in the first embodiment, and is excellent in wear resistance, decoration, and design. In order to impart decorativeness and design properties, it is preferable that the thickness of the DLC film is 1.0 μm or more. Thereby, it can be set as a color as shown in FIG.4 (B) and FIG.

  The plasma CVD apparatus shown in FIG. 1 can easily form a film on a large product such as an aluminum wheel because a small apparatus can have a wide effective film formation zone.

(Embodiment 3)
It is desirable that the iron for business use is light in order to reduce heavy labor. If an iron is made of aluminum to reduce the weight, the frictional resistance increases and the wear on the bottom surface becomes significant. Therefore, if a composite hard coating is formed on the bottom surface of the aluminum iron by the same method as in the first embodiment, it can be expected to dramatically reduce friction and wear.

(Embodiment 4)
FIG. 6 is a photograph showing a state in which a composite hard coating is formed on an aluminum alloy door knob for an automobile by the same method as in the first embodiment. Since the doorknob is easily damaged, if a DLC film is formed, the doorknob is less likely to be damaged, and excellent decorativeness and design can be imparted.

DESCRIPTION OF SYMBOLS 1 ... Vacuum chamber 2 ... Work 4 ... Substrate bias power supply system 5 ... Gas system 6 ... Exhaust system 7 ... Silicon oxide film 8 ... Carbon containing silicon film 9 ... DLC film

Claims (4)

A film-forming member made of a non-ferrous metal material;
A silicon oxide film formed on the surface of the film-forming member;
A carbon-containing silicon film formed on the silicon oxide film;
A diamond-like carbon film formed on the carbon-containing silicon film;
Comprising
The non-ferrous metal material, alloy containing 6 5 wt% or more of aluminum, one selected from the group consisting of an alloy containing alloy and 7 0% or more by weight of titanium containing magnesium 8 0 wt% or more Ri material der,
The film-forming member is an automobile wheel, a composite hard coating member according to any der wherein Rukoto doorknob of commercial iron and automotive. In claim 1,
A composite hard coating member, wherein the silicon oxide film has a thickness of 0.01 to 5 μm, and the carbon-containing silicon film has a thickness of 0.01 to 5 μm. A silicon oxide film is formed on the surface of a deposition target member made of a non-ferrous metal material by a plasma CVD method using a first silicon compound gas and an oxygen gas,
A carbon-containing silicon film using a second silicon compound gas is formed on the silicon oxide film by a plasma CVD method,
A method for producing a composite hard coating member in which a diamond-like carbon film is formed on the carbon-containing silicon film by a plasma CVD method,
The non-ferrous metal material is selected from 6 5 wt% or more of aluminum alloy containing, 8 0 alloy or Ranaru group containing alloys and 7 0% or more by weight of titanium containing by weight% or more magnesium one material der is,
The film-forming member, method of producing a composite hard coating member, wherein the vehicle wheel, either der Rukoto the doorknob commercial iron and automotive. In claim 3,
Each of said 1st and 2nd silicon compound gas is hexamethyldisilazane, hexamethyldisiloxane, or tetramethylsilane, The manufacturing method of the composite hard film | membrane member characterized by the above-mentioned.