JP5131078B2 - Hard amorphous carbon-coated member and method for producing the same - Google Patents

Description

  The present invention relates to a covering member in which a surface of a base material is coated with a hard amorphous carbon film via an intermediate layer.

  Hard amorphous carbon (diamond-like carbon: DLC) with an amorphous structure is excellent in mechanical properties such as wear resistance and solid lubricity, corrosion resistance, insulation, visible / infrared light transmittance, oxygen Combined with barrier properties. Therefore, the DLC film is often coated on the surface of various base materials and used as a protective film. However, it is known that a hard DLC film has a very high internal stress in a state where it is coated on a substrate, and is easily peeled off from the surface of the substrate. If the adhesion between the substrate and the DLC film is low, there is a problem that it is difficult to form a thick DLC film, or the above-mentioned characteristics of the DLC are not exhibited well.

  As a method for improving the adhesion between the base material and the DLC film, a method such as forming appropriate irregularities on the surface of the base material to increase the adhesion between the two by the anchor effect, reducing the internal stress of the DLC film, etc. There is. For example, in Patent Document 1, in a DLC film formed on the surface of a substrate via an intermediate layer, a mixed component layer composed of components of the intermediate layer and carbon is provided between the intermediate layer and the DLC film, and the intermediate layer By improving the adhesion between the substrate and the DLC film, the adhesion between the substrate and the DLC film is improved. Patent Document 2 discloses a DLC film that is formed on the surface of a base material via an intermediate layer and has a lower silicon content in a portion farther from the base material.

Patent Document 3 and Patent Document 4 describe that when the oxygen concentration on the surface on which the DLC film is formed is high, the adhesion between the surface and the DLC film decreases. Therefore, in these documents, the adhesion to the surface of the DLC film is improved by reducing the oxygen concentration on the surface on which the DLC film is formed.
JP 2000-256850 A JP 2006-161075 A JP 2000-8155 A JP 2006-250348 A

  The anchor effect may require high temperature treatment to form irregularities on the surface of the substrate (see Japanese Patent No. 3453033), and is not suitable for a substrate with low heat resistance. In addition, when the surface needs a certain level of smoothness, such as a sliding member, the unevenness formed on the base material may affect the surface of the DLC film. Sometimes.

  In the case where another layer is formed between the intermediate layer and the DLC film or the components of the DLC film are inclined as described in Patent Document 1 and Patent Document 2, the film forming apparatus and the film forming conditions are used. Becomes complicated and the film forming procedure becomes complicated. When such a film forming process is performed in large quantities, the film thickness and the film composition tend to vary, so that sufficient adhesion may not be obtained.

  As described above, as described in Patent Document 3 and Patent Document 4, the DLC film is considered to be difficult to adhere to a surface on which oxygen exists like an oxide. However, the present inventors have found that in a covering member having a DLC film coated on a base material via an intermediate layer, depending on the composition of the intermediate layer and the DLC film, the intermediate layer may contain oxygen due to the inclusion of oxygen. It was newly found that the film was firmly adhered.

  That is, an object of the present invention is to provide a hard amorphous carbon-coated member having a novel structure excellent in adhesion between a substrate and a hard amorphous carbon film, and a method for producing the same.

The hard amorphous carbon-coated member of the present invention includes a base material, an intermediate layer formed on the surface of the base material and containing molybdenum and / or titanium, and a hard amorphous carbon film formed on the surface of the intermediate layer. And comprising
At least at the interface between the intermediate layer and the hard amorphous carbon film, the intermediate layer contains oxygen and carbon, and the hard amorphous carbon film contains silicon.

The hard amorphous carbon-coated member of the present invention includes a base material, an intermediate layer containing aluminum formed on the surface of the base material, a hard amorphous carbon film formed on the surface of the intermediate layer, With
At least at the interface between the intermediate layer and the hard amorphous carbon film, the intermediate layer contains oxygen, and the hard amorphous carbon film contains silicon.

  In the hard amorphous carbon-coated member of the present invention, the intermediate layer contains oxygen (O) and the hard amorphous carbon film contains silicon (Si) at the interface between the intermediate layer and the hard amorphous carbon film. Therefore, a strong bond between Si and O is obtained at the interface between the intermediate layer and the hard amorphous carbon film. As a result, the hard amorphous carbon film is strongly adhered to the substrate via the intermediate layer. Further, when carbon (C) is contained in the intermediate layer at the interface, the main component of the intermediate layer and the main component of the hard amorphous carbon film coexist at the interface, so that the hard amorphous at the interface The internal stress of the carbon film is relaxed, and the adhesion between them is further improved.

  In the case of a hard amorphous carbon-coated member having the above-described configuration, the hard amorphous carbon film is firmly adhered to the base material via the intermediate layer even when produced at a low temperature of 300 ° C. or lower. Therefore, even a base material made of a material whose characteristics deteriorate due to exposure to a high temperature is suitable.

  The hard amorphous carbon-coated member of the present invention can be easily produced by the following method for producing a hard amorphous carbon-coated member of the present invention.

The method for producing a hard amorphous carbon-coated member of the present invention includes an oxygen-containing metal layer forming step of forming an oxygen-containing metal layer containing molybdenum and / or titanium on the surface of a base material and containing oxygen on at least the surface portion;
Depositing carbon and silicon on the surface of the oxygen-containing metal layer to form a hard amorphous carbon film containing silicon and diffusing carbon from the surface into the oxygen-containing metal layer; and
It is characterized by including.

Moreover, the method for producing a hard amorphous carbon-coated member of the present invention includes an oxygen-containing metal layer forming step of forming an oxygen-containing metal layer containing aluminum on the surface of a base material and containing oxygen on at least a surface portion;
A hard amorphous carbon film forming step of forming a hard amorphous carbon film containing silicon by depositing carbon and silicon on the surface of the oxygen-containing metal layer;
It is characterized by including.

  The best mode for carrying out the hard amorphous carbon-coated member and the method for producing the same of the present invention will be described below.

  The hard amorphous carbon coating member of the present invention includes a base material, an intermediate layer formed on the surface of the base material, and a hard amorphous carbon film formed on the surface of the intermediate layer. Below, a base material, an intermediate | middle layer, and a hard amorphous carbon film are demonstrated.

[Base material]
The substrate is not particularly limited in its shape and material. However, it is desirable to use a base material made of a material having high adhesion to an intermediate layer described later. Therefore, it is preferable to use a substrate made of a metal such as iron, steel, aluminum, aluminum alloy, titanium, titanium alloy, magnesium, magnesium alloy, copper, copper alloy, cemented carbide, etc. . Furthermore, the hard amorphous carbon-coated member of the present invention can be produced by low-temperature treatment at 300 ° C. or lower as will be described in detail later. Therefore, it may be a substrate made of aluminum, aluminum alloy, magnesium, magnesium alloy, etc. having low heat resistance, or steel, titanium, titanium alloy, etc. whose strength is reduced by processing at high temperature.

[Middle layer]
[Intermediate layer containing molybdenum and / or titanium]
The intermediate layer is formed on the surface of the substrate and contains molybdenum and / or titanium. The intermediate layer contains oxygen and carbon at least at the interface between the intermediate layer and the hard amorphous carbon film (described later). Note that, of the interface portion, the surface portion of the intermediate layer in contact with the hard amorphous carbon film is referred to as an intermediate layer side interface portion. That is, in the intermediate layer, at least the intermediate layer side interface includes oxygen and carbon. Molybdenum and titanium constituting the intermediate layer can diffuse carbon from the surface of the film even if oxygen is taken into the surface portion. Therefore, it is easy to make oxygen and carbon exist at the interface portion on the intermediate layer side.

  The intermediate layer preferably has a thickness of 10 to 900 nm, more preferably 200 to 700 nm. If the intermediate layer is too thin, the surface of the base material is not sufficiently covered, leaving a portion where the base material is exposed, and the adhesiveness between the intermediate layer and the hard amorphous carbon film may not be exhibited well. Also, if the intermediate layer is too thick, the intermediate layer may break because the strength is lower than that of the hard amorphous carbon film or the surface of the substrate, which is not preferable.

The intermediate layer preferably contains 4 atomic% or more, more preferably 7 atomic% or more of oxygen in the intermediate layer side interface when the entire intermediate layer side interface is 100 atomic%. If even a small amount of oxygen is contained in the interface portion on the intermediate layer side, the effect of suppressing the separation of the hard amorphous carbon film can be obtained, but the adhesiveness is improved by setting it to 4 atomic% or more. On the other hand, the intermediate layer preferably contains 50 atomic% or less, more preferably 30 atomic% or less of oxygen in the intermediate layer side interface when the entire intermediate layer side interface is 100 atomic%. The oxygen amount obtained from the stoichiometric composition of the molybdenum oxide (MoO ₂₎ and titanium oxide (TiO ₂₎ is 66 atomic%. Since stable MoO ₂ and TiO ₂ have high insulation, it is difficult to form a stable plasma when forming a hard amorphous carbon film, and it may be difficult to form a film. It is good to set it to 50 atomic% or less.

  All of the above oxygen contents are values when the intermediate layer side interface is defined as 10 nm from the surface on which the hard amorphous carbon film is formed. It suffices that at least the predetermined amount of oxygen is included in the interface portion on the intermediate layer side, and oxygen may be included only in the interface portion on the intermediate layer side or may be included in the entire intermediate layer. At that time, the oxygen content on the substrate side of the intermediate layer (excluding the interface portion on the intermediate layer side) is not particularly limited as long as it does not affect the adhesion between the substrate and the intermediate layer.

  The intermediate layer preferably has a carbon diffusion layer diffused inward from the surface on which the hard amorphous carbon film is formed. In the case where the surface portion of the intermediate layer is a carbon diffusion layer, a compositional gradient state occurs between the intermediate layer and the hard amorphous carbon film, so that the adhesion between them is further improved. At this time, the diffusion layer preferably has a diffusion depth of 50 nm or more, more preferably 100 nm or more. Moreover, it is preferable that carbon is diffused so that the carbon content is 10 atomic% or more when the entire diffusion layer is 100 atomic%.

[Intermediate layer containing aluminum]
As the intermediate layer, an intermediate layer containing aluminum and oxygen in the intermediate layer side interface may be used. When oxygen is incorporated into a film, the surface of the film becomes dense, and diffusion of carbon hardly occurs. However, a hard amorphous carbon-coated member having an intermediate layer containing aluminum exhibits high adhesion even when no carbon is present at the interface portion on the intermediate layer side.

  The intermediate layer preferably has a thickness of 10 to 900 nm, more preferably 200 to 700 nm. If the intermediate layer is too thin, the surface of the base material is not sufficiently covered, leaving a portion where the base material is exposed, and the adhesiveness between the intermediate layer and the hard amorphous carbon film may not be exhibited well. Also, if the intermediate layer is too thick, the intermediate layer may break because the strength is lower than that of the hard amorphous carbon film or the surface of the substrate, which is not preferable.

The intermediate layer preferably contains 4 atomic% or more, more preferably 7 atomic% or more of oxygen in the intermediate layer side interface when the entire intermediate layer side interface is 100 atomic%. If even a small amount of oxygen is contained in the interface portion on the intermediate layer side, the effect of suppressing the separation of the hard amorphous carbon film can be obtained, but the adhesiveness is improved by setting it to 4 atomic% or more. On the other hand, the intermediate layer preferably contains 50 atomic% or less, more preferably 30 atomic% or less of oxygen in the intermediate layer side interface when the entire intermediate layer side interface is 100 atomic%. This is because the adhesion is lowered when the surface is covered with an oxide of aluminum. Incidentally, 60 atomic% is a value determined from the stoichiometric composition of aluminum oxide _(Al 2 _{O 3).} Since Al ₂ O ₃ has high insulating properties, it is difficult to form a stable plasma when forming a hard amorphous carbon film, and the film formation may be difficult. The following is recommended.

  All of the above oxygen contents are values when the intermediate layer side interface is defined as 10 nm from the surface on which the hard amorphous carbon film is formed. It suffices that at least the predetermined amount of oxygen is included in the interface portion on the intermediate layer side, and oxygen may be included only in the interface portion on the intermediate layer side or may be included in the entire intermediate layer. At that time, the oxygen content on the substrate side of the intermediate layer (excluding the interface portion on the intermediate layer side) is not particularly limited as long as it does not affect the adhesion between the substrate and the intermediate layer. If it is stipulated, the amount of oxygen contained in the intermediate layer is 4 atomic% to 50 atomic%, further 7 atomic% to 30 atomic%, assuming that the entire intermediate layer is 100 atomic%. preferable. In addition, as already demonstrated, the intermediate | middle layer containing aluminum does not have a carbon diffusion layer.

[Hard amorphous carbon film]
The hard amorphous carbon film is formed on the surface of the intermediate layer, and contains silicon at least at the interface between the intermediate layer and the hard amorphous carbon film. Of the interface portion, the surface portion of the hard amorphous carbon film in contact with the intermediate layer is referred to as a hard amorphous carbon film side interface portion. That is, in the hard amorphous carbon film, at least the hard amorphous carbon film side interface includes silicon. As described above, the intermediate layer side interface includes oxygen (O). Since the hard amorphous carbon film contains silicon (Si), covalent bonding O—Si—C is formed at the interface between the intermediate layer and the hard amorphous carbon film. The adhesion between the films is improved, and as a result, the adhesion between the substrate and the hard amorphous carbon film is also improved.

  What is necessary is just to select the film thickness of a hard amorphous carbon film | membrane suitably according to the use of a hard amorphous carbon coating | coated member. If it prescribes | regulates, it is 0.5-10 micrometers, Furthermore, it is 0.8-3 micrometers. If the thickness of the hard amorphous carbon film is within this range, high adhesion is maintained.

  The hard amorphous carbon film contains 4 atomic% or more, further 7 atomic% or more of silicon in the hard amorphous carbon film side interface when the entire hard amorphous carbon film side interface is 100 atomic%. Is preferred. If silicon is contained in the hard amorphous carbon film side interface, even if a little, the effect of suppressing the peeling of the hard amorphous carbon film can be obtained, but the adhesion is improved by making it 4 atomic% or more. To do. The upper limit of the silicon amount at the hard amorphous carbon film side interface is not particularly limited, but when the entire hard amorphous carbon film side interface is 100 atomic%, the hard amorphous carbon film side interface It is preferable to contain silicon at 30 atomic% or less, more preferably 25 atomic% or less.

  The above silicon contents are values when the hard amorphous carbon film side interface is defined as 100 nm from the surface in contact with the intermediate layer. It suffices that at least the hard amorphous carbon film side interface portion contains the predetermined amount of silicon, and silicon may be contained only in the hard amorphous carbon film side interface portion, or hard amorphous carbon film side interface portion. It may be contained in the entire carbon film. In the case where the entire film is a hard amorphous carbon film containing silicon, the silicon content of the surface layer of the hard amorphous carbon film that is the outermost layer of the hard amorphous carbon coating member is not particularly limited. The hard amorphous carbon film may contain hydrogen, oxygen, nitrogen, etc. in addition to carbon and silicon. However, in the case of aiming at low friction characteristics for tribological applications, a hard amorphous carbon film containing at least silicon in the surface layer is preferable, and the composition thereof is equivalent to the composition of the hard amorphous carbon film side interface part. A uniform composition throughout is desirable in terms of production and quality.

  The hard amorphous carbon-coated member of the present invention has a hard amorphous carbon film on the outermost surface, and the hard amorphous carbon film is firmly adhered to the base material via the intermediate layer, so that the protective film is formed on the surface. It is suitable for various members that require Specific applications of the amorphous carbon-coated member of the present invention include sliding parts such as bearings, valve-operating parts, sliding parts used in automobile engines, auxiliary equipment, air conditioners, and corrosion resistance of pumps and piping. Examples include parts, machine sliding parts such as gears and piston rings, and the like.

  An example of the method for producing the hard amorphous carbon-coated member of the present invention will be described below.

[Method for producing hard amorphous carbon-coated member]
The manufacturing method of the hard amorphous carbon-coated member of the present invention is a manufacturing method capable of easily manufacturing the hard amorphous carbon-coated member of the present invention already described in detail. The method for producing a hard amorphous carbon-coated member of the present invention includes an oxygen-containing metal layer forming step and a film forming diffusion step. Below, each process is demonstrated.

  The oxygen-containing metal layer forming step is a step of forming an oxygen-containing metal layer containing molybdenum and / or titanium on the surface of the base material and containing oxygen on at least the surface portion. The oxygen-containing metal layer can be formed by previously forming a film made of molybdenum and / or titanium and then exposing the film to an atmosphere containing oxygen. That is, first, a metal film is formed on the surface of the substrate by vapor deposition such as physical vapor deposition (PVD) or chemical vapor deposition (CVD), plating, or the like. By leaving the substrate on which the metal film is formed in an atmosphere containing oxygen, such as in the air, the surface portion of the metal film is oxidized. When it is desired to incorporate oxygen into the entire metal film, the film made of molybdenum and / or titanium may be deposited in an atmosphere containing oxygen. Thereafter, the base material on which the metal film is formed may be exposed to an atmosphere containing oxygen. If the oxygen-containing metal layer forming step is performed by these methods, the oxygen-containing metal layer can be formed at, for example, 300 ° C. or less without exposing the substrate to a high temperature.

  The film formation diffusion step is a step of depositing carbon and silicon on the surface of the oxygen-containing metal layer to form a hard amorphous carbon film containing silicon and diffusing carbon from the surface into the oxygen-containing metal layer.

  If only a hard amorphous carbon film is deposited on the surface of the oxygen-containing metal layer, a known vapor deposition method may be used. In order to diffuse carbon from the surface of the oxygen-containing metal layer, a hard amorphous carbon film is used. It is necessary to control the plasma discharge to the surface of the oxygen-containing metal layer during the deposition of the carbonaceous film. The most preferable method is a direct current plasma CVD method using a pulse power source as a discharge power source, as will be described in detail below.

  In the direct current plasma CVD method, a base material (material to be processed) on which an oxygen-containing metal layer is formed is placed in a vacuum vessel, and a processing gas is introduced. Next, plasma is generated by glow discharge by applying electric power between the two electrodes of the positive electrode and the negative electrode, and the processing gas introduced between the electrodes is turned into plasma. At this time, since the material to be processed is arranged in contact with the negative potential side electrode, a film is formed by depositing plasma-formed cations on the surface of the material to be processed. In particular, by using a pulse power source as a discharge power source, it is possible to generate a strong plasma instantaneously by generating a glow discharge in pulses, and because the pulse discharge has a downtime, a low current of 300 ° C. or less Low temperature film formation is possible. Therefore, even in the case of low temperature film formation, the occurrence of arc discharge is suppressed and stable discharge can be obtained. Furthermore, when plasma is generated by applying a high voltage of 2% to 70%, 5% to 70%, 0.6 kV or more, and 1 to 10 kV to the source gas, the temperature is as low as 300 ° C. or less. However, it is easy to diffuse carbon from the surface to the inside of the oxygen-containing metal layer. That is, it is desirable to use a high voltage pulse power source as the discharge power source. At this time, the repetition frequency of the pulse waveform is not particularly limited. However, when the pulse width is 50 μsec, it is preferable to set the frequency to 0.4 kHz or more, and further 1 to 9 kHz. Here, the “duty ratio” is a ratio of the ON state or the OFF state in one period of the rectangular wave, and in this specification, indicates the ratio of the ON state. That is, the larger the duty ratio, the longer the ON state.

  The processing gas is composed of a source gas containing at least one selected from an organic metal-containing gas containing silicon and a halogen compound gas, or a mixture of the source gas and a diluent gas containing at least one selected from hydrogen and a rare gas It is desirable to consist of gas. You may mix hydrocarbon gas as needed. The type, mixing ratio, or flow rate ratio of the processing gas may be appropriately selected so that the composition of the obtained hard amorphous carbon film has a desired composition.

At this time, the hydrocarbon gas is preferably methane, ethylene, acetylene, benzene, hexane or the like. Further, the organometallic-containing _{gas, Si (CH 3) 4 [} TMS], Si (CH 3) 3 H, Si (CH 3) 2 H 2, Si (CH 3) H 3, SiH 4, SiCl 4, SiH ₂ F ₄ or the like is desirable. The halogen compound gas is preferably silicon tetrachloride. The dilution gas is desirably hydrogen gas, helium gas, neon gas, or the like. One or more of these can be used in combination.

  It is also possible to form hard amorphous carbon films having different compositions in the thickness direction by changing the deposition conditions such as the mixing ratio of source gases, deposition temperature, and voltage during deposition. is there. Therefore, a hard amorphous carbon film having a different composition is formed at the interface portion on the hard amorphous carbon film side and other portions by, for example, tilting the silicon concentration in the thickness direction of the hard amorphous carbon film. May be.

  In the method for producing another hard amorphous carbon-coated member of the present invention, the oxygen-containing metal layer forming step includes a step of forming an oxygen-containing metal layer containing aluminum on the surface of the base material and containing oxygen on at least the surface portion. It is. The oxygen-containing metal layer can be formed by forming a film made of aluminum in advance and then exposing the film to an atmosphere containing oxygen. That is, first, an aluminum film is formed on the surface of the substrate by vapor deposition such as PVD or CVD, plating, or the like. By leaving the base material on which the aluminum film is formed in an atmosphere containing oxygen, such as in the air, the surface portion of the aluminum film is oxidized. When it is desired to incorporate oxygen into the entire metal coating, the aluminum film is preferably deposited in an atmosphere containing oxygen. Thereafter, the substrate on which the aluminum film is formed may be further exposed to an atmosphere containing oxygen. If the oxygen-containing metal layer forming step is performed by these methods, the oxygen-containing metal layer can be formed at, for example, 300 ° C. or less without exposing the substrate to a high temperature.

  Note that an oxygen-enriched layer having a higher oxygen concentration than other portions is easily formed on the surface portion of the aluminum film. The oxygen-enriched layer is preferably 2 to 50 nm, more preferably 5 to 30 nm. By simply leaving the substrate on which the aluminum film is formed in the atmosphere, an oxygen-containing metal layer in which an oxygen-concentrated layer of 2 to 50 nm is formed on the surface portion of the aluminum coating can be easily obtained.

  Another method for producing a hard amorphous carbon-coated member of the present invention is to form a hard amorphous carbon film that forms a hard amorphous carbon film containing silicon by depositing carbon and silicon on the surface of an oxygen-containing metal layer. Including a membrane process. The hard amorphous carbon film can be formed by a known CVD method or PVD method such as a plasma CVD method, an ion plating method, or a sputtering method. However, for example, when processing is performed at a low temperature of 300 ° C. or lower, it is desirable to form a hard amorphous carbon film by a direct current plasma CVD method using a pulse power source as a discharge power source. Note that the direct-current plasma CVD method has already been described.

  As mentioned above, although embodiment of the hard amorphous carbon coating | coated member of this invention and its manufacturing method was described, this invention is not limited to the said embodiment. The present invention can be implemented in various forms without departing from the gist of the present invention, with modifications and improvements that can be made by those skilled in the art.

  Hereinafter, the present invention will be specifically described with reference to examples of the hard amorphous carbon-coated member and the method for producing the same.

[Production of oxygen-containing metal layer (intermediate layer)]
Two types of steel materials (bearing steel: SUJ2, martensitic stainless steel: SUS440C) were prepared as base materials. The base material made of bearing steel had a surface hardness: HRC62 and a surface roughness (arithmetic average roughness): Ra 0.01 μm. The base material made of stainless steel had a surface hardness: HRC60 and a surface roughness: Ra 0.007 μm.

  An unbalanced magnetron sputtering apparatus (UBMS504 manufactured by Kobe Steel, Ltd.) was used on the surface of these substrates, and molybdenum film, titanium film, aluminum film, and niobium, vanadium, chromium, silicon, tungsten, gold as comparative examples. Ten kinds of metal coatings made of copper and copper were formed. The film formation conditions were film formation pressure: 0.1 to 10 Pa, film formation temperature (substrate surface temperature): 240 ° C., and film formation time: film thickness was controlled to be 300 to 600 nm.

  Each substrate on which the metal film was formed was taken out from the UBMS apparatus and left in the air for 50 hours. The hardness of the surface of the base material made of SUJ2 after deposition (the surface without the metal coating) was HRC60. Since the hardness of the base material before film formation was HRC62, it was shown that the strength reduction of the base material was suppressed by forming the film at 240 ° C.

[Deposition of hard amorphous carbon film]
Next, an amorphous carbon (DLC-Si) film containing silicon was formed using a DC plasma CVD apparatus illustrated in FIG. The DC plasma CVD apparatus 9 includes a stainless steel chamber 90, a base 91, a gas introduction pipe 92, and a gas outlet pipe 93. The gas introduction pipe 92 is connected to various gas cylinders (not shown) via valves (not shown). The gas outlet pipe 93 is connected to a rotary pump (not shown) and a diffusion pump (not shown) via a valve (not shown).

  The substrate 100 is disposed on a base 91 installed in the chamber 90. When the substrate 100 is disposed, the chamber 90 is sealed, and the gas in the chamber 90 is exhausted by a rotary pump and a diffusion pump connected to the gas outlet pipe 93.

  When forming a DLC-Si film on the substrate 100, first, argon or the like is introduced into the chamber 90 from the gas introduction pipe 92. Thereafter, when the high voltage pulse power supply 8 is operated and a DC voltage is applied between the stainless steel anode plate 94 provided inside the chamber 90 and the base 91, discharge starts. The surface temperature of the substrate 100 can be raised to a predetermined film formation temperature by ion bombardment due to this discharge. Next, dilution gas and source gas are introduced from the gas introduction pipe 92. Thereafter, when a predetermined power is applied between the stainless steel anode plate 94 provided inside the chamber 90 and the base 91 (base material 100), a discharge 95 is started, and DLC-Si is applied to the surface of the base material 100. A film is formed.

To the substrate on which the metal film was formed in the previous step, hydrogen gas was introduced into the apparatus at 100 sccm and argon gas was introduced at 100 sccm, the gas pressure was adjusted to 13 Pa, and a DC voltage of 3.0 kV (88 mA) was applied. Then, ion bombardment for 1 hour was performed. By this ion bombardment, the surface temperature of the substrate was raised to 220 ° C., which is the deposition temperature of the DLC-Si film. In addition, the DLC-Si film was adjusted to a gas pressure of 13 Pa by introducing CH ₄ gas at 100 sccm and TMS gas at 6 sccm with hydrogen gas and argon gas introduced at a rate of 100 sccm, and a direct current of 3.0 kV (95 mA). A film was formed by applying a voltage. At this time, the pulse oscillation conditions of the high-voltage pulse power supply 8 were a duty ratio: 5% (pulse width: 50 μsec (pause: 950 μsec)) and a repetition frequency: 1 kHz. A DLC-Si film having a thickness of 1 μm was formed by film formation for 3 hours.

  As a comparative example, using a thyristor power supply instead of a high voltage pulse power supply, a DLC-Si having a thickness of 1 μm is formed on the surface of a SUJ2 base material on which a chromium film is formed and a SUJ2 base material on which a titanium film is formed. A film was formed. The thyristor power source was 200 V (0.5 A) at a film forming pressure of 400 Pa, and the film forming temperature was 250 ° C.

  The Si content of the obtained DLC-Si film was determined by electron beam probe microanalysis (EPMA). The Si content of the DLC-Si film formed using the high-voltage pulse power source is 16 at%, the H content is 23 at%, and the Si content of the DLC-Si film formed using the thyristor power source is 12 at%, The H content was 30 at%, and Si and H were uniformly distributed in the film in any sample, and the content was almost constant in the thickness direction.

[Evaluation 1]
[Cross-section observation and element distribution analysis]
Among the hard amorphous carbon coated members obtained by the above procedure, an intermediate layer containing molybdenum, titanium or aluminum, a DLC-Si film formed by a direct current plasma CVD method using a high voltage pulse power source, The cross section of the hard amorphous carbon-coated member provided with Cross-sectional observation and element distribution analysis were performed by Auger electron spectroscopy (AES analysis). The results are shown in FIGS.

  FIG. 1 shows secondary electron images and element distributions obtained by measuring a cross section of a hard amorphous carbon-coated member having an intermediate layer containing molybdenum (Mo) by Auger electron spectroscopy. In the intermediate layer containing Mo, the presence of oxygen was observed in the entire intermediate layer. The oxygen content when the entire intermediate layer was 100 at% was 8 at%. In addition, the oxygen content of the surface portion when the surface portion of the intermediate layer (intermediate layer side interface portion: 10 nm from the surface) was 100 at% was also about 8 at%. This oxygen is presumed that oxygen remaining in the UBMS apparatus was taken into the film. Further, carbon diffused from the surface of the intermediate layer to the inside was also confirmed, and a large amount was detected at the interface with the DLC-Si film. That is, it was found that carbon was diffused from the surface of the intermediate layer when the DLC-Si film was formed. It is presumed that a dense oxide film is difficult to form on the surface of the molybdenum film, and carbon easily diffused into the molybdenum film. The carbon diffusion depth was about 200 nm, but the carbon content was high. Moreover, the detailed examination result of the carbon spectrum by AES analysis suggests the formation of a compound of Mo in the intermediate layer and C in the DLC-Si film at the interface between the intermediate layer and the DLC-Si film.

  The structure of the hard amorphous carbon coating member provided with the intermediate layer containing Mo is schematically shown in FIG. An intermediate layer 2 is formed on the surface of the substrate 1. The intermediate layer 2 is a molybdenum film containing oxygen. The surface portion (intermediate layer side interface portion) 2 'of the intermediate layer 2 is a carbon diffusion layer. A DLC-Si film 3 is formed on the surface of the intermediate layer 2 (surface portion 2 '). The diffusion layer is formed by diffusing carbon from the surface of the intermediate layer 2 when the DLC-Si film 3 is formed. The hard amorphous carbon film side interface is indicated by 3 '.

  FIG. 2 is a secondary electron image and element distribution obtained by measuring the cross section of a hard amorphous carbon-coated member having an intermediate layer containing titanium (Ti) by AES analysis. In the intermediate layer containing Ti, the presence of oxygen was observed in the entire intermediate layer. When the surface part of the intermediate layer (intermediate layer side interface part: 10 nm from the surface) was 100 at%, the oxygen content in the surface part was 20 at%. This oxygen is presumed to be that not only oxygen remaining in the UBMS apparatus was taken into the film but also the surface portion of the titanium film was oxidized in the atmosphere. Further, carbon diffused from the surface of the intermediate layer to the inside was also confirmed. That is, it was found that carbon was diffused from the surface of the intermediate layer when the DLC-Si film was formed. Moreover, the detailed examination result of the carbon spectrum by AES analysis suggests the formation of a compound of Ti of the intermediate layer and C of the DLC-Si film at the interface between the intermediate layer and the DLC-Si film.

  FIG. 3 is a secondary electron image and element distribution obtained by measuring the cross section of a hard amorphous carbon-coated member having an intermediate layer containing aluminum (Al) by AES analysis. In the intermediate layer containing Al, the presence of an oxygen-enriched layer was observed on the surface portion on the DLC-Si film side. When the surface part of the intermediate layer (intermediate layer side interface part: 10 nm from the surface) was 100 at%, the oxygen content in the surface part was 20 at%. This oxygen is presumed that the surface portion of the aluminum film was oxidized in the atmosphere. However, no carbon diffusion into the intermediate layer was confirmed. It is considered that carbon could not move into the intermediate layer because the oxygen-enriched layer formed on the surface portion was dense.

  In addition, about the hard amorphous carbon coating | coated member provided with the intermediate | middle layer containing Al, the cross section was observed with the transmission electron microscope (TEM). The results are shown in FIG. It was found that an Al oxide film was formed with a thickness of 10 nm from the surface of the intermediate layer.

[Evaluation of adhesion]
The peel strength (adhesion strength) of the DLC-Si film was measured by a Rockwell test and a scratch test. Here, from the standpoint of practicality and stability of the evaluation method, the load when the DLC-Si film was peeled in the observation using an optical microscope was defined as the adhesion force.

  For the Rockwell test, the adhesion strength was evaluated from the peeling form of the DLC-Si film around the indentation on the C scale. In the scratch test, a conical diamond (indenter diameter: 0.2 mm) was used, and the table speed was 10 mm / min and the load increasing speed was 100 N / min. The results are shown in FIG. 6 and FIG.

  FIG. 6 is a graph showing the relationship between the type of intermediate layer and the adhesion strength of the hard amorphous carbon-coated members of Examples and Comparative Examples, and shows the adhesion strength when two types of substrates are used. In the graph, the black bar indicates the adhesion when a SUJ2 substrate is used, and the right bar indicates the adhesion when a SUS440C substrate is used. Even if any base material was used, there was no great difference in the adhesion force, but the adhesion of the hard amorphous carbon-coated member using the SUS440C base material was slightly inferior. Thereafter, the type and adhesion of the intermediate layer are evaluated for the hard amorphous carbon-coated member using the SUJ2 base material. When an intermediate layer containing Au and Cu that did not form carbides was used, the adhesion was the lowest value of 12 to 15 N. Comparing the intermediate layer containing an element that forms carbide, the adhesion was about 15 to 20 N in the case of Nb, V, Cr, Si, and W, whereas it was 25 to 30 N in the case of Ti, Al, and Mo. Remarkably excellent adhesion. In particular, the hard amorphous carbon-coated member provided with the intermediate layer containing Mo and the intermediate layer containing Ti showed the highest value of 30N. This is a result showing that the improvement in adhesion is not only due to the diffusion of carbon into the intermediate layer but also due to oxygen contained in the intermediate layer.

  V, Cr, Si, and W are elements that easily form carbides. Among them, Cr and Si, which are easily oxidized in the atmosphere, form a dense oxide on the surface of the intermediate layer, so that carbon is intermediate. It is thought that they could not move into the layer. Regarding V and W, the degree of oxidation was low, and the surface of the intermediate layer was smooth as described later (FIG. 8), so that the carbon diffusion layer was hardly formed, and the adhesion was not improved. Conceivable.

  As is clear from FIG. 4, the hard amorphous carbon-coated member provided with the intermediate layer containing Al showed high adhesion, although no carbon was present in the intermediate layer. However, the result exceeding the adhesion force of the member provided with the intermediate layer containing Ti and the member provided with the intermediate layer containing Mo was not obtained.

  FIG. 7 is a graph showing the relationship between the type of the intermediate layer and the adhesion strength of the hard amorphous carbon-coated members of Examples and Comparative Examples produced by the above-described procedure. The adhesion force when a Si film is formed is shown. In the graph, the black bar indicates the adhesion when a DLC-Si film is formed using a high voltage pulse power supply, and the white bar on the right side indicates the adhesion when a DLC-Si film is formed using a thyristor power supply. Respectively. In addition, the data which attached | subjected the same mark in FIG. 6 and FIG. 7 are the same data obtained from the same sample.

  When the DLC-Si film was formed directly on the base material without forming the intermediate layer, the use of the thyristor power supply showed higher adhesion than the high voltage pulse power supply. However, in the case where the intermediate layer was formed, a higher adhesion was obtained when the high voltage pulse power source was used regardless of the type of the intermediate layer. This is because, by using a high voltage pulse power source, the surface of the oxygen-containing metal layer (intermediate layer) is irradiated with high voltage ions to diffuse the carbon to the intermediate layer and the interface between the intermediate layer and the DLC-Si film. This is because bonding occurs in the film and adhesion is improved.

  Furthermore, regarding the diffusion of carbon to the intermediate layer, the influence of the surface roughness of the surface of the intermediate layer on which the DLC-Si film is formed can be considered. For example, a diffusion layer of 400 nm was formed in the intermediate layer containing Ti (FIG. 2), but even if a DLC-Si film was formed on a Ti bulk body having a smooth surface under the same conditions, the diffusion layer was only about 8 nm. It is because it is not formed. FIG. 8 shows the results of surface observation of the intermediate layer containing Ti or the intermediate layer containing W by a scanning electron microscope. In the intermediate layer containing Ti, fine irregularities were observed on the surface, but the surface of the intermediate layer containing W was flat. The improvement in adhesion is presumed to be caused not only by the anchor effect due to the irregularities on the surface of the intermediate layer, but also due to the ease of forming the diffusion layer due to the irregularities.

  The intermediate layer containing Ti had an oxygen content of 20 at% at the interface portion on the intermediate layer side, but if the oxygen content of the intermediate layer was 12 to 28 at%, it was an error range, and in this range about 30 N Adhesion can be obtained. The intermediate layer containing Mo had an oxygen content of 8 at% at the interface portion on the intermediate layer side. However, if the oxygen content of the intermediate layer was 7 to 15 at%, it was an error range. Is obtained. Further, the intermediate layer containing Al had an oxygen content of 20 at% at the interface portion on the intermediate layer side, but if the oxygen content of the intermediate layer was 10 to 30 at%, it was an error range, and in this range about 25 N Adhesion can be obtained.

[Evaluation 2]
DLC-Si films were formed at different duty ratios to produce hard amorphous coating members, and the adhesion to the duty ratio was evaluated.

  A hard amorphous material comprising an intermediate layer containing Mo or an intermediate layer containing Ti in the same manner as described above except that the duty ratio when forming the DLC-Si film is changed within a range of 5% to 80%. A carbon-coated member was produced. At any duty ratio, the temperature of the substrate during the formation of the DLC-Si film did not exceed 300 ° C. In addition, although the pulse power supply was used for the discharge power supply, up to 5 to 67% was implemented with a high voltage pulse power supply and 80% with a DC pulse. FIG. 9 shows the relationship between the duty ratio and the discharge voltage.

  Thereafter, the peel strength of the DLC-Si film was measured by the method described above. The results are shown in FIG. When the duty ratio was 5% to 67%, a high adhesion of 25 N or more was obtained. However, when the duty ratio exceeded 67%, the adhesion decreased. When the duty ratio is increased, the current increases, but it is presumed that the voltage decreases as can be seen from FIG. Note that when the carbon diffusion layer of the hard amorphous coating member including the intermediate layer containing Ti on which the DLC-Si film was formed with a duty ratio of 25% was analyzed by AES, the diffusion depth was about 250 nm.

[Evaluation 3]
DLC-Si films having different silicon contents were formed to produce a hard amorphous coating member, and the adhesion to the silicon content was evaluated.

  A hard amorphous carbon-coated member provided with an intermediate layer containing Mo or an intermediate layer containing Ti is manufactured in the same manner as described above except that the flow rate ratio of the source gas when the DLC-Si film is formed is changed. did. All members were manufactured with a duty ratio of 5%.

  Thereafter, the peel strength of the DLC-Si film was measured by the method described above. Further, the amount of Si contained in the DLC-Si film of each member was measured by EPMA. Note that the amount of Si was substantially constant in the thickness direction of the DLC-Si film. The results are shown in FIG. The adhesion of the DLC film not containing Si was less than 20N. On the other hand, high adhesion was obtained in the DLC-Si film containing Si. In particular, when the Si content was 6 to 22 at%, no significant change was observed in the adhesion. That is, it was found that the adhesion of the intermediate layer containing oxygen can be ensured by the fact that the hard amorphous carbon film contains Si.

It is a drawing substitute photograph which shows the result of having measured the cross section of the hard amorphous carbon coating | coated member with the intermediate | middle layer containing molybdenum by the Auger electron spectroscopy analysis, Comprising: A secondary electron image and element distribution are shown. It is a drawing substitute photograph which shows the result of having measured the cross section of the hard amorphous carbon coating | coated member with the intermediate | middle layer containing titanium by the Auger electron spectroscopy, Comprising: A secondary electron image and element distribution are shown. It is a drawing substitute photograph which shows the result of having measured the cross section of the hard amorphous carbon coating | coated member with the intermediate | middle layer containing aluminum by the Auger electron spectroscopy analysis, Comprising: A secondary electron image and element distribution are shown. It is a drawing substitute photograph which shows the result of having observed the cross section of the hard amorphous carbon coating | coated member with the intermediate | middle layer containing aluminum with the transmission electron microscope. It is sectional drawing which shows typically an example of the hard amorphous carbon coating | coated member of this invention. It is a graph which shows the relationship between the kind of intermediate | middle layer, and contact | adhesion power about the hard amorphous carbon coating member of an Example and a comparative example, Comprising: Adhesion power at the time of using 2 types of base materials, respectively is shown. It is a graph which shows the relationship between the kind of intermediate | middle layer, and adhesive force about the hard amorphous carbon coating member of an Example and a comparative example, Comprising: Adhesive force at the time of forming a DLC-Si film using two types of power supplies, respectively Indicates. The surface observation result by the scanning electron microscope of the intermediate layer containing Ti or the intermediate layer containing W is shown, respectively. It is a graph which shows the relationship between the duty ratio at the time of forming a hard amorphous carbon film, and discharge voltage. It is a graph which shows the relationship between the duty ratio at the time of forming a hard amorphous carbon film, and adhesive force. It is a graph which shows the relationship between the silicon content of a hard amorphous carbon film, and adhesive force. It is explanatory drawing of a DC plasma CVD film-forming apparatus.

Explanation of symbols

1: Substrate 2: Intermediate layer 2 ′: Intermediate layer side interface (surface portion of intermediate layer)
3: Hard amorphous carbon film (DLC-Si film) 3 ': Hard amorphous carbon film side interface 8: High voltage pulse power supply 9: DC plasma CVD apparatus

Claims (14)

A base material, an intermediate layer formed on the surface of the base material and containing molybdenum and / or titanium, and a hard amorphous carbon film formed on the surface of the intermediate layer,
The intermediate layer has a carbon diffusion layer diffused inward from the surface on which the hard amorphous carbon film is formed,
At least at the interface between the intermediate layer and the hard amorphous carbon film, the intermediate layer contains oxygen and carbon, and the intermediate layer is at least 10 nm from the surface on which the hard amorphous carbon film is formed. A hard amorphous carbon-coated member comprising oxygen at an intermediate layer side interface up to 4 atomic% to 50 atomic%, and the hard amorphous carbon film containing silicon. The hard amorphous carbon film, according to claim 1 including at least said intermediate layer in contact with 30 atomic% 4 atom% of silicon in a hard amorphous carbon film side interface unit to 100nm from the surface less rigid amorphous Carbon coated member. A method for producing a hard amorphous carbon-coated member according to claim 1 or 2,
An oxygen-containing metal layer forming step of forming an oxygen-containing metal layer containing molybdenum and / or titanium on the surface of the substrate and containing oxygen at least on the surface portion;
Depositing carbon and silicon on the surface of the oxygen-containing metal layer to form a hard amorphous carbon film containing silicon and diffusing carbon from the surface into the oxygen-containing metal layer; and
The manufacturing method of the hard amorphous carbon coating member characterized by including. The method for producing a hard amorphous carbon-coated member according to claim 3, wherein the oxygen-containing metal layer forming step and the film forming diffusion step are steps performed at a temperature of the base material of 300 ° C. or lower. The film-forming diffusion process, according to claim 3 or 4 is a process to diffuse carbon into the oxygen-containing metal layer while depositing the hard amorphous carbon film by DC plasma CVD method using the pulsed power as discharge power supply A method for producing a hard amorphous carbon-coated member according to claim 1. 6. The hard amorphous carbon-coated member according to claim 5, wherein the film forming diffusion step is a step of generating a plasma by applying a pulse voltage having a duty ratio of 2% to 70% and 0.6 kV or more to the source gas. Manufacturing method. The hard amorphous layer according to any one of claims 3 to 6 , wherein the oxygen-containing metal layer forming step is a step of forming a film made of molybdenum and / or titanium and then exposing the film to an atmosphere containing oxygen. A method for producing a carbon-coated member. The method for producing a hard amorphous carbon-coated member according to claim 3 , wherein the oxygen-containing metal layer forming step is a step of depositing a film made of molybdenum and / or titanium in an atmosphere containing oxygen. . A base material, an intermediate layer formed on the surface of the base material and containing aluminum, and a hard amorphous carbon film formed on the surface of the intermediate layer,
At least at the interface between the intermediate layer and the hard amorphous carbon film, the intermediate layer contains oxygen, and the intermediate layer is at least 10 nm from the surface on which the hard amorphous carbon film is formed. A hard amorphous carbon-coated member comprising oxygen in an intermediate layer side interface portion of not less than 4 atom% and not more than 50 atom% , wherein the hard amorphous carbon film contains silicon. The hard amorphous carbon film, according to claim 9 including at least said intermediate layer in contact with 30 atomic% 4 atom% of silicon in a hard amorphous carbon film side interface unit to 100nm from the surface less rigid amorphous Carbon coated member. It is a manufacturing method of the hard amorphous carbon covering member according to claim 9 or 10,
An oxygen-containing metal layer forming step of forming an oxygen-containing metal layer containing aluminum on the surface of the substrate and containing oxygen on at least the surface portion;
A hard amorphous carbon film forming step of forming a hard amorphous carbon film containing silicon by depositing carbon and silicon on the surface of the oxygen-containing metal layer;
The manufacturing method of the hard amorphous carbon coating member characterized by including. The production of a hard amorphous carbon-coated member according to claim 11, wherein the oxygen-containing metal layer forming step and the hard amorphous carbon film forming step are performed by setting the temperature of the base material to 300 ° C or lower. Method. The hard amorphous carbon film forming step according to claim 11 or 12, wherein the hard amorphous carbon film forming step is a step of forming the hard amorphous carbon film by a direct current plasma CVD method using a pulse power source as a discharge power source. Of manufacturing a carbonaceous member. The method for producing a hard amorphous carbon-coated member according to claim 11, wherein the oxygen-containing metal layer forming step is a step of forming a film made of aluminum and then exposing the film to an atmosphere containing oxygen.