JP2001192864A - Hard film and coated member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film and a coated member having a low friction coeffi cient and best suited for utilization in a lubricating oil. SOLUTION: This coated member is obtained by providing the surface of a base material 1 with a film 2. This film is provided at least on a part of a sliding face. The film 2 is provided with a layer essentially consisting of carbon. Then, the coated member is used in the presence of lubricating oil. The lubricating oil desirably contains an aromatic compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard coating mainly composed of carbon and a coated member. In particular, to improve abrasion resistance, low coefficient of friction, low opponent aggressiveness (low abrasion of mating material), corrosion resistance and surface protection function,
The present invention relates to a hard coating and a coated member used in the general household field in the presence of a lubricant.

[0002]

2. Description of the Related Art Conventionally, automobile engines, fuel pumps,
2. Description of the Related Art Surface treatments have been applied to components used for sliding parts of various machines and the like in order to enhance the slidability. The slidability is determined by wear resistance, seizure resistance, and coefficient of friction.
In order to improve these properties, the surface of the member is nitrided,
Attempts have been made to modify or coat by plating, thermal spraying, or physical vapor deposition. Among them, it is known that surface coating by physical vapor deposition exhibits excellent sliding properties (for example, Japanese Patent Publication No. 1-52471, Japanese Patent Application Laid-Open No.
No. 120471).

[0003] In particular, diamond-like carbon (DL
Hard carbon films called C), iC, amorphous carbon, and the like are known as materials that are formed on the surface of a component to improve the slidability of the component. DLC is a material which is amorphous as a whole, although carbon is a main component and sometimes hydrogen, and carbon atoms have SP ² bonds or SP ³ bonds. And it is known that the coefficient of friction is low and the abrasion resistance is high because of its film properties and surface smoothness, and it is widely used.

[0004] Many of the parts used for sliding parts of internal combustion engines and various machines are used under lubricating oil. In recent years,
It is strongly desired to reduce the friction loss that occurs in these parts from the approach to environmental issues, and it is necessary to reduce the coefficient of friction under lubricating oil and improve the wear resistance in terms of material. is there.

[0005] The frictional force under lubricating oil is determined by the sum of the frictional force generated by solid-solid contact and the shearing force required to separate the lubricating oils, as shown in the following equation. F = A {αSm + (1−α) Sl} (Equation 1) F: friction force, A: load, α: ratio of solid-solid contact on sliding surface, Sm: friction coefficient of solid-solid contact, Sl :
Coefficient of friction between lubricants

Accordingly, in order to reduce the friction coefficient under lubricating oil, it is necessary to (1) reduce the solid-solid friction coefficient Sm;
(2) It has been considered to reduce the ratio α of solid-solid contact (increase the lubrication ratio with lubricating oil).

At present, for (1), it is considered effective to modify or coat the surface of the component by nitriding, plating, thermal spraying, CVD, or PVD. It has a remarkable effect compared to conventional materials.

Regarding (2), the surface of the component is super-polished to reduce the surface roughness and the ratio of solid-solid contact is reduced. By making it easy to form an oil film and increasing the oil film thickness,
Attempts have been made to increase the ratio of lubrication with lubricating oil.

On the other hand, it is mainly used as a protective layer of a magnetic recording medium.
DLC has been used. In this field, the structure of the DLC film is analyzed by Raman spectroscopy, EELS (Electron Energy Loss Spectroscopy), infrared spectroscopy, etc. In particular, for the purpose of further increasing the durability while maintaining the friction coefficient or reducing the friction coefficient, a proposal has been made to define the shape of the Raman spectrum by performing Raman spectroscopic analysis.
For example, the following document is known.

What defines the intensity ratio of peaks appearing around 1550 cm ^{-1 and} around 1340 cm ^-1 : JP-A-2-29919, JP-A-3-2919
No. 7109, No. 5-151560, No. 5-174368, No. 5-325175

What defines the area intensity ratio: JP-A-6-1112
No. 87, No. 6-267063, No. 6-349055, No. 7-85465, No. 7
-192254, 9-91686, 10-91935

What defines the fluorescence intensity ratio of these peaks: JP-A-8-329450, JP-A-9-153213, JP-A-11-25441,
No. 11-86275, No. 10-49856

[0013]

However, there is no example in which a hard carbon film is applied in a lubricating oil, and the coating conditions for use in a lubricating oil have not been optimized. Also, DL
There are several examples in which the hardness of C is specified (JP-A-1-226711, JP-A-5-17087, JP-A-9-40494, JP-A-5-117856). These are all aimed at improving the adhesion between the DLC and the substrate, and not at optimizing the coating conditions in the lubricating oil.

Regarding "reducing the solid-solid friction coefficient Sm", the friction coefficient of a material which is said to have both abrasion resistance and a low friction coefficient at present, such as DLC, is about 0.1. It is expected that it is difficult to create a material that reduces the odor. Therefore, "solid-solid friction coefficient S
It is difficult to further reduce the coefficient of friction under lubricating oil only by "reducing m."

Regarding “reducing the ratio α of solid-solid contact”, the parts may be slid under insufficient lubricating oil while the operating conditions of the parts become more severe, and the parts may be worn. . There is a problem that the effect of super-polishing and the introduction of a depression cannot be exerted if the surface morphology changes due to wear.

On the other hand, DLC as a protective layer of a magnetic recording medium
All the references described above relate to hard carbon coatings produced by CVD or sputtering. Also,
These hard carbon films contain about 20 at% or more of hydrogen. Further, the film thickness is extremely small, less than 0.1 μm, in terms of function as a protective layer of the magnetic recording medium.

On the other hand, when parts used for sliding parts such as an engine of an automobile, a fuel pump, and various machines are used, their use area is larger than that of a magnetic recording medium.
Higher durability is required. For these purposes, Japanese Patent Application Laid-Open Nos. 5-296248 and 5-186287 have been proposed, but a further reduction in friction coefficient and improvement in wear resistance are required.

Therefore, the main object of the present invention is to provide high wear resistance,
It is an object of the present invention to provide a hard coating capable of achieving a low friction coefficient in a lubricating oil and improving abrasion resistance while having characteristics of high seizure resistance and low aggressiveness of a partner, and a coated member thereof.

[0019]

SUMMARY OF THE INVENTION The hard coating of the present invention has been made to achieve the above-mentioned object, and is to be used in the presence of a lubricant and to have a carbon-based layer. Features. Hereinafter, each component requirement will be described in detail.

(Lubricant) The hard coating of the present invention can exert its effect even in the air, but has a large effect of lowering the friction coefficient in the presence of a lubricant. The lubricant is preferably one selected from the group consisting of engine oil, light oil, gasoline oil, gear oil, turbine oil, spindle oil, machine oil, mobile oil, aviation lubricant, and grease. In particular,
The lubricant in the case of claims 3 to 5 is preferably one in which an aromatic compound is added to the lubricating oil. Aromatic compounds are
A group of organic compounds including aromatic hydrocarbons such as benzene, naphthalene, and anthracene and derivatives thereof, which are carbocyclic compounds having a benzene nucleus. The content of the aromatic compound is preferably such that the ratio of carbon forming an aromatic ring to the total carbon content in the lubricating oil is 5% by weight or more. When this ratio is less than 5% by weight, the effect of improving lubricity is small.

It is not clear why DLC reduces the coefficient of friction and improves wear resistance under a lubricating oil containing an aromatic compound as compared to a lubricating oil not containing it. It is thought that the lubrication ratio of the steel has increased. The lubricating oil molecules on the material surface in the sliding state are adsorbed by Van der Waals force. If the adsorption power is high, a strong oil film is formed, the oil film thickness increases, and the lubricating oil lubrication ratio increases. Aromatic compounds
It is considered that a strong oil film is easily formed due to the high adsorptivity with the DLC surface, and the lubrication ratio under lubricating oil is increased by increasing the distance between the friction surfaces. As described above, since the oil film thickness of the lubricating oil is increased, the lubricating ratio in the lubricating oil is increased, and the area of the solid-solid contact is reduced. It is.

(Composition and Structure of Hard Coating) A typical example of the layer mainly composed of carbon is DLC. Say D here
LC includes both those consisting essentially of carbon and those consisting essentially of carbon and hydrogen. “Consisting substantially of carbon” means that the coating does not contain any element other than the other elements as impurities which cannot be avoided in production. In the case of a hard coating, there are many examples in which hydrogen is present particularly in a reaction atmosphere at the time of film formation. However, the hydrogen content of the hard coating substantially consisting of only carbon in the present invention is 5 at% or less, more preferably 1 at% or less.
at% or less.

A hard film having a low hydrogen content can be realized by forming the film in an atmosphere containing no hydrogen. Further, even in the case of forming a film in an atmosphere containing hydrogen, it is preferable to use a gas having a lower hydrogen content than methane, such as acetylene or benzene.

As for the coating structure, for example, as shown in FIG. 1, it is preferable that the coating 2 formed on the substrate 1 is composed of only DLC. However, another compound may be combined with the DLC coating. Other compounds to be compounded include those containing at least one selected from elements IVa, Va, Group VIa, iron group metals, Al and Si, and carbides, nitrides and carbonitrides of the Periodic Table. Can be Also,
There are the following configurations in the combining method.

DLC forms a compound layer 3 with other elements (FIG. 2). In this case, other elements and DLC are mixed and bonded at the atomic level, and it is confirmed by elemental analysis that other elements and DLC are mixed. However, XRD (X-ray diffract
ion) no diffraction peak is observed.

The other compound particles 5 are composited in the coating layer 4 composed of only DLC (FIG. 3A). Observation with a transmission electron microscope shows that other compounds are composited in a granular form.
This is the case where no clear laminated structure was observed and diffraction peaks of other compounds were observed by XRD diffraction. XR at this time
The particle size of another compound can be calculated from the half width of D diffraction. The particle size of the other compound is preferably 0.001 to 0.5 μm. In the test described below, other compounds having a particle size of less than 0.001 μm were not confirmed. On the other hand, if the particle size exceeds 0.5 μm, the friction and wear characteristics of other compounds will be affected, and the friction coefficient will rapidly increase.

A coating layer 6 composed of only DLC and another compound layer 7 are alternately laminated (FIG. 3B). this is,
This is a case where a clear laminated structure is observed by observation with a transmission electron microscope. The thickness per layer of other compound layers is 0.
It is desirable that the thickness be 0005 to 0.6 μm. The thickness of each layer is determined as follows. First, the deposition rates of the coating layer composed of DLC only and the coating layer composed of another compound are determined. Then, the layer thickness per layer is determined from the time required to form one layer. The transmission electron microscope was used to examine the critical layer thickness at which the laminated structure was observed.
At less than μm, no laminated structure was observed. Also,
Above 0.6 μm, the coefficient of friction increased. Other compounds generally have a higher coefficient of friction than coatings consisting of DLC only.Thicker layers have a greater effect on the friction and wear characteristics of other compounds, and the coefficient of friction increases rapidly. Become.
Therefore, it is preferable to form a layer consisting only of DLC on the outermost surface of the coating of the laminated structure.

Note that "a part (layer) consisting of only DLC"
"The part (layer) where DLC forms a compound with other elements", "the part (layer) where DLC is compounded with other compounds in a granular form" and "the other compound part (layer)" A granular composite structure or a laminated structure may be appropriately combined. That is, as shown in FIG. 4 (A), the entire coating has a granular composite structure composed of a granular portion 8 and a residual portion 9, and each of the granular portion 8 or the residual portion 9 is referred to as a “portion consisting only of DLC”, “ It is composed of "a part where DLC forms a compound with another element", "a part where DLC is compounded with another compound in a granular form", or "another compound part". Further, as shown in FIG. 4B, the entire coating is covered with the first layer 10 and the second layer 11.
Each of the first layer 10 or the second layer 11 is a “layer composed of only DLC”, “a layer in which DLC forms a compound with another element”, and It is composed of "a layer in which the compound is compounded in a granular form" or "another compound layer". In particular, in the case of “composite structure in which DLC forms compound layer 3 with another element” and “laminated structure”, “other element” may be amorphous.

(Coating Hardness) Knoop Hardness (H
It is desirable that k) be 1800 kg / mm ² or more and 8000 kg / mm ² or less. In particular, Knoop hardness of 2000 kg / mm ² or more, 600
It is preferably 0 kg / mm ² or less.

The measurement of the hardness is performed by a push-in method. Using a diamond Knoop indenter, load 50g, load load time 1
It is 0 seconds, and it is the average value of 10 measured values. If the surface of the coating is so uneven that the shape of the indentation is difficult to see, buff it with a # 8000 diamond paste so that the indentation shape can be observed.

It is not clear why the increase in hardness causes a decrease in the coefficient of friction, but the following is considered. Generally, the friction force is proportional to the true contact area and the load. When the solids come into contact with each other, the microscopic projections such as surface roughness and undulation do not contact the entire macroscopic contact surface. This is the true contact area. As the true contact area increases, the friction force increases, and the friction coefficient also increases. The true contact surface, which is a protruding portion, transits to plastic deformation beyond the elastic limit as the load increases, and the true contact area increases. Here, when the surface hardness is increased, the elastic modulus and elastic limit of the substance are also increased, so that the deformation amount is reduced even under the same load, and the true contact area is reduced. That is, an increase in surface hardness reduces the true contact area, and consequently,
Reduce frictional force.

(Surface Roughness of Coating) As for the surface roughness of the hard coating, the center line average roughness Ra is desirably 0.005 μm or more and 0.2 μm or less.

If the surface roughness of the hard coating is within the above range,
The coefficient of friction in lubricating oil can be reduced. The above-mentioned true contact area increases when there are many protrusions on the surface, that is, when Ra is large. Therefore, when Ra is 0.2 μm or less, the coefficient of friction in the lubricating oil is lower than that of a coating having merely high hardness (1800 or more and 8000 or less). The lower the surface roughness, the better, but Ra
It is technically difficult to produce a coating of less than 0.005 μm. Therefore, to achieve a lower coefficient of friction, Ra
It is preferable that the thickness be 0.005 μm or more and 0.2 μm or less. The surface roughness Ra is measured according to the method specified in JIS B0601. Specifically, the measurement distance is 2.5 mm, the measurement speed is 0.3 mm / s, and the cut-off value is 0.8 mm.

Among the factors that determine the surface roughness of the hard coating, the most important factor is the surface roughness of the substrate on which the coating is formed. For this reason, Ra is reduced by lapping the base material surface with an abrasive or a grindstone before forming a coating. If Ra is about 0.2 μm, it can be achieved by grinding. In addition, in the coating forming method, in the case of RF excitation plasma CVD method, ion beam evaporation method, sputtering method, etc.
A film with significantly reduced surface roughness can be formed.However, in the case of vacuum arc discharge vapor deposition, in order to reduce the surface roughness to 0.02 μm or less, use a polishing agent or grindstone to wrap the film after film formation. It is effective to do it.

It is preferable that both the above-mentioned conditions of hardness and surface roughness are provided. Among them, Ra (μm) × Hk
When (kg / mm ² ) = A, a film that satisfies that the numerical value A is 500 or less is desirable for keeping the opponent aggressiveness small. When the hardness of the coating film is high, the aggressiveness of the partner increases (the amount of wear of the partner material increases). Also, the opponent aggressiveness is enhanced by the rough surface roughness. However, the above numerical value A
By setting the surface roughness to 500 or less, it is possible to reduce the opponent's aggressiveness by reducing the surface roughness even if the hardness is high, and to reduce the opponent's aggressiveness by reducing the hardness even when the surface is rough. . In particular, to keep opponent aggression low,
Preferably it is 300 or less.

(Spectral Shape of Coating) The hard coating preferably has a peak at a wave number of 500 to 1,000 cm ^-1 in the Raman spectrum.

This Raman spectrum is obtained by Raman spectroscopy using an argon ion laser having a wavelength of 514.5 nm. More specifically, after removing the background from the waveform of the obtained spectrum, the peak waveform is separated by a Gaussian function, and each peak is optimized by the nonlinear least squares method.

[0038] In the hard coating of the present invention, during the 500～1000Cm ^-1, a peak waveform is observed in the total three places around 1340 cm ^-1 and near 1560 cm ^-1. No peak between 500 and 1000 cm ^-1 is observed for conventional hard coatings made by CVD. By adopting a coating structure having a peak between 500 and 1000 cm- ¹ , a further lower coefficient of friction can be realized.

Further, the wave number is 500 to 1000 cm.^-1Exists below
Peak intensity (I600) and 1340cm ^-1Exists nearby
The intensity ratio (I600 / I1340) to the peak intensity (I1340) is 0.0
If it is 2 or more and 2.5 or less, low friction coefficient and high wear resistance are possible.
It works.

[0040] This is because the amount of SP ³ bond with graphite or distortion of micro size increases, considered the friction coefficient is reduced. Here, the peak intensity (height) is used to organize, but it also corresponds to the peak integrated intensity ratio,
The peak integrated intensity ratio (S600 / S1340) is desirably 0.01 or more and 2.5 or less. When the peak integrated intensity ratio is less than 0.01, the coefficient of friction and the wear resistance are equivalent to those of the conventional hard coating. Further, in an embodiment of the present invention described later, it was not possible to produce a coating film having a peak intensity ratio of 2.5 or more.

It is preferable that these hard coatings consist essentially of carbon only. In the case of a hard coating consisting essentially of carbon, a peak is observed at 500 or more and 1000 cm ^-1 or less.

Further, the ratio of the hard film which is substantially made of only carbon, and integrated intensity of the peak around 1340 cm ^-1 and the integrated intensity of the peaks (S1560) in the vicinity 1560 cm ^-1 in the Raman spectrum (S1340) (S1340 / S1560) is 0.
When it is 3 or more and 3 or less, it shows a low coefficient of friction and high wear resistance. The conventionally proposed hard coating is mainly applied to a hydrogen-containing hard coating, and has a different film composition from the hard coating of the present invention.

Furthermore, it corresponds not only to the integrated intensity of the peak, but also to the peak intensity (height) ratio (I1340 / I1560). When it is 0.1 or more and 1.2 or less, it shows a low friction coefficient and high wear resistance. These peak intensity near 1560cm- ¹ and 1340c
m ratio of the peak intensity in the vicinity of ^-1, gratuitous both SP ^{2 /} SP ³ ratio, represents the abundance of bound states of the coating inside the carbon (SP ^2, SP ^3). These peak intensity ratio, but not indicate the content of direct SP ^2, it is possible to perform the ranking of the relative content. It was found that when the peak intensity around 1560 cm ^-1 was high, the friction coefficient was further reduced. That is, the coefficient of friction is reduced when SP ³ bonding is strong, the wear resistance was improved. If S1340 / S1560 is the case of a low SP ³ bond to beyond 3 and I1340 / I1560 exceeds 1.2, the friction coefficient and wear resistance were comparable to conventional hard coating. In addition, S1340 / S1560 is less than 0.3 and I1
When 340 / I1560 is less than 0.1, SP ³ bonding is increased, adhesion mosquito sufficient coating can not be obtained, could not withstand practical use.

Then, the sample substantially consists of only carbon, and the “peak near 1560 cm ⁻¹ ” in the Raman spectrum is 156.
If present between 0 cm ^-1 or more 1580 cm ^-1 or less, a low friction coefficient, high wear resistance can be realized. The peak position of the Raman spectrum is affected by the stress in the coating. In general, when the stress in the coating is high on the compression side, the Raman peak shifts to the high wavenumber side, and conversely, when the stress in the coating is high on the tension side, it shifts to the low wavenumber side. It has been found that the higher the stress of the hard coating on the compression side (the peak is on the higher wave number side), the lower the coefficient of friction and the higher the abrasion resistance. As a result of calculating this compressive stress by the amount of change in warpage before and after the synthesis of the base material (cantilever method),
The value was −4 GPa or more and −10 GPa or less. The compressive stress value and the peak position of the Raman peak near 1560 cm ^-1 showed a substantially proportional relationship as shown in the graph of FIG.

By Raman spectroscopy, a hard coating having all of the above characteristics exhibits the lowest coefficient of friction and the highest wear resistance in the present invention.

(Coating Density) The coating density is preferably from 2.6 to 3.6 g / cm ³ from the viewpoint of lowering the friction coefficient and improving the wear resistance. In particular, it is desirable that substantially only carbon is contained in this density range. For the measurement of the density, a value obtained by dividing the change in weight of the substrate before and after film formation by the deposition volume was used. In addition, a method of obtaining from plasmon energy in EELS (electron energy loss spectroscopy) or XPS (X-ray photoelectron spectroscopy) is also effective.

[0047] (SP ² bond ratio) of the carbon component having SP ² bond in the hard coating is desirably 1~40at.%. It has already been mentioned that SP ² binding affects the wear resistance and coefficient of friction of the coating under lubricating oil. When the carbon component having the SP ² bond is in the above range, it is effective for lowering the friction coefficient and improving the wear resistance. Various methods have been proposed for quantifying the binding ratio. In the present invention
By EELS, the peak intensity attributable to SP ² bonded carbon in the spectrum of the sample was determined for graphite (100 at.
%), And the SP ² ratio was determined by normalizing the peak intensity.

(Thickness of Coating) The thickness of the entire coating (if an intermediate layer described later is present, the thickness of the intermediate layer is not included) is 0.05 to
The thickness is preferably 100 μm. When the thickness is less than 0.05 μm, the period during which the friction coefficient can be reduced in a sliding state is short,
Not suitable for practical use. Conversely, if it exceeds 100 μm, the coating becomes brittle and easily broken. A more desirable range is 0.05 μm to 10 μm
m, and a more desirable range is 0.1 μm to 10 μm.

(Substrate) The above-mentioned hard coating is formed on a substrate. The substrate is preferably a component of an internal combustion engine. In particular, it is not used where the load area is light, such as a magnetic recording medium, and higher durability is required in the field of high load (1 kg / mm ² or more) mechanical parts and sliding parts. It is suitable to be applied to such parts.

The material of the substrate is not particularly limited. At least one selected from the group consisting of ceramics, iron-based alloys, aluminum alloys, and iron-based sintered bodies is suitable.
Examples of the ceramic include silicon nitride, alumina, zirconia, and the like. High-speed steel,
Examples include stainless steel and SKD. Examples of the aluminum alloy include duralumin. Further, a WC-based cemented carbide or cermet may be used.

(Formation of Intermediate Layer) Each of the above-mentioned coatings may be formed directly on the substrate, but an intermediate layer 12 (see FIGS. It is preferable to increase the force. As the material of the intermediate layer, a material having a coefficient of linear expansion between the substrate and the coating is preferable. For example, Periodic Table IV
a, Va, VIa group elements, iron group metals, Al and Si, and at least one selected from carbides, nitrides and carbonitrides thereof. This intermediate layer is based on Periodic Table 4
a, 5a, 6a group elements and their nitrides, carbides,
It is effective to use carbonitride as a single layer, but more effectively, a layer (metal layer) composed of an element of the periodic table 4a, 5a, or 6a or Si is disposed on the surface of the base material. These nitride, carbide and carbonitride layers (compound layers) are arranged on the film side. In this case, it is also effective that the transition from the metal layer to the compound layer is continuous in composition, that is, the element contents of carbon and nitrogen are continuously changed. Further, the transition from the compound layer to the amorphous layer may be stepwise in terms of composition, but the carbon content may be continuously increased. The thickness of such an intermediate layer is preferably 0.01 μm or more and 1 μm or less in order to improve the adhesion between the hard coating and the substrate.

(Method for Forming Coating) As means for forming the coating (including the intermediate layer), there are RF plasma CVD, DC magnetron / unbalanced magnetron sputtering, vacuum arc discharge evaporation, ion beam evaporation. ,
Laser ablation method and the like can be mentioned.

A layer in which another compound is composited in a granular form can be formed mainly by changing the film forming material and adjusting the film forming time.
That is, in the growth of the film, nuclei are first formed on the substrate surface,
This nucleus grows into numerous islands. Each of these islands grows and is integrated with an adjacent island to form a layered film. Therefore, before each island merges with the adjacent island, a film is formed with another material, and a film in which another material has penetrated between the islands is formed. If you look at it, you will be in a state where another compound is compounded in a granular form in another material.

In addition, the coating of the laminated structure is formed by completely changing the supply material to another material after the film is completely formed in the process of forming a film with a certain raw material, and until the material after the change is completely formed into a film. The film can be formed by continuing the film and repeating this process.

(Formation of coating) The coating is formed at a location where abrasion resistance is required. For example, of the base material, the surface that slides with the counterpart material, that is, the entire sliding surface is preferable, but may be a part of the sliding surface according to the shape of the base material.

[0056]

Embodiments of the present invention will be described below. A coating containing carbon as a main component was formed on a substrate directly or via an intermediate layer, and the presence or absence of peeling of the coating, the coefficient of friction, and the amount of wear were examined. The following conditions correspond to Test Examples 1 to 4 described below.
Is common in

As the base material, a WC-based cemented carbide, Si ₃ N ₄ , Al ₂ O ₃ ,
Al-based alloy, SKH51, SUS304c, SCM415 were used.

The film is formed by RF plasma CVD (RF-CV
D), ion plating (IP), vacuum arc discharge evaporation (VAD), and sputtering (SP) were used. RF-C
VD / IP is a method in which each is used in combination. RF
When using a -CVD, hydrocarbon gas (CH _4), using ammonia or N ₂ and hydrogen. When adding a metal element, it is added in a gaseous state such as chloride or alkoxide, or a solid raw material is evaporated. In the VAD method, a film was formed by using a metal or ceramic solid evaporation source with an atmosphere gas of a hydrocarbon-Ar system or using a carbon and metal or ceramic solid evaporation source without an Ar gas atmosphere or an atmosphere gas. In the SP method, carbon and metal or ceramic solid evaporation sources were sputtered in an Ar atmosphere using RF-magnetron sputtering. The specific condition range of each film forming method is as shown in Tables 1-4. Table 1 shows RF-CVD conditions, Table 2 shows VAD conditions, Table 3 shows SP conditions, and Table 4 shows IP conditions.
Are shown.

[0059]

[Table 1]

[0060]

[Table 2]

[0061]

[Table 3]

[0062]

[Table 4]

The material of the intermediate layer is TiN, TiCN, Al ₂ O ₃ , SiC
And the thickness is about 0.05 to 1.5 μm.

The sliding member used for the abrasion evaluation is a sample in which no peeling is observed after film formation or a sample in which the substrate itself is not deteriorated. The evaluation results are shown in Tables 5 to 10, in which the evaluation was performed by a circle and the evaluation was not performed by a cross. The evaluation was performed by a ball-on-disk test method. Opponent material is φ6mm SUJ2 ball, sliding radius 1mm, rotation speed 500rp
m, total rotation speed 10,000 times, load 10N, engine oil (10W
-30) Test under the conditions described in (3) and measure the frictional force. And
The friction coefficient was determined, and the groove cross-sectional area of the wear mark after the test was measured using a surface roughness meter to evaluate the wear resistance.
For comparison, Comparative Example 1 in which a coating was not formed on the SUS304 substrate was also prepared. The abrasion resistance was represented by the ratio of the cross-sectional area of the wear mark in each sample, with the cross-sectional area of the wear mark of DLC as Comparative Example 1 being 100. “Amount of wear” in each table indicates this cross-sectional area ratio. The coefficient of friction and the cross-sectional area ratio of wear marks are the average values of the samples that were evaluated. "With / without addition" indicates whether or not dodecylbenzene was added to the engine oil. The ratio of carbon forming the benzene nucleus of dodecylbenzene to the total carbon content in the lubricating oil was 10% by weight.

(Test Example 1) The above-described test was performed on samples having the coating structures shown in FIGS. Table 5 shows the results. The “other compounds” in each example of Table 5 are all amorphous. For example, in a sputtering method or a vacuum arc discharge evaporation method, "another compound" can be made amorphous by discharging each evaporation source simultaneously.

[0066]

[Table 5]

As shown in Table 5, Nos. 1-1 to 1-5 are coatings composed only of carbon, and Nos. 1-6 to 1-23 are coatings in which carbon forms a compound with another element. Film. It can be seen that the friction coefficient of any of the samples was reduced by containing dodecylbenzene in the lubricating oil. In addition, the film formation method is “RF
Since the peeling of the film was observed in a part of the film of “-CVD / IP”, another film forming method is preferable.

(Test Example 2) The above test was performed on a sample having the coating structure shown in FIG. 3 (A). That is, the coating in this sample is a coating composed of only DLC and other compounds are combined in a granular form. The test results are shown in Tables 6 and 7. In this table, "other compound constituent elements"
The constituent elements of "other compound particles 5" in (A) are shown, and the "particle size" indicates the outer diameter thereof.

[0069]

[Table 6]

[0070]

[Table 7]

As shown in Tables 6 and 7, it can be seen that the friction coefficient of each of the samples is reduced by containing dodecylbenzene in the lubricating oil. In addition, the film formation method is “RF-
Since the peeling of the coating film was observed in a part of the sample of “CVD / IP”, another film forming method is preferable. WC based cemented carbide substrate, those with _{Si 3 N 4, Al 2 0} 3 , the release of the film was not observed in any of the film forming method.

(Test Example 3) The above test was performed on a sample having the film structure shown in FIG. 3 (B). In this test example,
An intermediate layer was formed on the sample. Tables 8 and 9 show the test results. In this table, "Other compound layer" refers to Fig. 3 (B)
Indicates the constituent elements of the “other compound layer 7”, “other compound layer thickness” indicates the thickness of one layer of “other compound layer 7”, and “C layer thickness” indicates “from only DLC”. The thickness of one layer of the “coating layer 6” is shown, and the “film thickness” indicates the thickness of the entire coating layer. In this test example, no peeling of the coating film was observed in any of the samples in any of the film forming methods, and thus the evaluation (O / X) was omitted.

[0073]

[Table 8]

[0074]

[Table 9]

As shown in Tables 8 and 9, it can be seen that the friction coefficient of each of the Examples is lower than that of Comparative Example 1.

(Test Example 4) The above-described test was performed on a sample having the coating structure shown in FIG. In this test example, an intermediate layer was formed in all samples. Table 10 shows the test results. In this test example, no peeling of the coating film was observed in any of the samples in any of the film forming methods, and thus the evaluation (O / X) was omitted. In this table,
“Layer 1” means “remainder 9” described in FIG. 4 (A) or FIG.
FIG. 4B shows the “first layer 10”, and “layer 2” refers to FIG.
The “granular portion 8” described in (A) or the “second layer 11” illustrated in FIG. 4B is shown. In addition, "layer 1 structure", "layer 2 structure"
Means that the structure of each of these layers is as shown in FIG. 2, FIG. 3 (A) or FIG.
(B) is shown. Therefore, FIG.
In the case of taking the structure of (A), the column of “elements of layer 1 or layer 2” shows the elements of “other compound particles”. Further, the “film structure” indicates whether the overall configuration of the coating is either FIG. 4 (A) or FIG. 4 (B).

For example, in No. 4-4, the entire structure is as shown in FIG.
The “first layer” is composed of “a layer in which Cr is composited in the form of particles in DLC”, and the “second layer” is “a compound of N and Ti” in the DLC. Particle-Compounded Layer "
It is composed of No.4-1 shows the overall structure
(A) is a granular composite structure, the "remainder" of which
The "granular portion" is further composed of "a material in which" compound of C and Si "is combined in DLC in a particulate form".

[0078]

[Table 10]

As shown in Table 10, it can be seen that each of the examples has a lower coefficient of friction and a smaller amount of wear than Comparative Example 1.

(Test Example 5) A carbon film was formed on a substrate by an RF excitation plasma CVD method and a vacuum arc discharge vapor deposition method, and the characteristics of the obtained film were tested. The base material used was a high-speed steel, stainless steel, an iron-based alloy such as SKD, an aluminum alloy, or an iron-based sintered body. The substrate is subjected to ultrasonic cleaning in acetone for 10 minutes or more to clean the surface.

FIG. 5 shows an RF-excited plasma CVD apparatus. This apparatus comprises a horizontal plate-shaped substrate holder 22 in a vacuum chamber 21 and a heater on a side of the vacuum chamber facing the substrate holder 22 with the substrate holder 22 interposed therebetween.
23 are installed. The high frequency power supply 4 and the DC power supply 25 are connected to the substrate holder 22. The vacuum chamber 21 has a gas inlet 26 and a gas outlet 27.

In such an apparatus, the RF excitation plasma CV
When the film is formed by the method D, the source gas is CH ₄ , C ₂ H ₂ , C ₆ H
₆ is used. After setting the substrate 28 in the substrate holder 22 in the vacuum chamber 21, the inside of the apparatus is set to a gas exhaust port 27 of 2 × 10 ⁻⁵ Torr or less.
Evacuate from. After the temperature of the heater 3 in the apparatus is raised to a predetermined temperature, Ar gas is introduced from the gas inlet 26 into the vacuum chamber 21 to make the inside of the apparatus 20 mTorr. At the same time, a DC voltage of -1000 V is applied to the substrate holder 22 to generate Ar plasma, and an “Ar bombarding process” for removing contamination on the substrate surface by colliding Ar ions with the substrate 28 is performed. Then, Table 11
The film was formed under the following conditions.

[0083]

[Table 11]

FIG. 6 shows a vacuum arc discharge vapor deposition apparatus. This apparatus comprises a horizontal disk-shaped rotary table 11 in a vacuum chamber 30 and a substrate holder fixed vertically to the rotary table 31.
With 32. Targets 33 (cathode electrodes) are provided on opposite vacuum chamber side walls with the substrate holder 32 interposed therebetween, and each target 33 is connected to a DC power supply 34. Also, the substrate holder 32
, A predetermined voltage can be applied from a DC power supply 35 connected to the turntable 31. The vacuum chamber 31 is provided with a gas inlet 36 and a gas exhaust port 37.

In such an apparatus, solid carbon is used as the target 13. After the substrate 38 is set in the vacuum chamber 30, the inside of the apparatus is evacuated to 2 × 10 ⁻⁵ Torr or less from the gas exhaust port 37. Thereafter, Ar gas is introduced into the vacuum chamber 30 from the gas inlet 36, and the inside of the apparatus is set to 20 mTorr. At the same time, a DC voltage of -1000 V is applied to the substrate holder 32 to perform an Ar bombarding process. Next, a hard carbon film was formed under the conditions shown in Table 12 while introducing Ar gas into the vacuum chamber or evacuating without introducing gas.

[0086]

[Table 12]

The hardness was measured using a Knoop indenter made of diamond with a load of 50 g and a load application time of 10 seconds.
The average value of the points was adopted. When the unevenness of the coating surface was so large that the shape of the indentation was difficult to see, buffing was performed with a # 8000 diamond paste so that the indentation shape could be observed.

The surface roughness was an average value measured at eight points with a measurement distance of 2.5 mm, a measurement speed of 0.3 mm / s, and a cut-off value of 0.8 mm.

The coefficient of friction was measured using a pin-on-disk tester. Test conditions are: load weight 10N, rotation speed 104mm
The friction coefficient was measured in an atmosphere in engine oil using SUJ2 having a diameter of 6 mm / s and a mating member of SUJ2. Engine oil is 10
For W-40-SH, the test temperature is room temperature.

The surface roughness of the carbon film formed by the RF excitation plasma CVD method is mainly changed by lapping the base material surface from the grinding process using an abrasive, and changing the lapping time and the abrasive particle size. Adjust by doing. The carbon film formed by the vacuum arc discharge evaporation method was also changed mainly depending on the processing state of the substrate surface.
When the thickness was less than 0.02 μm, the surface of the carbon film was wrapped using a diamond paste. These surface roughness adjusting means are the same in each embodiment described later.

Table 13 shows that, for a coating having a surface roughness exceeding Ra = 0.2 and a Knoop hardness of 1800 or more and 8000 or less, the surface roughness Ra,
The film hardness, substrate type, film thickness, and coefficient of friction were summarized. As a comparative example, the friction coefficient of Comparative Example 5-1 where Ra exceeded 0.2 and Knoop hardness was 1738 was measured. That is, a coating having a hardness of 1800 or more and 8000 or less is effective in reducing the friction coefficient. The coating of the present invention is composed of carbon in an atomic percentage of 60% or more, and XRD: (X-ray diffractio
Analysis by n) confirmed that it was amorphous. These points are the same in the coating of the present invention in Tables 14 and 15 described below and in each of Examples described later.

[0092]

[Table 13]

Table 14 shows that the Knoop hardness is 1800 or less and Ra
The surface roughness Ra, coating hardness, substrate type, film thickness, and coefficient of friction were summarized for coatings having a value of 0.005 to 0.2. The coefficient of friction is lower than that of Comparative Example 5-1. In other words, if the coating Ra is 0.005 or more and 0.2 or less, the hardness is 1800
It is effective to reduce the coefficient of friction even if it is below.

[0094]

[Table 14]

Table 15 summarizes the surface roughness Ra, coating hardness, substrate type, film thickness, coefficient of friction, and torque reduction rate for coatings having a Knoop hardness of 1800 or more and 8000 or less and Ra of 0.005 or more and 0.2 or less. Was. FIG. 7 shows the relationship between the hardness and the coefficient of friction. In Table 13, Comparative Example 5-1 is plotted as x, a coating having a surface roughness Ra exceeding 0.2 is plotted as Δ, and a coating having a surface roughness Ra of 0.005 or more and 0.2 or less is plotted as ○. Knoop hardness of 1800 or more and 8000
And the coefficient of friction is lowest when Ra is 0.005 or more and 0.2 or less.

[0096]

[Table 15]

(Test Example 6) First, ultrasonic cleaning is performed in acetone to clean the surface of the base material. Thereafter, various intermediate layers were formed by the RF bipolar sputtering method. The deposition conditions are as follows: the sputtering atmosphere gas is Ar gas, and the atmosphere pressure is
5 Pa, ambient temperature 400 ° C., target applied power 500 W, substrate holder applied power 20 W. After the formation of the intermediate layer, an amorphous carbon film is formed by RF excitation plasma CVD or vacuum arc discharge evaporation. The film formation method and the film formation conditions of the RF excitation plasma CVD method and the vacuum arc discharge vapor deposition method are based on Test Example 5.

The measurement of the coefficient of friction was also performed under the same conditions as in the pin-on-disk test of Test Example 5.

Tables 16, 17, and 18 summarize the intermediate layer, the thickness of the intermediate layer, the surface roughness Ra, the coating hardness, the type of the base material, and the film.

[0100]

[Table 16]

[0101]

[Table 17]

[0102]

[Table 18]

FIG. 8 shows the relationship between hardness and coefficient of friction. In Table 13, Comparative Example 5-1 is plotted as x, a coating having a surface roughness Ra exceeding 0.2 is plotted as Δ, and a coating having a surface roughness Ra of 0.005 or more and 0.2 or less is plotted as ○. This result also has a Knoop hardness of 1800 or more and 8000 or less and Ra of 0.
The coefficient of friction was lowest when the value was 005 or more and 0.2 or less. Therefore, the introduction of the intermediate layer had no adverse effect on the coefficient of friction.

Test Example 7 In order to determine the adhesion to the substrate, a critical peeling load was measured by a scratch test. A diamond cone with a tip radius of 200 μm is moved in the lateral direction while pressing it vertically. At this time, the pressing load is increased at 11.5 N / mm. AE (Acoustic emission) generated when the substrate peeled from the film was detected by a sensor, and the pressing load when AE occurred was defined as the critical peeling load. At this time, since the occurrence of AE and the actual peeling position may be different, the final determination of the peeling load was made visually.

As a test piece, a film in which an intermediate layer was provided on a substrate by a sputtering method and an amorphous carbon film was formed thereon was used. Table 19 shows the results. As a comparative example, an amorphous carbon film formed directly on a base material without forming an intermediate layer is shown. With the introduction of the middle class,
It was found that the adhesion was increased.

[0106]

[Table 19]

Test Example 8 A film was formed in the same manner as in Test Example 1 under the conditions shown in Tables 11 and 12. Hardness measurement,
The method for measuring the surface roughness is as described in Test Example 5.
The friction coefficient was measured using a pin-on-disk tester. The test conditions were as follows: The load coefficient was 10 N, the speed was 26 mm / s, the total slip distance was 290 m, and the friction coefficient was measured in engine oil using SUJ2 having a diameter of 6 mm as a mating pin. Engine oil is 10W-
At 40-SH, the test temperature is room temperature. The wear amount of the mating member after the friction test was replaced by the projected area of the wear mark on the pin.

Table 20 shows that, for a coating having a surface roughness exceeding Ra = 0.2 and a Knoop hardness of 2,000 to 6,000, the surface roughness Ra,
The film hardness, substrate type, film thickness, and coefficient of friction are summarized. As a comparative example, the friction coefficient of an amorphous carbon film having Ra of more than 0.2 and a Knoop hardness of 1738 (Comparative Example 8-5) was measured. Compared with Comparative Example 8-5, the coefficient of friction is reduced. In other words, a coating having a hardness of 2,000 or more and 6,000 or less is effective in reducing the coefficient of friction.

[0109]

[Table 20]

Table 21 summarizes the surface roughness Ra, coating hardness, substrate type, film thickness, and friction coefficient of coatings having a Knoop hardness of 2,000 or more and 6000 or less and Ra of 0.005 or more and 0.2 or less.

[0111]

[Table 21]

FIG. 9 shows the relationship between hardness and friction coefficient. Table 2
Comparative Example 8-5 of 0 is plotted as x, a film having a surface roughness Ra exceeding 0.2 is plotted as △, and a film having a surface roughness Ra of 0.005 or more and 0.2 or less is plotted as ○. The coefficient of friction is lowest when the Knoop hardness is 2000 or more and 6000 or less and Ra is in the range of 0.005 or more and 0.2 or less.

Table 22 shows the wear amount of the mating member pin SUJ2 for the samples described in Table 21. The wear amount is a projected area when the pin wear portion is viewed from the load pressing direction. TiN
The value obtained by standardizing the wear amount of the counterpart material of each coating by the wear amount of the counterpart material (hardness 1748, Ra = 0.113) (wear ratio = wear amount of the counterpart material of each coating / TiN (hardness 1748, Ra = 0.113) Table 22 also shows the wear amount of the counterpart material.

[0114]

[Table 22]

FIG. 10 plots the relationship between Ra (μm) × Hk (kg / mm ² ) and the wear ratio. As a result, it was found that the wear ratio of the amorphous carbon film was proportional to Ra (μm) × Hk (kg / mm ² ). In addition, the same Ra (μm)
Even at × Hk (kg / mm ² ), it was found that the amorphous carbon film had lower aggressiveness than the TiN, CrN and (Ti, Al) N films. In order for an amorphous carbon film to have a lower aggressiveness than other nitrides, Ra
(Μm) × Hk (kg / mm ² ) may be 500 or less. Therefore, if it is intended to achieve a lower opponent aggressiveness with a low coefficient of friction, a coating satisfying that the numerical value A is 500 or less when Ra (μm) × Hk (kg / mm ² ) = A is used. It turns out that it is desirable.

Test Example 9 An intermediate layer is formed by the same method and conditions as in Test Example 6. After that, RF excitation plasma CVD
The amorphous carbon film is formed by a vacuum method or a vacuum arc discharge evaporation method. The film formation method and the film formation conditions of the RF excitation plasma CVD method and the vacuum arc discharge vapor deposition method are based on Test Example 5.

The measurement of the coefficient of friction was also performed under the same conditions as in the pin-on-disk test of Test Example 1. Tables 23 and 24 summarize the intermediate layer, intermediate layer thickness, surface roughness Ra, coating hardness, substrate type, film thickness, and friction coefficient. FIG. 11 shows the relationship between hardness and friction coefficient. Comparative Example 5 in Table 20 is plotted as x, a film having a surface roughness Ra of more than 0.2 or less than 0.005 as Δ, and a film having a surface roughness Ra of 0.005 or more and 0.2 or less as ○. The coefficient of friction is lowest when the Knoop hardness is in the range of 2000 to 6000 and Ra is in the range of 0.005 or more and 0.2 or less. This is the same result as in Test Example 8, and the introduction of the intermediate layer had no adverse effect on the coefficient of friction.

[0118]

[Table 23]

[0119]

[Table 24]

(Test Example 10) A scratch test was performed in the same manner as in Test Example 7, and the adhesion between the substrate and the coating film was examined. The test method and conditions are the same as in Test Example 7. Table 2 shows the results
See Figures 5 and 26. As a comparative example, an amorphous carbon film formed directly on a base material without forming an intermediate layer is shown. It was found that the adhesion was increased by the introduction of the intermediate layer.

[0121]

[Table 25]

[0122]

[Table 26]

(Test Example 11) Next, the above-mentioned coating film was formed on a cam of an engine part, and the torque was measured by a motoring test. Examples 5-3, 6-2, 6-6, 7-5, 7-16, 8-14,
A motoring test was performed on 8-38, and a comparative example was obtained.
A torque reduction of 10 to 30% was confirmed as compared with 5-1.

(Test Example 12) Film formation was performed by RF magnetron sputtering (SP), unbalanced magnetron sputtering (UBM), and vacuum arc discharge evaporation (VAD).
It was formed by a hot filament CVD (HCVD) method. The base material used was a high-speed steel, stainless steel, an iron-based alloy such as SKD, an aluminum alloy, or an iron-based sintered body. In order to clean the surface of the substrate, ultrasonic cleaning is performed in acetone for 10 minutes or more.

In the RF magnetron sputtering method, a film was formed in an Ar gas atmosphere using a solid carbon target. RF power can be applied to the target and the substrate holder. In the example, a hard carbon coating having an arbitrary Raman spectrum shape was able to be produced by changing each condition at a substrate applied bias of 150 W or less, an atmospheric pressure of 4 Pa or less, and a substrate temperature of 873 K or less.

On the other hand, in the unbalanced magnetron sputtering method, a solid carbon target is introduced as a raw material, an argon gas containing 0 to 50% of CH ₄ , C ₆ H ₆ and C ₂ H ₂ is introduced into an atmosphere, and a pulse is applied to the target. DC was applied, and pulsed or non-pulsed DC was also applied to the substrate. In the embodiment, the substrate applied bias is 600 V or less, the atmospheric pressure is ₄ Pa or less, CH ₄ , C
By changing each condition under the addition amounts of ₆ H ₆ and C ₂ H ₂ and the substrate temperature of 873 K or less, a hard carbon film having an arbitrary Raman spectrum shape could be produced.

Also in the vacuum arc discharge deposition method, a film was formed using a solid carbon target. Vacuum or Ar
Cathodic arc discharge is generated on the surface of a carbon target in an inert gas atmosphere such as the above to vaporize carbon. Then, the vaporized carbon is ionized and activated by the arc plasma, reaches the negatively applied substrate, and deposits a hard carbon film. In the examples, a hard carbon film having an arbitrary Raman spectrum shape could be produced by changing each condition at an atmosphere pressure of 4 Pa or less, a substrate temperature of 873 K or less, and a substrate voltage of 300 V or less.

The hot filament CVD method uses CH_Four, C₆H₆as well as
C₂H₂In a hydrogen atmosphere, using a gas selected from
A film was formed. Atmospheric pressure at this time, filament-
Substrate distance, CH_Four, C₆H₆, C₂H₂By changing the amount,
Hard carbon coating with arbitrary Raman spectrum shape
Could be produced. In particular, the embodiment is CH_Four, C
₆H ₆, C₂H₂Can be realized by reducing the volume to 50 vol% or less.
You.

By the above method, hard carbon films having different thicknesses were formed. The obtained film is subjected to Raman spectroscopic analysis by an argon ion laser having a wavelength of 514.5 nm. For the obtained spectrum, background removal and waveform separation using a Gaussian function were performed, and peak intensity and peak integrated intensity were calculated. The peak is 500cm ^{- 1}
During the ～1000Cm ^-1, it is separated into three peaks present 1340cm around ^-1, around 1560 cm ^-1.

The obtained hard carbon film was subjected to a friction and wear test by a pin-on-disk method. Atmosphere is lubrication by dropping 10W-30SG of gasoline oil, light oil and engine oil, hard carbon film disk, mating material is SUJ2 pin with tip radius R3mm, load 10N, rotation speed 250rpm (sliding speed 50mm / sec) ), The number of rotations was 50,000 times. At the end of the 50,000 sliding tests, the coefficient of friction was measured. After the sliding test, the shape of the disc wear mark was measured with a surface roughness meter, and the wear cross-sectional area was calculated from the geometric shape. And the comparative example
The wear amount of each film when the wear amount of 12-4 was set to 1 is shown in the table. In addition, the thickness and hydrogen content of each hard carbon film were measured. The results are shown in Tables 27 and 28.

[0131]

[Table 27]

[0132]

[Table 28]

(Test Example 13) Subsequently, the outer circumference of a φ8 mm shaft
In Examples 12-2, 4, 8, 10, 16, 20, 22, 23, 25, 27,
29 and 31 hard carbon films were formed. Then,
Made of silicon or Al₂O ₃Engine in combination with bearings made of
It was used under lubrication by dropping oil 10W-30SG. Comparative example
12-1 to 4
The decay life and the amount of wear increased 1.5 to 4 times.

(Test 14) Next, the piston skirt of the engine made of aluminum alloy AC8A was placed on the piston skirts of Examples 12-2, 4 and
Hard carbon films of 8, 10, 16, 20, 22, 23, 25, 27, 29 and 31 were formed and used under lubrication by dropping engine oil 10W-30SG. When these frictional resistances were measured,
A reduction in friction coefficient of about 20 to 80% was observed as compared with Comparative Examples 12-1 to 12-4.

(Test Example 15) Next, Examples 12-3, 7, 11, 16, 20, 21, 24, 26, 28, and 3 were applied to the shim surface of the valve.
Form a hard carbon coating of 0, engine oil 10W-30S
The cam torque was measured under lubrication by dropping G. Comparative Examples 12-1 to 1.5 compared with the coating formed 1-4
A decrease of about 60% was observed.

Test Example 16 A hard coating was formed on a substrate by the same film forming method as in Test Example 12, and the friction coefficient and the wear amount were measured by the same test. The wear amount is standardized with the wear amount of Comparative Example 16-1 as 1. The density of the obtained hard coating was also determined. The density was determined by dividing the weight change of the substrate before and after film formation by the deposition volume. Table 29 shows the test conditions and results.
Shown in

[0137]

[Table 29]

As shown in this table, it can be seen that each of the examples having a density of 2.6 g / cm ³ or more has a smaller coefficient of friction and a smaller amount of wear than Comparative Example 16-1.

Test Example 17 A hard film was formed on a substrate by the same film forming method as in Test Example 12, and the friction coefficient and the wear amount were measured by the same test. The wear amount is standardized with the wear amount of Comparative Example 17-1 as 1. In addition, the amount of carbon component having SP ² bonds in the obtained hard coating was also determined. The carbon component amounts, the intensity of the peak due to SP ² bonded carbon in the spectrum of the sample by EELS, was determined by normalizing the peak intensity in the case of the graphite (100at.%). Table 30 shows the test conditions and results.

[0140]

[Table 30]

As shown in the table, each of the examples in which the carbon component having an SP ² bond is in the range of 1 to 40 at.
It can be seen that the coefficient of friction is smaller and the amount of wear is smaller than that of 17-1.

Incidentally, the hard coating and the coated part of the present invention are not limited to the above-mentioned specific examples, and it is a matter of course that various changes can be made without departing from the gist of the present invention.

[0143]

As described above, according to the present invention,
By providing a coating containing carbon as a main component on the surface of the base material and using the coating in the presence of a lubricant, the friction coefficient can be reduced and the wear resistance can be increased. Therefore, in order to improve wear resistance, sliding characteristics, corrosion resistance and surface protection function, it is expected to be used as a sliding member used via lubricating oil in the fields of industry and households. In particular, it is expected to be used for sliding parts of automobile engines, fuel pumps, various machines, and the like.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a sliding member of the present invention having a coating made of only DLC.

FIG. 2 is a cross-sectional view of the sliding member of the present invention having a coating in which DLC and another compound are bonded.

FIG. 3 (A) is a cross-sectional view of the sliding member of the present invention in which another compound is compounded in a layer made of only DLC, and FIG.
It is sectional drawing of the lead member of this invention which made the layer which consists only of LC, and another compound layer into laminated structure.

FIG. 4A is a cross-sectional view of the sliding member of the present invention in which a granular portion is compounded in the remaining portion, and FIG. 4B is a cross-sectional view of the leading member of the present invention in which a first layer and a second layer have a laminated structure. FIG.

FIG. 5 is a schematic view of an RF excitation plasma CVD apparatus.

FIG. 6 is a schematic view of a vacuum arc discharge vapor deposition apparatus.

FIG. 7: Knoop hardness is 1800 or more and 8000 or less, and Ra
3 is a graph showing the relationship between hardness and coefficient of friction for films having a value of 0.005 or more and 0.2 or less.

FIG. 8 is a graph showing the relationship between hardness and coefficient of friction in the coating of the present invention having an intermediate layer formed thereon.

FIG. 9: Knoop hardness is 2000 or more and 6000 or less, and Ra
3 is a graph showing the relationship between hardness and coefficient of friction for films having a value of 0.005 or more and 0.2 or less.

FIG. 10 is a graph showing a relationship between Ra × Hk and a wear amount ratio.

FIG. 11 is a graph showing the relationship between the hardness and the coefficient of friction in the coating of the present invention having an intermediate layer formed thereon.

12 is a graph showing the relationship between stress and SP ³ peak position.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Base material 2 Coating 3 Compound layer 4 Coating layer consisting only of carbon and nitrogen 5 Other compound particles 6 Coating layer consisting only of carbon and nitrogen 7 Other compound layer 8 Granular part 9 Remaining part 10 First layer
11 Second layer 12 Intermediate layer 21, 30 Vacuum tank 22, 32 Substrate holder 23
Heater 24 High frequency power supply 25, 34, 35 DC power supply 26, 36 Gas inlet 27, 37 Gas outlet 28, 38 Base material 31 Rotary table
33 targets

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C23C 14/06 C23C 14/06 FM 16/27 16/27 16/30 16/30 28/00 28 / 00 B // C10N 30:06 C10N 30:06 30:12 30:12 40:02 40:02 F term (reference) 4H104 AA04A AA08A AA12A AA17A AA21A BA03A EA08A FA03 FA04 FA05 FA06 FA08 JA01 LA03 LA06 PA01 PA33 PA34 QA12 RA01 4K029 AA02 AA04 BA01 BA03 BA06 BA07 BA09 BA11 BA12 BA16 BA17 BA34 BA35 BA54 BA55 BA58 BB02 BB10 BC02 BD04 EA01 4K030 BA02 BA10 BA18 BA22 BA27 BA36 BA37 BA38 BA41 BA56 BA57 BA58 BB05 CA02 CA03 CA05 JA01 A01A23 A03 A04 A03 A03 A02 A03 A03 A02 A03 A03 A03 A03 A03 A02 BA11 BA13 BA18 BB02 BB17 BC01 BC02 BC06 CA13 CA14

Claims (27)

[Claims] 1. A hard coating which is used in the presence of a lubricant and comprises a carbon-based layer. 2. The hard coating according to claim 1, wherein the hard coating consists essentially of only carbon and hydrogen. 3. The hard coating is further selected from the group consisting of elements IVa, Va, VIa, iron group metals, Al and Si, and carbides, nitrides and carbonitrides thereof, as other compounds. 2. The hard coating according to claim 1, wherein the other compound is amorphous. 4. The hard coating according to claim 1, wherein a layer containing carbon as a main component and another compound layer are alternately laminated, and the other compound layer is made of a group IVa, Va, VIa element or an iron group of the periodic table. A metal, Al and Si, and at least one selected from carbides, nitrides and carbonitrides thereof, wherein the other compound layer has a thickness per layer of 0.0005 to 0.6 μm. The hard coating according to 1. 5. The hard coating, wherein another compound is granularly compounded in a layer containing carbon as a main component, and the other compound is a group IVa, Va, group VIa element, an iron group metal, The hard coating according to claim 1, comprising Al and Si, and at least one selected from carbides, nitrides and carbonitrides thereof, wherein the other compound has a particle size of 0.001 to 0.5 µm. . 6. The hard coating according to claim 1, wherein the thickness of the hard coating is 0.05 to 100 μm. 7. The hard coating is amorphous and has a Knoop hardness.
(Hk) is 1800kg / mm ²More than 8000kg / mm²Must be
The hard coating according to claim 1, wherein: 8. The hard coating is amorphous and has a surface roughness.
The hard coating according to claim 1, wherein Ra is not less than 0.005 µm and not more than 0.2 µm. 9. The hard coating is amorphous and has a Knoop hardness.
(Hk) is 1800kg / mm ²More than 8000kg / mm²Below and
Surface roughness Ra is 0.005 μm or more and 0.2 μm or less
The hard coating according to claim 1, wherein: 10. The hard coating according to claim 9, wherein A when Ra × Hk = A is 500 or less. 11. Knoop hardness of 2000 kg / mm ² or more, 6000 k
The hard coating according to claim 7, wherein the hardness is not more than g / mm ² . 12. The hard material according to claim 1, wherein the Raman spectrum obtained by Raman spectroscopy using an argon ion laser having a wavelength of 514.5 nm has a peak at a wave number of 500 or more and 1000 cm ^-1 or less. Coating. 13. wavenumber 500 above 1000 cm ^-1 intensity of peaks present below (I600) and 1340cm intensity of peaks present in the vicinity of ^-1 (I1340) and the intensity ratio of the (I600 / I1340) of 0.02 to 2.5 or less 13. The hard coating according to claim 12, wherein: 14. integrated intensity of a peak existing near 1340 cm ^-1 and the integrated intensity of the peak (S600) existing in a wave number of 500 or more 1000 cm ^-1 or less (S1340) and the intensity ratio of (S600 / S1340)
14. The hard coating according to claim 12, wherein is not less than 0.01 and not more than 2.5. 15. Substantially only carbon, 514.5 nm
Raman spectrum obtained by Raman spectroscopy using an argon ion laser having a wavelength of 1560
hard of claim 1 cm ^-1 vicinity of the peak intensity (I1560) and 1340 cm ^-1 vicinity of the peak intensity (I1340) and the ratio of (I1340 / I1560) is characterized in that 0.1 to 1.2 Coating. 16. Substantially only carbon, 514.5 nm
Raman spectrum obtained by Raman spectroscopy using an argon ion laser having a wavelength of 1560
Ratio (S1340 / S1560) between the integrated intensity of the peak near cm- ¹ (S1560) and the integrated intensity of the peak near 1340cm- ¹ (S1340)
3. The hard coating according to claim 1, wherein is not less than 0.3 and not more than 3. 17. Substantially only carbon, 514.5 nm
Raman spectrum obtained by Raman spectroscopy using an argon ion laser having a wavelength of 1560
hard coating according to claim 1, peak near cm ^-1 is characterized by the presence in the 1560 cm ^-1 or 1580 cm ^-1 or less. 18. The coating density of the hard coating is 2.6 to 3.6 g.
2. The hard coating according to claim 1, wherein the ratio is / cm ³ . 19. The hard coating according to claim 1, wherein the hard coating consists essentially of carbon only. 20. The hard coating according to claim 1, wherein a carbon component having an SP ² bond in the hard coating is 1 to 40 at.%. 21. The film thickness of the hard coating is 0.05 μm to 10 μm.
The hard coating according to any one of claims 7 to 20, wherein m is m. 22. The hard coating according to claim 1, wherein the lubricant contains an aromatic compound. 23. A lubricant comprising: engine oil, light oil, gasoline oil, gear oil, turbine oil, spindle oil, machine oil,
The hard coating according to claim 1, wherein the hard coating is one selected from the group consisting of mobile oil, aviation lubricating oil, and grease. 24. A coating member having a hard coating formed on at least a part of a substrate, wherein the hard coating is the hard coating according to any one of claims 1 to 23. . 25. An intermediate layer between the base material and the hard coating, the intermediate layer comprising an element of the 4a, 5a, 6a group of the periodic table, an iron group metal, Al and Si, and nitrides and carbides thereof. 25. The covering member according to claim 24, comprising at least one member selected from the group consisting of carbonitrides. 26. The covering member according to claim 25, wherein the thickness of the intermediate layer is 0.01 to 1 μm. 27. The covering member according to claim 24, wherein the base material is at least one selected from the group consisting of ceramics, iron-based alloys, aluminum alloys, and iron-based sintered bodies.