JP4201557B2 - Hard carbon film sliding member - Google Patents

Description

【００７８】
【表２】

【００７９】
【表３】

【００８０】
表１及び表２から明らかなように、本発明の各実施例１〜１４の試料（硬質炭素皮膜摺動部材）は、表３に示す比較例１〜７に比べて、いずれも摩擦係数がμ＝０．０４以下であり、潤滑油中であってもその固体潤滑性が有効に働き、低摩擦で耐摩耗性に優れた摺動部材であることを確認した。
【図面の簡単な説明】
【図１】円板基材の上に硬質炭素皮膜をコーティングした試験片を示す斜視図である。
【図２】本発明の評価に使用した摩擦試験装置の断面説明図（ａ）及びピンの配置を説明する斜視図（ｂ）である。
【符号の説明】
１０ 試験片（硬質炭素皮膜摺動部材）
１１ 円板基材
１２ 硬質炭素皮膜[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a low-friction hard carbon film sliding member, and in particular, a low-friction hard carbon film sliding part suitable for use in lubricating oil such as engine oil and transmission oil.MaterialIt is related.
[0002]
[Prior art]
The hard carbon film is a film made of amorphous carbon or hydrogenated carbon, and is aC: H (amorphous carbon or hydrogenated amorphous carbon), iC (eye carbon), DLC (diamond-like carbon or DLC). It is also called. For the formation, a plasma CVD method in which a hydrocarbon gas is plasma-decomposed and a film is formed, or a gas phase synthesis method such as an ion beam evaporation method using carbon or hydrocarbon ions is used.
[0003]
The hard carbon film has a high hardness, a smooth surface, excellent friction resistance, a low coefficient of friction due to its solid lubricity, and excellent sliding performance. For example, the friction coefficient of a normal smooth steel surface is 0.5 to 1.0 under no lubrication, whereas the hard carbon film has a friction coefficient of about 0.1 under no lubrication. Now, taking advantage of these excellent properties, machining tools such as drill blades and cutting tools, grinding tools, etc., plastic molds, valve cocks and capstan rollers are used under non-lubricated conditions. Application to sliding parts and the like is planned.
[0004]
In addition, in mechanical parts such as internal combustion engines that slide in lubricating oil, there is an increasing demand for reducing mechanical loss as much as possible from the viewpoint of energy consumption and environmental problems. It is desired that the friction be reduced by the hard carbon film having these solid lubricating properties.
[0005]
[Problems to be solved by the invention]
However, when the above-mentioned hard carbon film is coated on a sliding part and slid in lubricating oil such as engine oil or transmission oil, the smoothness is somewhat low friction. It exhibits a low frictional performance equivalent to that of a sliding member with a hard coating that has no properties, for example, a sliding member that has been subjected to an ion plating coating of titanium nitride (TiN) or chromium nitride (CrN). The problem became clear.
[0006]
In addition, molybdenum disulfide (MoS2) and polytetrafluoroethylene (PTFE) that have solid lubricity so as to realize low friction with a friction coefficient μ = 0.04 or less in lubricating oil such as engine oil and transmission oil. There are already many applications for sliding parts that have been treated on the surface, but if they are used under severe sliding conditions under higher surface pressure, the wear resistance is insufficient and the performance can be achieved in the initial stage. However, when used for a long period of time, there is a problem that it is worn out and its performance cannot be maintained.
[0007]
OBJECT OF THE INVENTION
The present invention has been made paying attention to these problems, and its solid lubricity works effectively even in lubricating oil, and wear resistance is low friction coefficient μ = 0.04 or less. It aims at providing the sliding member excellent in property.
[0008]
[Means for Solving the Problems]
As a result of earnest research to achieve the above object, as described in Japanese Patent Application Laid-Open No. 2000-297373 filed earlier, the friction coefficient can be reduced by adding a certain metallic element in the hard carbon film. However, since further reduction of the coefficient of friction is still desired, the amount of metal and oxygen contained in the hard carbon film and the effect of the correlation between these amounts on the friction properties in lubricating oil are studied. As a result of further overlapping, by defining the abundance ratios of the metal element and oxygen in the hard carbon film, it was possible to realize further low friction performance in the lubricating oil.
[0009]
  That is, the hard carbon film sliding member of the present invention is a hard carbon film sliding member used in lubricating oil, at least on the surface layer of the hard carbon film,Ti, W, Nb, Fe, Mo, Zn, Ga, Mn and NiAt least one selected from the group consisting ofSeedContains 4 atomic% to 20 atomic% of metal element, and 6 atomic% to 30 atomic% of oxygen,When the metal abundance ratio in the surface layer is X atomic% and the oxygen abundance ratio is Y atomic%, Y is 1.5 times or more and 2.6 times or less of X, and the thickness of the coating is 0 .5 μm or more and 10 μm or less, and surface roughness is Ra 0.1 μm or less.It is characterized by that.
[0011]
[Effects of the Invention]
  In the hard carbon film sliding member of the present invention, the above configuration makes it possible for the extreme pressure additive to be easily adsorbed on the surface and to form a reaction product on the surface, and hard carbon having low friction in lubricating oil. A film sliding member can be obtained. For example, mineral oil and synthetic oil used for engine oil and the like for the purpose of saving fuel are used as base oil, molybdenum dithiocarbamate is 50 to 1000 ppm in terms of molybdenum, and zinc dithiophosphate is 0.01 to 0.2 in terms of phosphorus. In the lubricating oil containing mass%, the additive film of molybdenum dithiocarbamate and zinc dithiophosphate added as extreme pressure additives in the lubricating oil is not formed on the surface of the conventional hard carbon film. The coefficient of friction was higher than that of a steel sliding member that does not form a carbon film.Ti, W, Nb, Fe, Mo, Zn, Ga, Mn and NiContaining at least one metal element selected from the group consisting of 4 to 20 atomic% in the carbon film, further containing 6 to 30 atomic% of oxygen in the carbon film,Furthermore, when the abundance ratio of the metal in the surface layer is X atomic% and the abundance ratio of oxygen is Y atomic%, Y is set to 1.5 times or more and 2.6 times or less of X, and the thickness of the coating is set to 0.5 μm to 10 μm and surface roughness Ra 0.1 μm or lessIn this case, it is presumed that the extreme pressure additive easily forms a film on the surface due to the cooperative action of the metal element and oxygen, and thereby a low friction coefficient is obtained.
[0012]
If the content of the metal element in the carbon film is less than 4 atomic%, the extreme pressure additive is difficult to adhere and the coefficient of friction increases, and if the content of the metal atom exceeds 20 atomic%, the hard carbon Since the bonding state between the carbons of the coating changes and the properties of the coating change, the coefficient of friction increases again. Also, if the oxygen content in the carbon film is less than 6 atomic%, the extreme pressure additive is difficult to adhere and the friction coefficient increases, and if the oxygen content exceeds 30 atomic%, the hard carbon film Since the bonding state between carbons changes and the properties of the film change, the friction coefficient increases again. Therefore, in this invention, low friction performance is implement | achieved by making content of the metal element and oxygen in a hard carbon film into the above-mentioned range.
[0014]
【The invention's effect】
According to the hard carbon film sliding member of the present invention, by including a predetermined amount of metal element and oxygen in the hard carbon film, the extreme pressure additive is easily adsorbed on the surface and a reaction product is formed on the surface. Therefore, even in the lubricating oil, the solid lubricity effectively works, and a sliding member having low friction and excellent wear resistance can be realized. For example, a sliding member having a friction coefficient μ = 0.04 or less. A moving member can be realized.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
  The hard carbon film sliding member of the present invention is a hard carbon film sliding member used in a lubricating oil, and at least the surface layer of the hard carbon film has elements IIb, III, IV, Va of the periodic table of elements. , VIa, VIIa and VIII at least one metal element selected from the group consisting of 4 atom% to 20 atom%, and oxygen 6 atom% to 30 atom%, tableWhen the abundance ratio of the metal in the surface layer is X atomic% and the abundance ratio of oxygen is Y atomic%, Y is 1.5 times or more of X.2.6 times or lessIt is supposed to be.
[0017]
  This makes it possible for the extreme pressure additive to be easily adsorbed on the surface and to form a reaction product on the surface, and to make a hard carbon film sliding member having low friction in a lubricating oil. By containing a relatively large amount of oxygen, the friction coefficient can be further reduced..
[0018]
More preferably, the hard carbon film sliding member is made of titanium (Ti), tungsten (W), molybdenum (Mo), niobium (Nb), and iron (Fe) as metal elements to be included in the hard carbon film. By including at least one selected from the group, it becomes more effective when the reactive film formation of the additive is taken into consideration, and the thickness of the film is 0.5 μm or more and 10 μm or less, and the surface roughness is Ra may be 0.1 μm or less.
[0019]
Here, if the thickness of the film is smaller than 0.5 μm, the adhesion strength is insufficient, and if it is larger than 10 μm, the residual stress in the film may increase and peeling may occur. The following is good. The surface is preferably finished to a smooth surface roughness Ra of 0.1 μm or less. Since the smoother the better, the lower limit of the roughness is not particularly defined. In practice, however, the surface roughness of an appropriate value is finished in consideration of the cost of the manufacturing process.
[0020]
In this way, the hard carbon film sliding member maintains sufficient adhesion strength and prevents the occurrence of peeling, has low friction in the lubricant, and is more excellent in sliding characteristics. Further, it is possible to prevent the deterioration of the low friction characteristic and the increase of the opponent attack due to the large surface roughness.
[0021]
The above-mentioned hard carbon film sliding member can be used for an adjusting shim or valve lifter of a valve mechanism of an internal combustion engine, thereby making it possible to further improve the valve performance of the internal combustion engine. Become
[0022]
Moreover, the hard carbon film sliding member of this invention can be obtained by forming the hard carbon film which added the metal element previously as a manufacturing method, and performing this plasma treatment or ion implantation process. According to this manufacturing method, there is an advantage that the amount and depth distribution of oxygen in the hard carbon film can be controlled over a wide range.
[0023]
Furthermore, the hard carbon film sliding member of the present invention can be obtained by forming a hard carbon film by an ion plating method or a sputtering method as a manufacturing method thereof, and adding oxygen to the atmosphere during the formation. it can. This manufacturing method is characterized in that the process is completed in one step, and the amount of oxygen in the hard carbon film can be controlled within a certain range by controlling the oxygen partial pressure. Further, if the oxygen partial pressure is changed as the process proceeds, a so-called gradient composition material in which the amount of oxygen in the film is changed according to the depth can be obtained.
[0024]
Further, the hard carbon film sliding member of the present invention is formed by forming a hard carbon film by a sputtering method as a manufacturing method thereof and disposing a metal oxide on a part of the sputtering target during the formation. It can be obtained by a method in which a metal and oxygen are contained. This manufacturing method also has the feature that the process can be completed in one step, and depending on the type of metal element, some oxides are supplied at a lower cost than single metal, thus reducing the manufacturing cost. There is an advantage that you can. Furthermore, although it is knowledge obtained experimentally in the process of achieving the present invention, if a metal oxide is used for a part of the target, the metal content in the film is reduced as compared with the case of using a single metal target. There is an effect that it can be easily increased.
[0025]
【Example】
Examples of the hard carbon film sliding member of the present invention will be described below together with comparative examples. In addition, the hard carbon film sliding member of this invention should just satisfy | fill the structural requirements described in the claim, and is not limited only to each Example.
[0026]
Example 1
After superfinishing the surface of the substrate made of carburized steel (JIS SCM415) to Ra 0.04 μm, the substrate surface was coated with a hard carbon film by magnetron sputtering using carbon as a target material. At this time, titanium dioxide (TiO 2) is formed on the target.₂), And simultaneously performing sputtering so that Ti and O enter the film. Argon was used as the gas during sputtering.
[0027]
When the surface roughness of the sample (hard carbon film sliding member) obtained by the above process was measured, the film surface roughness was Ra 0.09 μm without finishing. Further, the thickness of the film was 1.8 μm as a result of measuring a step between a portion where the hard carbon film was adhered and a portion where the hard carbon film was adhered with a surface roughness meter by masking a part of the sample in advance. It was.
[0028]
The abundance ratio of each element in the film was measured by Auger electron spectroscopy. First, in the analyzer, the sample surface was etched with argon gas for a certain period of time, and then the depth of the etched part was obtained from the analyzer. This was assigned linearly with respect to the total etching time to obtain the etching rate. The etching rate thus determined was 3.8 nm per minute.
[0029]
Next, the time for digging a certain depth based on the above etching rate is calculated back, and the operation of analyzing the composition by Auger electron spectroscopy is repeated a predetermined number of times after digging the sample for that time. The distribution in the depth direction (depth profile) was obtained. At this time, a total of four points were measured from 5 nm from the sample surface to a depth of 20 nm every 5 nm, and the average was defined as the “abundance ratio of each element in the surface layer”. As a result of this analysis, it was found that Ti was present at 16 atomic% and oxygen was present at 24 atomic% in the film.
[0030]
Next, the friction characteristics of the sample were evaluated. At this time, the sample was a test piece (hard carbon film sliding member) 10 in which a hard carbon film 12 was coated on a disk substrate 11 having a diameter of 30 mm and a thickness of 4 mm as shown in FIG. As a friction test apparatus, a pin-on-disk type wear test apparatus 20 as shown in FIG.
[0031]
The friction test apparatus 20 rotatably supports a work table 22 by a rotary shaft 21 having a motor 26 as a drive source, and the work table 22 is disposed in an oil bath 28 and the test piece 10 is fixed to the work table 22. To do. Further, on the upper surface of the work table 22, a holder 24H is arranged so as to be movable up and down, and three pins 24 are arranged radially on the holder 24H as shown in FIG. 2 (b). It is. At this time, the pin 24 is fixed so that it cannot rotate.
[0032]
The friction test apparatus 20 presses each pin 24 against the test piece 10 with a spring 25, and injects lubricating oil 28L into the oil bath 28 so that the test piece 10 and the pin 24 are immersed. The table 22 is rotated, the torque corresponding to the friction force generated between the pin 24 and the test piece 10 is measured by the load cell 27, and thereby the friction coefficient is calculated.
[0033]
The load by the spring 25 was 10 N, and the peripheral speed of the pin 24 was 0.02 m / s. The pin 24 is made of carburized steel (SUJ2) and has a cylindrical shape with a diameter of 5 mm and a length of 5 mm. As the lubricating oil 28L, commercially available automotive engine oil 0W-20 (with molybdenum dithiocarbamate) was used. The oil temperature was set to 80 ° C. with a temperature controller. Then, after the test piece 10 was immersed in the lubricating oil 28L, the measurement was started after a sufficient time had elapsed until the temperature of the test piece 10 coincided with the temperature of the lubricating oil 28L. Furthermore, in consideration of the initial familiarity effect, the friction coefficient of the test piece 10 was determined by using the measured value when 5 minutes had elapsed from the start of the test. As a result, the friction coefficient was 0.026.
[0034]
(Example 2)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, tungsten trioxide (WO₃), And simultaneously performing sputtering so that W and O enter the film. Argon was used as the gas during sputtering.
[0035]
When the surface roughness of the sample (hard carbon film sliding member) obtained by the above process was measured, the film surface roughness was Ra 0.07 μm without finishing. The thickness of the film was 2.1 μm. Furthermore, as a result of measuring the amount of W and O in the film by Auger electron spectroscopy in the same manner as in Example 1, it was found that W was contained at 5 atomic% and O was contained at 12 atomic%. Furthermore, as a result of measuring the friction coefficient in the same manner as in Example 1, the friction coefficient was 0.030.
[0036]
(Example 3)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, niobium pentoxide (NbO) is formed on the target.₅), And simultaneously performing sputtering so that Nb and O enter the film. Argon was used as the gas during sputtering.
[0037]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.08 μm, a film thickness of 3.4 μm, an Nb content in the film of 8 atomic%, and an O content of 14 atoms. %, And the coefficient of friction was 0.029.
[0038]
Example 4
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, ferric oxide (Fe₂O₃), And simultaneously performing sputtering so that Fe and O enter the film. Argon was used as the gas during sputtering.
[0039]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.06 μm, a film thickness of 2.0 μm, an Fe content of 10 atomic%, and an O content of 18 atoms. %, And the coefficient of friction was 0.029.
[0040]
(Example 5)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, molybdenum trioxide (MoO) is formed on the target.₃), And simultaneously performing sputtering so that Mo and O enter the film. Argon was used as the gas during sputtering.
[0041]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.07 μm, a film thickness of 3.0 μm, a Mo content in the film of 7 atomic%, and an O content of 18 atoms. %, And the coefficient of friction was 0.028.
[0042]
(Example 6)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, a zinc oxide (ZnO) plate was placed on the target, and sputtering was performed at the same time so that Zn and O entered the film. Argon was used as the gas during sputtering.
[0043]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.09 μm, a film thickness of 3.8 μm, a Zn content in the film of 10 atomic%, and an O content of 21 atoms. %, And the coefficient of friction was 0.036.
[0044]
(Example 7)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, gallium oxide (Ga₂O₃), And simultaneously performing sputtering so that Ga and O enter the film. Argon was used as the gas during sputtering.
[0045]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.07 μm, a film thickness of 2.2 μm, a Ga content of 17 atomic%, and an O content of 27 atoms. %, And the coefficient of friction was 0.033.
[0046]
(Example 8)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, manganese trioxide (Mn₂O₃), And simultaneously performing sputtering so that Mn and O enter the film. Argon was used as the gas during sputtering.
[0047]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.07 μm, a film thickness of 3.0 μm, an Mn content of 8 atomic% and an O content of 13 atoms. %, And the coefficient of friction was 0.031.
[0048]
Example 9
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, a nickel oxide (NiO) plate was placed on the target, and simultaneous sputtering was performed so that Ni and O entered the film. Argon was used as the gas during sputtering.
[0049]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.08 μm, a film thickness of 3.0 μm, a Ni content in the film of 8 atomic%, and an O content of 13 atoms. %, And the coefficient of friction was 0.031.
[0050]
(Example 10)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, titanium dioxide (TiO 2) is formed on the target.₂) And molybdenum trioxide (MoO)₃), And at the same time sputtering, Ti, Mo and O enter the film
I did it. Argon was used as the gas during sputtering.
[0051]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.08 μm, a film thickness of 2.6 μm, a Ti amount in the film of 5 atomic%, and an Mo amount of 3 atoms. %, The O content was 18 atomic%, and the friction coefficient was 0.028.
[0052]
(Example 11)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, a metal titanium plate (Ti) was placed on the target. The shape and dimensions of the metal titanium plate were the same as in Example 1. By simultaneously performing sputtering, Ti was allowed to enter the film. Argon and oxygen were mixed at a ratio of 9: 1 (volume ratio) as a gas for sputtering.
[0053]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.08 μm, a film thickness of 4.2 μm, a Ti amount in the film of 8 atomic%, and an O amount of 14 atoms. %, And the coefficient of friction was 0.032.
[0054]
(Example 12)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, titanium dioxide (TiO 2) is formed on the target.₂) A plate was placed and simultaneously sputtered to allow Ti and O to enter the film. Argon was used as the gas during sputtering.
[0055]
Further, plasma treatment was performed on the surface of the base material in order to increase the surface oxygen amount. The hard carbon film provided on the substrate surface is stored in a vacuum chamber, and the inside of the vacuum chamber is 5 × 10^-3 After evacuating to about Pa, high-frequency power (13.56 MHz) was sent from outside while oxygen was supplied into the vacuum chamber to generate oxygen plasma. The oxygen partial pressure was 1 Pa. In addition, a bias voltage of about 0.5 kV was applied to the sample with respect to the vacuum chamber (reference potential) so that oxygen efficiently reached the hard carbon film.
[0056]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.09 μm, a film thickness of 1.4 μm, a Ti content in the film of 10 atomic%, and an O content of 26 atoms. %, And the coefficient of friction was 0.027.
[0057]
(Example 13)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, titanium dioxide (TiO 2) is formed on the target.₂) A plate was placed and simultaneously sputtered to allow Ti and O to enter the film. Argon was used as the gas during sputtering.
[0058]
Furthermore, in order to increase the amount of surface oxygen, ion implantation treatment was performed on the substrate surface. The hard carbon film provided on the substrate surface is stored in a vacuum chamber, and the inside of the vacuum chamber is 5 × 10^-3 Then, while supplying oxygen from the ion gun into the vacuum chamber, a bias voltage of 6 kV was applied between the sample and the ion gun to drive oxygen into the hard carbon film from the surface.
[0059]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.06 μm, a film thickness of 1.5 μm, a Ti content in the film of 10 atomic%, and an O content of 24 atoms. %, And the coefficient of friction was 0.025.
[0060]
(Example 14)
As in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, the surface of the base material was coated with a hard carbon film by an ion plating method. At this time, carbon and titanium were supplied by arc discharge as an ion source. The gas supplied into the reaction vessel was a mixture of argon and oxygen at a ratio of 9: 1 (volume ratio).
[0061]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.09 μm, a film thickness of 5.6 μm, a Ti content in the film of 8 atomic%, and an O content of 16 atoms. %, And the coefficient of friction was 0.027.
[0062]
(Comparative Example 1)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, a metal titanium plate (Ti) was placed on the target. The shape and dimensions of the metal titanium plate were half that of Example 1. By simultaneously performing sputtering, Ti was allowed to enter the film. Argon was used as the gas during sputtering.
[0063]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.08 μm, a film thickness of 3.2 μm, a Ti amount in the film of 4 atomic%, and an O amount of 5 atoms. %, And the proportion of oxygen was less than in Examples 1-14. Moreover, the friction coefficient was 0.045 and became larger than Examples 1-14.
[0064]
(Comparative Example 2)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, titanium dioxide (TiO 2) is formed on the target.₂) And simultaneously performing sputtering so that Ti and O enter the film. Argon was used as the gas during sputtering.
[0065]
Further, in order to increase the amount of surface oxygen, plasma treatment was performed on the surface of the substrate in the same manner as in Example 12. The hard carbon film provided on the substrate surface is stored in a vacuum chamber, and the inside of the vacuum chamber is 5 × 10^-3 After evacuating to about Pa, high-frequency power (13.56 MHz) was sent from outside while oxygen was supplied into the vacuum chamber to generate oxygen plasma. The oxygen partial pressure was 10 Pa. In addition, a bias voltage of about 0.5 kV was applied to the sample with respect to the vacuum chamber (reference potential) so that oxygen efficiently reached the hard carbon film.
[0066]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.09 μm, a film thickness of 1.2 μm, a Ti content in the film of 10 atomic%, and an O content of 35 atoms. %, And the coefficient of friction was 0.053. That is, compared with Examples 1-14, there was much oxygen amount and the friction coefficient became large.
[0067]
(Comparative Example 3)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, a metal titanium plate (Ti) was placed on the target. The shape and dimensions of the metal titanium plate were twice those of Example 1. By simultaneously performing sputtering, Ti was allowed to enter the film. Argon was used as the gas during sputtering.
[0068]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.09 μm, a film thickness of 3.0 μm, a Ti content in the film of 8 atomic%, and an O content of 11 atoms. %, And the friction coefficient was 0.048, which was larger than those of Examples 1-14.
[0069]
(Comparative Example 4)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, titanium dioxide (TiO 2) is formed on the target.₂) Placed the plate. The shape and dimensions of the titanium dioxide plate were the same as in Example 1. By simultaneously performing sputtering, Ti and O were allowed to enter the film. Argon was used as the gas during sputtering. The film formation time was set to a quarter of that in Example 1.
[0070]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.08 μm, a film thickness of 0.4 μm, a Ti content in the film of 10 atomic%, and an O content of 17 atoms. As a result of measuring the coefficient of friction, peeling of the hard carbon film was partially observed at the sliding trace portion.
[0071]
(Comparative Example 5)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, titanium dioxide (TiO 2) is formed on the target.₂) Placed the plate. The shape and dimensions of the titanium dioxide plate were the same as in Example 1. By simultaneously performing sputtering, Ti and O were allowed to enter the film. Argon was used as the gas during sputtering. The film formation time was four times that of Example 1.
[0072]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.06 μm, a film thickness of 11 μm, a Ti content in the film of 11 atomic%, and an O content of 18 atomic%. Yes, as a result of measuring the friction coefficient, peeling of the hard carbon film was partially observed at the sliding trace portion. As a cause of this peeling, it is considered that the thickness of the film is excessive.
[0073]
(Comparative Example 6)
In the same manner as in Example 1, after superfinishing the surface of the base material made of carburized steel to a roughness Ra of 0.04 μm, a hard carbon film was coated on the surface of the base material by magnetron sputtering using carbon as a target material. At this time, titanium dioxide (TiO 2) is formed on the target.₂) Placed the plate. The shape and dimensions of the titanium dioxide plate were approximately three times that of Example 1. By simultaneously performing sputtering, Ti and O were allowed to enter the film. Argon was used as the gas during sputtering. The film formation time was the same as in Example 1.
[0074]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.06 μm, a film thickness of 4.2 μm, a Ti content in the film of 22 atomic%, and an O content of 35 atoms. %, And the coefficient of friction was 0.058, which was larger than Examples 1-14.
[0075]
(Comparative Example 7)
In the same manner as in Example 1, the surface of the base material made of carburized steel was limited to a treatment with a roughness Ra of 0.2 μm, and a hard carbon film was coated on the base material surface by magnetron sputtering using carbon as a target material. At this time, titanium dioxide (TiO 2) is formed on the target.₂) A plate was placed and simultaneously sputtered to allow Ti and O to enter the film. Argon was used as the gas during sputtering.
[0076]
The sample (hard carbon film sliding member) obtained by the above process has a film surface roughness of Ra 0.23 μm, a film thickness of 1.9 μm, a Ti content in the film of 8 atomic%, and an O content of 13 atoms. %, And the coefficient of friction was 0.068, which was larger than those of Examples 1-14. In this case, it is considered that the friction coefficient was increased due to the rough surface.
[0077]
  The results of Examples 1 to 14 and Comparative Examples 1 to 7 are summarized in Tables 1 to 3 below.
[Table 1]

[0078]
[Table 2]

[0079]
[Table 3]

[0080]
As is clear from Tables 1 and 2, the samples (hard carbon film sliding members) of Examples 1 to 14 of the present invention all have a coefficient of friction as compared with Comparative Examples 1 to 7 shown in Table 3. μ = 0.04 or less, and it was confirmed that the solid lubricity works effectively even in lubricating oil, and is a sliding member with low friction and excellent wear resistance.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a test piece in which a hard carbon film is coated on a disk substrate.
FIG. 2 is a cross-sectional explanatory view (a) of a friction test apparatus used for the evaluation of the present invention and a perspective view (b) illustrating the arrangement of pins.
[Explanation of symbols]
10 Test piece (Hard carbon film sliding member)
11 Disc base material
12 Hard carbon film

Claims (3)

A hard carbon film sliding member used in lubricating oil,
At least on the surface layer of the hard carbon film,
Ti, wherein W, Nb, Fe, Mo, Zn, Ga, at least one metal element 4 atomic% to 20 atomic% or less selected from the group consisting of Mn and Ni,
And containing 6 atomic% to 30 atomic% of oxygen,
When the abundance ratio of the metal in the surface layer is X atom% and the abundance ratio of oxygen is Y atom%, Y is 1.5 times or more and 2.6 times or less of X,
The thickness of the film is 0.5 μm or more and 10 μm or less,
A hard carbon film sliding member having a surface roughness of Ra 0.1 µm or less . A hard carbon film sliding member used in lubricating oil,
At least on the surface layer of the hard carbon film,
Containing at least one metal element selected from the group consisting of Ti, W, Nb, Fe, Mo, Zn, Ga, Mn, and Ni, in an amount of 5 atomic% to 17 atomic%,
And oxygen is contained in an amount of 12 atomic% to 27 atomic%,
When the abundance ratio of the metal in the surface layer is X atom% and the abundance ratio of oxygen is Y atom%, Y is 1.5 times or more and 2.6 times or less of X,
The thickness of the film is 1.4 μm or more and 5.6 μm or less,
A hard carbon film sliding member having a surface roughness of Ra 0.09 [mu] m or less . The hard carbon film sliding member according to claim 1 , wherein the hard carbon film sliding member is used for an adjusting shim or a valve lifter of a valve mechanism of an internal combustion engine .

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