JP2014091844A - Slide member, method for manufacturing the same, and slide structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slide member which can suitably form molybdenum disulfide on the surface of an amorphous carbon coating film without using a lubricant containing an organic molybdenum compound, and a method for manufacturing the slide member.SOLUTION: A method for manufacturing a slide member includes a step for forming an amorphous carbon coating film 13 on the surface of a substrate 11. When the amorphous carbon coating film 13 is formed, arc discharge is generated on the surface of a molybdenum-containing target made of molybdenum or molybdenum disulfide by controlling an impressed voltage applied to the molybdenum-containing target. Molybdenum particles or molybdenum disulfide particles are released from the molybdenum-containing target by the arc discharge to form the amorphous carbon coating film 13 in which particles 13a of the molybdenum particles or molybdenum disulfide particles are dispersed.

Description

  The present invention relates to a sliding member in which an amorphous carbon film is coated on a sliding surface of a base material, a manufacturing method thereof, and a sliding structure.

  In recent years, resource protection, reduction of environmental pollution, and prevention of global warming have attracted attention in various countries, and in particular, improvement of exhaust gas regulations has become a challenge even in the automobile industry. As one means for solving the problem, development of a technology for reducing fuel consumption has been undertaken. In particular, improving the sliding characteristics of the sliding member constituting the engine or the sliding member of the valve train reduces the energy loss and directly leads to a reduction in fuel consumption of the automobile.

  For example, in order to improve the wear resistance of such a sliding member and to obtain low friction characteristics, there is a technique for coating the sliding surface of the sliding member, and diamond-like carbon (DLC) is used as the coating material. Amorphous carbon materials such as are being used. The film (amorphous carbon film) formed of the amorphous carbon material is a hard film mainly composed of carbon, and can achieve both low sliding resistance and high wear resistance.

  As an example of such a sliding member, a sliding member in which a DLC film (amorphous carbon film) is formed on the surface of a base material on one sliding member among a pair of sliding members that slide relative to each other is proposed. The sliding member is configured to supply a lubricant containing molybdenum dialkyldithiocarbamate (Mo-DTC) as an organic molybdenum compound to the sliding member (see, for example, Patent Document 1). According to this technique, molybdenum disulfide is formed on the sliding surface of the sliding member by an organic molybdenum compound such as Mo-DTC. Thereby, the wear resistance of the sliding member can be improved.

  Further, as another technique, an amorphous carbon film is formed on the surface of the sliding member, and a slide in which W or Mo is contained in the amorphous carbon film by an arc vapor deposition method is used. A moving member has been proposed (see, for example, Patent Document 2). According to this invention, the wear resistance of the sliding member can be improved by containing 1 to 30 atm% of W or Mo.

JP 2009-114311 A JP 2011-084721 A

  However, in the technique described in Patent Document 1, the organomolybdenum compound reacts with frictional heat such as Fe and Cr of the mating member of the sliding member to generate molybdenum trioxide, and this DLC film is caused by this molybdenum trioxide. It has been found that (amorphous carbon coating) wear is accelerated. As a result, even if molybdenum disulfide is formed, the DLC film may be worn away.

  Furthermore, in the technique described in Patent Document 2, Mo is contained in the amorphous carbon film at the atomic level, and it is expected that molybdenum disulfide is formed by this Mo and S in the lubricating oil. However, it has been found that Mo contained in the amorphous carbon film is contained as a metal oxide in association with slight remaining oxygen in the atmosphere during film formation. Thereby, even if the lubricating oil contains an S component, molybdenum disulfide is not formed by the reaction between Mo in the amorphous carbon coating and S in the lubricating oil, and the sliding member has low friction. In some cases, characteristics could not be obtained.

  The present invention has been made in view of such points, and the object of the present invention is to suitably use molybdenum disulfide on the surface of the amorphous carbon film without using a lubricant containing an organic molybdenum compound. An object of the present invention is to provide a sliding member that can be generated and a method for manufacturing the same.

  In view of the above-mentioned problems, the inventors have intensively studied. As a result, in the conventional arc ion plating method, when molybdenum is vapor-deposited together with carbon on the surface of the substrate, the molybdenum-based target is used. When ionized molybdenum is released and the molybdenum itself oxidizes, by setting the voltage applied to the molybdenum target to a higher voltage than before, micron-order molybdenum particles can be released from the molybdenum-based target. As a result, a new finding was obtained that molybdenum could be contained in the surface of the amorphous carbon film in the form of particles.

  The present invention is based on the inventors' new knowledge, and the manufacturing method of the sliding member includes a step for forming an amorphous carbon film on the sliding surface of the substrate. The step of forming the amorphous carbon film generates an arc discharge on the surface of a molybdenum-based target made of molybdenum or molybdenum disulfide when the amorphous carbon film is formed. By releasing molybdenum particles or molybdenum disulfide particles from a molybdenum-based target, an amorphous carbon film in which molybdenum particles or molybdenum disulfide particles are dispersed in an amorphous carbon film is formed. Adjusting the voltage applied to the molybdenum target in order to generate arc discharge on the surface of the molybdenum target in the step of forming the carbonaceous film. More, and adjusting the particle size of the amorphous molybdenum particles dispersed in the carbon coating or molybdenum disulfide particles.

  According to the present invention, by adjusting the applied voltage applied to the molybdenum target, not only the molybdenum particles or molybdenum disulfide particles can be released from the molybdenum target, but also dispersed in the amorphous carbon coating. The particle size of the molybdenum particles or molybdenum disulfide particles to be adjusted can be adjusted.

  As a result, molybdenum particles or molybdenum disulfide particles are dispersed in the amorphous carbon coating. When a molybdenum target is used as the molybdenum target, unoxidized molybdenum in the molybdenum particles in the amorphous carbon coating reacts with the sulfur component in the lubricating oil during sliding, and the surface of the fluid member Molybdenum disulfide can be produced.

  On the other hand, when molybdenum disulfide is used for the molybdenum-based target, molybdenum disulfide particles are dispersed in the amorphous carbon coating, and therefore, when sliding, the disulfide is formed on the sliding surface of the sliding member. Molybdenum is supplied, which acts as a solid lubricant.

  More preferably, the applied voltage is adjusted so that the average particle diameter of the molybdenum particles or the molybdenum disulfide particles is in the range of 0.9 μm to 4.5 μm. According to this aspect, the friction coefficient and wear resistance of the sliding member can be reduced by containing the molybdenum particles or the molybdenum disulfide particles having an average particle diameter in such a range.

  That is, in the case of molybdenum particles having an average particle size of less than 0.9 μm, most of the molybdenum particles are oxidized when released from the molybdenum-based target. Similarly, in the case of molybdenum disulfide particles having an average particle size of less than 0.9 μm, molybdenum and sulfur on the surface of the molybdenum disulfide particles are decomposed, and as a result, most of the molybdenum of the molybdenum disulfide particles is oxidized. Become. As a result, when the sliding member is slid, molybdenum disulfide is hardly formed on the sliding surface.

  On the other hand, when the average particle diameter exceeds 4.5 μm, the surface roughness of the sliding surface becomes rough, attacks the mating member, promotes wear of the mating member, and reduces the friction coefficient. There is a risk that it will be difficult.

  In this application, the sliding member shown below is also disclosed. The sliding member according to the present invention is a sliding member in which an amorphous carbon coating is formed on a sliding surface of a substrate, and the amorphous carbon coating contains molybdenum particles or molybdenum disulfide particles. It is characterized by being distributed.

  According to the present invention, as described above, since the molybdenum particles are dispersed in the amorphous carbon coating, the wear resistance of the sliding member can be improved and the friction coefficient can be reduced. Specifically, when molybdenum particles are dispersed in the amorphous carbon coating, the molybdenum of the molybdenum particles in the amorphous carbon coating reacts with the sulfur component in the lubricating oil during sliding and flows. Molybdenum disulfide can be generated on the surface of the member. On the other hand, when molybdenum disulfide particles are dispersed in the amorphous carbon coating, molybdenum disulfide itself is supplied to the sliding surface of the sliding member during sliding, which is a solid lubricant. Acts as an agent.

  As a more preferred embodiment, the molybdenum particles or the molybdenum disulfide particles have an average particle size in the range of 0.9 μm to 4.5 μm. According to this aspect, as described above, the friction coefficient and wear resistance of the sliding member can be reduced by containing the molybdenum particles or the molybdenum disulfide particles having an average particle diameter in such a range. it can. When the average particle size is less than 0.9 μm, molybdenum disulfide is hardly formed on the sliding surface when the sliding member is slid. On the other hand, when the average particle diameter exceeds 4.5 μm, the surface roughness of the sliding surface becomes rough, attacks the mating member, promotes wear of the mating member, and reduces the friction coefficient. There is a risk that it will be difficult.

  Further, when the particles contained in the amorphous carbon film of the sliding member are molybdenum particles, it is preferable that a sulfur component is added to the lubricating oil. Specifically, when molybdenum particles are dispersed in the amorphous carbon coating, the molybdenum of the molybdenum particles in the amorphous carbon coating reacts with the sulfur component in the lubricating oil during sliding and flows. Molybdenum disulfide can be generated on the surface of the member.

  According to the present invention, molybdenum disulfide can be suitably generated on the surface of the amorphous carbon film without using a lubricant containing an organic molybdenum compound.

The typical conceptual diagram for demonstrating the manufacturing method of the sliding member which concerns on embodiment of this invention. The typical conceptual diagram of the sliding member manufactured by the manufacturing method shown in FIG. The table | surface which showed the film-forming conditions of the sliding member which concerns on Examples 1-7 and Comparative Examples 1-5. The typical perspective view for demonstrating the friction abrasion test done with the sliding member of Examples 1-7 and Comparative Examples 1-5. The table | surface which showed the result of the friction abrasion test of the sliding member which concerns on Examples 1-7 and Comparative Examples 1-5. The figure which showed the friction coefficient of the sliding member which concerns on Examples 3 and 7 and Comparative Examples 1 and 2. FIG. The figure which showed the result of the friction coefficient in the case where Mo-DTC is added to lubricating oil, and the case where it does not add in the sliding member which concerns on Example 3, 7 and Comparative Examples 1 and 2, and the wear depth. The figure which showed the relationship between the friction coefficient of the friction coefficient of the sliding member which concerns on Examples 1-4, and Comparative Examples 2 and 3, and a particle diameter (droplet average particle diameter). The figure which showed the relationship between the friction coefficient of the sliding coefficient and the particle diameter (Droplet average particle diameter) of the sliding member which concerns on Examples 5-7 and Comparative Examples 4 and 5. FIG. It is the photograph which showed the result of having observed the amorphous carbon film of the sliding member which concerns on Example 3 and Comparative Example 2 under the microscope, (a) is the photograph of the cross section of the sliding member which concerns on Comparative Example 2, (b) ) Is a cross-sectional photograph of the sliding member according to Example 3, (c) a surface photograph of the sliding member according to Comparative Example 2, and (c) a surface photograph of the sliding member according to Example 3. The figure which showed the X-ray-diffraction result of the surface of the amorphous carbon film of the sliding member which concerns on Example 3, 7 and the comparative example 3, and the analysis result of Example 3,7. The figure which showed the result of having analyzed the surface of the sliding member which concerns on Example 1, 3, 6 and Comparative Example 3, 5 after a friction abrasion test by XPS. The figure which showed the result of having measured the friction coefficient of the sliding member which concerns on Examples 3 and 6 and Comparative Examples 3 and 6 by the valve operating system test.

Hereinafter, the present invention will be described based on the present embodiment with reference to the drawings.
FIG. 1 is a schematic conceptual diagram for explaining a manufacturing method of a sliding member according to an embodiment of the present invention, and FIG. 2 is a schematic concept of a sliding member manufactured by the manufacturing method shown in FIG. FIG.

  As shown in FIG. 1, the film forming apparatus used in the method for manufacturing a sliding member according to the present embodiment is a generally known arc ion plating apparatus. However, in the arc ion plating method using the conventional arc ion plating apparatus, there is a method in which a metal target is sublimated by arc discharge, the metal is ionized, and the ionized metal is deposited (attached) on a substrate. Generally, this embodiment is different from the conventional ones in that metal particles are discharged from a metal target by arc discharge and attached to a substrate. In the following, when expressed as arc ion plating (AIP), this means that an arc ion plating apparatus is used, and unless otherwise specified in detail, from the metal target by arc discharge as described above. In this method, metal particles are released and adhered to a substrate.

  As shown in FIG. 1, in this embodiment, first, the intermediate layer 12 is provided on the surface of the base member 11 of the sliding member before the amorphous carbon coating 13 is coated. The intermediate layer 12 is a layer for increasing the adhesion between the base material 11 of the sliding member 10 and the amorphous carbon coating 13, and is made of a metal such as silicon, chromium, titanium, or tungsten. Note that the amorphous carbon coating 13 may be formed on the surface of the substrate 11 as long as adhesion between the substrate 11 and the amorphous carbon coating 13 can be secured.

  In this way, an amorphous carbon film 13 is formed on the surface of the substrate 11 on which the intermediate layer 12 is formed. The arc ion plating apparatus shown in FIG. 1 includes an arc power source, a bias power source for applying a negative bias voltage to a substrate 11 placed in a vacuum chamber, and hydrocarbon gas and nitrogen as carbon materials. In addition, an inlet for discharge gas such as argon is provided, and a molybdenum target is electrically connected to the arc power source.

  In this embodiment, when the amorphous carbon film 13 is formed, a voltage is applied between the molybdenum targets by an arc power source on the surface of the molybdenum target made of molybdenum or molybdenum disulfide to generate arc discharge. (generate). Thereby, molybdenum particles or molybdenum disulfide particles are released from the molybdenum target. That is, in this embodiment, the molybdenum target acts as a cathode of an arc power source, and molybdenum particles or molybdenum disulfide particles are released from the molybdenum target by arc discharge with the anode.

  More specifically, in the step of forming the amorphous carbon film, the applied voltage (specifically, the current value of the arc power supply) applied to the molybdenum target for generating arc discharge on the surface of the molybdenum target. Is adjusted by the adjusting unit to adjust the average particle diameter of the molybdenum particles or molybdenum disulfide particles dispersed in the amorphous carbon coating 13 to a range of 0.9 μm to 4.5 μm.

  In the present embodiment, the carbon of the amorphous carbon coating 13 itself is deposited by plasma CVD. Specifically, when the molybdenum particles or molybdenum disulfide particles are discharged from the molybdenum target by arc discharge, a hydrocarbon gas such as acetylene is introduced, and the molybdenum particles or molybdenum disulfide particles are generated by discharge along with the discharge of the molybdenum particles or molybdenum disulfide particles. Carbon is ionized by the high energy density plasma, and the substrate 11 is loaded with a negative bias voltage. Thereby, molybdenum particles or molybdenum disulfide particles and carbon ions can be attracted to the base material 11 and laminated.

  As the hydrocarbon gas, methane, ethylene, acetylene, benzene, or the like can be used. As the hydrocarbon gas, acetylene gas is preferably used, and an inert gas such as argon gas, helium gas, or nitrogen gas is preferably mixed with the hydrocarbon-based gas. Of course, other hydrocarbon gases can be used depending on other conditions. The flow rate of the hydrocarbon gas is preferably 10 to 25 sccm and the inert gas is preferably 200 to 500 sccm. Of course, the flow rate of the hydrocarbon gas is not limited to this range.

  Here, the amorphous carbon film is formed by plasma CVD. However, the amorphous carbon film may be formed by sputtering using a carbon target. As described above, the amorphous carbon film 13 is coated with molybdenum particles or molybdenum disulfide. As long as the particles can be dispersed, the production method is not particularly limited.

  In this way, as shown in FIG. 2, a sliding member in which the amorphous carbon film 13 is formed on the surface of the base material 11 on which the intermediate layer 12 is formed can be obtained. In the amorphous carbon film 13, particles 13a of molybdenum particles or molybdenum disulfide particles are dispersed, and the average particle size is in the range of 0.9 μm to 4.5 μm.

  According to the present embodiment, by adjusting the applied voltage applied to the molybdenum target by the adjustment unit, it is possible not only to release molybdenum particles or molybdenum disulfide particles from the molybdenum target, but also amorphous. The particle diameter of the molybdenum particles or molybdenum disulfide particles dispersed in the carbon coating can be adjusted.

  As a result, molybdenum particles or molybdenum disulfide particles 13 a are dispersed in the amorphous carbon coating 13. Here, when a molybdenum target is used as the molybdenum target, a lubricating oil to which a sulfur component is added as a lubricating oil, such as a known engine oil, is supplied to the sliding surface (the surface of the amorphous carbon coating 13). Dynamic structure. Molybdenum that is not oxidized among the molybdenum particles in the amorphous carbon coating 13 reacts with the sulfur component in the lubricating oil during sliding, and molybdenum disulfide can be generated on the surface of the fluid member.

  On the other hand, when molybdenum disulfide is used for the molybdenum-based target, the molybdenum disulfide particles are dispersed in the amorphous carbon coating 13, so that the sliding surface of the sliding member is moved to the sliding surface during sliding. Molybdenum sulfide is supplied, which acts as a solid lubricant. Thus, the friction coefficient and abrasion resistance of a sliding member can be reduced by containing molybdenum particles or molybdenum disulfide particles in the amorphous carbon coating.

  Here, in the case of molybdenum particles having an average particle diameter of less than 0.9 μm, most of the molybdenum particles are oxidized when released from the molybdenum target. Similarly, in the case of molybdenum disulfide particles having an average particle diameter of less than 0.9 μm, the molybdenum and sulfur on the surface of the molybdenum disulfide particles are decomposed, and as a result, most of the molybdenum in the molybdenum disulfide particles is oxidized. Will end up. As a result, when the sliding member is slid, molybdenum disulfide is hardly formed on the sliding surface. On the other hand, when the average particle diameter of the particles 13a exceeds 4.5 μm, the surface roughness of the sliding surface becomes rough, attacks the mating member, promotes wear of the mating member, and increases the friction coefficient. May be difficult to reduce.

Embodiments according to the present invention will be described below.
[Example 1]
As a base material, stainless steel (JIS standard: SUS440C quenching) of 6 mm × 15 mm × thickness 10 mm, surface roughness Ra (JIS standard) 0.03 μm, 0.3 to 0 so as to be an intermediate layer by sputtering. A chromium film having a thickness of 5 μm was formed. An amorphous carbon film in which molybdenum particles were dispersed was formed on the surface of the base material on which the intermediate layer was formed under the conditions shown in FIG. Specifically, using the arc ion plating apparatus shown in FIG. 1, a molybdenum target (purity of 99.9% by mass or more) is disposed, the degree of vacuum in the chamber is 2 × 10 ⁻³ Pa, An amorphous carbon film in which molybdenum particles are dispersed was formed under the conditions of a temperature of 200 ° C. (heater temperature), a flow rate of a film forming gas (acetylene gas) of 150 ml / min, an arc power supply current value of 40 A, and a bias voltage of 500 V. .

[Examples 2 to 4]
As in Example 1, a sliding member was produced in which the surface of the base material on which the intermediate layer was thus formed was coated with an amorphous carbon film in which molybdenum particles were dispersed. The difference from Example 1 is that the flow rate of the film forming gas (acetylene gas) and / or the current value of the arc power source (applied voltage applied to the molybdenum target) was adjusted under the conditions shown in FIG. is there.

[Examples 5 to 7]
In the same manner as in Example 1, a sliding member in which the surface of the base material on which the intermediate layer was thus formed was coated with an amorphous carbon film was produced. In the case of Example 5, the difference from Example 1 is that a molybdenum disulfide target (purity of 99.9% by mass or more) was used instead of the molybdenum target. In the case of Examples 6 and 7, FIG. The flow rate of the film forming gas (acetylene gas) and the current value of the arc power source (applied voltage applied to the molybdenum target) were adjusted under the conditions shown in FIG.

[Comparative Example 1]
A sliding member in which the surface of the base material on which the same intermediate layer as that in Example 1 was formed was coated with an amorphous carbon film was produced. The difference from Example 1 is that an amorphous carbon film was formed under the conditions shown in FIG. 3 without using a molybdenum target.

[Comparative Example 2]
A sliding member in which the surface of the base material on which the same intermediate layer as that in Example 1 was formed was coated with an amorphous carbon film was produced. The difference from Example 1 is that, as shown in FIG. 3, a target gas is formed by using a gas obtained by mixing acetylene gas and argon gas (acetylene gas flow rate 100 ml / min, argon gas flow rate 100 ml / min). This is a point in which a sliding member coated with an amorphous carbon coating containing molybdenum was manufactured using an unbalanced magnetron sputtering apparatus with an electric power of 2.00 kW and a bias voltage of 200 V.

[Comparative Example 3]
As in Example 1, a sliding member was produced in which the surface of the base material on which the intermediate layer was thus formed was coated with an amorphous carbon film in which molybdenum particles were dispersed. The difference from Example 1 is that the flow rate of the deposition gas (acetylene gas) is 100 ml / min and the current value of the arc power source is the current value of the arc power source used in the conventional arc ion plating method under the conditions shown in FIG. (AIP current value) 30 A.

[Comparative Example 4]
As in Comparative Example 2, a sliding member in which the surface of the base material on which the intermediate layer was formed in this way was coated with an amorphous carbon film was produced. The difference from Comparative Example 2 is that a molybdenum disulfide target (purity 99.9% by mass or more) was used instead of the molybdenum target.

[Comparative Example 5]
In the same manner as in Comparative Example 3, a sliding member in which the surface of the base material on which the intermediate layer was formed in this way was coated with an amorphous carbon coating was produced. The difference from Comparative Example 3 is that a molybdenum disulfide target (purity 99.9% by mass or more) was used instead of the molybdenum target.

<Friction and wear test>
As shown in FIG. 4, a frictional wear test (in combination with a block test piece 51, a ring test piece 52, and a lubricating oil 53 corresponding to the sliding members of Examples 1 to 7 and Comparative Examples 1 to 5 shown above. Block on-ring test: LFW-1 test, manufactured by FALEX).

  Specifically, a SAE 4620 carburized material (φ35 mm, width 8.8 mm, surface roughness Ra (JIS standard) 0.03 μm) is prepared as a ring test piece 52, and hot water is used so that the lubricating oil 53 is immersed in a part of this. The ring test piece 52 is rotated at 160 rpm (circumferential speed 0.3 m / s) in a state where the lubricating oil 53 is stretched on the bath 54 and the oil temperature is maintained at 80 ° C., and an oil film is formed on the surface of the test piece. The block test piece 10 was brought into contact with the outer peripheral surface of 52 and a continuous test for 30 minutes was performed while applying a load of 300 N (hertz 310 MPa). At this time, the rotational resistance (sliding resistance) acting on the ring test piece 52 was detected by a load cell attached to the apparatus, and the friction coefficient and the wear depth of the sliding member were measured. The result is shown in FIG.

  In addition, as the lubricating oil, a base oil (SAE viscosity grade 0W-20 commercial engine oil (lubricating oil to which a sulfur component is added) and a lubricating oil to which Mo-DTC is further added are prepared. A frictional wear test was conducted on these lubricating oils, and the results are shown in Fig. 5. Note that the low friction with the non-Mo-based additive oil in Fig. 5 is observed in the lubricating oil to which no Mo-DTC is added. On the other hand, when the coefficient of friction was 0.06 or less, it was marked as ◯, and when it was exceeded, it was marked as ×, and FIG. 7 shows friction coefficients and wear depths of the sliding members according to Examples 3 and 7 and Comparative Examples 1 and 2 when Mo-DTC is added to the lubricant and when it is not added. The result was shown.

<Measurement of particle size>
The average particle diameter (droplet particle diameter) of the molybdenum particles or molybdenum disulfide particles of Examples 1 to 7 and Comparative Examples 2 to 5 was measured using a scanning electron microscope (SEM). Here, the particle diameter of a droplet existing for an arbitrary field of view with a magnification of 1000 is measured and averaged. In addition, since the arc ion plating method under the conventional conditions of Comparative Example 2 and Comparative Example 4 is a condition in which no droplet is generated, the droplet itself hardly existed. For this reason, while observing the surface of the amorphous carbon coating, the slightly generated droplets were searched, and the particle size was measured to obtain the average particle size. The results are shown in the table of FIG.

  FIG. 8 shows the relationship between the coefficient of friction of the sliding member according to Examples 1 to 4 and Comparative Examples 2 and 3 and the particle diameter (droplet average particle diameter), and FIG. The relationship between the friction coefficient of the friction coefficient of the sliding member which concerns on 5-7 and the comparative examples 4 and 5, and a particle diameter (droplet average particle diameter) was shown.

  Further, FIG. 10 is a photograph showing the result of microscopic observation of the amorphous carbon film of the sliding member according to Example 3 and Comparative Example 2, and (a) shows the sliding member according to Comparative Example 2. Cross-sectional photograph, (b) is a cross-sectional photograph of the sliding member according to Example 3, (c) a surface photograph of the sliding member according to Comparative Example 2, and (c) a surface photograph of the sliding member according to Example 3. showed that.

<X-ray diffraction (XRD)>
X-ray diffraction was performed on the surfaces of the amorphous carbon coatings of the sliding members according to Examples 3 and 7 and Comparative Example 3. FIG. 11 shows photographs showing the X-ray diffraction results of the surfaces of the amorphous carbon coatings of the sliding members according to Examples 3 and 7 and Comparative Example 3, and analyzes of Examples 3 and 7 of Examples 3 and 7 Results are shown.

<X-ray photoelectron spectroscopy (XPS)>
The surfaces of the sliding members according to Examples 1, 3, 6 and Comparative Examples 3, 5 after the frictional wear test were subjected to X-ray photoelectron spectroscopy (XPS). The result is shown in FIG.

<Valve system test>
The friction coefficients of the sliding members according to Examples 3 and 6 and Comparative Examples 3 and 6 were measured by a valve train test. In the valve system test, an engine valve system test apparatus was used. Specifically, a slide member according to Examples 3 and 6 and Comparative Examples 3 and 6 was used as a shim that contacted the cam using a small engine cam cut out. Specifically, the shim corresponding to the sliding member is an outer type having a diameter of 25 mm and a surface roughness Rz (JIS standard) of 0.03 μm. In accordance with this shape, Examples 3 and 6 and Comparative Examples A shim was manufactured by the manufacturing method shown in FIG. In addition, the sliding member which concerns on the comparative example 6 is a sliding member which performed the lube light process to the molybdenum steel.

  And, as a lubricating oil, using Mo-DTC-free engine oil (SAE viscosity grade 0W-20 commercial engine oil (lubricant added with a sulfur component), the cam and shim are brought into contact with a spring load of 400 N, The friction coefficient was measured while rotating the cam at an engine speed of 2000 rpm, and the results are shown in FIG.

<Result 1>
As shown in FIG. 5, the sliding members according to Examples 1 to 7 had a lower coefficient of friction than Comparative Examples 1 to 6 regardless of the presence or absence of Mo-DTC. Also, as shown in FIG. 6, the sliding member containing the molybdenum particles of Example 3 and the sliding member containing the molybdenum disulfide particles of Example 7 have a friction coefficient as compared with Comparative Examples 1 and 2. Even when the lubricating oil was low and free of Mo-DTC, the coefficient of friction was as low as that of the lubricating oil containing Mo-DTC.

<Result 2>
As shown in FIG. 7, Comparative Example 1 under the same lubricating oil conditions was used for both the sliding member containing the molybdenum particles of Example 3 and the sliding member containing the molybdenum disulfide particles of Example 7. ,
Compared to the sliding member 2, the wear depth was small and the friction coefficient was low. In addition, when the Mo-DTC-containing lubricating oil was used, the wear amount of the amorphous carbon coating increased in any of Examples 3 and 7 and Comparative Examples 1 and 2.

<Result 3>
As shown in FIGS. 8 and 9, the friction coefficient of the sliding members according to Examples 1 to 4 containing molybdenum particles is lower than that of Comparative Examples 2 and 3, and the examples containing molybdenum disulfide particles. The friction coefficients of the sliding members according to 5 to 7 were lower than those of Comparative Examples 4 and 5.

<Result 4>
As shown in FIG. 10, the amorphous carbon coating of the sliding member according to Comparative Example 2 has almost no molybdenum particles (droplets), and the amorphous carbon coating of the sliding member according to Example 3 Molybdenum particles were dispersed. As shown in FIG. 11, in the photograph of Comparative Example 3, halos were copied, and in Examples 3 and 7, countless spots were copied, and intensity peaks existed at locations corresponding to Mo elements. That is, in the case of the sliding member according to Example 3, molybdenum particles are dispersed in the amorphous carbon coating, and in the case of the sliding member according to Example 7, disulfide is added to the amorphous carbon coating. It can be said that the molybdenum particles are dispersed.

<Result 5>
As shown in FIG. 12, the surface of the sliding member according to Examples 1, 3, and 6 had a peak in the binding energy indicating molybdenum disulfide, and Comparative Examples 3 and 5 did not have such a peak. .

<Result 6>
As shown in FIG. 13, the friction coefficient of the sliding members according to Examples 3 and 6 was lower than the friction coefficient according to Comparative Examples 3 and 6.

(Discussion)
From results 1 and 4, from the sliding members of Examples 1 to 4, the molybdenum particles were dispersed in the amorphous carbon coating, so that the sliding members of Examples 5 to 7 were amorphous. It is considered that the friction coefficient of these sliding members was reduced as compared with those of Comparative Examples 1 to 5 because the molybdenum disulfide particles were dispersed in the carbon coating.

  And from the result 5, the molybdenum of the molybdenum particles of the sliding members of Examples 1 to 4 reacts with the sulfur component of the lubricating oil during sliding to form a molybdenum disulfide layer, which is used as a solid lubricant. It can be said that the friction coefficient was reduced by acting. In the case of Comparative Example 1, molybdenum particles are not contained, and in the case of sputtering as in Comparative Example 2, sufficient molybdenum particles are dispersed to reduce the friction coefficient to form an amorphous carbon coating. It is considered that there is a high possibility that molybdenum is present in the amorphous carbon coating as molybdenum oxide particles because it is not contained and the particle size is small. In addition, since the sliding member according to Comparative Example 3 was formed with an amorphous carbon film by the conventional arc ion plating method, it was assumed that the amorphous carbon film had no molybdenum particles and particles were present. However, the particles are considered to be molybdenum oxide particles in which molybdenum reacts with a slight amount of oxygen in the chamber and molybdenum is oxidized.

  As shown in FIG. 8, the effective average particle diameter range in which the molybdenum particles can exist in the amorphous carbon coating is 0.9 μm or more. The coefficient of friction of the sliding member is reduced. Similarly, as shown in FIG. 9, the effective average particle size range in which the molybdenum disulfide particles can be present in the amorphous carbon coating is 0.9 μm or more. The friction coefficient of the sliding member is reduced by molybdenum disulfide particles of molybdenum sulfide particles.

  Furthermore, from the result 2, when the lubricating oil added with Mo-DTC is used, Mo-DTC reacts with the iron of the mating member of the sliding member by frictional heat to generate molybdenum trioxide. It is thought that the wear of the amorphous carbon film was promoted due to molybdenum oxide. As is clear from the result 6, the sliding members according to Examples 1 to 7 are considered to be able to reduce the friction coefficient without adding Mo-DTC, and also suppress the wear of the amorphous carbon coating. I think it can be done.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs can be made without departing from the spirit of the present invention described in the claims. It can be changed.

  11: substrate, 12: intermediate layer, 13: amorphous carbon coating, 13a: particles

Claims (5)

A manufacturing method of a sliding member including a step for forming an amorphous carbon film on a sliding surface of a substrate,
The step of forming the amorphous carbon film includes the step of generating an arc discharge on the surface of a molybdenum target made of molybdenum or molybdenum disulfide when forming the amorphous carbon film. Molybdenum particles or molybdenum disulfide particles are released to form an amorphous carbon film in which molybdenum particles or molybdenum disulfide particles are dispersed in an amorphous carbon film.
In the step of depositing the amorphous carbon coating, the amorphous carbon coating is dispersed by adjusting an applied voltage applied to the molybdenum target in order to generate arc discharge on the surface of the molybdenum target. A method for producing a sliding member, characterized in that the particle size of molybdenum particles or molybdenum disulfide particles to be adjusted is adjusted.   2. The method for manufacturing a sliding member according to claim 1, wherein an average particle diameter of the molybdenum particles or the molybdenum disulfide particles is adjusted to a range of 0.9 μm to 4.5 μm. A sliding member having an amorphous carbon film formed on a sliding surface of a substrate,
A sliding member characterized in that molybdenum particles or molybdenum disulfide particles are dispersed in the amorphous carbon coating.   The sliding member according to claim 3, wherein an average particle diameter of the molybdenum particles or the molybdenum disulfide particles is in a range of 0.9 μm to 4.5 μm. A sliding structure comprising the sliding member according to claim 3 and a lubricating oil supplied to the sliding member,
Particles contained in the amorphous carbon coating of the sliding member are molybdenum particles, and a sulfur component is added to the lubricating oil.

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