JP4779090B2 - Manufacturing method of hard carbon film covering member - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manufacturing method of a hard carbon film covering member applied to a member requiring wear resistance, such as a sliding member such as a bearing or a slide of various rotating devices, an information device storage device, and the like.
[0002]
[Prior art]
Film formation technology using an ion beam is an effective technique for synthesizing non-equilibrium materials that are unstable at room temperature and normal pressure due to the energy of the ion beam. For example, cubic boron nitride (cBN) that is harder than diamond and thermally stable than diamond, or diamond-like carbon (DLC) that has an amorphous structure but is hard and has excellent frictional properties. Can be mentioned.
[0003]
However, when processing the surface of a three-dimensional or complex shaped member using a film forming technique using an ion beam, the film forming speed or the etching speed depends on the ion beam irradiation angle from the directivity of the ion beam. Because of the difference, it is very difficult to form a film uniformly in a portion having a curvature. Under the present circumstances, it is indispensable to rotate and swing the mask and workpiece so that uniform film forming conditions can be maintained on the processing member, and there is a problem that processing time and processing cost are high and productivity is low.
[0004]
With respect to a film forming technique using an ion beam, a plasma ion implantation (PBII; Plasma Based Ion Implantation) has attracted attention as a film forming method for overcoming the above-mentioned problems. This is a film formation method proposed by the United States in 1986. A negative pulse voltage is applied to a processing member exposed to plasma to uniformly process ions in the plasma around the processing member. This is a method of irradiating a member, and research on surface modification (surface hardening) such as nitriding has been actively conducted.
[0005]
[Problems to be solved by the invention]
The above-described plasma ion implantation method has a problem in that when a pulse voltage is not applied when ion implantation of a rare gas or the like is performed, the surface of the processing member does not change even when exposed to plasma. Absent. However, when a film is deposited on a processing member by a treatment in reactive plasma, the film is deposited while no pulse voltage is applied, and the properties of the film greatly affect the characteristics of the entire film. . In general, a film formed while no pulse voltage is applied is mechanically fragile, which is a serious problem when a hard film having excellent mechanical characteristics such as friction characteristics is obtained.
[0006]
The present invention is intended to provide a method for producing a hard carbon film-coated member having improved solidity, adhesion to a processing member having a complicated shape, film characteristics (hardness, friction characteristics), and film formation speed.
[0007]
[Means for Solving the Problems]
The method for producing a hard carbon film-coated member according to the present invention is characterized in that a negative DC voltage is applied simultaneously to a processing member exposed to a hydrocarbon gas plasma, and a pulsed negative voltage is applied. It is what.
[0008]
According to the present invention, when a film is formed by the plasma ion implantation method, a negative DC voltage is applied to the processing member at the same time as applying a negative DC voltage. It is possible to produce a hard carbon film-coated member with improved characteristics (hardness, friction characteristics), film formation speed, and the like.
[0009]
That is, since a mechanically fragile film is formed on the surface of the processing member while the pulse voltage is not applied, a constant negative DC voltage is always applied while the pulse voltage is not applied. By actively attracting ions in the hydrocarbon-based gas plasma to the surface of the member, it is possible to improve the film quality of the hard carbon film on the surface of the processing member and the film formation speed.
[0010]
In the method for manufacturing a hard carbon film-coated member according to the present invention, the DC voltage applied to the processing member is preferably −0.2 kV to −2 kV.
[0011]
In the method for manufacturing a hard carbon film-coated member according to the present invention, the pulse voltage applied to the processing member is preferably −1 kV to −10 kV.
[0012]
In the manufacturing method of the hard carbon film coating | coated member which concerns on this invention, it is preferable to make the efficiency ratio of the pulse voltage applied to the said processing member into 1 to 50%.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to FIG.
[0014]
FIG. 1 is a schematic view of a film forming apparatus for producing a hard carbon film covering member according to the present invention.
[0015]
The vacuum vessel 11 is evacuated by an unillustrated evacuation device. The holder 13 on which the base member 12 as a processing member is installed is connected to a bias power source 15 that can apply a negative DC voltage and a pulse voltage via a highly insulated feedthrough 14. Plasma 16 is generated in the vacuum vessel 11. The plasma 16 introduces a hydrocarbon-based gas into the vacuum vessel 11 through a gas introduction tube 17 and introduces microwaves into the vacuum vessel 11 through a waveguide 18 from a power source 19. It is generated by forming a magnetic field that absorbs the microwaves introduced in the vicinity of the base material 12 most efficiently by a pair of electromagnetic coils 20a and 20b installed facing the left and right with respect to the center of the container 11.
[0016]
In addition to the generation of plasma with such a structure, various plasma sources such as high-frequency plasma, helicon plasma, and inductively coupled plasma may be used.
[0017]
Next, a manufacturing method of the hard carbon film covering member will be described using the film forming apparatus shown in FIG.
[0018]
First, the base material 12 is installed in the holder 13, and the vacuum vessel 11 is evacuated to a predetermined degree of vacuum. A desired hydrocarbon-based source gas is introduced into the vacuum vessel 11 through the gas introduction pipe 17 and set to a desired pressure. By flowing a desired current through the pair of electromagnetic coils 20a and 20b, a magnetic field capable of efficiently absorbing microwaves is formed at a desired location in the vacuum vessel 11. In this state, a microwave having a desired output is introduced from the microwave power source 19 into the vacuum vessel 11 through the waveguide 18 to generate plasma 16.
[0019]
Simultaneously with the generation of the plasma, a DC voltage having a desired voltage and a pulse voltage having a desired voltage and an efficiency ratio are applied from the bias power source 15 to the substrate 12 through the highly insulated feedthrough 14.
[0020]
Through the above steps, a hard carbon film is formed on the surface of the substrate 12 to manufacture a hard carbon film covering member.
[0021]
The DC voltage applied to the substrate is preferably -0.2 kV to -2 kV. If the DC voltage applied to the substrate is less than -0.2 kV, there is no difference from the case where the ion energy is low and no DC voltage is applied, and it may be difficult to sufficiently achieve the DC voltage application effect. is there. On the other hand, when the DC voltage applied to the substrate exceeds −2 kV, the film formation rate may be significantly reduced due to the etching effect of the irradiated ions.
[0022]
The pulse voltage applied to the substrate is preferably -1 kV to -10 kV. When the pulse voltage applied to the substrate is less than −1 kV, it is difficult to modify the carbon film deposited while the pulse voltage is not applied, because ions are deposited on the surface without being injected into the film. become. On the other hand, when the pulse voltage applied to the substrate exceeds −10 kV, ions implanted into the carbon film deposited while the pulse voltage is not applied penetrates, so that the carbon film is effectively modified. It becomes difficult to do.
[0023]
It is preferable that the efficiency ratio of the pulse voltage applied to the substrate is 1 to 50%. If the efficiency ratio of the pulse voltage applied to the substrate is less than 1%, the ions required for modifying the carbon film deposited while the pulse voltage is not applied are insufficient, and the film is sufficiently hard. It becomes difficult to form a film on the surface of the substrate. On the other hand, when the efficiency ratio of the pulse voltage applied to the substrate exceeds 50%, the deposition rate is remarkably reduced by etching of the carbon film deposited while the pulse voltage is not applied, or it is obtained by excessive ion irradiation. The resulting film may become porous and a hard film may not be obtained, or an abnormal discharge may occur between the substrate and the vacuum vessel, and stable operation may not be guaranteed.
[0024]
【Example】
Hereinafter, embodiments of the present invention will be described in detail using the film forming apparatus shown in FIG.
[0025]
Example 1
First, the base material 12 made of stainless steel (JIS: SUS304) was placed on the holder 13 in the vacuum vessel 11, and the vacuum vessel 11 was evacuated to a vacuum degree of 1 × 10 ⁻³ Pa or less. Methane as a raw material gas was introduced into the vacuum vessel 11 through the gas introduction pipe 17 and the pressure in the vessel 11 was controlled to 5 × 10 ⁻² Pa. Thereafter, a current of 300 A was passed through the pair of electromagnetic coils 20 a and 20 b to form a magnetic field (875 gauss) capable of efficiently absorbing microwaves at a location 100 mm away from the central portion in the vacuum vessel 11. In this state, a plasma 16 was generated by introducing a microwave (frequency: 2.45 GHz) having an output of 1 kW into the vacuum vessel 11 from the microwave power source 19 via the waveguide 18. Simultaneously with the generation of plasma, a DC voltage of -0.2 kV, a voltage of -2 kV, and a pulse voltage of 1% efficiency ratio are applied from the bias power source 15 to the substrate 12 through the high-insulation feedthrough 14, respectively. A hard carbon film covering member was manufactured by forming a hard carbon film. The film formation speed at this time was 20 μm / min.
[0026]
The structure of the obtained hard carbon film was examined by Raman spectrum analysis. As a result, the detected broad peak consisting of the main peak and 1380 cm ^-1 vicinity of the shoulder band near 1520 cm ^-1, the synthesis of diamond-like carbon film is a hard carbon film was confirmed.
[0027]
Further, the friction characteristics of the hard film were examined by a ball-on-disk friction tester. The conditions for the friction test were a SiC ball as the counterpart material, a load of 1 N, a speed of 0.1 m / sec, an atmosphere in dry air, and a temperature of room temperature. As a result, the friction coefficient of this hard carbon film was 0.02. The friction coefficient of the carbon film formed under the same conditions as described above except that no DC voltage and bias voltage were applied was 0.4. The friction coefficient of the carbon film formed under the same conditions as described above was 0.08 except that only a pulse voltage having a voltage of −2 kV and an efficiency ratio of 1% was applied.
[0028]
Therefore, it can be seen that the hard carbon film formed in Example 1 has a smaller friction coefficient, and the friction characteristics are greatly improved.
[0029]
Furthermore, the hard carbon film formed in Example 1 shows a coefficient of friction of 0.02 without peeling even in a friction test at a load of 20 N by a ball-on-disk friction tester, and the adhesion and durability are greatly improved. It was confirmed that it was improved.
[0030]
(Example 2)
First, the base material 12 made of high-speed tool steel (JIS: SKH51) was installed in the holder 13, and the vacuum vessel was evacuated to a vacuum degree of 1 × 10 ⁻³ Pa or less. Acetylene as a source gas was introduced into the vacuum vessel 11 through the gas introduction pipe 17 and the pressure in the vessel 11 was controlled to 5 × 10 ⁻² Pa. Thereafter, a current of 250 A was passed through the pair of electromagnetic coils 20 a and 20 b to form a magnetic field (875 gauss) capable of efficiently absorbing microwaves at a location 150 mm away from the center in the vacuum vessel 11. In this state, a plasma 16 was generated by introducing a microwave (frequency: 2.45 GHz) with an output of 700 W from the microwave power source 19 into the vacuum vessel 11 through the waveguide 18. Simultaneously with the generation of the plasma, a DC voltage of −0.5 kV, a voltage of −5 kV, and a pulse voltage with an efficiency ratio of 10% are applied to the substrate 12 from the bias power supply 15 through the high-insulation feedthrough 14, respectively. A hard carbon film covering member was manufactured by forming a hard carbon film. The film formation speed at this time was 30 μm / min.
[0031]
The structure of the obtained hard carbon film was examined by Raman spectrum analysis. As a result, the detected broad peak consisting of the main peak and 1380 cm ^-1 vicinity of the shoulder band near 1520 cm ^-1, the synthesis of diamond-like carbon film is a hard carbon film was confirmed.
[0032]
Further, the friction characteristics of the hard film were examined by a ball-on-disk friction tester. The conditions for the friction test were a SiC ball as the counterpart material, a load of 1 N, a speed of 0.1 m / sec, an atmosphere in dry air, and a temperature of room temperature. As a result, the coefficient of friction of this hard carbon film was 0.03. The friction coefficient of the carbon film formed under the same conditions as described above except that no DC voltage and bias voltage were applied was 0.5. The friction coefficient of the carbon film formed under the same conditions as described above was 0.09 except that only a pulse voltage having a voltage of −5 kV and an efficiency ratio of 10% was applied.
[0033]
Therefore, it can be seen that the hard carbon film formed in Example 2 has a smaller friction coefficient, and the friction characteristics are greatly improved.
[0034]
Furthermore, the hard carbon film formed in Example 2 shows a coefficient of friction of 0.03 without peeling even in a friction test at a load of 20 N using a ball-on-disk friction tester, and the adhesion and durability are greatly improved. It was confirmed that it was improved.
[0035]
【The invention's effect】
As described above, according to the present invention, a hard carbon film that is hard and has excellent frictional properties can be satisfactorily adhered to the substrate. In addition, it is a method that can be processed into a member having a complicated shape in the film formation method using an ion beam, and the film formation speed can be improved. it can.
[0036]
Therefore, according to the present invention, it is possible to provide a method of manufacturing a hard carbon film-coated member that contributes to the improvement of performance and life for industrial machines such as tools and bearings, engines, and space equipment.
[Brief description of the drawings]
FIG. 1 is a schematic view of a film forming apparatus for producing a hard carbon film covering member according to the present invention.
11 ... Vacuum container,
12 ... base material,
13 ... Holder,
15 ... Bias power supply,
16 ... Plasma,
19 ... Microwave power supply,
20a, 20b ... electromagnetic coils,

Claims (4)

A method for producing a hard carbon film-covered member, comprising applying a negative DC voltage to a processing member exposed to a hydrocarbon-based gas plasma at the same time as applying a pulsed negative voltage. 2. The method of manufacturing a hard carbon film-coated member according to claim 1, wherein a DC voltage applied to the processing member is -0.2 kV to -2 kV. The method of manufacturing a hard carbon film-coated member according to claim 1, wherein a pulse voltage applied to the processing member is -1 kV to -10 kV. The method for producing a hard carbon film-coated member according to claim 1, wherein an efficiency ratio of a pulse voltage applied to the processing member is 1 to 50%.

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