JPH0662978B2 - Method for producing solid lubricating film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention applies a polytetrafluoroethylene film (hereinafter referred to as “PTFE film”) onto a substrate with excellent adhesion to provide moisture resistance and low friction. The present invention relates to a method for producing a solid lubricating film having a coefficient.

<Prior art> As a method of depositing a thin film on a predetermined substrate surface, conventionally, a thin film forming material such as vacuum heating deposition, RF sputtering deposition, ion beam sputtering deposition, ion plating, chemical vapor deposition (hereinafter referred to as CVD), etc. There is known a method of depositing. However, in these vapor deposition methods, a polymer thin film such as polytetrafluoroethylene (hereinafter referred to as “PTFE”) that has an insulating property and has a problem of thermal denaturation is deposited on the substrate with high efficiency and good adhesion. It was very difficult to get it done.

<Problems to be solved by the invention> For example, when vacuum heating deposition, RF sputtering deposition, or ion plating is applied to the PTFE film formation, resistance heating, thermoelectrons or accelerated electrons are generated on the PTFE target and the substrate. It will denature the PTFE membrane. Further, when the ion beam sputter deposition is used, the surface of the PTFE target is charged by the electric charge of the ion beam, the incidence of the ion beam is blocked, and the sputter deposition does not proceed. Also, CV
When the PTFE film is formed by D, there is a drawback that the adhesion between the substrate and the PTFE film is weak.

In view of the above problems, it is an object of the present invention to provide a method for producing a solid lubricating film using an RTFE film that is free from thermal denaturation and has good adhesion.

<Means for Solving Problems> The inventors of the present invention have conducted various studies to achieve the above-mentioned object, and according to the sputtering deposition using a high-speed atomic beam,
It was found that a PTFE film having excellent adhesion without heat denaturation was obtained. Furthermore, it has been found that the sputtering deposition using the high-speed atomic beam can easily produce a molybdenum sulfide film, which has been difficult to produce in the past.

The structure of the present invention based on such knowledge is to form a molybdenum sulfide sputtering film on a substrate using a high-speed atomic beam, and then irradiate the polytetrafluoroethylene target with the high-speed atomic beam to deposit the molybdenum sulfide sputtering film. It is characterized in that a polytetrafluoroethylene spatula vapor deposition film is formed in layers on the film. Here, in the case of forming a molybdenum sulfide sputtering film, the composition ratio of molybdenum to sulfur is 2 to 2 atoms of (molybdenum) MoS ₂ by using a molybdenum target, a sulfur target and a composite target. Can be used as a single atom to form a molybdenum disulfide (MoS ₂ ) film having a desired value. In the case of simply using the molybdenum sulfide target, the insulating sulfur tends to escape and the composition ratio of the target and the composition ratio of the film tend to change.

<Examples> Hereinafter, preferred examples of the present invention will be described in detail.

First, an example of a fast atom beam source device for generating a fast atom beam used in the present invention is shown, but the present invention is not limited to this.

FIG. 1 is an explanatory view of a fast atom beam source device. As shown in the figure, this fast atom beam source device has cathodes on both end surfaces.
It has a cathode case 3 to be 4a and 4b. here,
Both the cathodes 4a and 4b are grounded, and the cathode 4b is provided with a gas inlet 1. On the other hand, inside the cathode case 3, round bar-shaped anodes 2 are arranged in the upper and lower portions in the figure at the center of both end faces, and these anodes 2 are connected to a power source 8 provided outside. There is. A particle beam outlet 5 made of Graphite Mesh is formed in the center of the cathode 4a, and a cylindrical neutralizing mechanism 6 is directly connected to the particle beam outlet 5.

Next, a method of using the high-speed atomic beam source device having such a configuration will be described.

First, by introducing an inert gas such as Ar from the gas inlet 1 into the cathode casing 3 10 ^{- 1} Torr~10 ^- as about ³ Torr, the number of anode 2 from a few 100V relative to the cathode 4a, 4b k
Hold at high V potential. Then, anode 2 and cathode 3
The electrons emitted from a and 3b are accelerated toward the anode 2,
Cathode on the opposite side, passing through the middle of the two anodes 2
After reaching 4b and 4a, the velocity is lost, and the velocity is further accelerated toward the anode 2 to repeat the above-mentioned behavior. A high-frequency vibration called so-called Barkhausen-Kurz vibration is generated between the cathodes 4a and 4b centering on the anode 2, and the oscillating electrons collide with gas molecules,
Plasma is effectively formed. The positive ions in the formed plasma are attracted and accelerated by the cathodes 4a and 4b, pass through the particle beam outlet 5, and enter the neutralizing mechanism 6 having a cylindrical shape. When the incident ion beam collides with the side wall in the neutralization mechanism 6, the ion beam is combined with the secondary electron generated by the ion bombardment from the side wall and neutralized to become a fast atom beam. Further, the ion beam may undergo charge conversion when colliding with the side wall of the neutralization mechanism 6, and may become a high-speed atom beam. Further, the electrons oscillating in the Barkhausen-Kurz bond with the ions in the vicinity of the cathode 4a where the velocity becomes 0 to neutralize them, thereby creating a high-speed atomic beam. Due to such a main mechanism, the ion beam becomes the fast atom beam 7 and is emitted from the neutralization mechanism 6.

Comparative Example A comparative example, which is a conventional technique in which PTFE is deposited by sputtering using the above high-speed atomic beam source device, will be described with reference to the drawings.

FIG. 2 is an explanatory view of a high-speed atomic beam sputtering deposition apparatus. In the drawing, 9a and 9b are the fast atom beam sources described above, and 10a and 10b.
Is a fast atom beam radiation path radiated from these fast atom beam sources 9a and 9b, and 12 is a substrate made of SUS440C (JIS standard stainless steel). Here, the PTFE target 11 is held so as to be able to retract backward so as to be separated from the high-speed atomic beam source radiation paths 10a and 10b. The substrate 12 is held by a holder 13 so that it can rotate at a constant angle. All of these components are arranged in a vacuum chamber (not shown),
This vacuum chamber is evacuated to an arbitrary degree of vacuum by an exhaust pump (not shown).

Using such a device, a PTFE solid lubricating film is formed on the substrate 12 as follows.

First, an exhaust pump operated, the vacuum chamber 10 ^{- 6} Torr
After the degree of vacuum, fast atom beam source 9a, by introducing an inert gas (e.g. Ar) to 9b 10 ^{- 3} ~10 ^- to ⁴ Torr gas pressure.

After that, the target 11 is retracted so as to be separated from the fast atom beam radiation path 10b, and then the cathode of the fast atom beam source 9b is
3 between 4a and 4b (see Fig. 1) and anode 2 (see Fig. 1)
The surface of the substrate 12 is cleaned by applying a high voltage of about kV and irradiating an electrically neutral Ar atomic beam toward the substrate 12 through the neutral mechanism 6 (see FIG. 1).

Next, the PTFE target 11 is extruded and set in the high-speed atomic radiation source radiation path 10a, and the high-speed atomic radiation source 9a produces a faster Ar.
By irradiating the PTFE target 11 by irradiating it with an atomic beam, as shown in FIG.
A TFE sputtering film 14 is formed.

Example Next, an example according to the present invention in which a molybdenum sulfide film is formed on a substrate and a PTFE film is further formed by using the same apparatus as that used in the comparative example will be described. The apparatus for carrying out this embodiment is equipped with a Mo-S composite target 16 as shown in FIG. 4 which is movable in the same manner as the target 11 in FIG. This Mo-S composite target 16
Is formed by stacking two fan-shaped molybdenum targets 16b and 16c on the sulfur target 16a. Can be changed. This makes it possible to change the composition ratio of S and Mo in the sputtering film.

In this example, first, the same operation as in the above-described comparative example was performed. Then, the Mo-S composite target 16 shown in FIG. 4 is extruded into the fast atom beam radiation path 10a, and the Mo-S
Impact the S compound target 16 with a high-speed Ar atomic beam. Thus, a molybdenum sulfide film having a thickness of 0.1 μm is formed on the surface of the yellow plate 12.

Next, the Mo-S composite target 16 is connected to the high-speed atomic beam radiation path 10a.
When the operation of Example 1 is performed after moving so as to separate from the above, as shown in FIG. 5, on the molybdenum sulfide film 15 formed on the substrate 12, the PTFE sputtering film 1 with a thickness of 0.1 μm is formed.
4 is formed in layers.

Here, an experiment in which the characteristics of the molybdenum sulfide film as the lower layer film are investigated is shown above.

Mo target 16b, 16c of the above-mentioned Mo-S composite target 16
By changing the apex angle θ of 8: 1,6: 1,4: 1,
Adjusted to 2: 1, 1.5: 1 and 0.3: 1, and sputter-deposited. Molybdenum sulfide films a, b, c, with a thickness of 0.2 μm, respectively.
Formed d, e, f. Then, after heat treatment under reduced pressure at 300 ° C. for 2 hours, the friction characteristics of each film were examined. Results are shown in FIG. In addition, this friction characteristic is a diameter of 6 mm when 500 g is applied.
It was measured by a reciprocating test using a ball indenter of No. 1 and FIG. 6 shows the relationship between the number of times of sliding and the measured value of the friction coefficient at that time.

As shown in the figure, it can be seen that the MoS ₂ film exhibits the best characteristics. Therefore, a MoS ₂ film was formed also in the above-mentioned embodiment.

The solid lubricating film as shown in FIG. 5 formed as described above has no hygroscopicity because the molybdenum molybdenum sulfide film 15 is covered with the PTFE film 14, and has stable friction characteristics for a long time. Is obtained. Further, since the molybdenum sulfide film 15 is interposed, deformation of the substrate surface is prevented and excellent friction characteristics are obtained even when the surface of the PTFE film is worn.

FIG. 7 shows the friction characteristics of the solid lubricating films obtained in the comparative example and the example. This friction characteristic is similar to the above-mentioned method,
It was measured by a reciprocal test using a ball indenter with a diameter of 6 mm applied with 500 g, and FIG. 7 shows the relationship between the number of times of sliding and the coefficient of friction. As shown in the same figure, in both cases of the comparative example and the example, it is about 0.15 which is almost the same, which shows that it is excellent as a solid lubricating film. However, the embodiment according to the present invention in which the MoS ₂ layer is formed below the PTFE layer is
Especially, when the number of sliding times is about 50 times or less, it is shown that the lubricating film has an excellent friction coefficient. This is because the MoS ₂ film prevents the deformation of the substrate surface as described above.

In the above-described examples, the PTFE sputtered vapor deposition film and the molybdenum sulfide sputtered vapor deposition film were both subjected to spatter vapor deposition using a high-speed atom beam and were not subjected to any special post-treatment, but these sputter vapor deposition films were formed. However, at the same time, when the sputtered vapor deposition film is irradiated with a high-speed atomic beam (for example, Ar atomic beam), the high-speed atom (Ar) atoms themselves are also injected into the substrate or the surface of the sputtered vapor-deposited film, and the atoms in the substrate or in the film are recoiled to repel these atoms. Since a new mixed phase is formed at the boundary, mutual adhesion becomes stronger and the film becomes more difficult to peel off.

Further, when the above solid lubricant film is deposited on the curved substrate surface by sputtering, if the substrate is held and rotated within a certain angle range, a uniform curved solid lubricant film can be formed on the substrate surface. .

Further, when a spherical substance such as a ball of a ball bearing is rotated without holding, a spatter substance is vapor-deposited to form a uniform solid lubricating film on the ball surface.

<Effects of the Invention> As described above in detail with reference to Comparative Examples and Examples, according to the method for producing a solid lubricating film of the present invention, PT
Since a molybdenum sulfide film with a desired ratio can be satisfactorily formed under the FE layer, by interposing a molybdenum sulfide film with a low coefficient of friction between the PTFE film and the substrate, deformation and wear of the substrate surface can be prevented. The solid lubricating film can be prevented to have excellent durability. Further, since the molybdenum disulfide film having hygroscopicity is covered with the PTFE film, it has no hygroscopicity and can contribute to the improvement of preservability over a long period of time.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a high-speed atomic beam source device for carrying out the present invention, FIG. 2 is an explanatory diagram of a high-speed atomic beam sputtering apparatus used in the examples, and FIG. 3 is a comparative example. FIG. 4 is a cross-sectional view showing a formed solid lubricant film on a substrate, FIG. 4 is an explanatory view showing a Mo—S composite target of one embodiment according to the present invention, and FIG. 5 is formed by one embodiment according to the present invention. FIG. 6 is a cross-sectional view showing a solid lubricating film on the substrate, FIG. 6 is a friction characteristic diagram of a molybdenum sulfide solid lubricating film, and FIG. 7 is a friction characteristic diagram of solid lubricating films formed in Comparative Examples and Examples. In the drawing, 1 is a gas inlet, 2 is an anode, 3 is a cathode case, 4a and 4b are cathodes, 6 is a neutralization mechanism, 7 is a fast atom beam, 9a and 9b are fast atom beam sources, and 10a and 10b are Fast atom beam radiation path, 11 is a PTFE target, 12 is a substrate, 13 is a holder, 14 is a PTFE film, 15 is a molybdenum sulfide film, 16 is a Mo-S composite target, h is a sulfur target 16a is a fast atom beam source 9a. It is the exposed part.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C10M 107: 38) C10N 10:12 30:06 50:08 70:00 (72) Inventor Tadashi Shimokawa Man 3-9-11 Midoricho, Musashino-shi, Tokyo Inside Nippon Telegraph and Telephone Corporation Musashino Electro-Communications Research Laboratory (56) Reference JP-A-55-81147 (JP, A)

Claims (2)

[Claims] 1. A high-speed atom beam is used to form a molybdenum sulfide sputter-deposited film on a substrate, and then a high-speed atom beam is applied to a polytetrafluoroethylene target to form a polytetrafluoroethylene sputter-deposited film on the molybdenum sulfide sputter-deposited film. A method for producing a solid lubricating film, which comprises forming a vapor-deposited film in layers. 2. The molybdenum sulfide sputter-deposited film is formed by irradiating a composite target of a molybdenum target and a sulfur target with a high-speed atomic beam to form a molybdenum disulfide (MoS ₂ ) sputter-deposited film on a substrate. The method for producing a solid lubricating film according to claim 1, wherein