JP4997404B2 - Tribomicroplasma coating method and coating apparatus - Google Patents

Description

The present invention relates to a tribomicroplasma coating method and a coating apparatus for forming a coating film on a sliding surface using a tribomicroplasma generated in a gap between frictional contact points such as a sliding surface of a machine.

  Conventionally, as a technology for forming a protective film for imparting wear resistance or the like on various friction or sliding surfaces of a sliding device, a wet or dry coating technology has been used. A machine-resistant element such as a wear-resistant hard film has been previously plasma-coated and then incorporated into the apparatus.

On the other hand, using plasma to form a thin film on a solid surface is a well-known technique. Examples of the known plasma coating method include a plasma CVD method and a sputtering method.
In any of these apparatuses, a sample or a coating material is placed in a vacuum chamber, and a high voltage is applied between the sample and the target from the outside, and a sputtering gas or a reactive gas is introduced. In addition, there is a problem that a large and expensive apparatus is required for performing ion irradiation.

  As described above, when a lubrication film is formed on a gear or other equipment, the machine element is preliminarily plasma-coated with a wear-resistant hard film, and then this coated film is used in an actual machine for incorporation into the equipment. In some cases, there was also a problem of having to perform an initial familiar operation.

In view of the above, the present invention uses plasma generated in the gap between the sliding surfaces of the actual machine, performs plasma coating on the spot, and performs plasma coating while sliding, so that familiar operation can be performed simultaneously with coating. Provide technology.
Also, a tribo that can be coated with a film with extremely high wear resistance and good lubricity by coating with a tangential force constantly applied to the thin film by friction or sliding, generating orientation of the structure in the film by the tangential force. providing microplasma coating how and the coating apparatus.

The inventor has discovered that tribomicroplasma is generated in the gap between the frictional contact points. That is, direct imaging of plasma generated at the frictional contact point was successful, and the existence of the plasma became clear. This suggested that plasma coating technology is possible.
And it turned out that this plasma generate | occur | produces in the clearance gap of the friction contact point of almost all materials, such as an insulator, a semiconductor, and a metal oxide film. In the present invention, the inventor has obtained knowledge that plasma coating can be performed in situ using the tribomicroplasma naturally generated in the gap between the frictional contact points, and the present invention has been completed.

Based on the above findings, the present invention provides the following inventions.
By 1) it is friction or sliding rotating body and the sliding member, to generate a tribo microplasma between them, by positively charged and the other negatively one sliding body and the rotating body, and rotation sliding member A plasma sputtering film comprising at least a part of the other substance constituting the sliding body or the rotating body is formed on one or both of the bodies, and the tribomicroplasma coating method 2) friction between the sliding body and the rotating body or apparatus for sliding, apparatus for generating tribo microplasma by friction or sliding between the sliding body and the rotating body, positively charges the other negatively one slide body and the rotating body, sliding body and the rotating body A tribo microplasma coating apparatus comprising an apparatus for forming at least a part of the other substance of the sliding body or the rotating body on one or both of

According to the present invention, for example, a lubricating film can be coated on a sliding surface of a machine by using plasma generated on the spot, so that it is expensive to use a high voltage that generates plasma as used in the prior art. There is a great advantage that a plasma coating apparatus is not required and coating can be performed directly on the sliding surface of the actual machine.
Furthermore, in the case of the conventional method, the running operation must be performed after thin film coating. In the present invention, the running operation is performed simultaneously with the thin film coating. it can.
Furthermore, the thin film can be oriented in the sliding direction by the action of the tangential force due to friction, and it has an excellent effect of being able to coat an extremely durable lubricating and wear-resistant thin film.

Hereinafter, the present invention will be described with reference to illustrated examples. FIG. 1 is a diagram illustrating the principle of a pin disk (sliding body and rotating body) contact tribo microplasma coating apparatus according to the present invention. In this description, the sliding body and the rotating body will be described by replacing them with the pin slider 2 and the rotating disk 3 for convenience.
In the pin disk contact type tribo microplasma coating apparatus 1, tribo microplasma 4 is generated in the gap between the contact points of the pin slider 2 and the rotating disk 3 which are samples. Using this, tribo microplasma coating is performed.

First, the atmospheric tribomicroplasma CVD method will be described. In the present CVD method, a reactive gas 5 is blown into a plasma 4 generated at a frictional contact point through a pipe 6 to perform tribo microplasma CVD coating.
In the atmosphere control type tribo micro plasma CVD coating method, the contact point between the pin 2 and the disk 3 is placed in the vacuum chamber 7, and the inside of the vacuum chamber 7 is once exhausted through the valve 8 by the turbo molecular pump 9 and the rotary pump 10. While the gas pressure is measured by the gas pressure gauge 11, the reactive gas 5 is introduced to a predetermined pressure through the variable leak valve 12, and CVD coating is performed at the most efficient gas pressure.

At this time, the load mechanism 13 adjusts the load, and the rotating mechanism 14 adjusts the rotational speed of the disk to select the optimum friction condition. Further, in order to perform CVD coating on a wide range of surfaces, the pin slider is moved by a predetermined distance in the radial direction by the slider moving mechanism 15 for coating.
Since active elementary particles such as electrons, positive ions, radicals, photons (photons), and excited molecules and reaction intermediates exist in the plasma, various stable molecular gases such as methane, ethane, and propane are used. Even with simple gases, polymer coatings of these molecules are possible.

When the air pressure is lowered as well as in the atmosphere, the plasma becomes larger and stronger and decreases after reaching the maximum point. As described above, the pressure at which the plasma is maximum is about 1000 Pa in the case of air, hydrocarbon gas, or the like. Therefore, it is advantageous for plasma CVD coating.
In fact, when an experimental atmosphere control type plasma CVD apparatus was made with butane gas, it was found that a polymer thin film was formed most efficiently at 1000 Pa and had a friction / wear reduction effect. That is, it was confirmed in the butane gas atmosphere that the plasma coating was maximized at the gas pressure of 1000 Pa at the contact point of the diamond pin / silicon nitride disk.
In addition, sapphire material could be sputter coated on the pin surface by tribomicroplasma coating with diamond pin / sapphire disk combination in an argon atmosphere.

Plasma is generated by discharge of ambient gas due to a high electric field due to frictional charging between insulating solids. There is what is called a charge train in frictional charging, and the order of the charge train determines whether the solid is positively charged or negatively charged.
For example, when glass and nylon are rubbed, glass is positively charged and nylon is negatively charged. If the former is selected as a pin and the latter as a disk, the pin is positively charged and the disk is negatively charged as shown in FIG. 1C. To do.
Conversely, if the former is selected as the disk and the latter as the pin, the pin is negatively charged and the disk is positively charged. Which combination is better should be determined experimentally.

The CVD coating films 16 and 17 are formed on both the disk surface and the pin slider surface, and depending on the combination of the triboelectric charge trains, which occurs more frequently.
For example, amorphous silicon using silane (SiH ₄ ) as a reactive gas for raw materials, metal and metal compound films using organic metals, methane, acetone, carbon monoxide, etc., and diamond by a mixture of these gases and hydrogen It is considered that a thin film by a conventional plasma CVD method such as a thin film or a diamond-like carbon film (DLC film) by methane can be formed.

Next, a triboplasma sputtering method is used. In this case, a reactive gas is not required as in the conventional sputtering method.
If a pin is used as the target, the pin material can be coated on the disk surface, and conversely, if the target material is used for the disk, the pin can be coated with the disk material.
In this case, the order of frictional charging is important, and a material for which the target material is negatively charged is selected. On the other hand, the sample on which the coating film is to be formed needs to be a combination of materials that are positively charged by frictional charging.

As the sample, any material may be used as long as it is a material that generates triboelectric charging, regardless of whether it is organic or inorganic. The target material may be anything as long as it is an insulating material that generates frictional charging.
For example, silicon nitride (Si ₃ N ₄ ), oxide, organic polymer, etc., which are used as conventional sputtering targets.
In the atmospheric tribomicroplasma coating method, air is naturally used as a sputtering gas, but it should be noted that in this case, the film is likely to be oxidized.
In an atmosphere control type tribo plasma coating apparatus, it is recommended to use an inert gas such as an argon gas as in the prior art.

Next, although it is a place where coating is performed, as shown in the coating film formation plan view of FIG. The areas where the plasma generation regions 18 and 19 and the coating film B are formed are the same.
According to the experiment, the plasma generation range is generated so as to greatly exceed the friction track 20 as shown in FIG. 2, so that the coating can be performed in a wider range than the friction track.
Also, in the tribomicroplasma CVD coating, it has been experimentally confirmed that the lubricating thin film such as a polymer formed on the surface of the disk is transferred to the surface of the pin during sliding. Coating is possible.

3 and 4 are diagrams for explaining the principle for coating the sliding surface for the sliding bearing and the sliding surface of the gear with a lubricating thin film. In FIG. 3 and FIG. 4, the sliding bearing and the gear are placed in the vacuum chamber, but the coating can be performed in the atmosphere as in the pin disk type tribo microplasma coating apparatus.
In any case, tribo microplasma coating is performed using tribomicroplasma generated between the shaft 21 and the bearing 22 of the sliding bearing and between the gear 23 and the gear 24.
If the combination of the sample pin and disk is replaced with a shaft and bearing in a sliding bearing and a tooth and tooth in a gear, the coating apparatus and coating method are the same as in the case of a combination of a pin and a disk.

Thus, the present invention can perform plasma coating while performing plasma coating on the spot using plasma generated in the gap between the sliding surfaces of the actual machine.
In addition, the film can be coated with a tangential force constantly applied to the thin film by friction or sliding, and the orientation of the structure in the film can be generated by the tangential force. Therefore, the film has extremely high wear resistance and good lubricity. A tribomicroplasma coating film can be provided.

  According to the present invention, it can be used to form a coating film for any equipment with sliding parts such as gears, sliding bearings, etc., and has a wide range of technologies such as machinery industry, lubricant industry, dry plating industry, thin film coating industry, etc. It has an excellent effect that it can be applied to.

It is explanatory drawing of a pin disk (sliding body and rotary body) contact type tribo microplasma coating apparatus. It is explanatory drawing which shows the tribomicroplasma generation | occurrence | production area | region at the time of forming a coating film. It is a schematic explanatory drawing of the tribomicroplasma coating apparatus for slide bearings. It is a schematic explanatory drawing of the tribomicroplasma coating apparatus for gears.

Explanation of symbols

1: Pin disk contact type tribo micro plasma coating device 2: Pin slider, 3: Rotating disk 4: Tribo micro plasma, 5: Reactive gas 6: Pipe, 7: Vacuum tank, 8: Valve 9: Turbo molecular pump 10: Rotary pump 11: Gas pressure gauge 12: Leak valve 13: Load mechanism 14: Rotating mechanism 15: Slider moving mechanism 16, 17: CVD coating film 18, 19: Plasma generation region 20: Friction track 21: Slide bearing shaft 22: Bearing 23, 24: Gear

Claims (2)

By friction or slide sliding body and the rotating member, to generate a tribo microplasma between them, by positively charged and the other negatively one sliding body and the rotating body, the slide member and the rotating member A tribomicroplasma coating method comprising forming a plasma sputtered film comprising at least a part of the other substance constituting the sliding body or rotating body on one or both sides. Sliding body and apparatus of rubbing or sliding the rotating body, apparatus for generating Tribo microplasma by friction or sliding between the sliding body and the rotating body, positively charged and the other negatively one slide body and the rotating body And a tribo microplasma coating apparatus comprising: an apparatus for forming at least a part of the sliding body or the other material of the rotating body on one or both of the sliding body and the rotating body.