JPS62235393A - Solid lubricant film having high hardness and formation thereof - Google Patents

Abstract

PURPOSE:To obtain a hard solid lubricant film having high hardness and excellent abrasion resistance and lubricity, by compounding hard carbon forming a lubricant film to a silicone having lower concentration than the carbon. CONSTITUTION:A solid lubrication film composed of hard carbon containing silicon is formed on a solid surface by introducing a silane gas and a hydrocarbon gas or carbon fluoride gas at a flow ratio of 0.2-0.7 and carrying out plasma CVD or vacuum CVD of the gaseous mixture. The flow ratio of the silane gas is maintained at a high level and is gradually lowered simultaneous to the gradual increase of the flow ratio of the hydrocarbon gas or fluorinated carbon gas, thereby increasing the silicon concentration at the surface contacting with the solid and lowering the concentration on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-hardness solid lubricant film having high hardness and excellent lubricity.

[Conventional technology]

Various hard materials are being studied as surface treatment methods for mechanical parts, tools, and the like. For example, 'I''iN, TiC1B,
C,5iiN4. A hard film such as AQ, O, etc. is formed by sputtering, CVD, ion blasting, or the like. However, when the above-mentioned various hard films are applied to the sliding parts of mechanical parts, tool blade surfaces, etc., concentrated stress occurs because the hard films themselves do not have lubricity, and the interface between the base and the hard surface causes concentrated stress. Phenomena such as peeling were observed. In addition, solid lubricants are relatively soft and easily deformed, causing gradual wear and tear, leading to deterioration in the precision of parts, and having a relatively short lifespan.

In addition, a hard carbon film called diamond-like carbon is being studied, and due to its high hardness, it is expected to be used as a surface treatment method for sliding mechanical parts and tools.For example, hydrocarbon gas such as CH4, etc.
Alternatively, a film formed by ion beam evaporation, low pressure CVD, etc. using a gas obtained by adding hydrogen gas to the above-mentioned hydrocarbon gas is made of a hard carbon film such as amorphous carbon, cubic diamond, or Graphi 1-. It is known.

[Problem that the invention seeks to solve]

Although the above-mentioned hard carbon film has high hardness, it does not have lubricity or has low adhesion to the substrate, so as mentioned above, even if it is used for sliding mechanical parts or tools, there will be problems with the lifespan. was there. An object of the present invention is to obtain a high hardness solid (121) having wear resistance, lubricity, and excellent adhesion to the substrate.

[Means for solving problems]

The present invention uses hydrocarbon gas or fluorocarbon gas and silane gas and adjusts the flow rate ratio of the above gases to achieve lubricity, excellent adhesion to the substrate, long life, high hardness and resistance. It is designed to form a highly hard solid lubricant film that also has abrasive properties.

[Effect]

The inventors have found that the adhesion of the hard carbon is improved by incorporating silicon into the hard carbon, but hard carbon with a high silicon concentration increases the coefficient of friction and impairs lubricity. therefore,
In order to form a hard carbon film that meets the above requirements, the silicon concentration must be high on the surface where the hard carbon contacts the solid, and the silicon concentration must be low on the surface of the hard carbon. Furthermore, by using a low pressure CVD method or a plasma CVD method using ethylene gas and silane gas, and changing the respective flow rates of the ethylene gas and silane gas in the reaction process, a range with a different ratio of silicon to carbon is formed. We discovered this and formed a hard carbon film with a high silicon concentration on the solid contact surface and a low silicon concentration on the surface.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a block diagram showing an example of the method for forming a high hardness solid lubricant film according to the present invention, and Fig. 2 shows the frictional characteristics of the high hardness solid lubricant film when the flow rate ratio of silane gas and ethylene gas is changed. 3 is a diagram showing the change in friction life when the flow rate ratio of silane gas and ethylene gas is changed, and FIG. 4 is a diagram showing the friction characteristics of the high hardness solid lubricant film according to the present invention. In this example.

As shown in Figure 1, microwave electron cyclotron resonance (r:cR) can promote film formation reactions by highly activated plasma and ion bombardment with moderate energy.
A highly hard solid lubricant film was formed using a CVD method using excited plasma. In FIG. 1, microwaves are guided into a plasma generation chamber 2 through a rectangular waveguide 1. In FIG. - The plasma generation chamber 2 satisfies the cavity resonator conditions. A magnetic coil 3 is arranged around the plasma generation chamber 2 to form a magnetic field that satisfies the ECR conditions inside the plasma generation chamber 2, and to form a diverging magnetic field in the sample chamber 7 for drawing out plasma. It is.

Using the attached equipment, ethylene gas, silane gas, and argon gas were introduced through the introduction holes 4 and 4', and the flow rate ratio of ethylene gas and silane gas was changed to form a high-hardness solid lubricant film on sample 5. 6 is a cooling water injection hole.

Regarding the high hardness solid lubricant film formed by the above method, S
IMS, IR1 Temperature Programmed Desorption Spectrometry (TDS; Therm
al Desorption 5pectroscope
y) was considered. The results confirmed that films with different 5i-C ratios were formed by changing the mixing ratio of ethylene gas and silane gas, but hydrogen was contained in the film as C-HX and Si-Ify. It was revealed that these ratios also correspond to the ratios of ethylene gas and silane gas.

The crystallinity was examined using X-ray diffraction and Raman spectroscopy, and the structure was close to amorphous.

Next, a friction test was conducted. A test piece on which a high-hardness solid lubricant film was formed was oscillated from outside the vacuum chamber, and a stainless steel ball indenter was pressed against it to create friction. A silicon wafer 5i (100) surface finished with mechanochemical boriding was used as the base material of the test piece. After forming a high-hardness solid lubricant film, it was adhered to an aluminum base and a friction experiment was conducted.

Figure 2 shows the friction characteristics of a high-hardness solid lubricant formed by changing the flow rate ratio of silane gas and ethylene gas.
When the ratio of H, /CH, is greater than 1.33, the friction coefficient is 0.2 or more. For the above case, Si
When the ratio of H4/CFI4 is 0.11 to 0.66, the coefficient of friction shows a very small value of about O and OS. The above value is smaller than the point where SiH4 is O, that is, the friction coefficient μ=0.15 of diamond-like carbon. Furthermore, the friction coefficient tends to decrease with annealing.

FIG. 3 is a diagram showing the change in friction life with respect to the flow rate ratio of SiH4 and C2H4. Here, the friction life is the friction coefficient μ
It was defined as the number of frictions until it reached = 0.3 or more. S
i H4/Cz I-14 ratio is 0.25 to 0.
Within the range of 44, the friction life is 105 times or more. On the other hand, SiH4/C has a small flow rate of silane gas.
, Il, = 0.1 or less, the friction life fluctuated greatly and in the case of no annealing, a high friction coefficient was achieved with a relatively small number of cycles. In contrast, the friction life shows a small value even when only ethylene is flowed.

Even when S I H4/Cz H4 is large, the friction life shows a small value. Furthermore, the friction life tends to increase with annealing.

Figure 4 shows the friction characteristics of the high hardness solid lubricant film according to the present invention, (a) is the result in the atmosphere, S x )
When the flow rate ratio of i4/CH4 is 2/9, the friction coefficient μ = 0.25 at first, but gradually decreases to μ = 0.1.
It becomes about 2 to 0.25, and for more than 10” cycles, μ
= approximately 0.05 to 0.08, and the value of the friction coefficient is small. Beyond 1Os cycles, μ increases rapidly. When annealed, the coefficient of friction is slightly lower after 10 to 40 times, but the lifespan is almost the same.

As shown in (b), the friction characteristics in vacuum show that the annealed material has a longer life. The friction coefficient gradually decreases until the 12th time. In particular, the friction coefficient μ = 0 for about 11 to 300 times. Old and showing very small values. Then, from the 300th time onward, the value rapidly increases to about μ=0.6. Here, the value μ=0.01 indicates a low coefficient of friction compared to tungsten disulfide and molybdenum disulfide films. On the other hand, as the ratio of SiH4 increases, the phenomenon of low friction in vacuum is no longer observed, and the friction coefficient rapidly increases.

From these results, it is believed that using an appropriate mixing ratio will exhibit a low coefficient of friction in vacuum.

Furthermore, micrographs of the friction piece when the coefficient of friction increases rapidly show that the carbon-rich film suffers significant damage when the coefficient of friction increases. In other words, the film has lubricating properties,
This shows that the coefficient of friction increases when the lubricity is lost. On the other hand, a film with a large amount of SL exhibits a high coefficient of friction even though the film is present on the surface. A film formed at an appropriate flow rate has wear resistance and lubricity.

From the above results, the desired high hardness solid lubricant film can be obtained by setting the flow rate ratio of silane gas and hydrocarbon gas to 0.2 to 0.7, but if the friction life is emphasized, the above flow rate ratio should be set to 0.2 to 0.7. ~
It is preferable to set it in the range of 0.5. Further, in the method for forming a hard carbon film according to the present invention, the flow rate of silane gas is initially increased to increase the silicon concentration in the film, and then the flow rate of hydrocarbon gas is increased.
By distributing the silicon concentration under appropriate conditions, it is possible to obtain a film that has excellent adhesion to the underlying solid surface and excellent lubricity. By changing the conditions in the lubricant film forming process as described above, a highly hard solid lubricant film can be formed depending on the purpose. That is, by incorporating silicon, the coefficient of friction is reduced and the lubricity is increased, and as the silicon concentration increases, it is possible to obtain a highly hard solid lubricant film that has better adhesion to the solid surface.

In order to further impart a solid lubricating effect, the effect will be even greater if a solid d'4 synovial film of molybdenum disulfide, tungsten disulfide, black button fluoride, etc. is formed on the lubricating film formed under the above conditions. Become.

In the above example, the case of ethylene gas was described, but
C1I4. Methanes such as C, H, and C2II2.

Ethylene-based, acetylene-based hydrocarbons, or CF4.
A similar effect can be obtained by forming a thin film by introducing a mixed gas of fluorinated carbon such as C, FG, C, F, etc., fluorinated hydrocarbon gas, silane gas, and Argon gas. When using fluorocarbon gas, etching tends to occur under conditions where it is placed in plasma and an accelerating voltage is applied. In this case, only the extreme surface is fluorinated. Therefore, first, a carbon-based film is formed using a hydrocarbon-based gas as the main component.
Thereafter, by plasma treatment with fluorocarbon gas, it is possible to make only the extreme surface layer water-repellent.

Furthermore, when the sample is outside the plasma and the acceleration energy of ions is small, as in the apparatus of the above embodiment, a carbon film containing fluorine is deposited. In this case, a fluorinated membrane is obtained, and the membrane has water repellency.

Furthermore, by increasing the silicon concentration near the underlying solid, it is possible to obtain a high hardness solid lubricant with good adhesion to the underlying solid.

〔Effect of the invention〕

As described above, the high hardness solid lubricant film and the method for forming the same according to the present invention are characterized in that the high hardness solid lubricant film having high hardness and wear resistance is formed on a solid surface and the method for forming the same includes silane gas and hydrocarbon gas or fluoride gas. Using plasma CVD or low pressure CVD performed by introducing carbon gas, the flow rate ratio of the silane gas and hydrocarbon gas or fluorocarbon gas is set to 0.2 to 0.7, and hard carbon containing silicon on the solid surface is produced. By forming a lubricating film, the hard carbon contains an appropriate concentration of silicon, so it has a low coefficient of friction and lubricity, and furthermore, on the contact surface with solids with a high silicon concentration, it will not adhere to the solids mentioned above. It has a large force and has lubricating properties, so it has a long friction life and provides stable friction characteristics over a long period of time. Therefore, bearings, motors,
Seals, valves, screws, internal surfaces of the sliding industry, joints,
Vane.

If applied to mechanical parts such as chains, parts with long-term reliability and little deterioration in precision can be obtained. moreover.

By taking advantage of its strong adhesion to the underlying solid, its high hardness, and its lubricity, it can be applied to tools such as cutting tools, and has great effects on workability, service life, etc. Furthermore, since it has wear resistance and lubricity, when applied to storage devices such as magnetic disks and magnetic heads, it has the effect of significantly increasing crush resistance and wear resistance.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of the method for forming a high hardness solid lubricant film according to the present invention, and Fig. 2 shows the frictional characteristics of the high hardness solid lubricant film when the flow rate ratio of silane gas and ethylene gas is changed. 3 is a diagram showing the change in friction life when the flow rate ratio of silane gas and ethylene gas is changed, and FIG. 4 is a diagram showing the friction characteristics of the high hardness solid lubricant film according to the present invention. ■...Rectangular waveguide 2...Plasma generation chamber 3
...Magnetic coil 4.4'...Silane gas, ethylene gas introduction hole 5...
Sample 7...Sample chamber τ・1 Figure

Claims (1)

[Claims] 1. In a high-hardness solid lubricant film having high hardness and wear resistance formed on a solid surface, the hard carbon forming the lubricant film contains silicon at a concentration lower than that of the carbon. A high-hardness solid lubricant film featuring 2. The high hardness solid lubricant film as set forth in claim 1, wherein the silicon has a high concentration on the surface in contact with the solid and a low concentration on the surface. 3. In a high-hardness solid lubricant film having high hardness and wear resistance to be formed on a solid surface, carbonization with the silane gas is performed using plasma CVD or low pressure CVD, which is performed by introducing silane gas and hydrocarbon gas or fluorocarbon gas. A method for forming a highly hard solid lubricant film, which comprises forming a silicon-containing hard carbon lubricant film on a solid surface by setting the flow rate ratio of hydrogen gas or fluorocarbon gas to 0.2 to 0.7. 4. The above flow rate ratio initially increases the flow rate ratio of silane gas,
The method according to claim 3, characterized in that the flow rate ratio of silane gas is sequentially lowered and the flow rate ratio of hydrocarbon or fluorocarbon gas is sequentially increased, so that the silicon concentration is increased on the side in contact with the solid. Method for forming hard solid lubricant film.