JPS63128167A - Electrically conductive solid lubricative film - Google Patents

Abstract

PURPOSE:To make a lubricative film electrically conductive and to improve the mechanical properties of the film by sputtering a fluoropolymer contg. chlorine as a target with one or more kinds of plasma gases selected among inert gases, gaseous fluorocarbons and gaseous oxygen. CONSTITUTION:Substrates 3 are fixed in a substrate holder 2 in a vessel 1 and a target 4 is set. A sheet or film of a fluoropolymer contg. chlorine such as polychlorotrifluoroethylene is used as the target 4. The vessel 1 is evacuated to a prescribed pressure in two steps with a rotary oil pump 10 and a diffusion oil pump 9 and the whole vessel 1 is heated with a heater 16. One or more kinds of plasma gases selected among the inert gases such as Ar and He, gaseous fluorocarbons such as CF4 and freon and gaseous O2 are then introduced to a set pressure from a plasma gas cylinder 15 and plasma is stably generated by impressing high frequency voltage to an electrode 6 from a power source 8.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a conductive solid lubricant that is resistant to oxidation, exhibits stable conductivity in air, and exhibits excellent solid lubricant properties even in vacuum. It concerns membranes.

[Prior art and its problems]

Conventionally, this type of solid 'IAWI film is known to be formed by sputtering using polytetrafluoroethylene (PTFE) as a target and an inert gas as plasma gas.

However, the sm characteristics of this solid lubricant film under circumferential motion are unstable in a region where the number of oscillations is small, as shown in Figure 5, and furthermore, the life of the solid lubricant film, which indicates the lubricating ability, is shortened in a vacuum. There is. Also, this solid imm
The peritoneal electrical resistance value is large and the membrane is insulative, which has the disadvantage that it cannot be applied to parts that require electrical conductivity and lubricity, such as electrical contacts and touch panels. Furthermore, the mechanical strength of this solid lubricant film is very low, and the film easily peels off or falls off from the deposition surface, resulting in a loss of lubricating function.

[Means for solving problems]

Therefore, in this invention, chlorine-containing fluoropolymer is targeted, inert gas, fluorocarbon gas, M
The above-mentioned problems are solved by using one of the elementary gases or 2TI or more as the plasma gas.

FIG. 1 shows an example of an apparatus for manufacturing the conductive solid lubricant film of the present invention, which uses high-frequency sputtering. In FIG. 1, reference numeral 1 is a vacuum container, 2 is a substrate holder, 3 is a substrate, 4 is a target, 5 is a shutter, 6 is a high frequency electrode, 7 is a matching box, 8 is a high frequency power supply,
9 is an oil diffusion pump, 10 is an oil rotary pump, 11 is a main valve, 12 is a roughing valve, 13 is a suction valve for the oil diffusion pump, 14 is a variable valve for introducing plasma gas, 15
is a plasma gas cylinder, and 16 is a heater.

Next, the procedure for manufacturing the conductive solid side WJl1g using this apparatus will be described below.

First, a substrate 3 such as heat-treated stainless steel or a silicon wafer is attached to a substrate holder 2 in a container 1, and a target 4 is further set. Target 4 is a sheet of chlorine-containing fluoropolymer such as polychlorotrifluoroethylene (PCT FE).

Use film. Next, after operating the oil rotary pump 10, the rough evacuation valve 12 is opened to start exhausting. When the pressure reaches about 104 torr, the roughing valve 12 is operated to open the suction valve 13 for the oil diffusion pump, and the oil expansion pump 9 is operated to open the main valve 11, and in parallel with this, to enhance the exhaust effect. The heater 16 is activated to heat the entire container 1. The pressure inside container 1 is 10'Tor
When the degree of vacuum increases to about r, the variable valve 14 for plasma gas introduction is opened, plasma gas is introduced from the plasma gas cylinder 15, and the gas pressure is set. A high frequency voltage is applied to the high frequency electrode 6 by a high frequency power source 8, and the pressure inside the container 1 is adjusted by a main valve 11 so that plasma is stably generated. The input high frequency power is set by the capacitor in the matching box 7, and the pressure is readjusted by the main valve 11 to obtain a stable plasma state. Next, after 30 minutes of sputter cleaning to remove contaminants from the surface of the target 4, the shutter 5 is opened and a lubricant film is formed on the substrate 3.

As the plasma gas, one or a mixture of two or more of inert gases such as argon gas and helium gas, fluorocarbon gases such as CF4 and Freon gas, and hydrogen gases is used. When oxygen gas is used, it is preferably used as a mixed gas with an inert gas such as argon gas at a concentration of 10 to 30 vol%.

By the above operations, the intended conductive solid lubricant film is formed on the surface of the substrate 3. This solid wet W# film has a molecular skeleton made of halogenated carbon, and has good properties due to its low surface energy. It has 1'1 lubricity and exhibits electrical conductivity.

Figure 2 shows the solid R4 synovial film of the present invention on the substrate surface using polychlorotrifluoroethylene (PCTFE) as the target, CF4 gas or 20% oxygen mixed argon gas as the plasma gas, and stainless steel as the substrate. For a sample formed with a velocity of 3112. radius 2
This figure shows the results of determining the number of oscillations during the lubrication life by oscillating the material circumferentially at a 60° oscillation angle and pressing a stainless steel spherical indenter at 4.9N to create friction. The number of oscillations during the lubrication life here is the number of oscillations when the friction coefficient during the oscillation motion becomes 0.3 or more. From this graph, it can be seen that the lifespan is significantly longer than that of the conventional solid film that uses polytetrafluoroethylene (PTFE) as the target and argon as the plasma gas. Furthermore, the average coefficient of friction of these solid lubricant films was 0.28, and it was confirmed that the solid lubricant films had excellent lubricity.

In addition, Figure 3 shows the number of circumferential oscillations and friction coefficient in the air and vacuum of the solid 11 obtained by using polychlorotrifluoroethylene (PCTFE) as a target and argon gas mixed with 20% oxygen as plasma gas. It shows the relationship between From this, the friction coefficient is 0°3 degrees even after 105 cycles in vacuum, which is an excellent T! It can be seen that it exhibits 1-slip durability.

Figure 4 shows the solid lubricant film (target: PCTF) of the present invention.
This shows the C1s region of the spectrum obtained when the structural analysis of E, plasma gas (freon) was performed using Xta photoelectron spectroscopy (XPS).

From this, it is considered that this solid lubricant film is mainly composed of CF, with some CF2 in the main chain and CF3 in the terminal. Further, in the infrared spectroscopy (IR) spectrum, a main peak is observed at a wave number of 1640c-1, and only a subpeak is observed at a wave number of 1400α-1, so that the carbon in the CF is considered to be SP2 carbon. From these analysis results, this solid lubricant film is 1fufu SP2
Polyfluorinated acetylene with carbon atoms connected: (CF=C
F), it is thought that the high lubrication ability appears due to the Coulomb repulsion between the main chains due to the high electron density on the fluorine atom.

Next, regarding the electrical characteristics of the solid lubricant film of the present invention,
During X-ray photoelectron spectroscopy measurements, no charge-up phenomenon accompanying electron emission was observed, indicating that the film was conductive, and the extent of this was determined by measuring the contact electrical resistance of the lubricating film.
The resistivity is 103 to 0 cm or less. Furthermore, it is possible to further lower the resistivity by doping the film with electron-donating or electron-withdrawing ions using an ion implantation method or a Ti decomposition anti-oxidation method. It was also found that this solid lubricant film was hardly etched in oxygen plasma and had excellent environmental resistance.

〔Effect of the invention〕

As explained above, the conductive solid lubricant film of the present invention is produced by sputtering a chlorine-containing thread fluoropolymer as a target and using one or more of inert gas, fluorocarbon, and oxygen as a plasma gas. Since it is obtained, it has a low coefficient of friction, high mechanical strength, excellent durability with low friction characteristics, and is electrically conductive. Therefore, this lubricating film can be suitably applied to maintenance-free bearings, electrical contacts, etc.

[Brief explanation of the drawing]

FIG. 1 shows 1! for obtaining the conductive solid lubricant film of the present invention! J
A schematic configuration diagram showing an example of the f1 device, FIG. 2 is a graph showing the number of cycles of the lifetime of the solid im lubricant film of the present invention and the conventional one, and FIG. 3 is a graph showing the number of circumferential swings of the conductive solid lubricant film of the present invention rf
A graph showing the relationship with the Jta coefficient, Fig. 4 is a graph showing the spectrum of the conductive solid fII synovial film of the present invention obtained by X-ray photoelectron spectroscopy, and Fig. 5 shows the number of circumferential oscillations and friction of the conventional solid lubricant film. It is a graph showing the relationship with coefficients. 4...Target 15...Plasma is a bomb

Claims (1)

[Claims] A conductive solid lubricant film obtained by sputtering a chlorine-containing fluoropolymer as a target and using one or more of inert gas, fluorocarbon, and oxygen as a plasma gas.