JPH01225775A - Formation of ceramic coating film on inner surface of tubular material - Google Patents

Abstract

PURPOSE:To form a ceramic film generated by the decomposition of a raw gas on the inner surface of a tubular material at low temp. by introducing the raw gas into the material, and supplying a high-frequency power. CONSTITUTION:The gaseous mixture of TiCl4 and NH3, TiCl4 and CH4, AlCl3 and BCl3, SiH4 and N2O, SiH4 and NH3, (CH3)3Al and N2O, etc., is introduced into the tubular material 1-5 from a raw gas feeder 1-4 with H2, Ar, N2, etc., as the carrier gas. A high-frequency power is simultaneously supplied from a high-frequency generator 1-1 through a waveguide 1-8 to produce plasma in the material, hence the raw gas is decomposed, and the thin film of the TiN, TiC, AlB, SiO2, Si3N4, Al2O3, etc., as the ceramic material is formed on the inner surface of the tubular material 1-5. In this case, when the tubular material 1-5 is made of a material transmitting a high-frequency power such as quartz, the outside of the material 1-5 is coated with a metal to reflect the high-frequency power. In addition, a magnetic field generator is provided on the outside or inside of the material 1-5 to control the plasma state, and the quality and thickness of the ceramic film can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of forming a ceramic thin film on the inner surface of a tubular material and on the inner surface of an object connected to a tube.

(Prior art) So-called ceramic materials such as silicides, oxides, and nitrides have superior wear resistance, heat resistance, and corrosion resistance compared to metals and other materials, so they are suitable for use in machine tools and machine parts. Coating their surfaces with thin films is widely practiced for the purpose of improving the quality of their surfaces.

The main coating methods used for these are CVD (chemical vapor deposition), VD (plasma physical vapor deposition), and CVR (chemical vapor reaction). After the object is placed in a closed container and the ceramic raw material is introduced into the container, a thermal reaction and a plasma reaction occur to deposit a ceramic film on the surface of the material.

On the other hand, it has become clear that ceramic materials have the property of adsorbing pollutants such as gas molecules to their surfaces significantly less than metals. It is used for storage.

Manufacture of products that require high purity and high cleanliness by coating the inner surface of tubular materials with a ceramic thin film.
It becomes possible to store and safely extract highly corrosive materials.

However, it is difficult to apply conventional methods to coating the inner surface of a tubular material, and no practical method has been developed. The reason for this is the following drawbacks of the conventional method.

■If the object is a long object with a tubular shape, the sealed container will become huge.

(2) It is difficult to supply the raw material gas to the inside of the tube and control the gas reaction inside, so it is impossible to control the quality and film thickness formed.

■Since plasma reaction does not occur inside the long tube in normal equipment, it is difficult to reduce the reaction temperature.

Furthermore, in recent years, there have been reports that a ceramic film was formed inside a long tube by flowing raw material gas from one end of the tube, heating a part of the tube from the outside, and moving the heating area. (Journal of
) Iterials, 5science 21(1
986) 751-756. ), since this method uses a pyrolysis method for the ceramic formation mechanism, it is necessary to heat it to a high temperature, and it has the disadvantage that it can only be applied to materials that have heat resistance above the heating temperature.

Specifically, the report states that i, ioo are used to form a TiN film.
oC heating was required. In addition, the fact that high temperatures are required for film formation means that when the material temperature is lowered after film formation, stress is generated between the film and the material due to the difference in thermal expansion coefficient between the tubular material and the formed film. It means,
Peeling and cracking of the membrane are likely to occur.

Therefore, in this method, there are significant restrictions on the combinations of the formed film and the tubular material, and in order to expand the combinations of materials and films, it is necessary to form a stress buffer film between the target film and the tubular material, etc. The manufacturing process will inevitably become more complex.

(Problems to be Solved by the Invention) It is an object of the present invention to solve the above-mentioned problems, and further to provide an apparatus for forming a uniform and high-quality ceramic film on the inner surface of a tubular material and the inner surface of an object connected to the tubular material at a low temperature. It is in.

(Means for Solving the Problems) The gist of the present invention is to introduce high-frequency power into a tubular material into which a ceramic raw material has been introduced, and to form a ceramic film on the inner surface of the tubular material and on the inner surface of an object connected to the tubular material and the tube. The method of manufacturing a coating film is characterized by precipitating a coating film, which will be described in detail below.In the present invention, a raw material gas is introduced from one end of a material having a tubular shape and exhausted from the other end, and the inside of the pipe is The tube is maintained in a reduced pressure or pressurized state. In this state, plasma is generated inside the tube by introducing high frequency power from one end of the tube, causing a decomposition reaction of the raw material gas and forming a ceramic film on the inner surface of the tube. In the present invention, When the tubular material is a conductor such as metal, it is possible to generate uniform plasma inside the tube even if it is a long tube by effectively using the phenomenon of high frequency power propagating inside the tube. A ceramic film having uniform film quality and film thickness in all directions can be formed.

Furthermore, by selecting the frequency of the high-frequency power introduced into the tube depending on the inner diameter and shape of the tube, a ceramic film can be formed on any shape of the tube material.

Furthermore, the high-frequency power frequency is changed during film formation, and the high-frequency mode propagating inside the tube (magnetic field and electrolytic distribution state)
By changing , it is possible to make the film thickness distribution and film quality uniform.

The tubular material has a low ability to reflect high frequency power, such as quartz, etc.
Furthermore, in the case of a material that has the property of transmitting high-frequency power, a ceramic film can be formed on the inner surface of the tube by covering the outside of the material with a material having a high reflective ability, such as a metal tube (FIG. 3).

To finely control the quality and thickness of the ceramic film formed on the inner surface of the tube, a magnetic field generator is installed outside the tube, and by changing the magnetic field strength and position applied to the tube, the plasma state inside the tube can be controlled from outside the tube. It is also possible to control the film quality and film thickness (Fig. 4).

In the above configuration, film quality can also be improved by applying appropriate heating from outside the tube.

[For production]

FIG. 1 shows an example of a block diagram of the basic configuration of an apparatus corresponding to the method of the present invention, in which solid lines indicate the flow of high-frequency power and broken lines indicate the flow of raw material gas.

FIG. 2 shows an apparatus compatible with the method of the present invention, showing details of the gas introduction section and high frequency introduction section of FIG. 1.

The configurations of the gas exhaust section and the high frequency reflection section are the same as those of the introduction section, and the gas introduction section serves as the exhaust section.

FIG. 3 shows a drawing corresponding to the method of the invention, showing only the parts added to FIGS. 1 and 2.

FIG. 4 is a diagram corresponding to the method of the present invention, and shows parts added to FIG. 1 and FIG. 2 or 3.

Next, an application example of the present invention is shown in Fig. 5. This application example is an effective method for large diameter tubular materials. In this example, a gas reaction is generated only in a part of a large-diameter pipe, and the reaction is moved along the inner circumference of the pipe, which is used to match high-frequency power to a large-diameter pipe (tuning). ) has the advantage of being easy to characterize.

Figure 6 shows another application example in which a waveguide for introducing high-frequency power is inserted into the inside of a tubular material, and plasma is generated by moving the waveguide and the tubular material relatively. It has the advantage of being able to change the area and control the membrane condition at a desired position within the tube. It is also possible to arrange the high frequency introduction part and the gas flow introduction part interchangeably.

All of these applications can also be used in combination with any of the methods of the present invention.

FIG. 7 shows still another application of the present invention, which is a modification of the method of the present invention, in which a magnetic field generator is placed inside a tubular material. This example is effective when the tubular material is ferromagnetic and a magnetic field cannot be applied from the outside.

In this example, the raw material gas flows counter-currently to the high-frequency flow and the exhaust flow, but the same effect can be expected even if the high-frequency flow and the exhaust flow are replaced with each other as shown in parentheses.

(Example) An example of the present invention will be described based on the basic configuration shown in FIG. 1, taking as an example a case where a TiN film is formed on the inner surface of a stainless steel pipe with an inner diameter of 4# (outer diameter of 174 inches).

When the pipe has a circular cross-sectional shape, the high frequency f that can be propagated in the pipe is f = 2.99x 1 when the inner diameter is D (cm).
It is known from electromagnetic theory that (No / (1,841xπXD)[1-1z], and D=0.4cm
In this case, the frequency is 13 [GHz] or more. Oscillators of this frequency range are widely used and can be easily obtained for this purpose.

For TiN film formation, T i C14 and N H are used as raw materials.
3, and these were N2. By supplying H2, Ar, etc. as a carrier gas from one end of the pipe and simultaneously exhausting it with an exhaust device installed at the other end, the pressure inside the pipe can be reduced to 10-3.
Maintain the pressure between torr and 10 torr.

In this state, when the high frequency wave is supplied with a power of about 10 W to 1 KW into the tube, plasma is generated in the tube, and this plasma promotes the decomposition and reaction of the raw material gas, and TiN is deposited on the inner surface of the tube.

In the case of the present invention, film precipitation is observed on the inner surface of the tube even at room temperature, but the outside of the tube is heated to about 200°C to 500°C in order to improve the adhesion between the inner surface of the tube and the precipitate and the quality of the deposited film. . However, this degree of heating is unlikely to cause peeling of the membrane due to the coefficient of thermal expansion between the membrane material and the tube material, and there are many tube materials that can withstand this degree of heating. It is possible to apply it to numerous combinations of materials.

In addition to the examples mentioned here, Ti
C14 and CH4, AlCl3 and BCJ! By combining 3 and H2, etc., films such as TiC, AiB, etc.
To'N20. S i H4(S 1t-1zCJ!z
> and NH3, (CH3) 3 AJ! It is also possible to generate S ioz, S i3N4, A1203, etc. from and N20, respectively.

T i CJ! The reaction formula when forming a TiN film using a and NH3 as raw material gases is T i C124+ 4/3Nl13 → Ti
N+4HCj! + 1/6N2.

Since T i C14 is solid at room temperature, it needs to be supplied after being gasified, which is carried out as follows.

The T i C1a container is maintained at 30'C, and t-1z (or N2) gas is supplied from one end of the container at 3 CC (3 CC) per minute.
SCC)l) injected with H saturated with T i C14
2 Take out the gas.

In this example, the supply amount of T i C14 per minute is approximately 2
．． It will be about 8Xl0-6m01.

Further, the NH3 gas is made from a gas diluted to about 10% with 1"2 or a gas, and is supplied at a rate of 3.7 x 10-6 nof per minute by supplying 1 CC (1 CC) 1) per minute.

After mixing the above two gases, they are further used as a carrier gas +
12 or gas flow rate 20-303CC)! It was diluted with water and then supplied into the tube. With this method, about 300 TiN films can be formed per minute, but if the feed rate of each source gas is increased by one order of magnitude, the amount of precipitation will also increase by about one order of magnitude.

In addition, in the case of films such as TiC and AIB, the reaction formula can be written as %formula%. In this case as well, a good film can be formed within the above-mentioned raw material supply amount range.

〔Effect of the invention〕

According to the present invention, it is possible to form a uniform and high quality ceramic film at low temperature on the inner surface of a tubular inorganic material and the inner surface of an object connected to the pipe, and it is also possible to form a ceramic film on a long object.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating an embodiment of the present invention;
Figures 2 to 4 are detailed and partial views of Figure 1, and Figures 5 (a) and 5 (b) are radial and longitudinal cross-sectional views showing application examples of the present invention. , FIG. 6, and FIG. 7 are explanatory diagrams each showing an example of application of the present invention. In FIG. 1, 1-1 is a high-frequency generator 1-2 is a high-frequency directional coupler 1-3 is a high-frequency absorber 1-4 is a raw material gas supply device 1-5 is a tubular material 1-6 is a high-frequency reflection adjuster 1-7 is a gas exhaust device 1-8 is a waveguide in Figure 2, 2-1 is a waveguide 2-2 is a waveguide 7, a flange 2-3 is a quartz plate (high wave transmission window), 2-4 is a waveguide The O-ring 2-5 is the manifold 2-6, the gas inlet 2-7 is the tubular material 2-8, the plasma generation area 2-9 is the high-frequency wave reflector, and 3-1 is the tubular material 3-2 is the high-frequency reflector. In Fig. 4, 4-1 is a tubular material 4-2 is a magnetic field generating coil 4-3 is a supporting part 4-4 is a trolley 4-5 is a rail part 4-6 is a gas flow, and a plasma flow in Fig. 5. , 5-1 is a large diameter 5-2 is a gas, high frequency confinement device 5-3 is a gas flow and plasma in FIG. 6, 6-1 is a waveguide 6-2 is a tubular material in FIG. 7, 7-1 The tubular material 7-2 represents the gas introduction pipe 7-3, and the stone 7-4 represents the gas outlet. Figure 3 Figure 4 Procedure Amendment 4 Export) May 16, 1985 Commissioner of the Patent Office Noko January! yβo, 1988 Patent Application No. 50790 Name of the process Name ゛ Toyo Stouffer Chemical Co., Ltd. Contents of the detailed description of the invention column and simple amendments to the drawings in the specification ■9 Of the column of the detailed description of the invention Correct the following matters. 1. On page 5, line 14 of the specification, the word "apparatus" has been corrected to "method." 2. On page 12, line 4 of the specification, the phrase "solid at room temperature" has been corrected to "liquid at room temperature." ■0 Correct the following items in the brief explanation column of the drawing. 1. On page 14, line 16 of the specification, the phrase "high wave transmission window" has been corrected to "high frequency transmission window." 2. On the 18th line of the same page, the word "manifold" has been corrected to "manifold."

Claims (4)

[Claims] (1) A method for producing a coating film, which comprises introducing high-frequency power into a tubular material into which a ceramic raw material has been introduced, and depositing a ceramic film on the inner surface of the tubular material and on the inner surface of an object connected to the tubular material and the tube. (2) Formation of a ceramic thin film characterized in that the tubular material of claim 1 is a conductive material and has at least one opening, and high frequency power is introduced into the interior through at least one opening. Method. (3) When the tubular material according to claim 1 is a material that transmits high-frequency power, a coating characterized in that a ceramic thin film is formed inside the tubular material by coating the outer surface of the tubular material with a high-frequency reflective material. How to form a film. (4) In the forming method according to any one of claims 1 to 3, a magnetic field generator is provided at one or more locations outside or inside the tubular material, and the magnetic field generator is moved relative to the tubular material. A method for forming a coating film characterized by making it possible.