CN106282973A - Apparatus and method for coating film on inner wall of pipe - Google Patents

Abstract

The invention discloses a device for coating a film on the inner wall of a pipe, which comprises a power supply and an inner electrode capable of being inserted into the pipe to be coated, wherein the inner electrode is of a double-layer structure, the inner layer is a conductor, the outer layer is a dielectric layer, the inner electrode is arranged in the pipe to be coated and is connected to the power supply in a use state, the pipe to be coated is made of a conductive material and is also connected to the power supply, and in a power-on state, dielectric barrier discharge is generated between the inner electrode and the pipe to be coated, a gas raw material is excited to generate plasma, and film deposition. The invention also discloses a method for coating the inner wall of the tube by adopting the device for coating the inner wall of the tube. The invention relates to a device and a method for coating a film on the inner wall of a tube, which adopts a dielectric barrier discharge structure form consisting of an inner electrode with a dielectric layer on the surface and a conductive tube to be coated, so that the device can realize uniform discharge under high pressure and even atmospheric pressure, and further utilize a high-frequency high-voltage power supply to excite and generate uniform plasma or relatively uniform plasma to realize the deposition of a film on the inner wall of a metal tube.

Description

Apparatus and method for coating film on inner wall of tube

technical field

The invention relates to the technical field of plasma material surface modification, in particular to a device and method for coating the inner wall of a tube.

Background technique

In actual industrial applications, there are a large number of inner surfaces of tubular workpieces that need to be modified, such as: oil pipelines in oil fields, chemical pipelines, automobile cylinders, and gun barrels and gun barrels in the military field. The inner walls of these tubular workpieces working in harsh environments need to be strengthened. The common method of modifying the inner wall of pipe fittings is mainly industrial electroplating, but the film deposited by the electroplating method has poor adhesion to the substrate, and a large amount of waste liquid that will pollute the environment is produced during the treatment process.

Plasma-enhanced chemical vapor deposition can well solve the problems existing in the electroplating method, and has been widely used in the field of thin film deposition on the surface of materials, and it is also used in the coating process of the inner wall of the tube. However, there are problems that the equipment structure is complex and needs to be carried out under vacuum conditions. At the same time, due to the limited structural space of the pipe fittings, it is difficult to achieve uniform discharge, which affects the quality of the coating film.

Dielectric barrier discharge is a form of discharge that can achieve uniform discharge at higher pressures, even at atmospheric pressure, and can be applied to the plasma-enhanced chemical vapor deposition process, but because dielectric barrier discharge requires a small distance between the two electrodes to achieve Uniform discharge, so dielectric barrier discharge is generally only used in thin film deposition or modification on the surface of objects with a small thickness, and there is no suitable dielectric barrier discharge coating equipment for the inner surface of tubular workpieces.

Contents of the invention

The technical problem to be solved by the present invention is that in the prior art, the device for coating the inner wall of the tube using the plasma-enhanced chemical vapor deposition method has a complex structure and needs to be carried out under vacuum conditions, and then aims at conductive tubular workpieces, such as metal tubes To provide a device with simple structure and capable of coating the inner wall of a tube by plasma-enhanced chemical vapor deposition under atmospheric pressure. The present invention also provides a coating method using the above-mentioned device.

In order to solve the problems of the technologies described above, the technical scheme adopted in the present invention is as follows:

The device for coating the inner wall of a tube of the present invention includes a power supply and an inner electrode capable of being inserted into the tube to be plated. The inner electrode has a double-layer structure, the inner layer is a conductor, and the outer layer is a dielectric layer. In use, the The inner electrode is arranged in the tube to be plated and connected to the power supply. The tube to be plated is made of conductive material and is also connected to the power source. Generate dielectric barrier discharge, excite gas raw material to generate plasma, and realize thin film deposition.

Preferably, the conductor is graphite, metal or alloy.

Preferably, the inner electrode is cylindrical.

Preferably, the medium layer is a quartz tube or a glass tube.

Preferably, the power supply is a high-frequency high-voltage power supply.

Preferably, the device for coating the inner wall of the tube further includes auxiliary vacuum equipment.

The present invention also provides a method for coating the inner wall of a tube by using the device for coating the inner wall of the tube, comprising the following steps:

Inserting the internal electrode into the tube to be plated and connecting the internal electrode and the tube to be plated to the power supply respectively, and passing through the gap between the inner wall of the tube to be plated and the internal electrode The gas raw material is injected to generate a dielectric barrier discharge between the inner electrode and the tube to be coated to excite the gas raw material to generate plasma, and then the plasma enhanced chemical vapor deposition method is used to realize film deposition.

Preferably, vacuuming is performed on the gap between the inner wall of the tube to be plated and the inner electrode, so that the film deposition is performed under low pressure.

The beneficial effects of the present invention are as follows:

The device and method for coating the inner wall of the tube of the present invention adopt a kind of internal electrode with a dielectric layer on the surface and a conductive tube to be plated to form a dielectric barrier discharge structure, so that the invented device can be used under high pressure, even under high pressure. Uniform discharge is realized under atmospheric pressure, and then uniform plasma or relatively uniform plasma is generated by high-frequency and high-voltage power supply excitation to realize thin film deposition on the inner wall of the metal tube.

The device for coating the inner wall of the tube of the present invention utilizes the principle of dielectric barrier discharge to provide a device for coating the inner wall of the tube, which has lower requirements on the vacuum system, simple structure of the discharge device, cost saving, and higher deposition rate. The outer layer of the internal electrode is a non-conductive dielectric layer, such as quartz or glass, which will not form an arc during the discharge process, and the safety of the device is higher.

Moreover, the device for coating the inner wall of the tube of the present invention can adjust the size of the inner electrode according to the characteristics of the tube to be coated, and has high flexibility; it can adjust the composition of the discharge gas according to the coating material and type; it has the advantages of good coating uniformity, strong film base bonding, etc. advantage.

Description of drawings

Fig. 1 is the structural representation of the pipe to be plated and the inner electrode part in the use state of the device for coating the inner wall of the pipe of the present invention;

Fig. 2 is the longitudinal sectional schematic view of the pipe to be plated and the inner electrode part in the use state of the device for coating the inner wall of the pipe of the present invention;

Fig. 3 is a cross-sectional schematic view of the tube to be plated and the inner electrode part in the use state of the device for coating the inner wall of the tube of the present invention

In the picture:

1 inner electrode, 2 tube to be plated, 11 conductor, 12 dielectric layer.

detailed description

The technical solutions and beneficial effects of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

The device for tube inner wall coating of the present invention includes a power supply and an inner electrode 1 that can be inserted into the tube 2 to be plated. The inner electrode 1 has a double-layer structure, the inner layer is a conductor 11, and the outer layer is a dielectric layer 12. Next, the inner electrode 1 is set in the tube 2 to be plated and connected to the power supply. The tube 2 to be plated is made of a conductive material and is also connected to the power source. In the energized state, a dielectric barrier discharge is generated between the inner electrode 1 and the tube 2 to be plated. , to excite the gas raw material to generate plasma to realize thin film deposition.

The device for coating the inner wall of a pipe of the present invention is applicable to any conductive tubular member, such as a metal pipe or an alloy pipe.

In the present invention, the conductor 11 can be graphite, metal or alloy.

In the present invention, the shape and size of the inner electrode can be determined according to the shape and inner diameter of the tube 2 to be plated. When the tube 2 to be plated is cylindrical, the inner electrode 1 is set to be cylindrical to help generate more uniform plasma. The size of 1 is determined according to the inner diameter of the tube to be plated, as long as the distance between the inner wall of the tube to be plated 2 and the inner wall of the inner electrode 1 is suitable for realizing the dielectric barrier discharge process.

In the present invention, the dielectric layer on the internal electrode 1 can be any suitable non-conductor, for example, it can be a quartz tube or a glass tube.

The power supply in the present invention can be a high-frequency high-voltage power supply.

In the present invention, it is possible to choose whether to set up auxiliary vacuum equipment according to the level of coating requirements.

The present invention also provides a method for coating the inner wall of a tube by using the above-mentioned device for coating the inner wall of the tube, comprising the following steps:

The internal electrode 1 is inserted into the tube 2 to be plated and the internal electrode 1 and the tube 2 to be plated are respectively connected to the power supply, the inner wall of the tube 2 to be plated and the internal electrode 1 The gas raw material is passed into the gap between the internal electrodes 1 and the tube 2 to be coated, so that a dielectric barrier discharge is generated between the inner electrode 1 and the tube 2 to excite the gas raw material to generate plasma, and then the plasma-enhanced chemical vapor deposition method is used to realize film deposition.

In the case of high coating requirements, vacuuming can be performed on the gap between the inner wall of the tube 2 to be coated and the inner electrode 1, so that the thin film deposition can be carried out under a lower pressure state.

Of course, in the case of low coating requirements, the auxiliary vacuum equipment and vacuuming operation can also be omitted.

Those skilled in the art will appreciate that the embodiments described here are to help readers understand the principles of the present invention, and it should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can research and make various other specific modifications and combinations based on the technical revelations disclosed in the present invention without departing from the essence of the present invention, and these modifications and combinations are still within the protection scope of the present invention.

Claims (8)

1. The device for coating the inner wall of a tube is characterized in that: it includes a power supply and an internal electrode (1) that can be inserted into the tube (2) to be plated, the internal electrode (1) is a double-layer structure, and the inner layer is a conductor (11), the outer layer is a dielectric layer (12), in use, the inner electrode (1) is arranged in the tube to be plated (2) and connected to the power supply, the tube to be plated (2) It is made of conductive material and connected to the power supply. In the energized state, a dielectric barrier discharge is generated between the inner electrode (1) and the tube (2) to be plated, and the gas material is excited to generate plasma to realize film deposition. . 2. The device for coating the inner wall of a tube according to claim 1, characterized in that: the conductor (11) is graphite, metal or alloy. 3. The device for coating the inner wall of a tube according to claim 2, characterized in that: the inner electrode (1) is cylindrical. 4. The device for coating the inner wall of a tube according to claim 3, wherein the dielectric layer is a quartz tube or a glass tube. 5 . The device for coating the inner wall of a pipe according to claim 4 , wherein the power supply is a high-frequency high-voltage power supply. 6 . The device for coating the inner wall of the tube according to any one of claims 1 to 4 , characterized in that: the device for coating the inner wall of the tube also includes auxiliary vacuum equipment. 6 . 7. The method for coating the inner wall of the tube using the device for coating the inner wall of the tube according to any one of claims 1 to 6, is characterized in that it comprises the following steps: The inner electrode (1) is inserted into the tube to be plated (2) and the inner electrode (1) and the tube to be plated (2) are connected to the power supply respectively, and the tube to be plated ( 2) The gas material is passed into the gap between the inner wall of the inner electrode (1) and the inner electrode (1), so that a dielectric barrier discharge is generated between the inner electrode (1) and the tube (2) to be plated to excite the gas material to generate plasma body, and then use the plasma enhanced chemical vapor deposition method to achieve thin film deposition. 8. The method according to claim 7, characterized in that: vacuumize the gap between the inner wall of the tube to be plated (2) and the inner electrode (1), so that the film is deposited in a low-pressure state conduct.