A preparation method for inner surface arc ion plating

Abstract

This invention discloses a novel method for inner surface arc ion plating. It automatically adjusts the magnetic field current frequency and maximum magnetic field current based on the target's cone angle and height, achieving uniform spiral motion of the arc spot on the target. The cathode arc source motion device is designed to achieve spiral motion of the cathode arc source, and the workpiece rotation motion device is designed to achieve controlled rotational motion of the workpiece. This invention helps improve the service stability and reliability of ultra-high-temperature protective coatings such as molybdenum and iridium, and is conducive to promoting the development and advancement of spacecraft.

Description

Technical Field

[0001] The present invention relates to the field of engine design, and in particular to a method for preparing the inner surface of a thrust chamber of a high-performance engine by arc ion plating, which can be applied to a trajectory and attitude control engine of a spacecraft. Background Art

[0002] Bipropellant orbit and attitude control engines are an important component of modern space vehicles and are widely used in orbit control, attitude adjustment, etc.

[0003] In recent years, the development of new aircraft has placed increasing demands on engine performance, requiring higher specific impulse and longer service life, thereby improving the trajectory change efficiency and on-orbit life of aircraft or weapons. The engine's permissible operating temperature is a major factor in determining its specific impulse, and the performance of the engine's thrust chamber base material and the high-temperature, oxidation-resistant coatings on its internal and external surfaces determine both its permissible temperature and service life.

[0004] Currently, arc ion plating can increase the permissible operating temperature of engines by 100°C and 700°C, respectively, significantly improving engine performance. However, conventional arc ion plating methods suffer from poor coating uniformity, which affects the stability and reliability of engines during service. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a preparation method for arc ion plating on the inner surface of the thrust chamber body of a bipropellant liquid propellant trajectory and attitude control engine. This method significantly improves the thickness uniformity of the ultra-high temperature protective coating on the inner surface of the thrust chamber body, and improves the service stability and reliability of the ultra-high temperature protective coating.

[0006] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0007] A novel method for preparing inner surface arc ion plating comprises:

[0008] (1) Processing target material, the target material is divided into two parts: cylindrical section and conical section;

[0009] (2) Inputting the target cone angle and target height into the cathode arc source electromagnetic field control system, the cathode arc source electromagnetic field control system automatically adjusts the magnetic field current frequency and the magnetic field maximum current according to the input target cone angle and target height;

[0010] (3) Insert the arc starter into the cylindrical section of the target material, insert the arc starter needle into the arc starter shell, use polytetrafluoroethylene to insulate the arc starter needle from the arc starter, connect the arc starter needle to a high voltage power supply of 10,000 to 50,000 V, and the target material, arc starter, and arc starter needle constitute a cathode arc source;

[0011] (4) The cathode arc source performs an up and down spiral motion under the control of the cathode arc source electromagnetic field control system;

[0012] (5) The workpiece is located directly above the cathode arc source, and the workpiece is embedded in the rotating mechanism and rotates under the drive of the rotating mechanism;

[0013] (6) The arc starter is ignited under the control of the cathode arc source electromagnetic field control system, the target material arcs and ionizes ions, and uniform deposition is achieved on the inner surface of the workpiece during the movement of the cathode arc source and the workpiece.

[0014] Preferably, the target material is pure molybdenum or iridium.

[0015] Preferably, the maximum outer diameter of the target is 40 to 60 mm, the height of the target is 40 to 200 mm, and the cone angle of the target is 10° to 90°.

[0016] Preferably, the magnetic field current frequency = 0.75×the target cone angle; the magnetic field maximum current = 0.25×the target height.

[0017] Preferably, the arc starter is made of stainless steel and the arc starting needle is made of refined copper.

[0018] Preferably, the inner diameter of the arc starter is 10 to 20 mm larger than the maximum outer diameter of the target material, the outer diameter of the arc starter is 60 to 100 mm larger than the inner diameter, and the length of the arc starter needle is 30 to 60 mm.

[0019] Preferably, the cathode arc source has a vertical movement speed of 10 to 200 mm / min, a rotational movement speed of 5 to 20 r / min, and a vertical movement stroke of 0 to 200 mm.

[0020] Preferably, the workpiece material is niobium-tungsten alloy or rhenium.

[0021] Preferably, the maximum outer diameter of the workpiece is 20-100 mm, and the height is 30-300 mm.

[0022] Preferably, the rotating mechanism is made of niobium-tungsten alloy material, and the rotation speed is 1 to 10 r / min.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention adopts a combination of electromagnetic field control of arc spot movement and mechanical movement, avoiding the shortcomings of single electromagnetic field control of arc spot movement or single mechanical movement, greatly improving the uniformity of coating deposition, and can increase the uniformity of coating thickness to ±5%, effectively ensuring the stability and reliability of the engine during service. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1Schematic diagram of inner surface arc ion plating preparation. DETAILED DESCRIPTION

[0026] In order to further improve the operating temperature and service life of the engine nozzle, the arc ion plating method is used to prepare ultra-high temperature protective coatings. For example, molybdenum, iridium, etc. can effectively increase the allowable temperature of the engine. In order to improve the service reliability and stability of the ultra-high temperature protective coating, it is very important to ensure the uniformity of the coating thickness in the axial and circumferential directions of the thrust chamber body.

[0027] The present invention proposes for the first time a new method for preparing ultra-high temperature anti-oxidation coatings by arc ion plating on the inner surface. This preparation method will further improve the uniformity of the coating on the inner surface of the thrust chamber body, help improve the service stability and reliability of ultra-high temperature protective coatings such as molybdenum and iridium, and promote the development and progress of spacecraft.

[0028] A novel method for preparing inner surface arc ion plating comprises the following steps:

[0029] Step (1), cathode arc source, the specific method is as follows:

[0030] (1.1) Processing target: the target material is molybdenum or iridium, and the target is divided into two parts: cylindrical section and conical section. The maximum outer diameter of the target is 40-60 mm, the height of the target is 40-200 mm, and the cone angle is 10°-90°.

[0031] (1.2) The arc starter is made of stainless steel. The inner diameter of the arc starter is 10 to 20 mm larger than the maximum outer diameter of the target material. The outer diameter of the arc starter is 60 to 100 mm larger than the inner diameter. The arc starter needle is made of refined copper and has a length of 30 to 60 mm. The distance between the front end of the arc starter needle and the target material is controlled at 1 to 3 mm.

[0032] (1.3) The arc starter is inserted into the cylindrical section of the target material, and the arc starter needle is inserted into the outer shell of the arc starter. Polytetrafluoroethylene is used to insulate the arc starter and the arc starter. The arc starter needle is connected to a high-voltage power supply of 10,000 to 50,000 V. The target material, arc starter and arc starter constitute a cathode arc source.

[0033] Step (2), electromagnetic field control system, the specific method is as follows:

[0034] (2.1) Input the target cone angle and target height into the cathode arc source electromagnetic field control system. According to the input target cone angle and target height, the cathode arc source electromagnetic field control system automatically adjusts the magnetic field current frequency and the magnetic field maximum current.

[0035] (2.2) Current frequency (Hz) = 0.75 × target cone angle; Maximum magnetic field current (A) = 0.25 × target height.

[0036] Step (3), mechanical motion system, the specific method is as follows:

[0037] (3.1) The arc source makes an up-and-down spiral motion. The speed of the arc source's up-and-down motion is 10-200 mm / min, the speed of its rotational motion is 5-20 r / min, and the up-and-down motion stroke is 0-200 mm.

[0038] (3.2) The workpiece is located directly above the cathode arc source. The workpiece material is niobium-tungsten alloy or rhenium. The maximum outer diameter of the workpiece is 20 to 100 mm and the height is 30 to 300 mm. The workpiece is embedded in the rotating mechanism. The rotating mechanism is made of niobium-tungsten alloy and the rotation speed is 1 to 10 r / min.

[0039] Example:

[0040] The present invention uses the manufacturing of an engine thrust chamber body with a size of φ60×90mm (φ60mm is the inner diameter of the engine thrust chamber body, and 90mm is the total length of the engine thrust chamber body) as an example to describe the specific implementation of the method of the present invention by depositing an iridium coating on the inner surface of the engine thrust chamber body. (a) Preparation of cathode arc source:

[0041] (1) Processing target: the target material is iridium, and the target is divided into two parts: cylindrical section and conical section. The maximum outer diameter of the target is 50 mm, the height of the target is 80 mm, and the cone angle of the target is 20°.

[0042] (2) The arc starter is made of stainless steel with an inner diameter of 60 mm and an outer diameter of 140 mm. The arc starter needle is made of refined copper with a length of 40 mm. The distance between the front end of the arc starter needle and the target material is controlled at 2 mm.

[0043] (3) The arc starter is inserted into the cylindrical section of the target material, and the arc starter needle is inserted into the arc starter shell. Polytetrafluoroethylene is used to insulate the arc starter and the arc starter. The arc starter needle is connected to a 20,000V high-voltage power supply. The target material, arc starter and arc starter constitute a cathode arc source.

[0044] (b) Preparation of electromagnetic field control system:

[0045] (1) The target cone angle and target height are input into the cathode arc source electromagnetic field control system. According to the input target cone angle and target height, the cathode arc source electromagnetic field control system automatically adjusts the magnetic field current frequency and the magnetic field maximum current.

[0046] (2) The current frequency is adjusted to 15HZ and the maximum current of the magnetic field is 20A.

[0047] (c) Mechanical motion system preparation:

[0048] (1) The arc source makes an up-and-down spiral motion. The speed of the arc source's up-and-down motion is 70 mm / min, the speed of its rotational motion is 10 r / min, and the up-and-down motion stroke is 80 mm.

[0049] (2) The workpiece is located directly above the cathode arc source. The workpiece material is rhenium, the maximum outer diameter of the workpiece is 60 mm, and the height is 90 mm. The workpiece is embedded in the rotating mechanism. The rotating mechanism is made of niobium tungsten alloy material, and the rotation speed is 5 r / min.

[0050] Figure 1 Schematic diagram of inner surface arc ion plating preparation. Figure 1 An electromagnetic coil is wound around the outer surface of the magnetic tube and passed into the furnace cavity. The target material and the magnetic tube are connected by threads. The arc starter is sleeved on the cylindrical surface of the target material. The workpiece is placed directly above the target material. The workpiece rotates under the drive of the rotating mechanism, and the target material performs an up and down spiral motion.

[0051] Experimental verification shows that the inner surface arc ion plating of the present invention achieves uniform deposition of molybdenum coating on the inner surface of the engine thrust chamber body with a size of φ60×90mm, and the thickness uniformity of the molybdenum layer in each part reaches 50±2μm.

[0052] This invention provides a novel arc ion plating method for the inner surface of an engine thrust chamber. Through the design of a cathode arc source electromagnetic field control system, the magnetic field current frequency and maximum magnetic field current are automatically adjusted according to the target material's cone angle and height, achieving uniform spiral motion of the arc spot on the target. The design of a cathode arc source motion device also enables spiral motion of the cathode arc source. The design of a workpiece rotation motion device also enables controllable rotation of the workpiece.

[0053] This invention proposes for the first time a novel preparation method for inner surface arc ion plating. This preparation method uses a combination of electromagnetic field-controlled arc spot motion and mechanical motion to increase coating uniformity from the current ±15% to ±5%, greatly improving the service stability and reliability of the engine and laying a solid technical foundation for the development of a new generation of spacecraft. The static performance of the ultra-high temperature protective coating: The high-temperature oxidation resistance life at 1800°C is increased from the current no less than 10 hours to no less than 30 hours, and the number of thermal shock resistances from 1700°C to room temperature is increased from no less than 1000 times to no less than 1500 times. This will help improve the service stability and reliability of ultra-high temperature protective coatings such as molybdenum and iridium, and will promote the development and progress of spacecraft.

[0054] The contents not described in detail in the specification of the present invention belong to the prior art known to those skilled in the art.

Claims

1. A preparation method for inner surface arc ion plating, characterized in that: include: (1) Processing target material, the target material is divided into two parts: cylindrical section and conical section; (2) Inputting the target cone angle and target height into the cathode arc source electromagnetic field control system, the cathode arc source electromagnetic field control system automatically adjusts the magnetic field current frequency and the magnetic field maximum current according to the input target cone angle and target height; (3) Insert the arc starter into the cylindrical section of the target material, insert the arc starter needle into the arc starter shell, use polytetrafluoroethylene to insulate the arc starter needle from the arc starter, connect the arc starter needle to a high voltage power supply of 10,000 to 50,000 V, and the target material, arc starter, and arc starter needle constitute a cathode arc source; (4) The cathode arc source performs an up and down spiral motion under the control of the cathode arc source electromagnetic field control system; (5) The workpiece is located directly above the cathode arc source, and the workpiece is embedded in the rotating mechanism and rotates under the drive of the rotating mechanism; (6) The arc starter is ignited under the control of the cathode arc source electromagnetic field control system, the target material arcs and ionizes ions, and uniform deposition is achieved on the inner surface of the workpiece during the movement of the cathode arc source and the workpiece; Magnetic field current frequency = 0.75 × target cone angle; magnetic field maximum current = 0.25 × target height.

2. The method for preparing inner surface arc ion plating according to claim 1, characterized in that: The target material is pure molybdenum or iridium.

3. The method for preparing inner surface arc ion plating according to claim 2, characterized in that: The maximum outer diameter of the target is 40 to 60 mm, the height of the target is 40 to 200 mm, and the cone angle of the target is 10° to 90°.

4. The method for preparing inner surface arc ion plating according to claim 1, characterized in that: The arc starter is made of stainless steel, and the arc starting needle is made of refined copper.

5. The method for preparing inner surface arc ion plating according to claim 4, characterized in that: The inner diameter of the arc starter is 10 to 20 mm larger than the maximum outer diameter of the target material, the outer diameter of the arc starter is 60 to 100 mm larger than the inner diameter, and the length of the arc starter needle is 30 to 60 mm.

6. The method for preparing inner surface arc ion plating according to claim 1, characterized in that: The cathode arc source has a vertical movement speed of 10 to 200 mm / min, a rotational movement speed of 5 to 20 r / min, and a vertical movement stroke of 0 to 200 mm.

7. The method for preparing inner surface arc ion plating according to claim 1, characterized in that: The workpiece material is niobium-tungsten alloy or rhenium.

8. The method for preparing inner surface arc ion plating according to claim 7, characterized in that: The maximum outer diameter of the workpiece is 20-100mm, and the height is 30-300mm.

9. The method for preparing inner surface arc ion plating according to claim 8, characterized in that: The rotating mechanism is made of niobium-tungsten alloy material, and the rotating speed is 1 to 10 r / min.

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