Electrode assembly for a high-power pulsed xenon lamp and method for producing same

Abstract

The application discloses an electrode assembly for a high-power pulse xenon lamp and a preparation method thereof, and aims to solve the technical defects of poor reliability and stability of a large mass of traditional electrodes. The electrode assembly is mainly composed of an electrode head, an electrode rod and a lead seat, and the materials of the components are respectively cerium-tungsten alloy, niobium and stainless steel. The electrode head and the electrode rod are stably connected through interference connection of brazing, the electrode rod and the lead seat adopt a multiple connection structure of brazing, mechanical connection and micro interference connection, and the assembled electrode assembly is subjected to degassing, brazing connection and electrode activation treatment in a high-temperature and high-vacuum environment at one time, so that the electrode material pollution caused by repeated heating is effectively avoided. The electrode assembly has simple overall structure, reliable preparation, excellent current passing property, outstanding anti-burning performance, and significantly improved reliability and stability, and meets the long-term stable working requirement and scale production of the high-power pulse xenon lamp.

Description

Technical Field

[0001] This invention relates to the field of electric light source manufacturing technology, specifically to an electrode assembly for a high-power pulsed xenon lamp and its preparation method, which is particularly suitable for the field of pump light sources for high-power laser drivers used in inertial confinement fusion (ICF) research where reliability, stability and service life requirements are extremely high. Background Technology

[0002] High-power pulsed xenon lamps, as a special type of electric light source capable of releasing high-intensity flashes in an extremely short time, possess significant technical advantages such as high brightness and wide spectral coverage. Their working principle involves the formation of high-temperature plasma through xenon gas breakdown discharge, which then radiates a concentrated, intense flash pulse. In the field of inertial confinement fusion (ICF) research, they have become the preferred core pump source for high-power laser drivers. The comprehensive performance and lifespan of these xenon lamps directly determine the operational stability and overall efficiency of high-power laser drivers, playing an irreplaceable role in related cutting-edge scientific research.

[0003] As a core functional component of high-power pulsed xenon lamps, the electrode undertakes three key missions: first, to withstand the pulsed high voltage to break down the gas medium inside the lamp; second, to construct a stable discharge channel; and third, to achieve efficient conduction of high current. Under the extreme conditions of high-energy pulses, the electrode must simultaneously withstand multiple harsh tests, including high temperature, high pressure impact, and ion bombardment. It is highly susceptible to failures such as ablation, material sputtering, and structural deformation, which directly lead to a shortened lifespan and decreased operational stability of the xenon lamp. Therefore, the electrode of a high-power pulsed xenon lamp must meet stringent technical specifications, including high strength, excellent high-temperature resistance, ablation resistance, and good conductivity.

[0004] Existing electrode assemblies still have many shortcomings in structural design and manufacturing processes. For example, Chinese patent document CN104051224B discloses a "high-temperature metal-sealed high-power pulsed xenon lamp and its preparation method." The disclosed electrode assembly consists of an electrode head, an electrode rod, and a lead seat, made of tungsten alloy and stainless steel, respectively. The connection method of this electrode assembly is to insert a solid, thin-diameter electrode rod into a blind hole in the electrode head and the lead seat, and then fix it by brazing. This solution has poor connection reliability, and in actual use, failures such as electrode head detachment or electrode rod breakage frequently occur; the blind hole structure on the electrode head and the lead seat increases the difficulty of cleaning and easily leaves contaminants that affect performance; there is a problem of exposed brazing filler metal during the brazing process, resulting in serious contamination of the electrode assembly; the thin electrode rod has poor current conduction performance under the skin effect, which aggravates electrode heating and material sputtering; the assembly structure has many sharp points, which easily cause the tip discharge effect, not only causing severe electrode ablation but also leading to poor discharge consistency, further affecting the stable operation of the xenon lamp.

[0005] Chinese patent document CN108565204B discloses an "Electrode Connection Device for a Pulsed Xenon Lamp." This disclosed electrode connection device consists of components such as electrodes, electrode caps, adapters, and leveling caps. Its complex structure and high manufacturing difficulty mean that connecting it to the lamp tube may render the entire lamp unusable. The electrode head and electrode rod are connected via interference fit or brazing. Interference fit lacks guidance, making assembly difficult, and brazing may cause solder overflow, contaminating the electrode surface. The electrode and electrode cap are only connected via interference fit and threaded mechanical connection; vibrations during xenon lamp operation may cause the electrode to detach and fail. Furthermore, the electrode structure is in direct contact with the lamp tube glass, and the heat generated by the current keeps the glass-metal joint in a state of constant thermal cycling, easily leading to joint failure.

[0006] In summary, existing high-power pulsed xenon lamp electrode assemblies generally suffer from insufficient structural reliability, easy connection failure, easy introduction of contamination during the manufacturing process, and mismatch between electrical and thermal properties, making it difficult to meet the application requirements of high power, long life, and extremely stable operation. Therefore, there is an urgent need for a new type of electrode assembly and manufacturing method with a more scientific structural design, more robust connection, superior manufacturing process, and comprehensive improvement of electrode performance. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing high-power pulsed xenon lamp electrode assemblies in terms of structural reliability, connection stability, manufacturing process and overall performance, and to provide a high-power pulsed xenon lamp electrode assembly and its manufacturing method that has a reasonable structural design, high connection strength, excellent anti-burn-off performance, high manufacturing efficiency and low pollution risk.

[0008] The technical solution of the present invention is as follows:

[0009] An electrode assembly for a high-power pulsed xenon lamp, characterized in that it comprises:

[0010] An electrode head made of cerium-tungsten alloy and having a two-section arc-shaped emitting surface, wherein the end of the electrode head is provided with a first boss and a second boss in sequence along the axial direction, and the outer diameter of the first boss is smaller than the outer diameter of the second boss.

[0011] An electrode rod made of niobium serves as the main current conductor and structural support. The electrode rod has a through hole along its axis, and its wall thickness is non-uniformly distributed along the axial direction, with the wall thickness in the middle section being less than the wall thickness in the connecting sections at both ends.

[0012] A lead socket made of stainless steel;

[0013] The electrode head forms an interference fit with the stepped hole at the left end of the electrode rod through a second boss at its end, and then forms a metallurgical bond through a single high-temperature brazing, thus forming a first composite connection interface. The right end of the electrode rod is screwed into the threaded section of the lead seat through its internal thread, and a micro-interference fit is achieved with the right end face of the electrode rod through a positioning step provided on the lead seat, and then forms a metallurgical bond through the single high-temperature brazing, thus forming a second composite connection interface.

[0014] The single-stage high-temperature brazing simultaneously completes the deep degassing of the electrode assembly, the brazing and sealing connection of the first composite connection interface and the second composite connection interface, and the activation treatment of the emission surface of the electrode head in a high vacuum environment.

[0015] Furthermore, the outer surface of the first boss is clearance-fitted or transition-fitted with the inner hole at the left end of the electrode rod for assembly guidance; the outer surface of the second boss is interference-fitted with the inner hole at the left end of the electrode rod, and the end face of the second boss is provided with a positioning surface for placing the brazing filler metal.

[0016] Furthermore, the right side wall of the electrode rod is provided with a lateral vent hole that communicates with the through hole.

[0017] Furthermore, the outer wall of the right end of the electrode rod and the outer wall of the threaded section of the lead seat are each provided with at least two parallel clamping planes.

[0018] Furthermore, the emitting surface of the electrode head is chemically and mechanically polished, with a surface roughness Ra≤0.05μm.

[0019] Second, the present invention also provides a method for preparing the above-mentioned electrode assembly, characterized by comprising the following steps:

[0020] S1. Perform chemical-mechanical composite polishing on the two-segment arc-shaped emitting surface of the electrode head;

[0021] S2. Perform deep cleaning on the electrode head, electrode rod and lead socket, including physical cleaning, chemical cleaning and high-temperature pure water boiling, and then dehydrate and dry them.

[0022] S3. Place the first brazing filler metal on the connecting surface at the right end of the electrode rod, and use a torque control tool to screw the lead seat onto the electrode rod until the preset torque is reached to complete the threaded connection and micro interference fit.

[0023] S4. Place the second brazing filler metal in the stepped hole at the left end of the electrode rod, insert and align the second boss of the electrode head, and then press the electrode head into the electrode rod within a preset constant pressure range to complete the interference fit;

[0024] S5. Perform final cleaning on the electrode assembly that has completed the mechanical pre-assembly in steps S3 and S4;

[0025] S6. Place the cleaned electrode assembly in a high-vacuum brazing furnace and perform a one-time heating process cycle, which simultaneously completes the following three key processes:

[0026] d) Deep degassing of the electrode rod and the electrode head;

[0027] e) High-temperature brazing connection between the first composite connection interface and the second composite connection interface;

[0028] f) Activation treatment of the electrode head emission surface.

[0029] Furthermore, in step S1, the chemical mechanical polishing is performed using a cerium oxide-based polishing slurry.

[0030] Furthermore, in step S3, the preset torque is 30 N·m.

[0031] Furthermore, in step S4, the preset constant pressure range is 15000 N to 18000 N, and the pressing operation uses a special pressure head that matches the arc shape of the electrode head's emitting surface.

[0032] Furthermore, in step S5, the final cleaning treatment is either ultrasonic cleaning with anhydrous ethanol followed by low-temperature drying, or argon / hydrogen plasma cleaning.

[0033] Furthermore, in step S6, the vacuum degree of the high-vacuum brazing furnace is not less than 5 × 10⁻⁶. -3 Pa; the one-time heating process cycle specifically includes:

[0034] First, the temperature is raised to the first temperature range and held for heat preservation to perform the deep degassing.

[0035] The temperature is then raised to the second temperature range and held to melt the brazing filler metal and complete the high-temperature brazing connection.

[0036] The electrode surface is then kept warm in the third temperature range to complete the activation process.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] 1) Due to the skin effect of high-power pulsed current, the current is mainly distributed on the surface of the electrode rod. Therefore, designing the middle section of the electrode rod as thin-walled not only reduces weight but, more importantly, ensures that this area has a sufficient effective conductive cross-sectional area, thereby reducing the risk of resistive heat and deformation caused by thermal stress. Meanwhile, to ensure the strength of the connection area, both ends are designed as thick-walled.

[0039] 2) Repeated heating exacerbates the segregation and oxidation of active cerium in cerium-tungsten materials, leading to unstable electron emission performance. Therefore, this invention employs a one-time vacuum heating process, which enables deep degassing of the material and controllable activation of the electrode surface while completing the connection, thereby ensuring the uniform distribution and stable valence state of cerium.

[0040] 3) It features a simple and reliable structure and excellent production efficiency. The optimized scheme significantly improves the overall reliability of the electrode assembly, effectively suppresses electrode burn-off, and ensures that the electrode has excellent conductivity and electron emission performance. At the preparation process level, this method can effectively reduce the risk of contamination during electrode preparation, not only achieving high preparation efficiency but also promoting the uniform distribution of cerium in the electrode and ensuring its valence stability. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the electrode assembly for a high-power pulsed xenon lamp. Detailed Implementation

[0042] The present invention will be further described below with reference to embodiments and accompanying drawings, but this should not be construed as limiting the scope of protection of the present invention.

[0043] A high-power pulsed xenon lamp electrode assembly includes an electrode head 1, an electrode rod 2, and a lead seat 3 connected in sequence. The electrode head 1 and the left end of the electrode rod 2 are connected by an interference fit followed by brazing, while the right end of the electrode rod 2 and the lead seat 3 are connected by a zero interference fit, a threaded connection, and brazing. The arc-shaped surface of the electrode head 1 has a two-segment arc transition and is machined with two-segment steps. The first segment, a thinner boss, serves as a guide structure when it has an interference fit with the left end of the electrode rod 2, and its fit with the electrode rod 2 is a zero-position fit. The second, thicker boss is used for an interference fit with electrode rod 2. Brazing filler is placed on the upper surface of the boss; after melting, the filler fills the gap and forms a metallurgical connection. Electrode rod 2 adopts a through-type design along its central axis, with the outer layer material removed to thin the tube wall. On the right side of electrode rod 2, perpendicular to its axis, there is a 3mm diameter through-hole for venting. The right end of electrode rod 2 has two screw-clamping planes parallel to its axis. Both ends of electrode rod 2 have two stepped holes; the smaller hole on the right is a threaded hole for threaded connection with the threaded end of lead seat 3. Lead seat 3 has two screw-clamping planes parallel to its axis. The materials of electrode head 1, electrode rod 2, and lead seat 3 are cerium-tungsten alloy, niobium, and stainless steel, respectively. Niobium is used in high-power pulsed xenon lamp vacuum devices to adsorb impurity gases from other materials or the environment. The electrode head and the left end of the electrode rod are connected by interference fit and brazing; the right end of the electrode rod is connected to the lead seat by thread. When the thread is screwed in, a slight interference fit step is pulled in to achieve a double mechanical connection, and then brazing is used to achieve a metallurgical connection. The brazing connection provides both a high-strength welded connection and an anti-loosening mechanical connection. The electrode head uses a two-section arc machining of the electrode emission surface and is polished; the two-section step of the electrode head is used for assembly guidance and interference fit, respectively.

[0044] Based on current throughput, strength, and skin effect, the electrode rod adopts a "thick at both ends and thin in the middle" appearance design. A 5mm diameter through hole is provided along the axial direction. The electrode rod has a diameter of 10mm and a wall thickness of 2.6mm, reducing the overall weight of the electrode assembly while meeting structural strength and current throughput requirements. The stepped hole structure inside the left end of the electrode provides guidance and connection reference for the interference fit of the electrode head, ensuring assembly reliability. A thread is machined in the stepped hole at the right end of the electrode rod for the threaded connection of the lead seat. A 3mm diameter through hole is opened perpendicular to the axial direction on the right side of the electrode rod to ensure degassing and venting of the electrode material. The thicker end of the right end of the electrode rod has two planes parallel to the axial direction for screwing assembly.

[0045] The lead holder has two planes parallel to the axis for screwing the lead holder and the electrode rod together.

[0046] The specific preparation process of the high-power pulsed xenon lamp electrode assembly and its preparation method of the present invention is as follows:

[0047] 1) After the electrode head is mechanically rough polished, it is subjected to chemical mechanical composite precision grinding and polishing using cerium oxide-based polishing slurry;

[0048] 2) The processed electrode head, electrode rod and lead seat are subjected to physical cleaning, chemical cleaning and high temperature pure water cleaning in sequence, followed by dehydration and medium temperature drying;

[0049] 3) Place the brazing filler metal into the stepped opening at the right end of the electrode rod, fix it in place with the clamping and fixing plane, and use a torque tool to screw it into the lead seat until the torque reaches 30 N·m;

[0050] 4) Place the solder in the stepped hole at the left end of the electrode rod screwed into the lead seat, and position the protruding step of the electrode head by inserting it into the hole along the axis of the electrode rod. Use a pressure head with the same arc surface as the electrode head to press the electrode head into the electrode rod at a constant speed. Set the pressing force in the range of 15000N-18000N.

[0051] 5) After plasma cleaning, the assembled high-power pulsed xenon lamp electrode assembly is placed in a vacuum high-temperature furnace to complete degassing, welding and activation in one go.

[0052] Example 1

[0053] See Figure 1 This embodiment provides a high-power pulsed xenon lamp electrode assembly, which consists of an electrode head 1, an electrode rod 2, and a lead seat 3.

[0054] Electrode head 1 is made of cerium-tungsten alloy (e.g., tungsten alloy with 1-2% cerium content). Its working end (emitting surface) is machined into a two-section smoothly transitioning arc surface to optimize electric field distribution and electron emission performance. The non-working end is machined with a two-section cylindrical step: the first section is a guide boss with a smaller diameter, and the second section is a connecting boss with a larger diameter. Both arc surfaces and steps require precision machining and polishing.

[0055] Electrode rod 2 is made of pure niobium (Nb1 grade or higher purity). It is a hollow tubular structure with an outer diameter of 10mm. Electrode rod 2 has a through hole along its axis, and a vent hole perpendicular to the axis and a clamping plane for assembly on the right side. Structurally, it adopts a "thickened at both ends and thinned in the middle" scheme, specifically: the wall thickness at both ends is 2.6mm, and the wall thickness in the middle section is reduced to about 1.8mm, in order to reduce weight while ensuring mechanical strength and current carrying capacity (satisfying the skin effect). A through center hole with a diameter of 5mm is provided along the axis. A stepped blind hole is machined on the left end for interference fit with the second boss of electrode head 1. An internally threaded hole (e.g., M8×1) is machined on the right end for connecting the lead seat. On the right side of the electrode rod, at a certain distance from the end face (e.g., 10mm), a through vent hole with a diameter of 3mm is drilled perpendicular to the axis. Two symmetrical parallel planes are machined on the outer circle of the right end of the electrode rod as clamping planes for applying torque.

[0056] The lead holder 3 is made of 304 or 316L stainless steel. One end is an externally threaded post (matching the internal thread of the electrode rod 2), with a positioning step designed at the root of the thread to achieve a slight interference fit with the end face of the electrode rod. The outer circle of the threaded post is also machined with two symmetrical parallel clamping planes. The other end is a standard lead post structure for connecting to an external power source.

[0057] Electrode head 1 and electrode rod 2 are connected by interference fit and then brazing. The second boss of electrode head 1 and the stepped hole at the left end of electrode rod 2 are designed for interference fit, with the interference amount controlled within 0.02-0.04mm. Brazing filler metal is placed at the assembly interface, and a strong metallurgical bond is formed through press fitting and subsequent vacuum brazing.

[0058] Electrode rod 2 and lead seat 3 are connected via threaded connection, slight interference fit, and then brazing. First, a preliminary connection is established and tightened through threaded engagement. When the positioning step surface of lead seat 3 is tightly fitted with the end face of electrode rod 2, a slight interference fit (clearance fit or zero-to-zero fit) is formed. Subsequently, brazing filler metal is pre-placed in the threaded engagement area and the end face mating area, and final sealing and reinforcement are achieved through vacuum brazing.

[0059] The fabrication of a high-power pulsed xenon lamp electrode assembly includes the following steps:

[0060] 1) Machine the electrode head 1, electrode rod 2, and lead seat 3 sequentially according to the required electrode assembly;

[0061] 2) The emitting surface of electrode head 1 is mechanically coarsely polished and mechanically finely polished sequentially using diamond abrasive, and then chemically and mechanically precision ground and polished using cerium oxide-based polishing slurry.

[0062] 3) Clean the polished electrode head 1, the processed electrode rod 2 and lead seat 3. Physically clean them in metal cleaning agent, then chemically clean them after changing the metal cleaning agent. After rinsing with pure water multiple times to ensure that there is no chemical cleaning agent, boil them in pure water at high temperature, dehydrate them and dry them in a clean environment at medium temperature.

[0063] 4) Place the electrode rod 2 vertically upwards at the right end, place the solder in the stepped hole, and screw it into the lead seat 3 using a tool with torque control. The torque should be controlled at 30 N·m, and the contact surfaces should be completely in contact.

[0064] 5) Place the left end of the electrode rod 2 vertically upward, place the solder in the stepped hole and insert the electrode head 1 to determine the position, and then use the same pressure head as the emission surface of the electrode head 1 to press the electrode head 1 step into the electrode rod 2 at a constant speed. The pressing force is set in the range of 15000N-18000N.

[0065] 6) After the assembled electrode assembly is plasma cleaned, it is placed in a vacuum high-temperature furnace to complete degassing, welding and activation in one go;

[0066] 7) After cooling, remove the electrode assembly to complete the fabrication of the high-power pulse xenon lamp.

[0067] The electrode assembly prepared in this embodiment is sealed to the stainless steel metal parts of the xenon lamp using methods such as laser welding to create a complete high-power pulsed xenon lamp. After standard lamp manufacturing processes such as venting, filling with high-purity xenon gas, and sealing, lifespan and performance tests are conducted.

[0068] Test conditions: Cyclic discharge tests were conducted under typical high-power laser pumping conditions (e.g., pulse width in milliseconds, current density in the thousands of A / cm²). Results show that, compared to xenon lamps using traditional electrodes, the electrode assembly of this invention exhibits: uniform electrode tip ablation at a low rate; no abnormal material sputtering contaminating the lamp tube; high cyclic consistency of various discharge parameters (e.g., peak current, light output); no mechanical failures such as electrode tip detachment or electrode rod breakage; and overall service life meeting or exceeding design requirements.

[0069] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention. Where there is no conflict, the above embodiments and features described therein can be combined with each other.

Claims

1. An electrode assembly for a high-power pulsed xenon lamp, characterized in that... ,include: An electrode head (1) made of cerium-tungsten alloy and having a two-section arc-shaped emitting surface, wherein the end of the electrode head (1) is provided with a first boss and a second boss in sequence along the axial direction, and the outer diameter of the first boss is smaller than the outer diameter of the second boss. An electrode rod (2) made of niobium and used as the main current conductor and structural support, the electrode rod (2) has a through hole along its axis, and its wall thickness is non-uniformly distributed along the axis, the wall thickness of the middle section is less than the wall thickness of the connecting section at both ends; A lead socket made of stainless steel (3); The electrode head (1) forms an interference fit with the stepped hole at the left end of the electrode rod (2) through the second boss at its end, and forms a metallurgical bond through a whole high-temperature brazing to form a first composite connection interface; the right end of the electrode rod (2) is screwed into the threaded section of the lead seat (3) through its internal thread, and a micro interference fit with the right end face of the electrode rod (2) is achieved by the positioning step set on the lead seat (3), and then forms a metallurgical bond through the whole high-temperature brazing to form a second composite connection interface; The first overall high-temperature brazing simultaneously completes the deep degassing of the electrode assembly, the brazing and sealing connection of the first composite connection interface and the second composite connection interface, and the activation treatment of the emission surface of the electrode head (1) in a high vacuum environment.

2. The electrode assembly for a high-power pulsed xenon lamp according to claim 1, characterized in that, The outer surface of the first boss is clearance-fitted or transition-fitted with the inner hole at the left end of the electrode rod (2) for assembly guidance; the outer surface of the second boss is interference-fitted with the inner hole at the left end of the electrode rod (2), and the end face of the second boss is provided with a positioning surface for placing the brazing filler metal.

3. The electrode assembly for a high-power pulsed xenon lamp according to claim 1, characterized in that, The electrode rod (2) has a lateral exhaust hole on the right side of its tube wall that communicates with the through hole.

4. The electrode assembly for a high-power pulsed xenon lamp according to claim 1 or 3, characterized in that, The outer wall of the right end of the electrode rod (2) and the outer wall of the threaded section of the lead seat (3) are provided with at least two parallel clamping planes.

5. The electrode assembly for a high-power pulsed xenon lamp according to claim 1, characterized in that, The emission surface of the electrode head (1) is chemically and mechanically polished, and the surface roughness Ra≤0.05μm.

6. A method for preparing an electrode assembly as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Perform chemical-mechanical composite polishing on the two-segment arc-shaped emitting surface of the electrode head (1); S2. Perform deep cleaning on the electrode head (1), electrode rod (2) and lead seat (3), including physical cleaning, chemical cleaning and high-temperature pure water boiling, and then dehydrate and dry them. S3. Place the first brazing filler metal on the connecting surface at the right end of the electrode rod (2), and use a torque control tool to screw the lead seat (3) onto the electrode rod (2) until the preset torque is reached, thus completing the threaded connection and micro interference fit; S4. Place the second brazing filler metal in the stepped hole at the left end of the electrode rod (2), insert and align the second boss of the electrode head (1), and then press the electrode head (1) into the electrode rod (2) within a preset constant pressure range to complete the interference fit; S5. Perform final cleaning on the electrode assembly that has completed the mechanical pre-assembly in steps S3 and S4; S6. Place the cleaned electrode assembly in a high-vacuum brazing furnace and perform a one-time heating process cycle, which simultaneously completes the following three key processes: a) Degassing the electrode rod (2) and the electrode head (1) to a depth; b) High-temperature brazing connection between the first composite connection interface and the second composite connection interface; c) Activation treatment of the emission surface of the electrode head (1).

7. The method according to claim 6, characterized in that, In step S1, the chemical mechanical polishing is performed using a cerium oxide-based polishing slurry.

8. The method according to claim 6, characterized in that, In step S3, the preset torque is 30 N·m.

9. The method according to claim 6, characterized in that, In step S4, the preset constant pressure range is 15000 N to 18000 N, and the pressing operation uses a special pressure head that matches the arc shape of the emitting surface of the electrode head (1).

10. The method according to claim 6, characterized in that, In step S5, the final cleaning process is either ultrasonic cleaning with anhydrous ethanol followed by low-temperature drying, or argon / hydrogen plasma cleaning.

11. The method according to claim 6, characterized in that, In step S6, the vacuum level of the high-vacuum brazing furnace is not less than 5 × 10⁻⁶. -3 Pa; the one-time heating process cycle specifically includes: First, the temperature is raised to the first temperature range and held for heat preservation to perform the deep degassing. The temperature is then raised to the second temperature range and held to melt the brazing filler metal and complete the high-temperature brazing connection. The electrode surface is then kept warm in the third temperature range to complete the activation process.

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