Copper-chromium contact surface modification method based on pulsed ion beam irradiation

Abstract

The invention discloses a method for modifying the surface of a copper-chromium contact based on pulsed ion beam irradiation, which comprises the following steps of: firstly cleaning the surface of the copper-chromium contact, then pre-cleaning the copper-chromium contact in a high-vacuum environment, and finally irradiating the surface of the contact by adopting a high-energy pulsed ion beam to form a modified layer. According to the method, surface nanocrystallization, defect repair and component homogenization are achieved through ion beam bombardment, the grain structure is remarkably refined, element distribution is improved, and the surface roughness is reduced, so that the insulation performance, arc ablation resistance and overall reliability of the contact are improved, and the method is suitable for surface strengthening treatment of the copper-chromium contact of the high-voltage vacuum circuit breaker.

Description

TECHNICAL FIELD

[0001] The application relates to the field of high-voltage electrical equipment manufacturing and the field of CuCr alloy materials, in particular to a method for surface modification of a copper-chromium contact based on pulsed ion beam irradiation. BACKGROUND

[0002] The rise of vacuum circuit breakers is the result of the joint action of power equipment technology iteration and environmental protection needs. With the global energy transformation and power grid upgrading, its market share in the medium and high voltage field will continue to expand, and it will expand to high voltage and intelligentization, becoming a key component of future green power systems.

[0003] As the core component of vacuum circuit breakers, CuCr contacts bear the main function of breaking current, and their organizational structure and force-electric performance directly determine the operation capacity of the equipment. Currently, CuCr contact materials for high voltage levels (72.5kV and above) mainly use vacuum arc melting and infiltration processes, but these processes have some significant drawbacks and technical shortcomings, limiting the performance improvement and large-scale application of contact materials. Vacuum arc melting process for preparing CuCr materials cannot prepare high Cr content materials, which is prone to organizational segregation, and the gas content is severely dependent on the control of the process. In the infiltration process, Cu may not completely fill the pores of the Cr skeleton, resulting in the aggregation of Cr particles in local areas, forming a brittle phase and reducing the anti-welding performance of the contact. In addition, the Cr particle size of CuCr contacts prepared by the infiltration method is usually large, which seriously restricts the arc ablation resistance and current breaking performance of the material.

[0004] The insulation capacity of the vacuum arc chamber is directly affected by the CuCr contact. Currently, CuCr materials for vacuum arc chambers with voltages of 126kV and above are prepared by arc melting and infiltration methods, which cause problems such as coarse grains, uneven distribution of two phases, and high gas content. During current breaking, the uneven distribution of high metal vapor density between the gap of the two contacts causes severe partial burning, and the height difference of the molten layer on the contact surface is large, thereby increasing the probability of tip discharge and seriously affecting the insulation withstand voltage, which seriously affects the safe and stable operation of the vacuum circuit breaker.

[0005] Current research on vacuum contact preparation techniques includes powder metallurgy and emerging 3D printing technology, and there are also studies on contact surface modification techniques, such as using laser and electron beam for remelting, and the use of nano-coating preparation technology has also been found. However, the contact surface is severely deformed after laser and electron beam remelting, and secondary machining is still required, which increases the cost and cannot solve the problem of large surface height difference and high tip discharge probability. The implementation of nano-coating is mostly achieved by spraying technology, which cannot guarantee the gas content and bonding strength requirements.

[0006] Therefore, how to provide a method for surface modification of copper-chromium contact is a problem that those skilled in the art need to solve urgently. SUMMARY

[0007] In view of the above problems, the present application is proposed to provide a method for surface modification of copper-chromium contact based on pulsed ion beam irradiation, which overcomes the above problems or at least partially solves the above problems.

[0008] To achieve the above-mentioned purpose, the present application adopts the following technical solutions: S1, cleaning treatment is performed on the surface of the copper-chromium contact; S2, the copper-chromium contact after cleaning treatment is placed in a vacuum chamber, and the vacuum chamber is pumped to a predetermined vacuum degree, and the surface of the copper-chromium contact is ion sputtering cleaned; S3, the surface of the copper-chromium contact is irradiated by a pulsed ion beam to form a modified layer on the surface of the copper-chromium contact.

[0009] Preferably, the cleaning treatment comprises: sequentially using deionized water and anhydrous ethanol to ultrasonically clean the surface of the copper-chromium contact.

[0010] Preferably, the predetermined vacuum degree is 5x10 -6 Pa.

[0011] Preferably, the ion sputtering cleaning comprises: introducing argon gas into the vacuum chamber, and sputtering cleaning the surface of the copper-chromium contact by a first argon ion beam.

[0012] Preferably, the sputtering cleaning time of the first argon ion beam on the surface is 1 to 10 minutes.

[0013] Preferably, the irradiation treatment comprises: irradiating the surface of the copper-chromium contact after the S2 step by a pulsed second argon ion beam to form a modified layer on the surface of the copper-chromium contact. Wherein, the energy of the second argon ion beam is higher than that of the first argon ion beam.

[0014] Further, the energy of the second argon ion beam ranges from 450keV to 500keV.

[0015] Further, the pulse beam current density of the second argon ion beam is 750A / cm² to 850A / cm².

[0016] Further, the pulse frequency of the second argon ion beam is single or 1Hz to 10Hz.

[0017] Preferably, it further comprises: after cooling the copper-chromium contact to room temperature in the vacuum chamber, inert gas is filled into the chamber, and then the copper-chromium contact is taken out.

[0018] The beneficial effects of the above-mentioned technical solution provided by the present invention include at least the following: The surface of CuCr contacts is treated using pulsed ion irradiation technology. Drawing inspiration from the plasma flow bombardment environment between contacts during aging, high-energy ion beams are used to bombard the contact surface, inducing nanocrystallization, defect repair, and compositional homogenization. Simultaneously, the surface is remelted and machined with lathe tool marks to obtain a CuCr contact modification layer with fine grains, high two-phase mixing, and a smooth surface. This enhances the insulation capability of the vacuum interrupter, ensuring the safe and stable operation of vacuum products. Furthermore, the preparation process is carried out in a vacuum environment, preventing the introduction of other gases or impurities. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 This is a process flow diagram provided in an embodiment of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] like Figure 1 As shown, this invention discloses a method for modifying the surface of copper-chromium contacts based on pulsed ion beam irradiation: S1. Clean the surface of the copper-chromium contact; S2. Place the cleaned copper-chromium contact in the vacuum chamber and evacuate the vacuum chamber to the predetermined vacuum level to perform ion sputtering cleaning on the surface of the copper-chromium contact. S3. The surface of the copper-chromium contact is irradiated with a pulsed ion beam to form a modified layer on the surface of the copper-chromium contact.

[0023] In one embodiment, the cleaning process includes ultrasonically cleaning the surface of the copper-chromium contact using deionized water and anhydrous ethanol in sequence.

[0024] Specifically, the arc-melted CuCr contacts are placed in an ultrasonic cleaning facility for ultrasonic cleaning: a frequency of 40 kHz is selected, and ultrasonic cleaning with deionized water is performed for 5 minutes, followed by water replacement and another 5 minutes of ultrasonic cleaning with deionized water. Then, ultrasonic cleaning with anhydrous ethanol is performed for 5 minutes for dehydration.

[0025] The purpose of cleaning is to remove macroscopic and microscopic contaminants from the surface, prevent the contaminant layer from being embedded in the substrate, ensure the uniformity of the irradiation effect, maintain the vacuum level and protect the equipment, and prevent volatile contaminants (such as water vapor and organic matter) from being released in the vacuum chamber, increasing the system pressure and disrupting the high vacuum environment.

[0026] In one embodiment, the predetermined vacuum level is 5 × 10⁻⁶. -6 Pa.

[0027] Specifically, the ultrasonically cleaned CuCr contact is placed on the sample holder / stage of the vacuum chamber, and the chamber door or cover is closed and sealed. The vacuum pump unit is started to evacuate the sealed vacuum chamber from atmospheric pressure (~10^5 Pa) to the required vacuum level of 5 × 10^6 Pa. -6 Pa. Ion beam irradiation or other vacuum environment treatments can only be carried out after the target vacuum level is reached.

[0028] In one embodiment, ion sputtering cleaning includes: introducing argon gas into a vacuum chamber and sputtering cleaning the surface of the copper-chromium contact using a first argon ion beam.

[0029] Furthermore, the sputtering cleaning time of the surface by the first argon ion beam is 1 to 10 minutes.

[0030] Specifically, in a vacuum chamber, a small amount of high-purity Ar gas is introduced, and the sample surface is bombarded for 5 minutes using a 200keV wide-beam Ar ion source. This step can remove the adsorbed gases and light-based contaminants from the last few atomic layers, which is the final guarantee for obtaining an atomically clean surface.

[0031] In one embodiment, the irradiation treatment includes: irradiating the surface of the copper-chromium contact after step S2 with a pulsed second argon ion beam to form a modified layer on the surface of the copper-chromium contact; The energy of the second argon ion beam is higher than that of the first argon ion beam.

[0032] Furthermore, the energy range of the second argon ion beam is 450 keV to 500 keV.

[0033] Furthermore, the pulsed beam current density of the second argon ion beam is 750 A / cm² to 850 A / cm².

[0034] Furthermore, the pulse frequency of the second argon ion beam is single or 1 Hz to 10 Hz.

[0035] Specifically, choosing Ar + As an inert gas, an energy of 500 keV was chosen to improve the ion implantation depth. A beam current density of 800 A / cm² was selected during the pulse, allowing it to operate at extremely high instantaneous power while maintaining a low average power, thus preventing continuous sample overheating.

[0036] For surface remelting to form a modified layer, a single pulse is usually sufficient, typically requiring only one or a few pulses. Excessive frequency can lead to cumulative heating, reduced cooling rates, and even overall sample overheating. These parameters collectively determine the rates of thermal shock and energy deposition, influencing defect generation and recovery, phase transition processes, and more.

[0037] In one embodiment, the method further includes: cooling the copper-chromium contact to room temperature in a vacuum chamber, filling the chamber with an inert gas, and then removing the copper-chromium contact.

[0038] Specifically, after irradiation, the sample was cooled to room temperature in a vacuum chamber, then high-purity nitrogen was slowly introduced into the chamber before it was finally removed. As shown in Table 1, scanning electron microscopy revealed that the microstructure of the modified layer was refined to 15-20 μm with no defective structures. EDS analysis showed that the distribution of Cu and Cr elements on the contact surface was more uniform and dispersed. The surface hardness of the modified layer was 115 HB. The conductivity reached 38% IACS, indicating that irradiation did not adversely affect the conductivity of the contact, and the aging efficiency of the vacuum interrupter was significantly improved compared to existing technologies.

[0039] Table 1

[0040] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0041] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for surface modification of copper-chromium contacts based on pulsed ion beam irradiation, characterized in that, Includes the following steps: S1. Clean the surface of the copper-chromium contact; S2. Place the cleaned copper-chromium contact in a vacuum chamber and evacuate the vacuum chamber to a predetermined vacuum level to perform ion sputtering cleaning on the surface of the copper-chromium contact. S3. The surface of the copper-chromium contact is irradiated with a pulsed ion beam to form a modified layer on the surface of the copper-chromium contact.

2. The method for modifying the surface of a copper-chromium contact based on pulsed ion beam irradiation according to claim 1, characterized in that, In step S1, the cleaning process includes: ultrasonically cleaning the surface of the copper-chromium contact using deionized water and anhydrous ethanol in sequence.

3. The method for modifying the surface of a copper-chromium contact based on pulsed ion beam irradiation according to claim 1, characterized in that, In step S2, the predetermined vacuum level is 5 × 10⁻⁶. -6 Pa.

4. The method for modifying the surface of a copper-chromium contact based on pulsed ion beam irradiation according to claim 1, characterized in that, In step S2, the ion sputtering cleaning includes: introducing argon gas into the vacuum chamber and using a first argon ion beam to sputter clean the surface of the copper-chromium contact.

5. The method for modifying the surface of a copper-chromium contact based on pulsed ion beam irradiation according to claim 3, characterized in that, The sputtering cleaning time of the first argon ion beam on the surface is 1 to 10 minutes.

6. The method for modifying the surface of a copper-chromium contact based on pulsed ion beam irradiation according to claim 3, characterized in that, In step S3, the irradiation treatment includes: irradiating the surface of the copper-chromium contact after step S2 with a pulsed second argon ion beam, so that a modified layer is formed on the surface of the copper-chromium contact. The energy of the second argon ion beam is higher than that of the first argon ion beam.

7. The method for modifying the surface of a copper-chromium contact based on pulsed ion beam irradiation according to claim 6, characterized in that, The energy range of the second argon ion beam is 450 keV to 500 keV.

8. The method for modifying the surface of a copper-chromium contact based on pulsed ion beam irradiation according to claim 6, characterized in that, The pulsed beam current density of the second argon ion beam is 750 A / cm² to 850 A / cm².

9. The method for modifying the surface of a copper-chromium contact based on pulsed ion beam irradiation according to claim 6, characterized in that, The pulse frequency of the second argon ion beam is single or 1 Hz to 10 Hz.

10. The method for surface modification of copper-chromium contacts based on pulsed ion beam irradiation according to claim 1, characterized in that, Also includes: After cooling the copper-chromium contact to room temperature in a vacuum chamber, an inert gas is introduced into the chamber, and then the copper-chromium contact is removed.

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