CN-122013093-A - High-gain copper-beryllium alloy secondary electron emitter and preparation method thereof

Abstract

The invention discloses a high-gain copper-beryllium alloy secondary electron emitter and a preparation method thereof, relating to the technical field of material preparation, wherein the preparation method comprises the following steps: pulse electrolytic polishing surface pretreatment is carried out on the copper-beryllium alloy base material formed by stamping, then the copper-beryllium alloy base material subjected to surface pretreatment is placed into a tubular furnace, argon-hydrogen mixed gas is introduced for gas washing, then vacuum pumping is carried out, the tubular furnace is heated, low-oxygen pressure thermal activation treatment is carried out on the copper-beryllium alloy base material in two steps, a beryllium oxide active layer with high secondary electron emission coefficient is formed on the surface, and the high-gain copper-beryllium alloy secondary electron emitter is obtained. The beryllium oxide active layer provided by the invention is uniform, compact and low in roughness, the secondary electron emission coefficient of the copper-beryllium alloy secondary emitter is high, the performance is stable, and the problems of insufficient and unstable performance of the conventional copper-beryllium alloy secondary electron emitter are effectively solved.

Inventors

• ZHOU FAN
• YANG YUTONG
• LI KAN
• DING JUNHAO
• WANG JINSHU
• LAI CHEN

Assignees

• 北京工业大学

Dates

Publication Date

20260512

Application Date

20260213

Claims (10)

1. 1. The preparation method of the high-gain copper-beryllium alloy secondary electron emitter is characterized by comprising the following steps of: s1, carrying out pulse electrolytic polishing surface pretreatment on a copper beryllium alloy substrate; s2, placing the copper-beryllium alloy substrate subjected to surface pretreatment into a tube furnace, vacuumizing, introducing argon-hydrogen mixed gas, and vacuumizing after gas washing; s3, heating the tube furnace, introducing oxygen, sealing and preserving heat, vacuumizing again, heating at the same time, introducing oxygen, sealing and preserving heat, vacuumizing and cooling after the end of heating, and obtaining the high-gain copper beryllium alloy secondary electron emitter.
2. 2. The method of producing a high gain copper beryllium secondary electron emitter according to claim 1, wherein in step S1, the beryllium content in the copper beryllium base material is 2.0-3.4 wt%.
3. 3. The method for preparing the high-gain copper-beryllium alloy secondary electron emitter according to claim 1, wherein in the step S1, pulse electrolytic polishing comprises the steps of cleaning a stamped copper-beryllium alloy substrate, immersing the copper-beryllium alloy substrate in a mixed acid solution, enabling the copper-beryllium alloy substrate to be parallel and opposite to a stainless steel sheet, enabling the copper-beryllium alloy substrate to be connected with a positive electrode of a pulse power supply, enabling the stainless steel sheet to be connected with a negative electrode of the pulse power supply, starting pulse electrolytic polishing, and then taking out the copper-beryllium alloy substrate to be washed and dried.
4. 4. The method for preparing a high-gain copper-beryllium secondary electron emitter according to claim 3, wherein in the step S1, the mixed acid solution comprises phosphoric acid, sulfuric acid and deionized water, and the volume ratio of the phosphoric acid to the sulfuric acid to the deionized water is 4-6:2-4:1-3.
5. 5. The method for manufacturing a high-gain copper-beryllium secondary electron emitter according to claim 3, wherein in the step S1, the distance between the copper-beryllium base material and the stainless steel sheet is 10-20 cm.
6. 6. The method of manufacturing a high gain copper beryllium secondary electron emitter according to claim 3, wherein in step S1, the pulse power supply voltage is 5-20V, the frequency is 50-100 Hz, the pulse width is 5 ms, and the electropolishing time is 60-120S.
7. 7. The method for manufacturing a high-gain copper-beryllium secondary electron emitter according to claim 1, wherein in the step S2, the vacuum is firstly applied to 10 -1 Pa, then argon-hydrogen mixed gas is introduced to the furnace until the gas pressure is 10 4 -10 5 Pa, and the vacuum is applied to 10 -4 Pa after the gas is washed.
8. 8. The method for manufacturing a high-gain copper-beryllium secondary electron emitter according to claim 7, wherein in the step S2, the ratio of hydrogen in the argon-hydrogen mixed gas is 5-8 vt%.
9. 9. The method for manufacturing a high-gain copper-beryllium secondary electron emitter according to claim 1, wherein in the step S3, the temperature of the tube furnace is raised to 500-600 ℃, oxygen is introduced into the tube furnace until the air pressure in the tube furnace is 1-5 Pa, then the tube furnace is sealed and kept at 2-5 min, vacuum is again pumped, the temperature is raised to 800-850 ℃, and then oxygen is introduced into the tube furnace again until the air pressure in the tube furnace is 5-20 Pa, and then the tube furnace is sealed and kept at 5-10 min.
10. 10. A high gain copper beryllium secondary electron emitter produced by the method of any one of claims 1 to 9.

Description

High-gain copper-beryllium alloy secondary electron emitter and preparation method thereof Technical Field The invention relates to the technical field of material preparation, in particular to a high-gain copper-beryllium alloy secondary electron emitter and a preparation method thereof. Background Copper-beryllium alloy has high strength, high conductivity and high toughness, and is commonly used as various elastic elements, various bearings and shaft sleeves. In addition, the beryllium copper alloy forms a beryllium oxide (BeO) active layer on the surface through oxidization, has higher secondary electron emission coefficient, and is a commonly used alloy type secondary electron emitter material. Secondary electron emission occurs on the surface of the material, and a remarkable electron multiplication effect can be formed through multistage multiplication, so that a weak photoelectric signal is amplified by millions of times. Vacuum electronic devices such as photomultiplier tubes, electron multipliers, image intensifiers, etc. all utilize this principle and require a higher secondary emission coefficient and stability of the secondary emitter material. The conventional copper-beryllium alloy secondary emitter is formed by heating copper-beryllium alloy in vacuum and introducing a certain amount of oxygen to oxidize, and a BeO film with the thickness of tens of nanometers is formed on the surface, but the film forming quality is affected by a plurality of factors, so that the secondary emission coefficient of the conventional heat-activated copper-beryllium alloy is generally not high and is very unstable, and the maximum secondary emission coefficient of the heat-activated copper-beryllium alloy secondary emitter reported in the literature is 3.0-9.2, and the difference is larger. Thin and uneven films with too low oxygen content are formed in the thermal activation process, the roughness of the films with too high oxygen content is high, and excessive oxidation exists on the base body at the bottom of the film layer, so that the secondary electron emission performance of the copper-beryllium alloy is not ideal. Because of toxicity of both metallic beryllium and BeO, the direct use of film deposition technology for preparing BeO film has difficulty, and the deposited BeO film has fine particle size and still has unsatisfactory secondary electron emission performance. Disclosure of Invention Aiming at the defects in the prior art, the invention provides the high-gain copper-beryllium secondary electron emitter and the preparation method thereof, and the problems of insufficient and unstable performance of the conventional copper-beryllium secondary electron emitter are effectively solved. In order to achieve the aim, the invention adopts the following technical scheme that the preparation method of the high-gain copper beryllium alloy secondary electron emitter comprises the following steps: s1, carrying out pulse electrolytic polishing surface pretreatment on a copper beryllium alloy substrate; s2, placing the copper-beryllium alloy substrate subjected to surface pretreatment into a tube furnace, vacuumizing, introducing argon-hydrogen mixed gas, and vacuumizing after gas washing; s3, heating the tube furnace, introducing oxygen, sealing and preserving heat, vacuumizing again, heating at the same time, introducing oxygen, sealing and preserving heat, vacuumizing and cooling after the end of heating, and obtaining the high-gain copper beryllium alloy secondary electron emitter. Further, in step S1, the beryllium content in the copper-beryllium alloy substrate is 2.0-3.4 wt%. The alloy base material has good plastic deformation performance and is stamped into the shape required by the electron dynode of the vacuum electronic device. Further, in the step S1, pulse electrolytic polishing comprises the steps of cleaning a stamped copper-beryllium alloy substrate, immersing the copper-beryllium alloy substrate in a mixed acid solution, enabling the copper-beryllium alloy substrate to be parallel and opposite to a stainless steel sheet, connecting the copper-beryllium alloy substrate with a positive electrode of a pulse power supply, connecting the stainless steel sheet with a negative electrode of the pulse power supply, starting pulse electrolytic polishing of the power supply, and then taking out the copper-beryllium alloy substrate to wash and blow-dry. Further, in step S1, the ultrasonic cleaning is sequentially carried out by using ethanol and deionized water for 1-3 min. Further, in step S1, 2 min is ultrasonically cleaned with ethanol and deionized water in sequence. In step S1, the cleaning is followed by drying with cold air. In step S1, a corner of the cleaned copper beryllium alloy substrate is clamped by a metal clamp, and is vertically immersed in the mixed acid solution. Further, in step S1, the mixed acid solution includes phosphoric acid, sulfuric acid, and deionized water. Further, in step S