The anode segmented form of the cylindrical anode layer Hall thruster will affect the distribution of the potential in the thruster, and thus the motion of electrons and the ionization rate of propellants in discharge plasma of thrusters are affected. In this paper, the effects of different anode segments (single anode, two segmented anodes, three segmented anodes and four segmented anodes) on ion beam distribution were analyzed from two aspects of experiment and simulation. The results were analyzed to guide the structural design of the anode. The results show that the ion current and ion beam energy of the two segmented anodes are higher. There are some differences in the beam current distribution of the four segmented anodes within the beam diameter of 35mm, and the other positions are basically the same. When the discharge voltage is 900V, the beam energy distribution under the two segmented anodes is about 32 eV higher than that on the three segmented anodes as a whole and 20eV higher than that of the single anode and the four segmented anodes (excluding the central axis and the edge). The research results provide a reliable theoretical basis for the anode design of cylindrical anode layer Hall thruster.

Heat pipe is a core component for spacecraft thermal control system with high sealing requirement. The malfunction of heat pipe can lead to complete failure of spacecraft thermal control system. Aiming at the technical bottleneck of heat pipe leak detection method, a leak detection of the spacecraft heat pipe based on mass spectrometry analysis technology was proposed with a test system established in this work. Ideal technical index requirement was achieved in the field test, which provides a feasible method for future spacecraft heat pipe leak detection.

In this paper, an indirect cavity pressure measuring method for small semitight device is presented, which is based on characteristics of cavity pressure unable to be directly measured by the vacuum gauge. This method is combined with principle of constant volume method and constant conductance method, which are used in vacuum materials outgassing rates field. For a typical semitight devices, simulation test and comparison work utilize the above method and microssensor in-situ method are carried out. The simulation test results show that the as-proposed cavity pressure detection method is simple and accurate, and can solve the problem of pressure cavity and change of semitight devices. This method is applicable to the real-time monitoring of cavity pressure changes during the process of filling oil of gyroscope, filling helium of mechanical refrigerator and filling xenon of electric propulsion system.

ITER will first achieve the controlled thermonuclear fusion reactor, which is comparable to the future practical fusion scale world-widely, to solve many physical and engineering problems involving in the fusion engineering. As one of the core components of the International Thermonuclear Fusion Experimental Reactor ITER, the key issue in the manufacturing process is the sealing performance of weld. The common leak detection method for sealing performance of weld is helium mass spectrometry vacuum pressure leak detection. This paper mainly introduces the optimization analysis and detection steps of the helium mass spectrometry pressure vacuum leak detection in coil leakage detection. The auxiliary mechanical pump is added to the connecting unit in the gas chamber of helium mass spectrometry pressure leak detection method, in order to avoid the excessive influence of the background signal due to the leakage of the connecting flange under vacuum conditions. This method improves the sensitivity and accuracy of the measurement data, reduced the chance of misjudgment, and expands the application range of helium mass spectrometry pressure vacuum leak detection method.

A plasma-assisted atomic layer deposition method was used to conformally coat the Al₂O₃ films on the surface of silicon-based nitride phosphor powders by a vibrating fluidized bed. The surface composition, morphology and water resistance of the phosphors before and after coating were tested by the Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and pH meter. The PL luminescence of the phosphor before and after coating was tested by a fluorescence spectrometer. The results show that the alumina is conformally coated on the surface of the phosphor particles. The coating greatly enhances the stability of the phosphor in water. A certain thickness of alumina coating improves the luminescence performance and slightly reduces the color temperature of the phosphor powders.

Graphene is a thin film material with six angle honeycomb layered structure, exhibiting an ultralow friction coefficient in vacuum. Aiming at the lubrication problem of cemented carbide drilling tool in space drilling, amorphous SiC thin films were deposited on cemented carbide substrates by magnetron sputtering, and in situ growth of graphene on cemented carbide was obtained by the bonded phase Co. This paper demonstrated the effects of annealing temperature, annealing time and C/Si atomic ratio on the quality of graphene, and summarized the mechanism of Co catalyzed amorphous SiC in the preparation of graphene. Which provided a theoretical basis for graphene in the application of vacuum drilling tool.

The surface metallization of the Ni-Zn ferrite substrate was carried out by using the evaporation coating technology. After the patterning process, the adhesion and weldability were tested and compared with that of the sample surface metallized by electroless plating. The results show that the surface prepared by evaporation coating of the metal film layer is superior to the electroless plating in appearance and adhesion, and has good solderability, which can content the requirements of metallization of Ni-Zn ferrite substrate and related products. At the same time, it proves that this technology is a promising and stable process surface metallization method in the application of high frequency and high power electronic ceramic substrates.

Diamond-like carbon ( DLC ) films were prepared using the RF magnetron sputtering with high purity carbon targets and high purity methane as carbon sources under different RF power. The structure and properties of the films were studied by the scanning electron microscopy, Fourier transform infrared spectroscopy and micro-hardness tester. The results show that the films is dense and uniform. With increasing the RF power, the growth rate and the proportion of carbon atom in the film increase. The films prepared at 200 W have high sp³ content, and its molecular structure and properties are more towards to diamond. The Vickers hardness of the films reaches 1123.42 MPa, and it was found that the hardness of DLC films increases first and then decreases with the increasing RF power. The graphitization degree of the DLC film increased.

To study the effect of N₂ pressure and flow on the growth of TiN films in magnetron sputtering, TiN films were grown at a substrate temperature of 300℃ for 2 hours using radio frequency magnetron sputtering equipment to change the air pressure and flow of N₂. The morphology of TiN films was characterized by electron scanning microscopy. TiN films with different micro morphology can be prepared by changing technological parameters.

Electron beam melting(EBM) is a kind of excellent vacuum metallurgy method. In this paper, a continuous casting system for EBM furnace was developed for refractory material melting. The conceptual design and detailed structural design of continuous casting system were proposed. The feeding mechanism installed horizontally can feed multiple bars once, while the dragging mechanism achieves the dropping and rotation of ingot, whose solidification processed in water cooled crucible. At last, the continuous casting system was developed successfully with the indexes meeting the design requirement and simple melting experiments were carried out with this developed EBM furnace.

This paper introduces the classification, working principle and characteristics of vacuum fine grain casting furnace used for producing aero-castings. It emphatically analyzesthe structure style and the core technology for fine grain casting furnace and double-properties casting furnace.Finally, it prospects the future development of domestic vacuum fine crystal (double-properties) casting furnace.

The C-shaped distorted specimens of martensitic precipitation hardening stainless steel were used to carry out the heat treatment distortion study by vacuum heat treatment and gas shielded furnace heat treatment. The metallographic microscope and SEM were used to analyze the microstructure of specimens with different deformation. The results show that the distortion of martensitic precipitation hardening stainless steel by vacuum adjustment and aging is less than that by gas shielded furnace adjustment and aging.The distortion of the specimens in the upper part of the vacuum furnace is larger than that in the lower part, but the anti-distortion performance is very good. The distortion of solution treatment process is greater than that of the adjustment. Deformation of specimens with different structural sizes varies greatly, which is very helpful for improving the test accuracy. The result of this study is instructive to control distortion of vacuum heat treatment.

In this work, the numerical calculation model for the flow area of the single-side dry scroll vacuum pump is established. The numerical simulation of the transient flow inside the single-side dry scroll vacuum pump was performed based on the CFD general software ANSYS-CFX and dynamics mesh method. The working process of the pump was also analyzed, especially the thermal field distribution in the pump under under-compression or over-compression. This work provides a meaningful exploration for the further study of the theory and design of dry scroll vacuum pump.

There are many kinds of screw extruder used for food processing. This paper introduces the design process of a intermeshing twin screw extruder, including the calculation and construction design of the screw, shaft core, kneading disc and cylinder design. Building block structure is used to make the machine adapt to different actual production conditions.

With the development of space technology, the requirement of pressure control, depressurization and repressurization for pressure sensitive components are proposed. In other words, the vacuum thermal test equipment should have the function of depressurization, repressurization and stable pressure, which can control the pressure. According to the principle of dynamic balance and automatic control technology, the principle of the pressure regulating system of vacuum thermal test equipment and design method are proposed. The results show that the equipment meets the requirement of the design, which ensures the pressure experiment carried out sucessfully.

In recent years, the possibility of large-scale application in industry has come true due to the development of additive manufacture, and the nondestructive testing of relevant products has been taken seriously. This paper briefly discussed the current application situation and the main defect characteristics in metal structure of additive manufacture, the main nondestructive testing methods which is suitable for the metal structure and its characteristics, test difficulty and research progress and the present status of nondestructive testing standards. And provide relevant suggestions based on the research direction.

Vacuum plasma welding chamber is the main equipment for electrode block welding in non-ferrous metallurgy industry. Welding gun, as the main components of vacuum plasma welding chamber, plays a decisive role in guaranteeing product quality and stabilizing equipment operation. The structure of welding gun is optimized and its rationality is verified by practice.

In view of the physical phenomena of water content in insulating materials and the physical process of water discharge in the process of transformer body treatment, scientific analysis and research are carried out, and the system principle and drying process of drying equipment are gradually improved. Therefore, a new pressure-swing vacuum drying technology, which is different from the traditional one, emerges at the historic moment and has been widely used. This paper introduces a new type of vacuum drying technology in detail.