A novel double bipolar pulse high power impulse magnetron sputtering power supply was designed and developed independently. The power supply contains three working modes including the discharge mode of conventional high power impulse magnetron sputtering (HiPIMS), the discharge mode of conventional bipolar pulse high power impulse magnetron sputtering (BP-HiPIMS) and the discharge mode of double bipolar pulse high power impulse magnetron sputtering (DBP-HiPIMS). Especially for the third mode, the double bipolar pulse has more advantages than that of the conventional single bipolar pulse. The effects of positive pulse on the discharge characteristics of Cr target in Ar atmosphere under the conditions of conventional BP-HiPIMS and novel DBP-HiPIMS were studied. The results show that the average substrate net ion current of both BP-HiPIMS and DBP-HiPIMS significantly increased with the increase of the positive pulse voltage. Compared with the conventional BP-HiPIMS mode, the DBP-HiPIMS mode has higher average substrate net ion current at different positive pulse voltages. When the positive pulse voltage was 100V, the average substrate net ion current of DBP-HiPIMS mode was 47.0% higher than that of the conventional BP-HiPIMS mode when the substrate bias was 0V and 30.3% higher when the substrate bias was 60V. The results show that the novel DBP-HiPIMS discharge mode can further improve the acceleration effect of positive pulse on ions, which will be conducive to the improvement of film quality.

To meet the needs of high-frequency, miniaturized vacuum microwave devices, to find suitable cathode materials and laser systems, the photocathode for microwave vacuum electronic devices were studied. The photocathode with diffusion barrier was prepared, by heating the layer of emissive material storage chamber to provides a controlled photoemissive layer for replacing the evaporation loss of the active material, thereby extending the life of the cathode and recovering from poisoning and exposure to the atmosphere. The Cs3Sb photocathode was prepared in an ultra-high vacuum system. The quantum efficiency is about 0.145% at the wavelength of 532 nm, when the photoelectric is illuminated by the continuous laser with an energy of 0.37 W, a current density of 29.2 mA/cm² of the photoemission can be obtained. If the photocathode is damaged by the high-intensity laser, it can be reheated and activated. The photoelectric emission can be restored to a certain degree and stabilized for a long time. This photocathode has the characteristics of reproducible activation and is expected to be ideal electronic source for microwave vacuum electronic devices.

In this paper, a new type of cold cathode ionization vacuum gauge with carbon nanotube(CNT) field emission cathode is designed. The device consists of a field emission cathode, an anode grid, and an ion collector, with the anode and ion collector coaxial arranged. The carbon nanotubes were grown directly on the metal substrate by chemical vapor deposition, and two types of cathodes with 4mm×5mm rectangle and Φ 0.1mm circular emission surfaces were investigated respectively. The carbon nanotube cathodes presented excellent field emission performance with turn-on electric field of 1.70 V/μm. In the nitrogen environment, the vacuum measurement performance of the gauges based on two kinds of cathodes is investigated respectively, the normalized current (I_i/I_a) range and the pressure show a good linear relationship from 10^-7 to 10^-3 Pa, and the measurement sensitivities of the gauges corresponding to the cathodes of rectangular and circular emission areas are 3.1×10^-2 Pa^-1 and 1.3×10^-2 Pa^-1, respectively.

The article reviews and summarizes the research works in last decades and recent development of on-chip electron sources including field emission on-chip electron sources, internal field emission on-chip electron sources and new thermionic on-chip electron sources. The article compares the basic principles, fabrication and working performance of such on-chip electron sources, including working voltage, working vacuum, emission current, emission current density and emission efficiency, and analyzes the advantages and disadvantages of various on-chip electron sources. A brief summary of the development status of on-chip electron source is made through these analyses.

The third-generation synchrotron requires to design a vacuum box with different shapes at different locations to ensure that the electron beam operates in an ultrahigh vacuum (<1.3E-8Pa) environment. As one of the key parts of the third-generation synchrotron device, the surface treatment of the material is the key problem in the manufacturing process. However, the surface treatment technology for 316LN special-shaped vacuum box of ultrahigh vacuum has not been published at home and abroad, and the research on the surface treatment technology of 316LN special-shaped vacuum box of ultrahigh vacuum has rarely been reported. Therefore, this paper puts forward a reasonable process plan for 316LN special-shaped vacuum box of ultrahigh vacuum surface treatment process, and designs and sets up a complete set of four-pole mass spectrometry residual gas detection and analysis system for 316LN special-shaped vacuum box of ultrahigh vacuum surface treatment process. It provides a theoretical basis for the study of the treatment of 316LN type vacuum box with ultra-high vacuum indication.

Superhydrophobic surfaces have possible crucial applications in self-cleaning, anti-icing and water drag reduction in water due to its unique wetting properties, which thus become eye-catching in recent years. However, most superhydrophobic surfaces are achieved by modification of organic materials with small surface energy, resulting in poor performances at high temperature, aging and tribology fields. In this paper, we present a robust superhydrophobic surface constructed by a special surface texture and a F-DLC modification layer. It realizes a water contact angle (WCA) of 152°, and the high temperature resistance, aging resistance and wear resistance are studied. The results show that the coating maintains the superhydrophobic properties after exposing to sunlight of 120 days and high temperature up to 350 ℃. After the wear testing against to 304 stainless steel for 20000 cycles, a high WCA more than 130° can still be obtained. The results suggest that the coating shows excellent robustness in high temperature, aging and wear, which promises the durable applications in aerospace, marine equipment and other engineering fields.

For titanium alloy defects, such as low surface hardness, poor wear resistance, high temperature oxidation, etc., the selection of appropriate surface modification technology can improve it. Because titanium alloy is very sensitive to fatigue performance, it has a great influence on its fatigue resistance after surface treatment. This paper summarizes various methods of surface modification of titanium alloy, such as electroplating, electroless plating, thermal spraying, laser processing, anodizing, micro-arc oxidation, physical vapor deposition technology and so on. According to the fatigue fracture state of titanium alloy and the characteristics of surface modification technology, the influence of the application of coating preparation technology, materials selection and structure design on the fatigue properties of titanium alloy matrix was discussed. The effect of coating on fatigue fracture process and the deformation mechanism of crack initiation/expansion were analyzed and summarized. The research trend of coating materials and structure in the future was prospected. This paper may provide reference for the preparation of high-strength, friction-resistant and surface-modified coatings that do not impair the fatigue properties of titanium alloy substrates.

This paper introduces the development and current situation of electromagnetic coils levitation melting ELM, cold crucible levitation melting CCLM, cold crucible semi-levitation melting semi- CCLM which is induction skull melting ISM, three types of vacuum melting casting technology. The application of this kind of technology in precision casting, material purification, ingot material and alloy preparation, gas atomization powder were discussed. The development trend of levitation melting technology in material type, equipment capacity, superheat of melt and operation process is indicated. With the development of water-cooled copper crucible technology, semi-levitation melting technology developed rapidly and evolved into various forms, which promoted the development of new materials. The fusion of laser and plasma heating technology has laid a foundation for the implementation of the new technology.

A water model of 1/4 linear scale for 210t RH degasser has been established. This paper study the specific methods of measuring mixing time and circulation flow rate in RH water model experiment by the thinking of the accuracy the economy the efficiency and the feasibility of the experiment. The reasonable position of the tracer was determined as the vacuum chamber and the optimal amount of tracer added was 427ml per ton of water. A reasonable measurement of the mixing time was made at a location 50 mm from the bottom of the ladle, near the ladle wall away from the dip tube.

Vacuum elevator is a new kind of elevator, which can realize the up-going and down-going of the car by controlling the differential pressure between the two sides of the car roof. At present, vacuum elevator has formed an industrial chain represented by PVE in foreign countries. In China, vacuum elevator is still in the developmental stage. The related patents mainly focus on three aspects as drive structure modification, accessory parts innovation and control system optimization. Compared with the traditional one, vacuum elevator does not need the pit, wire rope, traction wheel and other devices, and has obvious advantages such as quick assembly, environment-friend, energy saving, fashionable appearance, safety and reliability. Vacuum elevator has very broad application direction and market prospect.

After entering the nano era, the properties of nano-materials and nano-devices are not only determined by the properties of bulk materials, but also by the properties of material′s surface and interface. In order to avoid ucontrollable changes and damages caused by surface contaminations, the thin film materials and nano-scale devices must be processed in ultra-high vacuum environment. This paper introduces the necessity, functions and applications of Nano-X.

The metal 3D printing process has the advantages of high material utilization rate, easy to form complex structure and flexible customized production, etc. It is suitable for rapid manufacture of model-level test impellers, guide vanes, inducers and other small metal functional parts. Among them, the selective laser melting forming technology(SLM), as the main metal 3D printing technology, can obtain metallurgical bonding, tissue compactness, high dimensional accuracy and good mechanical properties. The SLM technology was used to directly form the impeller and vane of the main pump test prototype for a project. The material is 17-4PH stainless steel. The integrated printing of the impeller and the assembled shaft saves the assembly cost. The studies on printing model optimization, processing parameters and process monitoring ensure the successful printing of the tall integrated shaft impeller and guide vane with large diameter. The printing parts were heat treated and finish machining, and finally the gas-liquid two-phase performance test of the main pump prototype was carried out. The test results show that the rotating and stator components manufactured by SLM metal 3D printing technology is successfully applied in the prototype test of the main pump, which significantly shortens the processing cycle of the prototype, and the machining accuracy, surface quality and mechanical properties all meet the test requirements.

In recent years, additive/subtractive hybrid manufacturing (A/SHM) has become one of the main methods of intelligent manufacturing. It relies on additive manufacturing to realize material layer forming, using material reduction technology to improve surface quality and improve stress state. This technology takes into account the high precision of rapid prototyping and reduces material manufacturing for additive manufacturing. This paper first expounds the general situation of additive manufacturing technology and the overview of A/SHM. Then, the research on the surface residual stress and roughness of the materials in the process of A/SHM at home and abroad will be explained. Then the paper explains the research on theA/SHM of the equipment at home and abroad and the research on the surface quality of A/SHM. Finally, this paper summarizes and forecasts the main problems and future development trends of the A/SHM.

3D printing technology is a method of rapid molding technology, which is formed by bonding powder material layer by layer with binder injected from the head. Color 3D printing technology is the future development direction of traditional 3D printing technology, and the application prospect is very broad. OBJ file has the advantages of simple data format and can store model color information, and the article uses OBJ file as the data interface between CAD and color 3D printer. It realizes the color slicing algorithm for the three-dimensional color model based on the correct analysis of the OBJ file format.

In order to study the distribution of residual stress of multi-track overlapping plasma cladding of Co-based alloy under different process parameters to control the residual stress, orthogonal experiment was designed and nine groups of single-layer multi-track Co-based plasma cladding samples with different process parameters were prepared by plasma cladding. Blind-hole method was used to measure the residual stress at the starting location, intermediate location and finish location of each sample, and the influence of working current, scanning speed and powder feeding rate on the residual stress was analyzed. The residual tensile stress was distributed in the surface of the samples. The residual stress of start location was lower than the finish location, the residual stress parallel to the overlapping path was lower than that parallel to the scanning path. The working current was the most significant influence factor on the residual stress. The greater the working current is, the greater the residual stress is. With the increase of the scanning speed, the residual stress becomes smaller. With the increase of the powder feeding rate, the residual stress increase and then decrease.