The working principle and development status of vacuum arc remelting furnace and vacuum arc skull casting furnace are described. This paper introduces the development of vacuum arc remelting(VAR) technology control technology, and points out the important significance of arc detection and regulation for the safe operation of large vacuum arc skull furnace. Although the melt rate control realizes the stability of the profile of the melt pool mushy. However, the arc motion changes the heat distribution of the pool. The optimization of arc distribution state based on melt rate control is the development direction of high quality ingots and process equipment. According to the arc motion characteristics, the arc distribution model is divided into four categories: concentrated, diffusive, eccentric and rotating. The distribution model of diffusive arc plays an obvious role in improving the profile of melt pool and the quality of ingots. VAR control technology is divided into three components: arc distribution, melt pool characteristics and solidification process. Aiming at the electromagnetic characteristics of arc, magnetic field is used to detect and regulate the arc distribution, which will bring new technological innovation to VAR process. The control system with Hall effect magnetic field sensor array and Helmholtz coils has been applied in industrial VAR furnace to verify the effectiveness of the control system in arc detection and regulation.

This work introduces the system composition and design scheme of a large spacecraft leak rate testing for in-orbit spacecraft sealing performance requirement based on leak detection with helium mass spectrometer. The testing efficiency and automation level during spacecraft leak rate testing are improved because of the integrated optimization design, embedded plate construction and remote centralized control. Experimental verification of system leakage detection performance via atmospheric and vacuum helium mass spectrum leak detection shows that, the minimum detectable leakage rate are 7.5×10^-10Pa·m³/s with vacuum leak detection method and 2.0×10^-6Pa·m³/s with atmospheric accumulation leak detection method for two days. Variation rule of environmental parameters in collection chamber and air tightness under micro-positive pressure are studied, the results indicate that the relative humidity declines with the increasing temperature influenced by external environmental factors. The pressure drop is less than 80Pa within 24h after filling compressed air in the collection chamber with gauge pressure above 1500Pa, and the air tightness meets the requirements of the spacecraft leak rate detection.

Ni films with different thickness were prepared on the surface of Zr/ZrVFe porous getter by magnetron sputtering technology. The influence of Ni films on the gettering performance of the getter was studied. The surface morphology and elemental composition of getter were analyzed by SEM and EDS technology,and the gettering performance at room temperature was studied by constant volume method. The results show that during the getter activation process, H₂O, CO₂ and CO/N₂ have been desorbed below 350℃. When the activation temperature reaches 350-450℃, only H₂ and CH₄ remain in the desorption gas,and CH₄ is obtained by the reaction between the H₂ and the filament of the four-stage mass spectrometer. The as-prepared Ni film uniformly covers the getter surface without changing the getter surface morphology. The surface modification of getter by Ni film obviously increases the getter capacity. The equilibrium pressure of getter obtained by coating for 2h is the smallest and the adsorption performance is the best.

The intermediate refractive index material required for preparing gradient refractive index films is obtained by adopting the method of dual-source co-evaporation of MgF₂ and ZnS and controlling the deposition rate ratio of both materials. The G|HL|A double-layer anti-reflection film is graded into 5 layers, and keeping the total optical thickness unchanged, the gradient index anti-reflection film with a gradient of 1.91,1.77, 1.64, 1.48, and 1.38(wavelength of 532nm) along the thickness direction is prepared. All samples are tested for optical and laser damage characteristics. The results show that the refractive index of the composite film obtained by double source co-evaporation of MgF₂ and ZnS and the deposition rate ratio of the two materials satisfy the relationship deduced according to Drude theory. The refractive index of the composite film accords with the normal dispersion. Except for the material with the refractive index of 1.91, of which the absorption is large(extinction coefficient at 532nm is 0.01), the other composites show small absorption(extinction coefficients at 532nm are less than 0.002). When all the monolayer films are irradiated with 100mJ energy laser, the composite film with the refractive index of 1.64 has the lowest laser damage, showing higher resistance to laser damage than single-component ZnS and MgF₂ films. When the double-layer anti-reflection film is equivalent to five layers with graded refractive index, the passband range is extended from 205nm to 380nm, and the laser damage threshold is increased from 2.0J/cm² to 3.7J/cm², which is increased by 85%. It can be seen that it is feasible to prepare thin films with graded refractive index by adjusting the evaporation rate ratio of the two materials. As long as the ratio of the two materials is appropriate, using co-evaporation technology can obtain a composite film that has higher resistance to laser damage than a single-component film. The graded index anti-reflection film has better optical properties and higher laser damage threshold than double-layer anti-reflection film.

Vacuum arc ion plating is one of the most extensive surface treatment technologies in use now. However, in the actual industrial application, large surface particle of the prepared coating is still a major problem that plagues the advanced manufacturing. The reason lies on that the target is overheated, and then molten pool is formed to cause solution splash. The effective methods for reducing the occurrence of droplets include reducing the discharge power density, increasing the arc motion speed, as well as enhancing the cooling measures. In this paper, a numerical model was established for the arc source including new cooling structure and arc spot motion. The flow field of the cooling water inside the arc source and the temperature field of the arc source surface were simulated and analyzed, and the variation of the arc source under different boundary conditions was analyzed. The results in this paper may be helpful for the design of vacuum coating machine as well as the process development.

Tantalum-nitrogen compound thin film materials have the advantages of small resistance temperature coefficient, high chemical stability, good power tolerance and wide adjustable resistance range, which are the preferred materials for high performance resistive thin films. This paper reviews the research progress of tantalum-nitrogen compound functional thin film materials, and explores the core influencing factors for obtaining high performance thin film resistance from the preparation process parameters, post-processing methods, microscopic phase structure and element doping of the materials. Combined with the domestic and international research status, the continued development of tantalum-nitrogen compound thin film resistance is analyzed. In conclusion,tantalum-nitrogen compound thin films have become one of the keys to the development of electronic functional materials, and improving the film quality through element doping and post-treatment will be important means to further expand their application fields.

Aluminum Oxide (Al₂O₃) barrier films were prepared by plasma enhanced atomic layer deposition (PEALD) at 80℃ with flexible polyethylene terephthalate (PET) as substrate. The test results of X-ray photoelectron spectroscopy and ellipsometer show that the prepared Al₂O₃ films have high purity and good uniformity. Besides, Al₂O₃ films with different thickness were prepared by adjusting the deposition cycle. The effects of film thickness on surface morphology, surface roughness, optical transmission and water vapor transmittance rate (WVTR) were studied. The results show that Al₂O₃ film prepared with 500 deposition cycles exhibits the best performance, with a surface roughness of 1.52nm, an average transmittance (400-1200nm) of 90.4%, and a WVTR of 3.15×10^-3g·m^-2·d^-1.

The ITO films were deposited at room temperature by DC magnetron sputtering of a lab-made ITO target on organic glass substrates. The photoelectric property of the ITO film was evaluated by changing the process parameters of sputtering power, sputtering pressure, target distance and oxygen-argon flow ratio. The ITO films were characterized with ultraviolet visible near infrared spectroscopy. The results show that the transmittance of ITO films decreases with the increase of sputtering power and target-substrate distance. When the sputtering power is 110W and the target-substrate distance is 70mm, the transmittance and conductivity of ITO films are better. In the near-ultraviolet light band and the near infrared light band, the transmittance of the ITO film decreases as the sputtering pressure increases. When the oxygen-argon flow ratio is 4:30, the ITO film shows the best transmittance and comprehensive performance in the visible light range from 500nm to 600nm.

Fluorocarbon(FC) film exhibits characteristics of low dielectric constant and friction coefficient, high thermal stability and chemical inertness, strong ultraviolet absorption, etc. As a surface modification material, it is expected to improve environmental weatherability and insulation stability of dry reactors during operation. Research on FC film preparation by sputtering has the advantages of less contamination by impurity particles, large deposition area, low cost of reactants, and no environmental pollution. The plasma state during sputtering is a key factor affecting the quality of FC film. This paper discusses the synergistic effects of vacuum chamber temperature and substrate temperature on the chemical composition, microstructure, deposition rate and micromorphology of FC film. The results show that the temperature directly influence generation, transportation and deposition of sputtering components. The increment of temperature results in morphology evolution law of particle-cluster-three-dimensional network structure. Deposition rate, roughness, fluorine to carbon ratio and the proportion of sp³ hybrid carbon increase with the sputtering temperature. Therefore, FC film develops in the direction of PTFE-like film, which is expected to exhibit more excellent physio-chemical properties.

The vacuum tester can measure internal vacuum of the vacuum interrupter using the proportional relationship between ion current and pressure without disassembling it. The vacuum tester needs to be calibrated for different tube types before use. In this paper, the design of calibration system including installation of magnetic coil, shielding of strong magnetic fields, special lifting device for baking and carriage, and calibration theory are discussed. The calibration system consists of calibration chamber, ultra-high vacuum system, magnetic field coil, heating device, lifting system and vacuum tester. The basic principle of the calibration system is dynamic contrast method, with standard vacuum gauge, under the dynamic balance of pumping and charging, the data of standard vacuum gauge and ion current of the vacuum interrupter are obtained, then the calibration contrast curve is formed, which realizes the rapid, high-precision and wide-range calibration test.

Mo and Hf were respectively deposited onto the surface of cathode with Ba-W by ion beam assisted deposition to imitate the surface conditions of Mo-grids and Hf-grids when absorbing with electron emission substances in the grid-control TWT. The microstructure and composition of the samples were characterized. The ratios of thermo-electronic emission and secondary electron emission between two grids were compared. The results show that the amount of electron emission substances of the cathode adsorbed on the surface of Hf-grids was rather less than that of the Mo-grids. Hf-grids could effectively suppress the electron emission.

Due to the line radiation generated by light impurities in the Tokamak vacuum chamber, plasma energy is lost and hydrogen fuel concentration is reduced. Therefore, in order to improve the triple product of fusion, it is necessary to reduce the content of light impurities in the Tokamak vacuum chamber to a low level before the discharge starts. Light impurity elements are mainly adsorbed on the first wall of the device. At present,the impurities adsorbed on the first wall are desorbed mainly by means of discharge cleaning. In this paper, a set of differential pumping mass spectrometer analysis system is established, which can be used in Taylor discharge cleaning of J-TEXT Tokamak device. The higher pressure gas in the main vacuum chamber is introduced into the mass spectrometer chamber equipped with differential pumping system for analysis, so as to obtain the change of partial pressure of each gas in the cleaning process, which can be used to monitor the discharge cleaning effect. At the same time, by combining with several diagnostic systems such as magnetic measurement, electrostatic probe, H_α radiation and CⅢ radiation, the changes of plasma current, voltage, temperature, density and radiation in the discharge cleaning process are measured when changing the discharge cleaning parameters, providing reference for the optimization of J-TEXT hydrogen Taylor discharge cleaning parameters.

In order to test the thickness of thermal barrier coatings quickly and accurately in industrial production, this paper discusses a method of thickness measurement for PVD NiCrAlYSi coating and YSZ coating by using ball crater tester. First, The NiCrAlYSi coating and YSZ coating with thickness of 120μm was deposited on GH3039 superalloy substrate by arc ion plating and EB-PVD respectively. The relationship of particle size in polishing slurry, grinding time and dimension of ball crater was obtained. Then, according to the above experimental results, the thickness of NiCrAlYSi and YSZ coatings on superalloy specimens was measured by ball crater tester, and the results of ball crater tester and metallographical measurement were compared. The results show that the dimension of ball crater has a parabolic relation with milling time for the NiCrAlYSi coating and YSZ coating. Under the same conditions,the dimension of ball crater is the same when the size of particle in polishing slurry is 5μm and 10μm, both of which are much larger than that of the particle size of 1μm. The result of ball crater tester is highly identical with that of metallographical measurement, and the relative error is less than 6%.

High energy beam cladding coating is likely to appear crack, porosity and other quality defects in the making, which hinders its application in industry. In this work, the causes of cracks in high energy beam cladding coatings are analyzed, and the current dominated temperature gradient and stress control approaches and research progress are summarized from three aspects, including preparation of functional gradient coating,application of auxiliary cladding technology and pretreating measures. The main problems of quality control of high energy beam cladding coatings are presented, and the development prospect of quality control of high energy beam cladding coating is analyzed.

As the main equipment for the industrial production of metal powder, vacuum atomization milling equipment is widely used in key areas including additive manufacturing, powder metallurgy, aerospace and medical treatment. This paper focuses on the most common vacuum atomization milling technology, and their characteristics and development directions are deeply studied and discussed. Firstly, the technical background of atomized milling and the common classification of current milling methods are briefly introduced, and then combined with the core performance indicators of the technology and equipment used by the major atomization milling equipment manufacturers and metal powder suppliers, the vacuum atomization milling methods including VIGA(vacuum induction-melting gas atomization), EIGA(electrode induction-melting inert gas atomization), VIGA-CC(water-cooled copper crucible vacuum induction-melting gas atomizing) and PREP (plasma rotating electrode-comminuting process)are described in detail. The future development direction of atomization milling technology and equipment is also prospected.