Microwave vacuum electron devices are used in a wide variety of areas, such as radar, space technology and electron accelerators. The thermal cathode is one of the cores of the vacuum electron devices, its performances directly determine the reliability and lifetime of the electron devices. Therefore, a higher demand is put for thermal cathode. It is important to determine the temperature of the hot cathode accurately. The thermal electron emission performance of different cathodes is summarized and compared, including the comparison of the uniformity of hot electron emission between nano-particulated thin film cathode and traditional coated cathode, and the variation of ion current of evaporates from S-type cathode and M-type cathode (coated with iridium) and N-type cathode (coated with iridium nano-particulated thin films) with temperature and time. The temperature of the cathode surface and the cathode side (molybdenum tube) are tested by the infrared thermometer, optical pyrometer, and thermocouple thermometer (platinum and rhodium-platinum).

Spinning rotor gauge has excellent metrological characteristics in high vacuum. However, condensable gas, such as water vapor, is more likely to absorb or occur phase transition on the chamber or rotor surface. It would lead to the deviation of the measurand, what is more, the nonlinear change of the tangential momentum accommodation coefficient. Pointing at this problem, a balanced and stable pre-stage pressure of water vapor was generated by pumping and sublimating solid ice, and then the standard pressure was obtained by adiabatic expansion. The adsorption and desorption curves of water vapor molecules on the chamber surface were tested at room temperature (23 ℃) and high temperature (150 ℃), respectively. The corresponding adsorption and desorption amounts under the same pressure were calculated. Finally, the deviation between the measured value and the revised standard pressure was analyzed. The determination results show that it is challenging to obtain the accurate standard pressure at 23 ℃. Only the adsorption amount of water vapor molecules on the walls of chamber and its associated pipelines can be calculated after closing the valve. At 150 ℃, some water vapor molecules may adsorb on the walls of adjacent pipelines with temperature lower than 150 ℃, resulting in the measured pressure slightly lower than the standard pressure.

Internal vacuumization of thin-walled parts may cause circumferential or radial instability of the member and cause the member to be scrapped. This is a difficult problem for positive pressure quantitative leak detection of thin-walled parts. In this paper, a positive pressure-vacuum helium mass spectrometry leak detection method is proposed, which fills helium inside the thin-walled member and vacuumizes it outside. A quantitative leak detection tool with synchronous comparison of positive pressure standard leak holes is designed, which can be used for quantitative leak detection of positive pressure-vacuum helium mass spectrometry in the gauge pressure range of -0.1-0.1 MPa. Through the working condition pressure-vacuum helium mass spectrometry leak detection test on the stainless steel thin-wall neck parts with a wall thickness of 0.4 mm, the results show that the method has fast leak detection speed and high efficiency, and the leak detection sensitivity meets the requirements of minimum detectable rate, which can be well applied to the batch leak detection of thin-wall parts production line.

Three Cu-PET-Cu composite films with different thicknesses of Cu film were prepared by electron beam evaporation. The mechanical and electrical properties of Cu-PET-Cu composite films were studied by experiments and molecular dynamics simulation. The results show that the uneven deposition and rough surface are observed for the thin film, and the surface becomes flat with increasing Cu thickness. As the thickness of the Cu film increases, the tensile strength of the composite film increases, while the elongation decreases. The composite film has a highest tensile strength of 250 MPa and elongation of 20% when the thickness of composite film is 6.069 μm. The results of molecular dynamics simulation are consistent with those obtained by experiments. The resistivity of composite films decreases first, and then increases with increasing copper layer thickness. The minimum resistivity is 1.834×10^-6 Ω∙m, which is higher than that of pure copper.

The rare earth composite oxide of （Yb_0.1Gd_0.9）₂Zr₂O₇ （YbGdZrO） is a new kind of thermal barrier coatings （TBCs） materials suitable for applications above 1 200 ℃. TBCs specimens with different types of bond layers were prepared by depositing YbGdZrO ceramic coatings onto the surface of bonding layers of NiCoCrAlYHf or （Ni,Pt）Al by electron beam physical vapor deposition （EB-PVD） technique. The microstructure, chemical composition, phase structure, residual stress and thermal shock behavior of the coatings were characterized and analyzed. The results show that the surface of NiCoCrAlYHf bond layer is undulating, and the ceramic layer deposited on it has cauliflower-like texture and a high degree of disorder. The surface of the （Ni, Pt） Al bond layer shows a smooth "back ridge" morphology, and the columnar crystals of the deposited ceramic layer are tightly arranged and the flatness tends to be consistent. The contents of Gd and Zr elements in ceramic layer of the two TBCs specimens are close to that of the original ingot, while the Yb element content is greatly affected by the deposition temperature. With the increase of thermal shock times, the micro-cracks on the surface of NiCoCrAlYHf/YbGdZrO coating initiate and propagate, and pitting pits appear. The （Ni,Pt）Al/YbGdZrO coating is still relatively flat, without micro-cracks and sintering densification. Thermally grown oxide （TGO） layer appears in both coatings after 1 000 times of thermal shock. When the thermal shock reaches to 2 500 cycles, the averaged thickness increment of TGO layer growing on top of （Ni,Pt）Al bond coat is only 1.08 μm. The TGO residual stress of NiCoCrAlYHf/YbGdZrO TBCs is smaller than that of （Ni,Pt）Al/YbGdZrO specimen under the same condition. The ceramic layer elements of both TBCs have diffused to the bond coats, and a small amount remains in the TGO layer. Differently, the Al₂O₃ film formed by （Ni,Pt）Al/YbGdZrO TBCs shows stronger diffusion resistance for Gd element.

Sputter depth profiling has been widely used to characterize the depth distribution of elements in thin films. However, the complex sputtering process involved and the diversity of sample morphology may interfere with the accuracy of analysis. Aiming at the problem, the thin films depth profiling is briefly introduced firstly. Then, the physical backgrounds of the quantitative depth profiling and the expansion for the quantitative analysis of high-resolution depth profiling data are presented. A depth profiling quantitative analysis software based on the C# programming language is developed, the modules of the software is introduced in detail, and the specific implementation of the software written in C# is demonstrated. The software utilizes an MRI model and integrates functions for the transformation, convolution, and deconvolution of in-depth analysis data, which is capable of performing quantitative analysis on data from micro-area analysis techniques such as SIMS, AES, and XPS. Through optimized algorithms, the software achieves high-precision calculation of the depth resolution function. Users can input experimental data through an intuitive interface, and the software will automatically process the data and generate visual results. This software provides a convenient and efficient tool for general users, significantly enhancing the operability and accuracy of thin film depth profiling quantitative analysis.

The TiN and TiAlN coatings were deposited on annealed alloy steel by cathodic arc ion plating. The structure, composition and phase composition of the coatings were analyzed by scanning electron microscopy and X-ray diffractometer, the hardness of the coating was tested by micro Vickers hardness tester, the bonding properties of the coating were evaluated by indentation method, and the wear resistance of the coating was tested by reciprocating ball-disk friction and wear test. The results show that the surface of the TiN and TiAlN coatings are smooth. There are many "droplet" defects at the surface of TiAlN coating. Both TiN and TiAlN coatings grow in a preferred orientation. The preferred crystal plane of TiN coating is （111）, and that of the TiAlN coating is （200）. The hardness of annealed alloy steel coated with TiN and TiAlN coatings increases by more than 3 and 6 times, respectively. Although the hardness of TiAlN coating is significantly higher than that of the TiN coating and the friction coefficient is lower than that of the TiN coating, the TiAlN coating peeled off during wear due to the poor bonding performance between TiAlN coating and annealed alloy steel, which deteriorated the wear resistance of the alloy steel. The TiN coating can protect the annealed alloy steel substrate and significantly improve its surface wear resistance.

The SiO₂ aerogels based composite core materials were prepared by wet and dry molding techniques using SiO₂ aerogels and glass fiber short cutting as the main raw materials, and then the nano SiO₂ aerogels composite core vacuum insulation panels (VIP) were obtained by vacuum packaging technology. The microstructure of composite core materials with different SiO₂ aerogels contents (mass fraction) was studied, and the differences of the two processes on the thermophysical properties of VIP were compared and analyzed. The results show that the addition of SiO₂ aerogel makes the three-dimensional network structure of the short-cut fiber core become compact, but the high content of aerogel will lead to poor adhesion between the aerogel and the fiber. With the increase of SiO₂ aerogel content, the density of composite core material decreases, and the compression rate and rebound rate of vacuum insulation panel also decrease. The homogeneity of composite core material prepared by wet process is slightly poor when the aerogel mass fraction is 35%, while the thickness of composite core material prepared by dry process is less than 0.04 mm, and the homogeneity is better. The thermal conductivity of the composite core VIP prepared by the wet process increases significantly with the increase of SiO₂ aerogel content, while the VIP thermal conductivity increases relatively small under the dry process, and the thermal conductivity is more stable.

Vacuum freeze drying has been widely used. However, the temperature range of the current freeze-dryer is limited, which limits the application and development of freeze drying technology. An optimally designed vacuum freeze drying equipmengt is presented in this study, which broadens the operating range of temperature and vacuum degree. Toluene is freeze dried as a sample using this new designed equipment. The results show that the equipment can not only achieve the freeze-drying of toluene, but also significantly reduce the temperature difference of the sample in the vacuum process by introducing the metal sleeves, thereby avoiding the risk of sample melting and ensuring the smooth progress of the freeze-drying process. This research could provide a guidance for the freeze drying of low triple-point materials, and promote the popularization and application of vacuum freeze drying technology.

The cleanliness of the equipment is extremely important for semiconductor device performance. In the test equipment, the vacuum environment has lower suspended particles and residual gas content, which is closer to the true clean vacuum. The acquisition and maintenance of the clean vacuum is a key technology of semiconductor industry production, involving a variety of techniques. This paper introduces the development process of clean vacuum system technology equipment from the aspects of chamber material selection, chamber design and manufacture, cleaning and testing of internal surfaces, packaging and transshipment. The developed equipment can quickly obtain a working vacuum degree of 1×10^-4 Pa under load, and the residual gas and particle size indicators meet the process requirements.

With the rapid progress of the gas turbine, the demand for large-sized single crystal blades has increased significantly. However, there are obvious shortcomings in the preparation of large-size single crystal blades by traditional HRS method. Liquid metal cooling ( LMC ) method may be the first choice for the preparation of large-size single crystal blades in the future. In this context, this article first introduces the common structural forms, technical characteristics and current usage status of single crystal furnaces. Then, the shortcomings of existing single crystal furnaces in the preparation of large blades are elaborated. Finally, the technical characteristics of the new liquid metal cooled single crystal furnace and the future development prospects of this type of equipment are introduced.

With the development of science and technology, nickel-based superalloys have been widely used in high-precision fields such as aerospace and nuclear power, and their performance needs to be continuously improved. As a key link in the preparation process of nickel-based superalloy, melting directly affects the overall quality and properties of alloy materials, so it is very important to choose the appropriate melting process. At present, the commonly used melting processes include vacuum induction melting (VIM) and vacuum consumable remelting (VAR), etc., which have their own advantages and disadvantages in practical applications, and need to be rationally selected and matched to accurately control the parameters, so as to meet the increasing melting demand of nickel-based superalloys. In this paper, the melting method of nickel-based superalloy is analyzed and studied in order to provide reference for related melting work.

As an ideal marine engineering material, titanium alloys have been successfully applied in deep-sea submersibles, marine oil and gas exploration, and seawater desalination equipment due to its lightweight, high specific strength, and excellent resistance to seawater corrosion. Firstly, this paper expounds the principal vacuum melting techniques for the preparation of titanium alloys and analyzes the main performance characteristics of titanium alloys used in marine engineering. Then, the domestic and foreign titanium material system of marine engineering are introduced, and the grades, properties and main applications of some titanium alloys used in marine engineering in China are highlighted. Finally, the research progress and application status of titanium alloys in marine engineering facilities are comprehensively described and summarized, and its application prospects are discussed, aiming at providing theoretical reference and practical guidance for further application of titanium alloy.