Cathodic arc is an important material source for a variety of film and coating preparation processes. From the cathode spot on the cathode surface, the generation (phase transition) and expansion (transport) of plasma in the vacuum chamber, to the final deposition on the biased substrate to form a coating or film, this series of links contain complex physical processes. Deeply analyzing and understanding of the processes and related mechanisms will undoubtedly play an important role in guiding the coating preparation process. This paper briefly introduces the process of the discharge phenomena and the history of the related coatings development. Then the cathode discharge mechanism and the plasma behaviors closely related to the coating process, such as plasma velocity, sheath, oblique incidence and attachment coefficient are discussed. The aim is to help readers form a clear physical image and context for the process of cathode arc and its coating formation, and serve to guide the practice of scientific research and production.

Most studies on ferroelectric thin films are focused on perovskite structural materials. However, these traditional ferroelectric materials have a variety of problems, such as poor compatibility with Si, environmental pollution caused by Pb, large physical thickness, low resistance, and small band gap. Different dopants such as Si, Zr, Al, Y, Gd, Sr and La can induce ferroelectric or antiferroelectric properties in HfO₂ films, resulting in residual polari stion up to 45 µC·cm^-2 and coercivity (1~2 MV·cm^-1) approximately one order of magnitude greater than that of conventional ferroelectric films. At the same time, the thickness of HfO₂ films can be very thin (below 10 nm) and the band gap is large (~ 5 eV). These advantages over traditional ferroelectric materials can overcome the obstacles of traditional ferroelectric materials including ferroelectric field effect transistors and 3D capacitors in thin film memory applications. In addition, the electrical and thermal coupling of antiferroelectric films holds promise for a variety of applications, such as energy harvesting/storage, solid state cooling, and infrared sensors. HfO₂ doped thin films can be deposited by different deposition techniques, such as ALD, sputtering and CSD, and ALD has more obvious advantages in film deposition. In this paper, the recent progress of ferroelectric and antiferroelectric properties in HfO₂ doped thin films is reviewed. The effects of different doping elements, film thickness, grain size, electrode, annealing, and stress on the ferroelectric properties of HfO₂ thin films are described in detail.

The standard leak element is the essential calibration device for the helium mass spectrometry leak detector. To improve the sensitivity of the helium mass spectrometry leak detector, the lower leak limit of the standard leak element should be reduced. In view of the problem that it is difficult to reduce the lower leak limit of the standard leak element made of traditional materials by improving the processing technology. A new type of standard leak element based on subnanoporous graphene composite membranes was prepared using CVD method, and the helium permeation performance and preparation process stability were studied. The results show that the leak rate per unit area of single-layer graphene/PMMA composite membranes is 4.17×10^-12~1.09×10^-11 Pa·m³/(cm²·s·Pa), and the leak element with a lower limit leak rate of 10^-12 Pa·m³/s can be made by adjusting the penetration area of the composite membranes.

Arc ion plating was adopted to prepare three sets of chromium nitride (CrN) thin films with pulsed bias voltages of 50, 100, and 150 V, respectively on silicon, stainless steel and glass substrates. The phase components, surface morphology, mechanical properties and hydrophobicity at different temperatures of the films were analyzed. The results show that the as-prepared samples present a pure component, and there are some macro-particles on the surface of the films. The films fabricated at 100 V show excellent mechanical properties despite there are a lot of macro-particles on the surface. The films fabricated at 150 V have high hardness and excellent Young modulus, while the films fabricated at 50 V have high adhesion strength, indicating that mechanical properties of the CrN thin films are excellent. The films exhibit good hydrophobicity at room temperature (20 ℃), and the substrate material has little effect on the hydrophobicity. The hydrophobicity of the films decreases with increasing environmental temperatures. The films deposited at 50 V lose hydrophobicity when the ambient temperature rises to 80 ℃, and the films deposited at 100 V have the optimized hydrophobicity.

Graphene, a new two-dimensional material with excellent performance, has great potential for applications in the fields of aerospace, electronic devices, and bio-medical. Plasma enhanced chemical vapor deposition (PECVD) was used to prepare grapheneon copper foil using a mixture of hydrogen and methane gas. The mechanism of H₂ on the nucleation and growth of graphenein growth and cooling stage of PECVD was studied. The results show that in the PECVD process, the pre-etching of copper substrate by H₂ plasma before graphene growth would increase the roughness of the substrate, which is not conducive to the growth of low-density and large-size graphene grains. During the growth process, H₂ could etch multiple layers of graphene, and a single layer of graphene could be formed at higher H₂ flow rate. After the end of growth, holdingthe graphene in H₂ for a certain period of time, it would be etched into ribbons, and the etching would be intensified with the extension of holding time.

ZnSe:Co_x (x=0.1, 0.3, 0.5) nanocrystalline thin films were deposited on sapphire substrates by pulsed laser deposition at substrate temperature of 800 ℃. The crystal structure and optical properties of the thin films were investigated by X-ray diffraction, atomic force microscope, X-ray photoelectron spectroscopy, optical transmittance and photoluminescence spectra. The results show that the thin films with excellent crystalline quality and (111) preferred orientation are prepared. With increasing Co concentration, the crystalline quality, average transmittance and band gap of films decrease. There is a absorption band at the wavelength of about 700-850 nm in the film, which comes from the transition between ⁴A₂(4F)→⁴T₁(4P) energy levels of Co²⁺ in the tetrahedral crystal field composed of surrounding Se^2-. The films reach an overdoping state when the x value increases to 0.5, and the photoluminescence intensity of films decrease substantially due to the α-Co impurities un-incorporating into ZnSe lattice.

As a core component of Roots vacuum pump, the rotor has an important influence on the performance, and the design of rotor profile is critical to design rotor. In this study, the rotor profile is designed with the waist as the elliptical line, and its profile inside the pitch circle is composed of elliptical lines, while the profile outside the pitch circle is composed of the conjugate curves of elliptical lines. Firstly, the elliptical line located at the waist and its meshing angle are determined. Then, based on the meshing relationship between the two rotors, the conjugate curve of the profile line located outside the pitch circle is solved to obtain total rotor profile. Finally, the rotor of the Roots vacuum pump with a pumping speed of 70 L/s is designed, and the relationship of rotor volume utilization with independent variable parameters is analyzed. This profile has a significant advantage in the volume utilization rate that can be greater than 50%, compared to the rotor profile with the elliptical line at the top.

The computational fluid dynamics (CFD) method was used to simulate the screw dry vacuum pump by numerical simulation and calculation, and the analysis method for the flow field of screw dry vacuum pump was established. The flow area in the pump chamber was modeled in 3D, and the rotating and fixed domains were meshed separately with SCORG and ANSYS-ICEM softwares. The transient simulation method was used to obtain the distribution of pressure field, speed field and temperature field in the pump, and the parameters such as pumping rate were calculated. Perform mesh agnostic analysis was carried out, and the comparison between analysis results and the theoretical data shows that the numerical simulation results are reliable and in line with expectations.

Combining with the manufacturing process of special alloy, the vacuum system of VIDP furnace from ALD was analyzed according to the configuration and vacuum pumping capacity, and several optimization application measures were proposed. The interval time of Roots pump is set to 120-180 s. The starting up threshold of two paralleling pump units of low vacuum system is set to 1 000 Pa and 2 500 Pa. Different maintenance period (3-12 months) for different components of Roots pump and the specific operation process of filling argon to break the vacuum during alloy melting are provided according to volatile characteristics of special alloy. At last, suggestions for improving the ability of vacuum system of the VIDP-300 furnace are proposed.

Mars has always been considered the most likely place in the solar system where life outside of Earth has flourished and survived to this day. Therefore, the simulation of its surface environment plays an important role in the study of Mars. Based on the requirements of the Mars dust chamber system project of XX university's space simulation device, a system is designed to simulate the low-pressure environment on the surface of Mars. A vacuum pump group is used to reduce the pressure inside the Mars dust chamber, and a pneumatic regulating valve is used for high-precision dynamic pressure regulation to maintain stable pressure inside the Mars dust chamber. The system design technical parameters, system composition, working conditions and pumping speed calculation process are introduced in detail.

A standard leak element based on transfer-free polymethylmethacrylate (PMMA) or polyimide (PI) was developed. The fabrication process involved spin-coating PMMA or PI on a copper foil, followed by spin-coating photoresist on the opposite side, and subsequently creating small holes of different arrays with a diameter of about 10 μm on the copper foil using UV lithography. The flow conductance of helium through the leak element was measured by the differential pressure method. The results show that the samples all exhibite a molecular flow regime within the pressure range from 5 kPa to 10⁵ Pa. The flow conductance of transfer-free PMMA or PI shows a linear relationship with the effective permeation area, and the effective permeability area of PMMA or PI can be controlled by controlling the number of small holes, thereby obtaining different flow conductance. The transfer-free PMMA or PI materials developed in this study are ideal for low-permeation leak elements.

In order to meet the infrared load radiation calibration of a certain product in the high vacuum cold black environment, a composite PID control algorithm is designed and adopted. In the vacuum test of the large area array black body multi zone scaler, the high-precision index requirements of the large area array black body multi zone cross coupling temperature control are well met. The segmented approximation temperature control verification based on the combination of fuzzy control and traditional PID with strong engineering practicality has achieved an overall system temperature control accuracy of±0.1 K, meeting the design temperature control requirements.

Electron beam melting has the characteristics of high vacuum, high energy density, and precise control, and is widely used in the refractory metals industry. Relying on the electron gun technology and the LT102 device of the Research Institute of Physical and Chemical Engineering of Nuclear Industry, a set of feeding, melting, and casting ingot dragging devices for electron beam melting of refractory metals were designed. The technical requirements for the design of feeding, melting, and casting devices are mainly described, the smelting power for refractory metals is calculated, and the structural design function is introduced in detail. The developed feeding device has multiple work stations and refueling functions. The dragging device has functions of water cooling, pull-down, and rotation. The performance of the feeding and casting dragging device for the final assembly test meets the design requirements, and the equipment runs well in the overall melting experiment.

The application of hydrogenation reaction and dehydrogenation treatment in the preparation of zirconium-2 alloy powder is analyzed. The preparation work before powder preparation, hydrogenation reaction, dehydrogenation treatment, crushing and screening, separation are introduced in detail. Through hydrogenation and dehydrogenation process, pure zirconium-2 alloy powder can be obtained,the production efficiency is improved and the production cost is reduced.