The rare earth oxide ceramic designed as 4.5wt.%Gd₂O₃-5.5wt.%Yb₂O₃-10.5wt.%Y₂O₃-79.5wt.%ZrO₂ (GdYbYSZ) is a candidate material for thermal barrier coatings (TBCs), which will be suitable for application at higher temperatures. GdYbYSZ ceramic powders and bulks are fabricated by solid-state synthesis at temperatures above 1 300 ℃, and the powders have no phase transformation and exhibit excellent thermal stability despite long-term calcination at 1 100 ℃和1 300 ℃. The averaged thermal diffusivity and thermal conductivity of GdYbYSZ ceramics are approximately 2.1% and 5.1% lower than those of the conventional YSZ bulk respectively. The GdYbYSZ ceramic coatings are directly manufactured on the surface of (Ni, Pt)Al bond coat by means of electron beam physical vapor deposition (EB-PVD), whose phase structure consists primarily of cubic phase with co-existing of excess Y₂O₃ and ZrO₂. Meanwhile, elemental compositions of Y and Zr within as-deposited ceramic topcoats are higher than those in the ingot, and the constituents of Gd and Yb elements in these two types of specimens tend to be similar. A large number of regularly distributed “mud-like” microcracks appear on the surface of GdYbYSZ ceramic coating after the long-term alternating thermal cycling at 1 100 ℃. The transverse microcracks originating in the ceramic topcoat have elongated to the interface of ceramic coating and TGO layer that further cause the degeneration and separation of the interface. The spalling location of the GdYbYSZ ceramic coating mainly occurs at the upper and lower adjacent interfaces of the TGO layer. The serious rumpling, undulation, cross-linking, stress accumulation and rapid relaxation at the convex tip exist in the TGO layer are the critical factors to accelerating interfacial delamination and spallation failure of GdYbYSZ/(Ni, Pt)Al TBCs.

Plasma enhanced magnetron sputtering (PEMS) method was used to deposit TiCrSiCN and TiCrSiCON nanocomposite coatings using trimethylsilane (Si-C) and hexamethyldisiloxane (Si-C-O) precursors on H13 steel. The influences of oxygen on the microstructure, phases, surface energy, hardness,friction coefficient,wear resistance and high-temperature oxidation properties of the coatings were studied by SEM, AFM, XRD, EDS, etc. The results show that the oxygen-containing TiCrSiCON coating shows a rougher surface with a looser microstructure and typical columnar feature, compared with the oxygen-free TiCrSiCN coating. As a result, the surface energy of the oxygen-containing coating is higher than the oxygen-free coating. The addition of oxygen improves the hardness of the nanocomposite coating, thereby significantly enhancing the anti-wear property of the coating. As for the coefficient of friction, there is no obvious difference between TiCrSiCN and TiCrSiCON coatings. The Cr and O in the TiCrSiCON coating could form a dense oxide film which can improve its high-temperature oxidation property.

The high energy secondary electrons caused by electron beam will affect the quality of composite current collector during the roll to roll evaporation equipment working. The emissivity of secondary electron is proportional to the incident angle of the electron beam in a certain range, and the trajectory of electron beam can be biased in magnetic field. In this paper, one kind of electromagnetic bias coil was developed and designed based on simulation software and CAD modeling technology. Through parameter optimization, the matching magnetic field intensity and electron bias trajectory were obtained to reduce the incidence angle. At the same time, the influence of the electromagnetic coil parameters on bias were compared and analyzed. The results show that increasing the current, number of turns, coil size, coil number, and reducing the distance between the coil and the electron gun can all reduce the electron beam bias radius. By optimizing these parameters, the predetermined incidence angle can be obtained, and achieving low secondary electron emissivity, and providing a design basis for future equipment iteration upgrades.

The multistage gas distribution system of large-sized square carrier metal-organic chemical vapor deposition (MOCVD) for the preparation of gallium arsenide (GaAs) thin film in the photovoltaic industry is introduced. The core parameters in the design process of the reactor structure, such as the size of the showerhead hole and the spacing between the showerhead and carrier (chamber spacing) are discussed. Based on a self-developed MOCVD reactor model with a carrier of 36×4 inches wafers, the computational fluid dynamics (CFD) method and the gas reaction and surface reaction during GaAs film deposition were used to simulate the gas distribution and chemical vapor deposition (CVD) process with different parameters and chamber spacing. The relationship between cross-orifice pressure difference and gas flow distribution uniformity, and the effect of chamber spacing on gas flow and GaAs film deposition were investigated. The results show that after the primary "spider" plate divides the main gas inlet into 64 sub-gas intakes, the gas distribution uniformity is better, and the fluctuation amplitude of mass flow rate value is only 0.22%. Increasing the hole depth of the showerhead increases the hole pressure difference slowly and linearly, while reducing the hole diameter increases the pressure difference very quickly. Increasing the hole pressure difference of the showerhead can improve the uniformity of secondary gas separation, but the lifting effect is slow. The deposition rate is low and the uniformity is poor at large chamber spacing. With the decreasing of the spacing and the increasing of deposition rate, the deposition uniformity becomes better at first, and then becomes worse gradually due to the turbulence of gas flow.

As the most promising TiN film substitute material, TiAlN film has excellent properties such as high hardness, low friction coefficient, good high temperature stability and corrosion resistance. The TiAlN hard films are widely used in the fields petroleum, tools, molds, electric power and aircraft engines. The current application and research progress of domestic and foreign TiAlN films, the preparation methods, and the effects of process parameters on structure and properties of TiAlN films are summarized. The performance of TiAlN film is comprehensively introduced, the method to optimize the performance of TiAlN film is pointed out, and the research and application direction of TiAlN films are prospected. The TiAlN film will develop towards the multiple composite, multilayer structure, and nano multi-layer structure with the further research and the demand of application.

Graphene vacuum standard leak is a kind of new vacuum standard leak based on graphene-derived materials, and the lower limit of leakage rate is lower than the general helium permeation leak rate, which can be used in the calibration of ultra-sensitive leak detection system. Based on the material characteristics of graphene, the leakage rate of graphene vacuum standard leak will change with temperature. In this paper, the influence of temperature on the leakage rate of graphene vacuum standard leak was studied. By measuring the leakage rate of the standard leak in different temperature environments, the temperature coefficient and the change rule of the leakage were obtained. The results show that the leakage rate of graphene vacuum standard leak changes linearly with temperature, and the temperature coefficient is lower than 2.5%/℃.

A chip-level ion source structure with a triode-type field emitter is designed for the micro mass spectrometer of spacecraft, which consists of a gas ionization by electron impact and an ion extraction section. The structure of the ion source is composed of five layers of electrodes. A chip-level ion source prototype was prepared using MEMS technology, and the electron flow, ion flow and stability were tested. The results show that the chip-level ion source can generate an electron current of over 0.357 mA, and the received ion current can reach 527 pA, meeting the functional requirements of the ion source for micro mass spectrometers in space exploration missions.

High-precision transmission control of electron beams is important to ensure reliable applications of electron guns in metal melting, evaporation coating, and electron beam welding. The transmission control technology of electron beams in the evaporation environment of metal materials was studied, and a 30 kV electron beam deflection model was established based on CST particle simulation analysis software. The influence of the structure and position parameters of the deflection device on the distribution of electron beam was analyzed, and the control parameters and structure of the electron beam deflection that meet the requirements were obtained through simulation design optimization. The test results show that the electron beam transmission trajectory under the optimized structure is controllable, and the established 30 kV electron beam deflection system meets the requirements.

Mass spectrometer is an important instrument for gas monitoring analysis in many fields. It has the advantages of wide detection range, high sensitivity and faster response speed compared to the traditional gas sensor. A miniaturized process mass spectrometer is developed with a dual filament electron bombardment ionization source and a quadrupole as mass analyzer. The detector works in dual mode of Faraday cup and electron multiplier. The electronic control unit core is combined with a high frequency FPGA system, high current filament power supply, wide mass range RF power supply and high gain composite transconductance amplifier. The test results show that the miniaturized process mass spectrometer has superior properties which has reached the level of mainstream mass spectrometer in the market, and can be widely used in various gas detection occasions.

Aiming at the problem of engine performance degradation of vehicles due to low air pressure in high-altitude areas, a low-pressure dynamic testing system was designed based on the requirements of the XX project, which can be used to simulate high-altitude low-pressure environments, and carry out various dynamic tests of vehicles under low-pressure. The composition and process flow of the low-pressure simulation system and smoke exhaust system were introduced in detail, and the extraction rate and amount were calculated.

Using the causal analysis of TRIZ theory as a research tool, the basic reason and weakness that affect the base pressure of Roots vacuum pumps were obtained. The seal structure and rotor profile of the Roots vacuum pump were improved based on the enlightenment of the technological contradiction and the law of technological system evolution solution model, and then the ZJP70 Roots vacuum pump was optimized. The test results show that the base pressure of the optimized Roots vacuum pump is significantly increased under the same conditions. At the same time, the key indicators such as maximum zero flow compression ratio, overall leakage rate, and noise achieve significant improvement.

The gas tightness of envelope material is one of the important technicalities of aerostat products. In order to study the gas tightness of materials after processing, three materials with bearing layer made of Vectran, nylon and polyimide fabric were chosen as the research objects, and processing parameters here was consistent with the actual working conditions. The helium permeability of materials that were original, after being used and the joint position were tested. The variation of helium permeability was further analyzed. The research results show that the helium permeability of envelope material increases with the increase of kneading times and the area of sealing gap. Besides, the helium permeability of the gap containing the external hot strip is equivalent to that of the bulk material. This study could guide the choice of materials, the product processing and the assessment of overall leakage.

Aiming at the design of oil injection screw vacuum pump products, the design method of the oil gas separation system is introduced emphatically. Based on the working principle of the vacuum pump and combined with engineering practice, the design scheme of the oil and gas separation system and the oil and gas separation tank are first proposed. Then, the important components in the oil and gas separation tank such as the cylinder body and flange are analyzed and calculated, and the parameters including the nominal diameter and thickness of the cylinder body are determined. The structural type of bursting discs is selected based on its structural principle, and the bursting pressure and discharge area of bursting discs are determined. Finally, the three-dimensional design software is used to complete the design of the three-dimensional model of entire structure, thereby further verifying the structure rationality of the oil and gas separation system.

As an excellent vacuum smelting technology, the structural design of the water-cooled crucible, the core component of electron beam melting, is particularly important. The crucible cooling performance directly affects the performance and safety of electron beam melting. The influences of crucible water channel structure and melt pool morphology on the cooling capacity of crucibles were investigated through theoretical analysis, numerical simulation, and an experimental assessment. The crucible structure was determined through crucible material selection, melt pool utilization rate analysis, energy loss analysis and cooling calculation. A numerical simulation model was established and used to compare the cooling performance of two types of molten pool crucibles under different loading conditions, and experimental assessment was conducted on crucible with excellent performance. The results show that under different ingot thicknesses, the cooling water temperature and surface temperature of crucible B are lower than those of crucible A in numerical simulation, indicating that the shape of the molten pool and the structure of the water channel in crucible B are more reasonable and have better heat dissipation effects. The experimental assessment shows that the state of crucible B is stable and meets the design requirements.