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A novel nano-Si3N4 particle reinforced AgCuTi composite filler (AgCuTiC) was used to braze Ti6Al4V and Si3N4 ceramic in the study and brazing cycles that peak at 880 °C for 0–20 min. Effects of holding time on interfacial microstructure and mechanical property were studied by scanning electron microscopy, energy dispersive spectrometer, transmission electron microscopy, and universal testing machine...
In this study, a Zr-Cu-Ni-Al-N thin film metallic glass (TFMG) has been developed and applied for the diffusion barrier between copper and silicon. The Si/TFMG/Cu stacked structures with various TFMG thickness have been fabricated. Rapid thermal annealing was conducted at 500, 600, 700 and 800 °C. The X-ray diffraction analysis was applied to identify the formation of Cu3Si intermetallic compound...
Au-C70 nanocomposite thin films are deposited using thermal co-evaporation technique. Low atomic concentration of Au (∼3%) are used to avoid any deterioration of the properties of fullerene C70 when used with Au. These thin films are annealed in inert atmosphere at different temperatures for 30 min in order to promote the formation of nanocomposite material. Both the Au nanoparticles and fullerene...
Ti alloys are the most remarkable group of biomedical implant materials because of their properties such as low elastic modulus, low density, super bio-compatibility, high strength/density ratio. Metastable β-Ti alloys have lower elastic modulus compared to other types so it is possible to reduce the biomechanical mismatch and stress shielding effect of the implant-bone interfaces. Powder Injection...
Phase control is important to obtain high-performance CdTe solar cells when copper telluride is used as a back-contact for CdTe solar cells. In this paper single-phase CuTe was mainly controlled by the Cu/Te ratio via a co-evaporation method in combination with rapid thermal processing treatments. The alloy thin films as-deposited were mainly amorphous. After thermal treatments, the films experienced...
In this study, hot compression tests were performed at temperatures in range of 850–1150 °C and strain rates of 0.001–100 s−1 to study the hot deformation behavior of 26NiCrMoV 14-5 steel. The relationship between flow stress, temperature and strain rate was established using a power-law equation and the activation energy was determined in range of 200–600 kJ/mol. Some irregularities were observed...
A large scale 5-axis magnetically levitated turbomolecular pump is designed and fabricated in this paper. The rotor is supported by two radial active magnetic bearings (AMBs) and an axial AMB, and driven by a high-speed brushless DC Motor with a ring permanent magnet. The considerations discussed are described by design of an actual magnetic levitation turbomolecular pump with rated high-speed vacuum...
A novel surface treatment combined with depositing Cr films followed by plasma nitriding was carried out on the surface of the 2024 Al alloy. Nano-grained Cr films were firstly deposited on the substrate surface by using magnetron sputtering, then plasma nitrided at 490 °C for 8 h under a gas mixture of 25% N2+75% H2. Microstructures and mechanical properties of the as-obtained coatings were characterized...
Herein, pure Al coatings have been deposited on sintered NdFeB via multi-arc ion plating method. The effect of target current and working pressure on the microstructure and properties of these coatings have been investigated using scanning electron microscopy, laser scanning confocal microscopy, X-ray diffraction, tensile testing, electrochemical tests and neutral salt spray. The results showed that...
This study focused on developing a beneficial nitriding process for use on Ti-6Al-4V alloy surfaces, involving surface mechanical attrition treatment (SMAT), which does not contaminate the existing nanocrystalline layer. The average grain size of this layer was refined to 10 nm with random crystallographic orientation. Differential scanning calorimetry confirmed that the recrystallization temperature...
The main objective of the work was to investigate the microstructure of S-phase coatings obtained by reactive magnetron sputtering at different temperatures and with various nitrogen concentrations in the working atmosphere. Particular attention was paid to the formation of a diffusion sub-layer in the austenitic substrate. The coatings were deposited on austenitic stainless steel substrates in an...
X-Ray Photoelectron Spectroscopy was used to determine the valence band offset at Al2O3/β-Ga2O3 heterointerfaces. The Al2O3 was deposited either by Atomic Layer Deposition (ALD) or rf magnetron sputtering and the synthesis method was found to have a very significant effect on the resulting band alignment. The bandgaps of the materials were determined by Reflection Electron Energy Loss Spectroscopy...
The oxidation behavior of C/C-ZrC composites prepared by chemical liquid-vapor infiltration (CLVI) process was studied, and the effects of co-deposited ZrC on the oxidation resistance properties were also discussed. Results indicate that an excellent oxidation resistance of C/C-ZrC composites has been obtained due to introduction of co-deposited ZrC. After 240 min oxidation at 900 °C, the mass loss...
Micro-arc oxidation coatings were fabricated on 7E04 aluminum drillpipes materials in Na2SiO3-NaOH electrolyte system containing 3.0 g/L SiC particles at different current density (1, 5, 10, 15 and 20 A/dm2). The oxidation voltage, coating thickness, surface morphologies, surface micro-hardness, phase composition and potentiodynamic polarization curves of the MAO coatings were investigated. The results...
Using density functional theory, the electronic and adsorption behavior of CO and NO on borospherene is studied. The electronic and structural stability of borospherene is confirmed in terms of density of states spectrum and formation energy. The adsorption behavior is explored using adsorption energy, energy gap, charge transfer and average energy gap variation. The change in the projected density...
•Numerical approach addressing the pump down of reversibly adsorbed phase (e.g. water) in complex vacuum system.•Mathematical model based on the view factor (or angular coefficients) methods coupled with the Langmuir adsorption desorption kinetic model.•Model tested on a spherical vacuum system and results are compared to the ones obtained with the well-known Redhead model.•Model applied to a more...
The science payload of the Solar Orbiter mission that will be launched in 2018 comprises the RPW (Radio and Plasma Waves) experiment that will perform in situ and remote-sensing measurements (magnetic and electric fields). Some parts of this instrument will be made of Elgiloy for the antennas and must be protected from the intense solar radiation by a heat shield made in niobium. Emissivity of both...
It has been found that the kinetics of heating has an essential effect on copper films dispersion temperature. Annealing of nonequilibrium defects slightly slow down the diffusion processes in comparison with unannealed samples and it naturally increases the temperature of de-wetting of continuous films. It has been shown that the formation of liquid lead in continuous Cu-Pb polycrystalline films...
(100)Nb:SrTiO3/(110)ZnO heterojunction were epitaxially grown by RF magnetron sputtering. A typical rectification characteristic was observed before and after applying a magnetic field, but the rectifying effect was significantly enhanced after applying a magnetic field. From high and low frequency capacitance-voltage measurement, the interface state density is found to increase from 3.8 × 1012 to...
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