The alloying of steel surface with aluminum (Al) using Microsecond-pulsed Intense Electron Beams (MIEB-Al) was developed and optimized in order to be used for improving the corrosion resistance of ...the 316, 1.4970 and T91 steels, exposed to liquid Pb and Pb–Bi-eutectic. The procedure consists in two steps: (i) coating the steel surface with Al or an Al-containing alloy layer and (ii) melting the coating layer and the steel surface layer using intense pulsed electron beam. In order to cover the steel surface with an homogeneous and crack-free Al-alloyed layer, the following experimental conditions are required: Al coating thickness range 5–10
μm, electron kinetic energy 120
keV; pulse duration 30
μs; energy density 40–45
J/cm
2; number of pulses 2–3.
Using the mentioned procedure, the corrosion resistance of the 316, T91 and 1.4970 steels, exposed to Pb and Pb–Bi-eutectic with different oxygen concentrations and under different temperatures, was considerably improved due to the formation of a thin alumina layer (which thickness is lower than 1
μm for all the tested temperatures and durations) acting as an anti-corrosion barrier.
Recovery stress generation under thermal cycling has been experimentally studied in clamped shape memory Cu-Al-Ni single crystals up to 9% reversible strain. It is shown that such crystals are ...capable of repeated force generation upon heating up to 600 K and single actuation when heated to 700 K with a maximal stress of 350 MPa. The main principles of designing cyclic linear actuators are considered and a technique for calculating their force characteristics is proposed. The calculation is based on the mathematical model of linear actuator.
In this study we compare the growth of gallium oxide films by halide vapor phase epitaxy (HVPE) on various substrates under the same growth conditions. Gallium oxide films were deposited at 500 ...°C-600 °C on basal plane (0001) planar and patterned sapphire substrates, (0001) 2H-GaN, 4H-SiC, and 2 ¯ 01 bulk β-Ga2O3 substrates. The layers were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and cathodoluminescence (CL) techniques. Most of the films exhibit growth features of hexagonal symmetry. Sn-doped Ga2O3 films exhibit n-type electrical conductivity. Heterojunctions composed of n-type hexagonal Ga2O3:Sn and p-type GaN:Mg demonstrate diode-like I-V characteristics and emit light under forward bias.
TiOsub.2 films of 130 nm and 463 nm in thickness were deposited by ion beam sputter deposition (IBSD), followed by annealing at temperatures of 800 °C and 1000 °C. The effect of Hsub.2 , CO, COsub.2 ..., NOsub.2 , NO, CHsub.4 and Osub.2 on the electrically conductive properties of annealed TiOsub.2 thin films in the operating temperature range of 200–750 °C were studied. The prospects of IBSD deposited TiOsub.2 thin films in the development of high operating temperature and high stability Osub.2 sensors were investigated. TiOsub.2 films with a thickness of 130 nm and annealed at 800 °C demonstrated the highest response to Osub.2 , of 7.5 arb.un. when exposed to 40 vol. %. An increase in the annealing temperature of up to 1000 °C at the same film thickness made it possible to reduce the response and recovery by 2 times, due to changes in the microstructure of the film surface. The films demonstrated high sensitivity to Hsub.2 and nitrogen oxides at an operating temperature of 600 °C. The possibility of controlling the responses to different gases by varying the conditions of their annealing and thicknesses was shown. A feasible mechanism for the sensory effect in the IBSD TiOsub.2 thin films was proposed and discussed.
Gallium oxide films were grown by HVPE on (0001) sapphire substrates with and
without $\alpha$-Cr$_2$O$_3$ buffer produced by RF magnetron sputtering.
Deposition on bare sapphire substrates resulted ...in a mixture of
$\alpha$-Ga$_2$O$_3$ and $\epsilon$-Ga$_2$O$_3$ phases with a dislocation
density of about $2\cdot10^{10}$ cm$^{-2}$. The insertion of
$\alpha$-Ga$_2$O$_3$ buffer layers resulted in phase-pure $\alpha$-Ga$_2$O$_3$
films and a fourfold reduction of the dislocation density to $5 \cdot 10^9$
cm$^{-2}$.
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