Anodizing of Hydrogenated Titanium and Zirconium Films

Magnetron-sputtered thin films of titanium and zirconium, with a thickness of 150 nm, were hydrogenated at atmospheric pressure and a temperature of 703 K, then anodized in boric, oxalic, and tartaric acid aqueous solutions, in potentiostatic, galvanostatic, potentiodynamic, and combined modes. A study of the thickness distribution of the elements in fully anodized hydrogenated zirconium samples, using Auger electron spectroscopy, indicates the formation of zirconia. The voltage- and current-time responses of hydrogenated titanium anodizing were investigated. In this work, fundamental possibility and some process features of anodizing hydrogenated metals were demonstrated. In the case of potentiodynamic anodizing at 0.6 M tartaric acid, the increase in titanium hydrogenation time, from 30 to 90 min, leads to a decrease in the charge of the oxidizing hydrogenated metal at an anodic voltage sweep rate of 0.2 V·s−1. An anodic voltage sweep rate in the range of 0.05–0.5 V·s−1, with a hydrogenation time of 60 min, increases the anodizing efficiency (charge reduction for the complete oxidation of the hydrogenated metal). The detected radical differences in the time responses and decreased efficiency of the anodic process during the anodizing of the hydrogenated thin films, compared to pure metals, are explained by the presence of hydrogen in the composition of the samples and the increased contribution of side processes, due to the possible features of the formed oxide morphologies.

Structure and Phase State of Ti49.4Ni50.6 (at%) Hydrogenated in Normal Saline

The paper analyzes the surface structure and phase state of Ti49.4Ni50.6 (at%) hydrogenated at 295 K in normal saline (0.9% NaCl aqueous solution with pH = 5.7) at 20 A/m2 for 0.5–6 h. The analysis shows that the average hydrogen concentration in the alloy increases with the hydrogenation time tH as follows: slowly to 50 ppm at tH = 0.5–1.5 h, steeply to 150 ppm at tH = 1.2–2 h, and linearly to 300 ppm at tH = 2–6 h. According to Bragg–Brentano X-ray diffraction data (θ–2θ, 2θ £ 50°, CoKa radiation), the alloy in its scanned surface layer of thickness ~5.6 µm reveals a TiNiHx phase with x = 0.64 and x = 0.54 after hydrogenation for 4 and 6 h, respectively. The structure of this phase is identifiable as an orthorhombic hydride similar to β1–TiFeH0.94 (space group Pmcm), rather than as a tetragonal TiNiHx hydride with x = 0.30–1.0 (space group I4/mmm). Time curves are presented to trace the lattice parameters and volume change during the formation of such an orthorhombic phase from the initial cubic B2 phase in Ti49.4Ni50.6 (at%).

Exploring the Hydrogen-Induced Amorphization and Hydrogen Storage Reversibility of Y(Sc)0.95Ni2 Laves Phase Compounds

Rare-earth-based AB2-type compounds with Laves phase structure are readily subject to hydrogen-induced amorphization and disproportionation upon hydrogenation. In this work, we conducted the Sc alloying on Y0.95Ni2 to improve its hydrogen storage properties. The results show that the amorphization degree of Y0.95Ni2 deepens with the increasing hydrogenation time, pressure, and temperature. The Y(Sc)0.95Ni2 ternary compounds show a significant improvement in reversibility and dehydriding thermodynamics due to the reduced atomic radius ratio RA/RB and cell volume. Hydrogen-induced amorphization is fully eliminated in the Y0.25Sc0.7Ni2. The Y0.25Sc0.7Ni2 delivers a reversible hydrogen storage capacity of 0.94 wt.% and the dissociation pressure of 0.095 MPa at the minimum dehydrogenation temperature of 100 °C.

The Temperature Evolution of the Hydrogen Plasma Induced Structural Defects in Crystalline Silicon

Hydrogenated n and p doped Czochralski Si substrates have been studied by means of atomic force microscopy, scanning and transmission electron microscopy, Raman spectroscopy and microwave photoconductivity decay techniques. The measurements show that the surface is roughest in ndoped samples which are plasma treated at high frequency. The cone density was found to be highest on p-doped samples, which correlates well to the higher density of defects observed in pdoped samples. The surface cones were found to consist of nanograins, twins and stacking faults with random orientations, several hydrogen induced defects and bubbles. The size, density and formation depth of the subsurface defects were seen to depend on doping type, doping level, plasma frequency and hydrogenation time. Raman spectroscopy shows formation of nearly free hydrogen molecules, which are presumed to be located in nano-voids or platelets. These molecules dissolved at temperatures around 600°C. By means of the &-PCD measurements, it is demonstrated that hydrogen-initiated structural defects act as active recombination centres, which are responsible for the degradation of the minority carrier lifetime.

Characteristic of Deformation of Ti-6Al-4V Alloy with Hydrogen at High Temperature

The effects of hydrogen on the microstructure and hot deformation behavior of Ti-6Al-4V alloy were studied, and the differences of microstructure and high temperature compressive behavior between the specimens hydrogenised various time at 700 oC and with the same hydrogen contents were analyzed. The results showed that the addition of hydrogen decreases the deformation resistance of Ti-6Al-4V alloy at high temperature. The flow stresses of specimens with the same hydrogen content declined as the prolongation of hydrogenating time. The microstructure observation indicated that stick-type microstructure was obtained in Ti-6Al-4V alloy annealed at 700 oC for 2 hours. Hydrogenation at 700 oC for 2 hours resulted in fine α plate in β transformed microstructure. When the hydrogenation time was prolonged to 6 hours, the volume fraction of newly-formed α plates increased and the prior α plates became coarser.

Asphalt Modified by Partially Hydrogenated SBS Tri-Block Copolymers

This work examines the modification of asphalt with hydrogenated poly (styrene-butadiene-styrene) copolymer containing different amounts of butadiene and ethylene-co-butylene. The polymer composition can be described generically as poly (styrene−[(butadiene)1−x−(ethylene−co−butylene)x]−styrene), where x is the hydrogenated fraction of the molecule. These hydrogenated (SBEBS) copolymers were produced by in-situ hydrogenation following a Ziegler-Natta catalytic reaction of poly (styrene-butadiene-styrene) tri-block copolymers (SBS), which were previously synthesized by anionic polymerization. Control over the hydrogenation time produces SBEBS polymers with various degrees of saturation of the polybutadiene block, as characterized by FTIR, HNMR, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC). Polymer-modified asphalts (PMA) were obtained by a high-temperature mixing process with AC-20 asphalt (Salamanca, Mexico) and SBS or SBEBS copolymers. PMA samples were characterized before and after high-temperature storage tests by fluorescence microscopy, rheometry, and mechanical tests. Results indicate that PMA obtained from SBEBS contain a polymer matrix with well-dispersed asphalt rich phase, with improved mechanical and thermal stability over those PMA produced with SBS. Compatibility between SBEBS and the aromatic fraction of maltenes can explain the dispersion of the polymer in asphalt and the enhanced properties.

Structure Sensitive Hydrogenation Effects in Polysilicon High Voltage thin Film Transistors

Hydrogen passivation of grain boundary and in-grain defects is a key process step in the fabrication of high quality poly-Si TFTs. The sensitivity of the hydrogenation process to device geometry is therefore an important consideration. The effects of rf-plasma hydrogenation on the operating performance of a range of self-aligned and offset drain (Loff = 5 to 40 μm) poly-Si TFT configurations is reported. The hydrogenation of offset drain structures results in a predictable increase in the pre-threshold slope and a reduction in the device threshold voltage. However, extended hydrogenation (up to 12 h) can result in a significant reduction in the device drive current (by up to 2 orders). A similar effect is observed in metal field plate HVTFTs in which some portion of the offset region is un-modulated by the additional electrode. The on state conduction in the offset region is examined as a function of hydrogenation time, temperature and planar electric field. The increase in the on resistance is attributed to a reduction in the poly-Si defect density, which moderates carrier transport through the offset region.

Allons low linolenic acid summer rape

Allons (Brassica napus L.) is a low linolenic acid canola cultivar which produces seed oil with an average linolenic acid content of 2.5%. The low linolenic oil has a shorter hydrogenation time and greater stability than standard canola oil. Allons is higher yielding and contains higher seed oil and lower meal protein than the low linolenic cultivar Stellar. Allons is adapted to the long season B. napus canola growing areas of western Canada. Key words: Rape (summer), low linolenic, cultivar description