Titanium Hydrogen Research Articles

Features of Titanium Structure Formation During Thermal Diffusion Saturation with Hydrogen

Some features are provide for the change in structure and properties of commercial purity titanium during hydrogenation and their effect on formation of the final structure of semifinished products and objects after vacuum annealing. It is established that titanium hydrogenation kinetics by a thermal diffusion method and specimen structure formation are mainly determined by the temperature for introducing hydrogen.

Effect of hydrogen content in titanium on the structure of the front and the specific features of the combustion of a Ti + 0.5C granular mixture in a cocurrent nitrogen flow

Specific features of the combustion of a titanium–carbon black granular mixture in a quartz tube blown with nitrogen is studied. In contrast to the previous studies, titanium with increased hydrogen content is used. The gas flow (cocurrent filtration) is produced by applying a fixed pressure differential less than 1 atm across the inlet and outlet of the tube. The characteristics of the combustion of a Ti + 0.5C granular mixture in a nitrogen flow are investigated. It is shown that an increased content of hydrogen in titanium leads to the formation of a two-front combustion wave. It is demonstrated that the first and second fronts of the two-front structure arise due to the interaction of the charge with nitrogen. The velocities of propagation of the fronts increase with the nitrogen pressure differential.

Accessing alkali-free NASICON-type compounds through mixed oxoanion sol–gel chemistry: Hydrogen titanium phosphate sulfate, H1−xTi2(PO4)3−x(SO4)x (x=0.5–1)

We report a direct sol–gel synthesis and characterization of new proton-containing, rhombohedral NASICION-type titanium compounds with mixed phosphate and sulfate oxoanions. The synthetic conditions were established by utilizing peroxide ion as a decomposable and stabilizing ligand for titanyl ions in the presence of phosphates in a strong acidic medium. Thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), induction-coupled plasma optical emission spectroscopic (ICP-OES) elemental analysis, and Raman and 1H magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopic studies have determined the presence of sulfate and proton ions in the structure, for which the compositional range has been found to be H1−xTi2(PO4)3−x(SO4)x (x=0.5–1). The particulate products exhibit a nanocrystalline nature observed through characterization with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The N2 sorption isotherm measurements and subsequent Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) analyses confirmed the presence of the textural meso- and macropores in the materials. Future studies would determine the potential of the new compounds in various applications as battery materials, proton conductors and solid acid catalysts.

Hydrogen Concentration Measurements at Titanium Layers by Means of Thermo-EMF

The thermo-emf and electrical resistivity of hydrogenated titanium were measured. Hydrogen concentration in titanium varies from 0.005 to 0.25%. We have compared the methods regarding their sensitivity to the alteration of thermo-emf and electrical resistivity during titanium hydrogenation. The accuracy of the obtained results was verified by comparing them with the results for palladium. It was demonstrated that the method implementing thermo-emf is sensitive to hydrogen concentration in titanium at different depth of the alloy. On the basis of performed measurements, we have proposed a graphical method for detecting the change in titanium structure.

Hierarchical flower-like titanium phosphate derived from H-titanate nanotubes for photocatalysis

Nanosheet-assembled hierarchical flower-like titanium phosphate (TiP) is synthesized via hydrothermal treatment of H-titanate nanotubes (Ti-NT) at the optimized conditions of 0.1 M of H3PO4 and hydrothermal temperature of 130 °C. A possible formation mechanism for the TiP flowers, involving the disintegration of Ti-NT and the growth and assembling of TiP nanosheets, is proposed. The main compositions of the uncalcined TiP flowers are titanium hydrogen phosphate hydrates (Ti(HPO4)2·xH2O), which can be transformed to titanium phosphate (TiP2O7) after high temperature calcination. The photocatalytic activity of the prepared TiP flowers is increased with the increased calcination temperature, which may be attributed to the better photocatalytic activity of TiP2O7 than Ti(HPO4)2·xH2O and the increased crystallization of TiP2O7.

Terminal solid solubility determinations in the H–Ti system

The terminal solid solubility of hydrogen in titanium was measured by differential scanning calorimetry in the concentration range of 0.3–4.1 at.% which practically corresponds to the whole solubility range of hydrogen in α-Ti. The solvus enthalpy obtained in this range from the overall data set was 22.8 ± 0.5 kJ/molH. However, a more careful analysis of the experimental results shows that the solubility curve has two different behaviors as a function of concentration. In the high concentration range 1.4–4.1 at.% a solvus enthalpy of 29.0 ± 1.5 kJ/molH was obtained representing the α/α + δ equilibrium boundary. In the low concentration range, 0.3 at.% to 1.4 at.%, the slope was noticeably lower with 24.2 ± 1.5 kJ/molH for the solvus enthalpy. This last value should correspond to the [α]/[α + γ] equilibrium curve. Although it is possible this value might be influenced by the presence of tiny amounts of the now metastable δ phase–as its presence is revealed by X-ray diffraction analysis – anyway it is consistent with a α + δ ↔ γ peritectoid reaction temperature of 168 °C obtained from the literature.The eutectoid α + δ ↔ β decomposition temperature was determined using samples of high hydrogen contents, ranging from 9 to 11.0 at.%. This temperature was determined to be 319.9 ± 1 °C from the analysis of the DSC diagrams. The solubility limit [α]/[α + δ] at this eutectoid reaction was estimated to be 5.44 ± 0.27 at.%.The present results are believe to provide a closer approximation to the solubility values of H in α-Ti as presently reported in the literature.

Improvement of titanium hydrogenation by low energy ion irradiation

In this work a study of the improvement of titanium hydrogenation by low energy ion irradiation is presented. 3 mm titanium slices were irradiated at room temperature with 5 keV H ions and annealed at different temperatures (300, 450 and 600 °C) in a hydrogen atmosphere in order to study the absorption of hydrogen. ERDA measurements as well as X-ray diffraction analysis show an improvement in hydrogen absorption relative to those samples that were not irradiated previously to hydrogenation.

Influence of synthesis conditions on the structure and phase formation during the SHS hydration of titanium

SHS hydrogenation of titanium sponge in various modes of hydrogen deficiency and excess is investigated. According to data of the time-of-flight mass spectroscopy, a nonuniform H+ distribution is found over the sponge bulk during the synthesis in the H2 deficiency mode and a uniform one is found in the H2 excess mode. The surface structure of the Ti sponge before and after SHS hydrogenation is compared by SEM. An increase in structure lamination compared with the initial sponge is found for the hydrogenated sponge irrespective of the H2 content. Layers acquire a regular geometric shape and are arranged in a definite order with a repeated motif. Distances between the layers vary from the micron to nanometer sizes. The phase formation mechanism during the hydrogenation of titanium is investigated by time-resolved X-ray diffraction. The final product is formed through a series of intermediate phases according to the solid-phase mechanism: α-Ti → α-Ti[H] → β-Ti[H] → TiH2.

An experimental study of the (Ti–6Al–4V)–xH phase diagram using in situ synchrotron XRD and TGA/DSC techniques

Hydrogen has been investigated for decades as a temporary alloying element to refine the microstructure of Ti–6Al–4V, and is now being used in a novel powder metallurgy method known as “hydrogen sintering and phase transformation”. Pseudo-binary phase diagrams of (Ti–6Al–4V)–xH have been studied and developed, but are not well established due to methodological limitations. In this paper, in situ studies of phase transformations during hydrogenation and dehydrogenation of (Ti–6Al–4V)–xH alloys were conducted using high-energy synchrotron X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The eutectoid phase transformation of β↔α+δ was observed in the (Ti–6Al–4V)–xH alloy via in situ synchrotron XRD at 211°C with a hydrogen concentration of 37.5at.% (measured using TGA–DSC). The relationships of hydrogen composition to partial pressure and temperature were investigated in the temperature range 450–900°C. Based on these results, a partial pseudo-binary phase diagram of (Ti–6Al–4V)–xH is proposed for hydrogen compositions up to 60at.% in the temperature range 100–900°C. Using the data collected in real time under controlled parameters of temperature, composition and hydrogen partial pressure, this work characterizes relevant phase transformations and microstructural evolution for practical titanium–hydrogen technologies of Ti–6Al–4V.

Novel performance of ultrathin AlPO4 coated H2Ti12O25 Exceeding Li4Ti5O12 in cylindrical hybrid supercapacitor

Hydrogen titanium oxide, H2Ti12O25 is prepared by soft chemical method. A fabricated asymmetric hybrid supercapacitor using an AlPO4 modified H2Ti12O25 anode shows electrochemical performance superior to a Li4Ti5O12 anode, including cycling performance. The anode comprised of H2Ti12O25 coated with 3 wt.% AlPO4 shows the energy and power density of 41.1 Wh kg−1, 194.1 W kg−1, respectively, at a current rate of 0.1 A g−1 as well as the highest cycling performance, with 94.1% specific capacitance retained after 1000 cycles at a current rate of 3.0 A g−1. These excellent results are convincing evidence that H2Ti12O25 should be regarded as one of the more promising anode materials.

Hydrogen titanium oxide hydrate: excellent performance on degradation of methyl blue in aqueous solutions

Nanotube-assembled flower-like hydrogen titanium oxide hydrate (H2Ti2O4(OH)2), which has degradation capacity for methyl blue (MB) even in darkness, was prepared via a microwave solvothermal process. Physicochemical features of the hydrogen titanium oxide hydrate powders were characterized by X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, Fourier transform-infrared spectroscopy and UV/VIS/NIR spectrometry. The degradation of methyl blue (MB), methyl orange (MO) and Rhodamine B (Rhb) solution with a water-cooling system was carried out to study the photocatalytic properties of the powders. Results indicate that the H2Ti2O4(OH)2 has excellent performance on degradation of MB, which can be attributed to the hydroxyl group (–OH) from the surface of the catalysts confirmed by electron spin resonance signals (ESR). Furthermore, the intensity of ESR signals rapidly increased with the irradiation time and did not reach maximum after 11 min, which indicated that the photogenerated holes in the valence band of H2Ti2O4(OH)2 catalysts reacted rapidly with surface-bound water or the hydroxyl group and produced a large amount of ˙OH, which was beneficial for degrading MB. The degradation results indicate that these catalysts have potential uses in removing harmful carcinogens from water, in addition to possible applications in reducing the harmful effects of oil spills.

Measurements of the Laminar Concentration of Hydrogen in Titanium Using Eddy Currents Of Different Frequency

A method for the laminar determination of the hydrogen concentration in titanium, using eddy currents of different frequency, is proposed. The procedure for using a standard sample and a measuring system for specific technical situations are described.

Fracture resistance of endodontically-treated teeth submitted to bleaching treatment with hydrogen peroxide and titanium dioxide nanoparticles photoactivated by LED-laser

Objective: The aim of this study was evaluate the fracture resistance of endodontically-treated teeth after bleaching treatment using 15% hydrogen peroxide plus titanium dioxide nanoparticles (15HPTiO2) photoactivated by LED-laser, in comparison with protocols using 35% hydrogen peroxide (35HP), 37% carbamide peroxide (37CP) or sodium perborate (SP). Material and method: After endodontic treatment, fifty bovine extracted incisors were divided into five groups (n = 10): G1- without bleaching; G2- 35HP; G3- 37CP; G4- 15HPTiO2 photoactivated by LED-laser and G5- SP. In G2 and G4, the bleaching protocol was applied in 4 sessions, with a 7 day interval between each session. In G3 and G5, the materials were kept in the pulp chamber for 21 days, but replaced every 7 days. After 21 days, the crowns were subjected to compressive load at a cross head speed of 0.5 mm/min, applied at 135° to the long axis of the root using an eletromechanical testing machine, until fracture. The data were submitted to ANOVA and Tukey tests (p = 0.05). Result: The bleaching treatment in endodontically-treated teeth with 15HP plus TiO2 nanoparticles and photoactivated by LED-laser caused reduction of the fracture resistance similarly provided by 35HP, 37CP or SP (p>0.05). All bleaching treatments reduced the fracture resistance compared to unbleached teeth (p<0.05). Conclusion: All bleaching protocols reduced the fracture resistance of endodontically-treated teeth, but there were no differences between each other.

Ternary compounds in the magnesium–titanium hydrogen storage system

Mg–Ti–H samples were mechano-chemically synthesized by ball milling in argon atmosphere or under elevated hydrogen pressure. The detailed reaction mechanism during hydrogen release and uptake during continuous cycling was investigated by in-situ synchrotron radiation powder X-ray diffraction (SR-PXD) experiments. The thermal behaviour of the samples and hydrogen desorption properties were examined by simultaneous thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and mass spectrometry (MS) measurements. A ternary Ti–Mg–H compound with a fcc lattice form during mechano-chemical sample preparation in hydrogen atmosphere using metal powders, but not using metal hydrides as reactants. The amount of β-MgH2 increases during the first hydrogen absorption cycle at 300 °C at the expense of the high-pressure polymorph, γ-MgH2 and the amount of β-MgH2 remain constant during the following hydrogenations. This study reveals that the ternary compound tends to absorb increasing amounts of magnesium in the dehydrogenated state during cycling. A strong coupling between the amounts of magnesium in the ternary Ti–Mg–H phase and the formation of magnesium and magnesium hydride during hydrogen release and uptake at 300 °C is observed. The composition and the amount of the Ti–Mg–H phase appear to be similar in the hydrogenated state. Fast absorption–desorption kinetics at 300 °C and lower onset temperatures for hydrogen release is observed for all investigated samples (lowest onset temperature of desorption Ton = 217 °C).

Ion-Exchange Synthesis, Crystal Structure, and Physical Properties of Hydrogen Titanium Oxide H2Ti3O7

Hydrogen titanium oxide H2Ti3O7 was prepared from Na2Ti3O7 as a parent compound via Na(+)/H(+) ion exchange in acidic solution at 333 K. It crystallizes in the monoclinic system, space group C2/m, and the lattice parameters of a = 16.0380(8) Å, b = 3.7533(1) Å, c = 9.1982(3) Å, and β = 101.414(3)°. The crystal structure of H2Ti3O7 was refined to the conventional values of Rwp = 2.60% and Rp = 1.97% with a fit indicator of GOF = Rwp/Re = 1.90 by Rietveld analysis using powder neutron diffraction data. The basic (Ti3O7)(2-) framework in H2Ti3O7 was changed from that in the parent Na2Ti3O7. The atomic coordinate of hydrogen atoms were determined by this study for the first time. The hydrogen site in the layer space was refined with a strict H1-O3 distance of 0.80(2) Å and H2-O4 distance of 0.86(2) Å in H2Ti3O7, respectively. The structural stability of H2Ti3O7 was confirmed by bond valence sums. From these results, protons were suggested as the ordered occupation in the crystal structure.

Preparation of Grain-Oriented Ceramics with Bismuth Potassium Titanate-Barium Titanate and their Piezoelectric Properties

Bismuth potassium titanate ((Bi1/2K1/2)TiO3: BKT) powder were prepared using bismuth oxide (Bi2O3), potassium hydrogen carbonate (KHCO3) and titanium oxide (TiO2) raw materials. Barium titanate (BaTiO3: BT) platelike particles oriented along [110] direction were used as template particles. Barium titanate-bismuth potassium titanate (BT-BKT) ceramics had a tetragonal phase at -100 °C. The main composition was fixed to BKT 30 molar% because the Curie temperature (TC) was well above 200 °C at BKT 30 molar%. The orientation of [110]-oriented BT-BKT ceramics (BKT 30 molar%) was 54.6 %.

Structural and electrochemical properties of hydrogen titanium oxides

Abstract Hydrogen titanium oxide H 2 Ti 6 O 13 was prepared from Li 2 Ti 6 O 13 as a parent compound via Li + /H + ion exchange in acidic solution at 60 °C. It crystallizes in the monoclinic system, space group C 2/ m , and the lattice parameters of a = 14.6604(3) A, b = 3.74109(8) A, c = 9.2487(2) A, and β = 96.956(2)°. The crystal structure of H 2 Ti 6 O 13 was refined to the conventional values of R wp = 3.12% and R p = 2.45% with a fit indicator of GOF = R wp / R e = 1.39 by Rietveld analysis using powder neutron diffraction data. The basic (Ti 6 O 13 ) 2 − framework in H 2 Ti 6 O 13 was maintained nearly unchanged from that in the parent Li 2 Ti 6 O 13 . The hydrogen site in the tunnel space was refined with the strict O3 H1 distance of 0.94(1) A in H 2 Ti 6 O 13 . The structural stability of H 2 Ti 6 O 13 was confirmed by bond valence sums and 1 H-MAS NMR measurement. The total protonic conductivity in H 2 Ti 6 O 13 was estimated to be σ total = 8.32 × 10 − 6 S cm − 1 at room temperature from the results of AC-impedance measurements. This value is comparable to that of the well-known good protonic conducting ramsdellite-type H 2 Ti 3 O 7 .

SHS hydrogenation of titanium: Some structural and kinetic features

Hydrogenation of Ti sponge was performed in conditions of hydrogen deficiency (a) and excess (b). The extent of conversion was low and non-uniform in case (a) and close to unity in conditions (b). The combustion products were characterized by XRD, SEM, time-of-flight mass spectrometry (TOF MS), and time-resolved XRD.

EFFECT OF IRRADIATION WITH PULSED ION BEAM ON THE MICROSTRUCTURE OF TiH 2

Titanium has long been of interest as hydrogen storage material since titanium has a high affinity to hydrogen isotopes. Titanium deuteride or tritide is an important nuclear material used in the field of nuclear technology. Investigations concerning hydrogen–titanium system seem to mainly focus on the hydrogen thermal desorption spectra so as to study hydrogen desorption kinetics from metal hydride and to determine the rate–controlling step, but little is known on the evolution of its compositional changes under a much more un–equilibrium condition. In the past two decades, the intense pulsed ion beam (IPIB) technique has received extensive attention as a tool for surface modification of materials. Compared with conventional ion implantation, IPIB irradiation into materials possesses a higher energy density with shorter pulse width and be typical of more intense thermal–mechanical effect. From such a point of view, considering the features of extreme high heating and cooling rate of IPIB, IPIB as a method to evaluate the stability characteristics of titanium hydride film is utilized in order to determine a predictable behavior of the film’s evolution under an extreme un–equilibrium external condition. In current study, TiH2 films irradiated by intense pulsed ion beam have been investigated by using scanning electronic microscopy, surface profilometer, X–ray diffraction and slow positron annihilation, in order to evaluate the effect of irradiation with pulsed ion beam on the microstructure of TiH2. Three sets of TiH2 films are irradiated several shots * D} <2bj ^SG 11205136 mlL-C : 2013–03–18, ml['-C : 2013–07–20 j3 : ℄ n, , 1987 W, %e DOI: 10.3724/SP.J.1037.2013.00122 1270 p ` AE x 49 * at energy density ranging from 0.1 J/cm to 0.5 J/cm. No noticeable phenomenon of melting and change of phase structures have occurred to samples under irradiation of 0.1—0.3 J/cm. However, phenomenon of melting and indication of cracking has been detected on the surface after energy density reaches 0.5 J/cm. Besides, desorption of hydrogen from the film, and a titanium hydride with a body centered tetragonal structure (bct), seldom reported by researchers and formed under extreme conditions, has also been identified only after energy density of IPIB reaches 0.5 J/cm. S parameter of slow positron annihilation reflects that the crystal defect structures have been greatly changed by IPIB irradiation, in which S parameter reaches a large value at 0.3 J/cm with 1 shot, while a small one at 0.5 J/cm with 5 shots.

Structural and phase mechanism and rate of interaction between TiCu, Ti3Cu4, and Ti2Cu3 intermetallics and hydrogen. II. Destructive hydrogenation of intermetallics

The structural and phase mechanism and the rate of TiCu, Ti3Cu4, and Ti2Cu3 destructive hydrogenation (DH) are studied at 773 K under a hydrogen pressure of 1.0 MPa. The mechanism of destructive hydrogenation of the intermetallics consists in the formation of a hydrogen solid solution, selective hydrogenation of titanium, and subsequent formation of intermediate intermetallics and copper. The destructive hydrogenation products are nondestructive TiH1.9–Cu matrix composites. The rate of TiCu, Ti3Cu4, and Ti2Cu3 destructive hydrogenation is limited by the rates of hydrogen dissociation on the intermetallic surface and the diffusion of titanium hydride. The products of TiCu, Ti3Cu4, and Ti2Cu3 destructive hydrogenation are recombined in vacuum and hydrogen atmosphere.