12137-20-1Relevant academic research and scientific papers
Kinetics and Neutral Transition-Metal Atoms in the Gas Phase: Oxidation of Ti(a3F) by NO, O2, and N2O
Ritter, David,Weisshaar, James C.
, p. 1576 - 1581 (1989)
We describe a general technique for measurement of the kinetics of ground-state neutral transition-metal atoms in a fast flow reactor with 0.75 Torr of He buffer gas using a laser vaporization source and a laser-induced fluorescence detection.For the oxygen atom transfer reactions Ti(a3F) + OX TiO + X, with OX = NO, O2, and N2O, we obtain 300 K effective bimolecular rate constants of (7.8 +/- 0.6) 1E-12, (1.5 +/- 0.4) 1E-12 and (4.0 +/- 1.4) 1E-13 cm3sec-1, respectively.All three reactions are exothermic yet inefficient at 300 K, indicating the presence of activation barriers.For the secondary reaction TiO(X3Δ) + NO products, we obtain the effective bimolecular rate constant (2.2 +/- 0.4) 1E-12 cm3s-1.A correlation argument based on separated fragments Ti + O + X can explain the inefficiency of the Ti(3d24s2,a3F) reactions by the need to switch electron configurations along low-energy adiabatic paths from ground-state reactants to energetically accessible TiO + OX product states.The argument should apply to many reactions of metal atom ground states having chemically inert ns2 configurations.
Composition dependent semiconductor-metal transition in new mixed valent Ti-oxides
Kodenkandath, Thomas
, p. 1587 - 1592 (1997)
A composition dependent semiconductor-metal transition is observed in a new series of Ti oxides of the type LnBa2Ti3Oy (Ln = La, Gd and Y) in which Ti is in lower and/or mixed valent state. The new phases have been synthesised by the dc arc melting technique and characterised by powder X-ray diffraction, thermal analysis, electrical and magnetic measurements. Single phase compounds are found to form only when the nominal (average) Ti valence (VTi) is between 3.67 to 2.33. The crystal structure is simple cubic in which Ln/Ba and various Ti ions occupy respectively the A- and B-sites of a disordered ABO3 perovskite type lattice. The semiconductor-metal transition is also found to depend on the VTi. The compounds show semiconducting behaviour for 3.67 Ti > 2.67 and are metallic when VTi = 2.33 which is the lowest possible value of VTi in the system. No evidence for superconductivity has been observed in any of the metallic compositions down to 15 K.
Exploring the thermal transformation of mesoporous titania using spectroscopic ellipsometry
Choi,Mamak,Ozin,Peiris
, p. 825 - 828 (2008)
Spectroscopic ellipsometry was used to investigate the optical properties of a series of 2D-hexagonal and 3D-cubic mesoporous titania samples subjected to different annealing temperatures. Below a critical temperature, the dispersion of the index of refraction of the composite structure exhibits strong anisotropy, while above the critical temperature the structure reverts to an isotropic medium. Scanning electron microscopy and X-ray measurements corroborate the ellipsometry results.
Growth of ordered titanium oxide films on Ag(100)
Kaneko,Ono,Ozawa,Edamoto
, p. 32 - 35 (2007)
Titanium oxide films grown on Ag(100) have been investigated with low-energy electron diffraction, X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. As Ti is deposited on Ag(100) at room temperature in an O2 atmosphere at 10-5-10-7?Torr, a disordered TiO2-like film is formed. As the surface is subsequently heated at 600 {ring operator}C, though the composition of the film is nearly unchanged, the film changes into an ordered film with (5×1) periodicity [(5×1) TiO2 film]. On the other hand, as Ti is deposited in O2 at 5.0×10-9-1.0×10-8?Torr, a disordered TiO-like film is formed. As the surface is subsequently heated at 600 {ring operator}C, the composition of the film is nearly unchanged and the film changes into an ordered film with (1×1) periodicity [(1×1) TiO film]. Ultraviolet photoelectron spectroscopy measurements show that the (1×1) TiO film has an electronic state around the Fermi level, and the state is ascribed to a partially filled Ti 3d state which has been theoretically expected to exist in a TiO crystal.
Interfacial reactions between titanium film and single crystal α-Al2O3
Koyama, M.,Arai, S.,Suenaga, S.,Nakahashi, M.
, (1993)
Titanium is commonly used to join metals and ceramics by active metal brazing methods. In this work, titanium was sputter deposited on to single-crystal α-Al2O3 substrates and the interfacial reactions between the titanium film and t
TiO epitaxial film growth on MgO(001) and its surface structural analysis
Suzuki, Taku,Souda, Ryutaro
, p. 506 - 511 (2000)
The metallic TiO single crystal film formed epitaxially on MgO is reported. It was found that the simultaneous supply of Ti vapor and O2 gas on the MgO(001) surface resulted in the TiO(001) film formation. The surface structure of the TiO(001)
High rate reactive magnetron sputter deposition of titanium oxide
Kubart,Depla,Martin,Nyberg,Berg
, (2008)
A systematic experimental study of reactive sputtering from substoichiometric targets of TiOx with x ranging from 0 to 1.75 is reported. Experimental results are compared with results from modeling. The developed model describes the observed behavior and explains the origins of the unexpectedly high deposition rate. The behavior is shown to originate from the presence of titanium suboxides at the target surface caused by preferential sputtering of the oxide. The model can be used for optimization of the target composition with respect to the deposition rate and film composition in a stable hysteresis-free reactive sputtering process.
Reaction between titanium and zirconia powders during sintering at 1500°C
Lin, Kun-Lin,Lin, Chien-Cheng
, p. 2220 - 2225 (2007)
Zirconia-titanium (ZrO2-Ti) composites have been considered potential thermal barrier graded materials for applications in the aerospace industry. Powder mixtures of Ti and 3 mol% Y2O3 partially stabilized ZrO2 in various ratios were sintered at 1500°C fo
Investigation of the electrochemical reduction of Na2Ti3O7 in CaCl2 molten salt
Liu, Kejia,Wang, Yaowu,Di, Yuezhong,Peng, Jianping
, p. 236 - 243 (2019)
Sodium titanate (Na2Ti3O7), as an intermediate product for producing TiO2 through alkaline process, was used as precursor to prepare Ti metal successfully by FFC Cambridge Process. For the aim to gain insight into the electro-reduction mechanism, the sintered Na2Ti3O7 pellets(～1.83 mm thinkness, open porosity ～20%) were electrolysed using them as cathodes against graphite counter electrode in the molten CaCl2. The experiments were carried out at 900 °C and the applied voltage was 3.1V. Partially reduced samples were prepared by terminating the reduction process after different electrolysis times. The obtained samples were characterised by means of X-ray diffraction analysis, SEM and EDS. The results show that Na2Ti3O7 reacts easily with molten CaCl2 as 2Na2Ti3O7 + 2CaCl2 → Ca2Ti2O6 + 4TiO2 + 4NaCl and Ca2Ti2O6 → 2CaTiO3. The electrochemical reduction of sodium titanate proceeds via sequential formation of CaTiO3, titanium sub-oxides (such as Ti4O7, Ti3O5, Ti2O3 and TiO), CaTi2O4, Ti-O solid solution and Ti. The whole reduction can be divided into three stages: the first stage is that Ca2+ ions from electrolyte are inserted into Na2Ti3O7 particles leading to the formation of titanium sub-oxides and calcium titanates(CaTiO3 and CaTi2O4); the second stage is that calcium titanates are reduced into Ti-O solid solution from outside to inside of the pellets; the third stage is that the formed Ti-O solid solution is further deoxidised to form Ti metal.
Fabrication and structural characterization of TiO nanoparticle soft-landed on substrate by the magnetron sputtering-gas aggregation method
Tanemura,Kajino,Miao,Koide,Tanemura,Toh,Kaneko,Mori
, p. 79 - 82 (2005)
We have succeeded to fabricate the thin film mainly or entirely consisting of nano-crystallites TiO on a substrate at room temperature by using the magnetron sputtering combined with the gas aggregation method which has the capability to deposit grown small particles and/or clusters of the desired compound material on the substrate in soft-landed mode. The important experimental parameters to control the growth of TiO particles are identified as partial pressure of additional oxygen gas, growth-reaction distance L td, and LN2 cooling of growth chamber. The smallest averaged diameter of TiO nano-particles is 5.62 nm and size distribution being from 2 to 8 nm under 50 mm of Ltd. The compositional uniformity is confirmed by EDS and EELS. The chemical state of the film observed by Ti 2P XPS peak confirms the primarily growth of TiO and indicates the formation of minor content of amorphous Ti1-xOx and/or Ti1-xC x particularly at the surface of the film. EDP Sciences, Societa? Italiana di Fisica, Springer-Verlag 2005.
