Reaction of the hydrogen-absorbing intermetallic compound TiFe with oxygen. II. Kinetics of oxidation of TiFe in air

Chuprina, V. G.; Shalya, I. M.; Zenkov, V. S.

doi:10.1007/bf00559966

Cited by 5 publications

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“…The K e decreases with time for the same reason. Similar effects are observed in oxidation of TiFe at the same temperatures (t > 800°C) [15].…”

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confidence: 72%

“…In the process, the concentration of interstitial titanium ions in the rutile lattice increases, which facilitates the diffusion of titanium toward the outer boundary of the scale. As in oxidation of TiNi [9] and TiFe [15], the notches skin over and Ti 2 O 3 occurs on the outside surface of the scale, as in high-temperature oxidation of TiNi [16] and Ni 3 (Al, Ti) [17]. The oxidation mechanism changes: the counterdiffusion of titanium ions is superimposed on the diffusion of oxygen.…”

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confidence: 95%

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Oxidation of TiAl intermetallic

Chuprina

Shalya

2007

Powder Metall Met Ceram

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The oxidation kinetics of TiAl intermetallic at 500-900°C in air is studied using a gravimetric method, and the phase composition of the scale is studied using an x-ray phase analysis. At t > 600°C, the kinetics of oxidation is described by a parabolic equation. The oxides TiO 2 (rutile), γ-Al 2 O 3 , α-Al 2 O 3 , Ti 2 O 3 are found in the scale. It is shown that at the first stage the γ-Al 2 O 3 and low-titanium oxides form on the sample surface at t < 70°C. At t ≥ 850°C, the Ti 2 O 3 forms on the external surface of the scale, TiAl 3 is found in the sublayer at the alloy/scale interface. It is shown that at t ≤ 800°C the process is controlled by oxygen diffusion. At t > 800°C, the oxidation mechanism changes: counterdiffusion of titanium ions through interstitial sites in TiO 2 lattice occurs.There is a need for data on the properties of titanium-aluminum alloys to create high-temperature oxidationresistant structural alloys of relatively low density [1]. Particular emphasis is placed on intermetallic compounds, including TiAl whose properties can be changed by alloying [1,2]. Of practical importance is to study the oxidation resistance of titanium-aluminum intermetallics [3].Our objective is to study the isothermal oxidation of TiAl alloy in air at temperatures 500-900°C. That this intermetallic compound exists over a wide concentration range is indicated by the phase diagrams of the Ti-Al system in many publications [1,4,5]. However, different authors specify different limits for this range. For the purpose of this study, we prepared alloys of titanium with 50 and 56 at.% (36 and 40 wt.%) of aluminum by smelting in an arc furnace with nonconsumable tungsten electrode in argon followed by homogenizing annealing in a vacuum furnace at 1000°C for 50 h. The charge was iodide titanium and electrolytic aluminum. A chemical analysis of the prepared samples revealed no significant deviation from the charge composition (±0.1 %).The annealed ingots were analyzed in molybdenum radiation using a DRON-3 x-ray diffractometer. Then, the ingots were turned into powders, which were annealed in vacuum at 700°C for 2 h to relieve stresses. After that, x-ray diffraction pattern were recorded with a Debye camera (diameter 150 mm) with copper radiation. The calculated data for plotting a Debye powder diagram are collected in Table 1, which includes, for each reflection, the values of sin 2 ϑ (ϑ is the Bragg reflection angle) and their relative intensities I/I 0 (on a 10-point scale). The x-ray patterns were indexed as in [6,7].The studies confirmed that the smelted alloy with 56 at.% Al is single-phase and has a CuAu-type tetragonal face-centered lattice with a = 0.390 ± 001 nm and c = 0.408 ±0.002 nm, which is in agreement with published data [1,[4][5][6][7]. The x-ray diffraction patterns of the Ti-50 at.% Al alloy show, except for the intensive reflections of TiAl, weak reflections that, according to [6], may belong to Ti 3 Al (Table 1). A metallographic analysis shows that this phase amounts to approximately 5%.To study the ai...

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“…The K e decreases with time for the same reason. Similar effects are observed in oxidation of TiFe at the same temperatures (t > 800°C) [15].…”

supporting

confidence: 72%

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confidence: 95%

Oxidation of TiAl intermetallic

Chuprina

Shalya

2007

Powder Metall Met Ceram

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“…Moreover, the TiFe alloy has relatively high activation against gaseous impurities such as oxygen. 3 Thus, modification is required for further practical uses.…”

Section: Introductionmentioning

confidence: 99%

Enhancing the hydrogen storage capacity of TiFe by utilizing clusters

Takahashi

Isobe

2014

Phys. Chem. Chem. Phys.

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The titanium iron (TiFe) alloy is a notable hydrogen storage material which can operate at ambient temperature. However, low hydrogen storage capacity is a major drawback that is needed to be overcome. Enhancement of the hydrogen capacity of TiFe is considered by utilizing TiFe clusters within the density functional theory. Calculations reveal that TiFe clusters can absorb large amounts of hydrogen. Furthermore, the desorption energies of Ti1Fe1H6 are lower than that of bulk TiFeH where the physical origins of low desorption energies are considered to be due to the closed shell structure of Ti1Fe1. This indicates that the Ti1Fe1H6 has the possibility to operate at near ambient temperature; therefore, only hydrogen gas pressures are required to control the hydrogen storage and release.

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“…6 In addition to that, TiFe alloys have low hydrogen storage capacity and react with gaseous impurities. 7 On exposure to air, the formation of a passive thin surface oxide layer hinders the hydride formation. Hence drastic activation conditions are required to completely saturate the alloy.…”

Section: Introductionmentioning

confidence: 99%

“…However, the activation of this alloy requires high temperature and pressure conditions, therefore, it becomes a drawback for industrial applications 6 . In addition to that, TiFe alloys have low hydrogen storage capacity and react with gaseous impurities 7 . On exposure to air, the formation of a passive thin surface oxide layer hinders the hydride formation.…”

Section: Introductionmentioning

confidence: 99%

Tuning the hydrogen storage properties of TiFe clusters via Zr substitution

Kumar

Pati

et al. 2020

Energy Storage

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Titanium-Iron alloy is a well-known material for hydrogen storage applications at room temperature. The limitations of TiFe alloy is its low hydrogen storage capacity, higher activation temperature, and pressure. In order to improve the hydrogen adsorption of TiFe alloy, TiFe clusters with Zr atom as a dopant are investigated using first-principle calculations. The structure of the Zr-substituted and unsubstituted clusters was optimized and it is found that the binding energy of the Zr-substituted TiFe clusters is higher than TiFe clusters, thus, the doping Zr atom stabilizes the TiFe clusters. Hydrogen adsorption over Zr doped TiFe cluster is investigated, where, Zr is revealed to be an active site for hydrogen adsorption except Ti 3 Zr 1 Fe 4 cluster. Hence, Zr substitution stabilizes the TiFe clusters and hydrogen storage properties were tuned by the introduction of the Zr atom.

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Reaction of the hydrogen-absorbing intermetallic compound TiFe with oxygen. II. Kinetics of oxidation of TiFe in air

Cited by 5 publications

References 4 publications

Oxidation of TiAl intermetallic

Oxidation of TiAl intermetallic

Enhancing the hydrogen storage capacity of TiFe by utilizing clusters

Tuning the hydrogen storage properties of TiFe clusters via Zr substitution

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