Eigenschaften und Anwendungen von Titannitrid und Titancarbid

Münster, Arnold

doi:10.1002/ange.19570690902

Cited by 24 publications

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“…In contrast, the material converted to Ti-nitride shows no measurable photoresponse -as would be expected from a metal. 26,27 In summary, in the present work we have shown that ammonia-based heat treatments of TiO 2 nanotubes can not only be used in a classical approach to nitrogen dope the material (and, thus, impart visible light semiconductive behavior), but alsounder suitable conditions -to create arrays of Ti-nitride tubes that exhibit semimetallic conductivity.…”

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“…a value comparable to typical semi-metals, 35 and characteristics in line with the literature. 26,27 Such high conductivity values could enable the use of the material as a 'conductive' nanotube electrode as can easily be seen, not only from the conductivity measurements in Fig. 3a, but also from the cyclic voltammograms in Fig.…”

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confidence: 92%

“…24,25 Nevertheless, a drastic improvement in conductivity can be achieved by full conversion of TiO 2 to titanium nitride. 26,27 For TiO 2 particles this can be achieved using a heat treatment in NH 3 at much higher temperatures (typically 41000 1C) [28][29][30] with a conversion sequence as proposed (for example) by Z. Zhang et al 31 Nevertheless, our own preliminary efforts have revealed that a key problem in the conversion of TiO 2 nanotube layers to conductive nitride tubes is that conventional TiO 2 nanotube structures decay at elevated temperatures (due to sintering or collapse), as shown in ESI, † Fig. S1.…”

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NH3 treatment of TiO2 nanotubes: from N-doping to semimetallic conductivity

et al. 2014

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In the present work we show that a suitable high temperature ammonia treatment allows for the conversion of single-walled TiO 2 nanotube arrays not only to a N-doped photoactive anatase material (which is already well established), but even further into fully functional titanium nitride (TiN) tubular structures that exhibit semimetallic conductivity.Several functional features have made TiO 2 one of the most studied compounds in materials science over the past few decades. This unique role is, to a large extent, due to its semiconductive nature, which is key to the successful use of the material in photocatalysis 1-3 and solar cells. 4,5 In these applications, the optical propertiesnamely, a band-gap of 3.0-3.2 eV and the energetic location of the band edge positions relative to the redox potential of the environment -are crucial. TiO 2 has the potential for an even wider range of applications including as an electrode for Li-intercalation, 6 a support in methanol fuel cells 7 or in supercapacitors, 8 but such uses as an electrode material are hampered by the moderate electron conductivity of TiO 2 . 9 In this context, a conversion of the material to a semimetallic nitride 10-12 may be highly promising because, in such electrode configurations, electron transport through the material to the back contact is of utmost importance for the performance of the devices. A fact common to photoelectrochemical and electrode applications is that nanostructured electrodes are beneficial, as they provide a large surface area for adsorption, reaction, and intercalation processes. Nanostructured electrodes are classically prepared from TiO 2 nanoparticles compacted onto a metallic or transparent-conducting-oxide (TCO) back contact. However, in recent years 1D nanostructures have attracted wider interest, as their morphology provides defined geometries that allow for ideal ion and charge transport pathways, e.g. directional electron transport to the back contact and highly defined ion diffusion pathways. One of the most straightforward approaches used to create defined 3D titania electrodes is the formation of ordered TiO 2 nanotube arrays via the self-ordering anodic oxidation of Ti metal sheets. 13,14 In order to improve the optical and electronic properties of nanostructured TiO 2 electrodes, a large amount of effort in past and current research has been dedicated to doping, 15,16 or band-gap engineering of the materials using a wide range of transition metals such as vanadium, cerium, manganese and nickel, 17-21 or nonmetals such as C, N and S. 15,16,22,23 At present, the most successful approach for varying the optical and electrical properties remains N-doping, which can be conducted using various techniques. 24 At low to medium nitrogen concentrations, most reports describe the formation of N-substitutional states close to the valence band of TiO 2 . This has been successfully used to narrow the optical absorption edge and cause the well-established activation of TiO 2 in the visible range of the optical spectrum.Nitrogen...

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NH3 treatment of TiO2 nanotubes: from N-doping to semimetallic conductivity

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“…In particular, TiN is applied as a coating material for cutting tools to improve their hardness. Profitable using of titanium and TiN has expanded in many areas of industrial applications such as aerospace, chemical plants and automobiles [3][4][5][6][7]. Only a limited number of studies deal with surface properties of these powders or with the effect of particle size on the oxidation behaviour [8 -10].…”

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Oxidation of Nanometer‐Sized Titanium Nitride and Micrometer‐Sized Titanium Particles with Titanium Nitride Traces up to 1473 K in Air

Schulz

Eisenreich

Fietzek

et al. 2010

Part & Part Syst Charact

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This study compares the oxidation behaviour of TiN particles (nanometer-sized to micrometer-sized) to titanium particles with traces of titanium nitride (micrometersized) regarding the similarities of the formation of the products. These particles were investigated between 323 K and 1473 K in air using high-temperature X-ray diffraction, SEM, and the methods of thermal analysis (TG and DSC). The oxidation of the nanometer-sized TiN particles forms anatase and rutile in two partially overlapping successive steps, whereas the anatase transforms completely to rutile at higher temperatures. The investigated titanium particles directly transform to rutile. Traces of TiN in titanium particles induce the formation of traces of anatase phase which similar to the oxidation of TiN particles transforms to rutile phase. A Jander model for three-dimensional diffusion was utilized for describing the oxidation kinetics of the both oxidation steps occurring with TiN. A least squares fit procedure gives good agreement of the calculated curves to measured TG and DSC curves and adequate approximation to intensities of X-ray measurements. The amount of TiN oxidized to anatase was found to be about 46 %. The kinetic parameters were determined: for the first step of TiN oxidation, the pre-exponential factor was 1.33 · 10 6 lm 2 /s and the activation energy was 180.5 kJ/mol as well as for the second step 5.51 · 10 3 lm 2 /s and 197.6 kJ/mol, respectively.

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Über die Oxydation metallischer Hartstoffe

Münster

1959

Zeitschrift für Elektrochemie, Berichte der Bunsengesellschaft

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The oxidation of TiN, TiC and TiB2 has been investigated between 600 and 1100°C. In the case of TiN. the rate of oxidation can be described by a linear‐parabolic law. The only oxidation product is TiO2 (rutile which is formed at the inner phase boundary. The nitrogen escapes almost completely to the gas phase. The activation energy of the diffusion through the oxide layer as calculated from the isothermes agrees fairly well with the value obtained for the oxidation of titanium metal. It is concluded that the kinetics of the oxidation is not influenced to a considerable extent by the diffusion of the nitrogen.The oxidation of TiC is governed by a purely parabolic law yielding almost the same activation energie as obtained for Ti and TiN. The oxide layer is rutile containing 0,1–0,2 weight % of carbon. The rutile is formed at the inner phase boundary. Oxygen diffuses through the oxide layer to the inner phase boundary whereas carbon diffuses outwards, being oxidized to CO and CO2 at the outer surface.The oxidation of TiB2 follows a parabolic law below 850 and above 950°C. The activation energies are different in both cases. The 900°C isotherme can be described by a cubic law. At 700°C the oxide layer is a fine‐grained mixture of TiO2 and B2O3. At higher temperatures we have phase separation on the macroscopic scale. Three zones may be distinguished: Glassy B2O3, TiO2 and the fine‐grained mixture. Above 1000°C the B2O3 begins to evaporate more and more. At 1100°C it is not found by X‐ray diffraction. Both oxides are formed at the inner phase boundary.

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Eigenschaften und Anwendungen von Titannitrid und Titancarbid

Abstract: 1939]. 74 291 [1941]. 78 24 '251 (19451. A. Mhnsier u. W . k u p i e r t ' Z . Elektrochem. 57, 558 119531. E. Junker, 2. anorg. Chem. k28, 97 [19361. E. P. Beljakoua, A. Komar u. V. V. Michajlov, Metallurge 74, 23 [1939]' 75 5 [1940].

Cited by 24 publications

References 27 publications

NH3 treatment of TiO2 nanotubes: from N-doping to semimetallic conductivity

NH3 treatment of TiO2 nanotubes: from N-doping to semimetallic conductivity

Oxidation of Nanometer‐Sized Titanium Nitride and Micrometer‐Sized Titanium Particles with Titanium Nitride Traces up to 1473 K in Air

Über die Oxydation metallischer Hartstoffe

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