Synthesis of the B1-type tantalum nitride by shock compression

Mashimo, Tsutomu; Tashiro, Suguru; Toya, T.; Nishida, Minoru; Yamazaki, Hideyuki; Yamaya, Susumu; Ohishi, Kazuo; Syono, Yasuhiko

doi:10.1007/bf01159819

Cited by 47 publications

(28 citation statements)

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“…For d phase, the mismatch of lattice parameter is within 0.9% compared with experimental values. 13,[20][21][22] From above, it is clear that the agreement of our calculation with experiment and other theoretical values is seen to be quite good. The good agreements show that the choice of pseudopotential and approximation is reasonable for the current study and our present calculations are reliable.…”

Section: Resultssupporting

confidence: 61%

“…13 These wide ranges of interesting applications have lead to much efforts that have been devoted to this fascinating material. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] In the past, a number of studies mainly focus on cubic d phase of TaN by the various methods [14][15][16][17][18][19] and also synthesized by diverse methods, [20][21][22] calculations show very high bulk modulus (above 328 GPa) and suggest that TaN is in cubic d phase with high hardness. Compared to the cubic phase, the e and h phases have not been studied deeply.…”

Section: Introductionmentioning

confidence: 99%

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Structure and mechanical properties of tantalum mononitride under high pressure: A first-principles study

Chang

Zhao

Zhou

et al. 2012

Journal of Applied Physics

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The structure and mechanical properties of tantalum mononitride (TaN) are investigated at high pressure from first-principles using the plane wave pseudopotential method within the local density approximation. Three stable phases were considered, i.e., two hexagonal phases (e and h) and a cubic d phase. The obtained equilibrium structure parameters and ground state mechanical properties are in excellent agreement with the experimental and other theoretical results. A full elastic tensor and crystal anisotropy of the ultra-incompressible TaN in three stable phases are determined in the wide pressure range. Results indicated that the elastic properties of TaN in three phases are strongly pressure dependent. And the hexagonal h-TaN is the most ultraincompressible among the consider phases, which suggests that the h phase of TaN is a potential candidate structure to be one of the ultraincompressible and hard materials. By the elastic stability criteria, it is predicted that h-TaN is not stable above 53.9 GPa. In addition, the calculated B/G ratio indicated that the e and d phases possess brittle nature in the range of pressure from 0 to 100 GPa. While h phase is brittleness at low pressure (below 8.2 GPa) and is strongly prone to ductility at high pressure (above 8.2 GPa). The calculated elastic anisotropic factors for three phases of TaN suggest that they are elastically highly anisotropic and strongly dependent on the propagation direction.

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Section: Resultssupporting

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Structure and mechanical properties of tantalum mononitride under high pressure: A first-principles study

Chang

Zhao

Zhou

et al. 2012

Journal of Applied Physics

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“…[7] The lattice parameter (a ϭ 4.337 Å ) for this CaF 2 -type with a body-centered tetragonal superstructure TaN x 5.77 5.01 [12] nitride obtained by Gatterer et al [6] from the elements at 2000°C and a pressure of 40 bar, and that obtained by Mashimo et al [7] (a ϭ 4.336 Å ), are almost identical. Finally, the θ-phase crystallizes hexagonal in the Bh WCtype structure type with a simple hexagonal stacking of the metal layers.…”

Section: Introductionmentioning

confidence: 75%

“…[1] Another modification of tantalum mononitride, the δ-phase with a face-centered cubic B1 NaCl-type structure, was observed by Gerstenberg and Calbick [16] in thin films; it was also recently synthesized from the ε-phase by shock compression. [7] The lattice parameter (a ϭ 4.337 Å ) for this [1] TaN 0.04 3.315 [2] β-phase α-phase with a cubic 3 ϫ 3 ϫ 3 superstructure TaN 0.05 10.11 (3ϫ 3.369) [1] γ-phase (β-Ta 2 N) hexagonal close-packing of the tantalum atoms TaN 0.41 3.041 4.907 [1] TaN 0.5 3.042 4.905 [2] TaN 0.5 4.928 [3] an anti-Li 2 ZrF 6 -type superstructure with aЈ ϭ Ί3a 5.283 (Ί3 ϫ 3.050) TaN 0. 43 4.919 [4] 5 [3] hexagonal, distorted B35 CoSn-type TaN 1.00 5.196 2.911 [5] δ-phase face-centered cubic, B1 NaCl-type TaN 0.92 4.337 [6] TaN 0.97 4.336 [7] θ-phase hexagonal, Bh WC-type TaN [3] TaN x cubic, CaF 2 -type TaN x 5.02 [11] CaF 2 -type with a body-centered tetragonal superstructure TaN x 5.77 5.01 [12] nitride obtained by Gatterer et al [6] from the elements at 2000°C and a pressure of 40 bar, and that obtained by Mashimo et al [7] (a ϭ 4.336 Å ), are almost identical.…”

Section: Introductionmentioning

confidence: 97%

Plasma‐Enhanced CVD Synthesis and Structural Characterization of Ta₂N₃

2004

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Keywords: Tantalum / Nitrides / Plasma-enhanced chemical vapor deposition / X-ray diffraction / Electron microscopy Microcrystalline tantalum nitride films were prepared on various substrates from TaCl 5 precursor and nitrogen gas using the plasma-enhanced chemical vapor deposition (PECVD) method. Syntheses carried out at 600−650°C led to single-phase samples of the tantalum nitride Ta 2 N 3 with a defect fluorite-type structure. The anion vacancies were found to order resulting in a 2 ϫ 2 ϫ 2 cubic superstructure of the C-Ln 2 O 3 type (space group Ia3 , Z = 16) with a = 9.8205(4) Å according to a Rietveld refinement of the X-ray IntroductionThe binary TaϪN system is quite rich in compounds with well-defined and variable stoichiometries. The formal oxidation state of tantalum covers the whole range from nearly zero to the maximum of ϩ5. These compounds can be divided into four groups: solid solutions of nitrogen in tantalum, the phase with the approximate stoichiometry Ta 2 N, three phases with a nearly 1:1 composition, and nitrogenrich nitrides. A few comprehensive reviews of tantalum nitride structural chemistry are available.[1Ϫ3] Results of the previous structural studies in this binary system are summarized in Table 1.Up to 5 at.% of nitrogen can be dissolved in the bodycentered cubic lattice of elemental tantalum, for example by heating of Ta powder in ammonia at 600Ϫ700°C.[3] The lattice constant of such solid solutions increases slightly to 3.315Ϫ3.369 Å compared to that of the pure metal (a ϭ 3.311 Å ). Observation of additional weak reflections suggests a cubic superstructure with the unit cell tripled in all directions and with a β ϭ 3a α ϭ 10.11 Å . The γ-phase with the composition range TaN 0.41Ϫ0.5 , also denoted as β-Ta 2 N, [4] crystallizes with a hexagonal unit cell.[1Ϫ4] Its crystal structure can be described as a hexagonal close packing of the tantalum atoms with the nitrogen atoms filling half of the octahedral interstices. While the earlier studies suggested a statistical distribution, [1,2] electron- [3] and neutron-diffraction [4] investigations revealed a trigonal P31m supercell with aЈ ϭ Ί3a, isostructural to β-Nb 2 N [14] and of the anti-Li 2 ZrF 6 -type.[15] The γ-phase can be obtained by nitriding of tantalum powder in gaseous ammonia at 800Ϫ900°C or from the elements at 2000°C. [1,3] The hexagonal ε-phase was proposed by Schoenberg [1] to have a B35 CoSn-type structure with the composition TaN 1.00 ; the same description was given by Brauer and Zapp.[2] In this structure type the nitrogen atoms are at the center of slightly distorted tantalum octahedra. Later, Christensen and Lebech [5] showed that the nitrogen atoms are displaced from these ideal positions reducing their coordination sphere to a square pyramid. The unit cell determined by Christensen and Lebech [5] (a ϭ 5.196 Å , c ϭ 2.911 Å ) is quite similar to that given by the other authors.[1Ϫ3] The ε-phase can be obtained as a product of nitriding of Ta powder at temperatures at Ͼ 1100°C. [1] Another modification of tantalum ...

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“…The low-temperature and high-pressure phase of TaN (denoted as θ-TaN) has the WC structure [17,18], while the high-temperature and high-pressure phase of TaN (denoted as δ-TaN) has the NaCl structure [18][19][20]. Due to the inherent richness in the phase diagram of the Ta-N system [21], this complexity leads to difficulty in synthesizing single-crystal TaN [22] and determining the physical properties of stoichiometric TaN.…”

Section: Introductionmentioning

confidence: 99%

First‐principles study of the structural stability and electronic structures of TaN

Cao

Hou

Yuan

2008

Physica Status Solidi (b)

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Using the plane‐wave pseudopotential method within the generalized gradient approximation, we have studied the structural stability and electronic structures for several TaN phases. Our results show CoSn is the calculated ground‐state structure of TaN among the five crystallographic structures that have been studied. The order of energetic stability of phase structures of TaN from low to high is: CsCl < ZnS‐B3 < NaCl < WC < CoSn. The higher stability of TaN in the CoSn and WC structures is due to the formation of pseudogap around the Fermi level and the stronger hybridization between N‐2p states and Ta‐5d states. TaN in all structures studied has a metallic nature. The calculated bulk modulus indicates that TaN in the WC structure may be a less compressible material. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Synthesis of the B1-type tantalum nitride by shock compression

Cited by 47 publications

References 4 publications

Structure and mechanical properties of tantalum mononitride under high pressure: A first-principles study

Structure and mechanical properties of tantalum mononitride under high pressure: A first-principles study

Plasma‐Enhanced CVD Synthesis and Structural Characterization of Ta₂N₃

First‐principles study of the structural stability and electronic structures of TaN

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Synthesis of the B1-type tantalum nitride by shock compression

Cited by 47 publications

References 4 publications

Structure and mechanical properties of tantalum mononitride under high pressure: A first-principles study

Structure and mechanical properties of tantalum mononitride under high pressure: A first-principles study

Plasma‐Enhanced CVD Synthesis and Structural Characterization of Ta2N3

First‐principles study of the structural stability and electronic structures of TaN

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Plasma‐Enhanced CVD Synthesis and Structural Characterization of Ta₂N₃