The vanadium-nitrogen system: a review

Carlson, O. N.; Smith, J. F.; Nafziger, R. H.

doi:10.1007/bf02817263

Cited by 52 publications

(54 citation statements)

References 31 publications

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“…[4][5][6][7][8][9] In the vanadium-nitrogen system, three nitride phases, ␤V 2 N 1−x ͑⑀-Fe 2 N type͒, ␦VN 1−x ͑NaCl type͒, and ␦ЈVN 1−x have been identified and their crystal structures, ranges of homogeneity and melting or decomposition temperatures are determined. 10 The variation in the composition of these phases is known to be due to vacancies on the nitrogen sublattice. 10 Properties of these nitrides are known to depend strongly on their chemistry and structural state.…”

Section: Introductionmentioning

confidence: 99%

“…10 The variation in the composition of these phases is known to be due to vacancies on the nitrogen sublattice. 10 Properties of these nitrides are known to depend strongly on their chemistry and structural state. 11,12 The ground-state properties and phase stability of some of these phases have been studied in a previous work 13 via density functional theory ͑DFT͒ based electronic-structure totalenergy calculations.…”

Section: Introductionmentioning

confidence: 99%

“…13, the ␦ЈVN 1−x was not considered due to the ambiguity regarding the crystal-structure data. 10 Onozuka 14 identified ␦ЈVN 1−x after prolonged annealing of ␦VN 1−x ͑0.18Յ x Յ 0.26͒ at 500°C. This phase is found to have an ordered arrangement of N atoms with doubling of the lattice parameter of the NaCl-type structure.…”

Section: Introductionmentioning

confidence: 99%

“…A series of metastable phases is also reported to form between the V terminal solid solution ͑V͒ and ␤V 2 N 1−x . Carlson et al 10 have proposed a metastable phase diagram for the vanadium end of the V-N system in their review. Although the metastable phases are considered to involve ordering of interstitial N atoms in one or another distortion of the bcc lattice of elemental vanadium, their crystal structures have not been studied thoroughly.…”

Section: Introductionmentioning

confidence: 99%

“…The metastable phase with highest V concentration in this aging sequence with V 16 N stoichiometry is found to have an unit cell 16 times larger than that of the bcc vanadium. 10,15 This supercell is identified as a face-centered orthorhombic cell with a s = 1.2140 nmХ 4a V , b s = 1.2504 nmХ 4a V , and c s = 0.3035 nmХ a V . From the composition and symmetry, the superlattice cell is inferred to contain 16 subcells and consists of 32 V atoms and 2 N atoms for a net stoichiometry of V 16 N with the N atoms occupying the ͑000͒ and ͑1/2,1/2,1/2͒ superlattice sites.…”

Section: Introductionmentioning

confidence: 99%

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Cluster expansion Monte Carlo study of phase stability of vanadium nitrides

et al. 2010

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Phase stability of stable and metastable vanadium nitrides is studied using density functional theory ͑DFT͒ based total-energy calculations combined with cluster expansion Monte Carlo simulation and supercell methods. We have computed the formation enthalpy of the various stable and metastable vanadium nitride phases considering the available structural models and found that the formation enthalpies of the different phases decrease in the same order as they appear in the experimental aging sequence. DFT calculations are known to show stoichiometric V 2 N to be polymorphic in ⑀-Fe 2 N and -Fe 2 N structures within a few meV and VN to be more stable in WC͑B h ͒ phase than in the experimentally observed NaCl͑B1͒ structure. As these nitrides are known to be generally nonstoichiometric due to presence of nitrogen vacancies, we used cluster expansion and supercell methods for examining the effect of nitrogen vacancies on the phase stability. It is found that nitrogen vacancies, represented by ᮀ, stabilize ⑀-Fe 2 N phase of V 2 N 1−x ᮀ x and NaCl͑B1͒ phase of VN 1−x ᮀ x compared to -Fe 2 N and WC͑B h ͒ phases respectively, rendering the computed phase stability scenario to be in agreement with experiments. Analysis of supercell calculated electronic density of states ͑DOS͒ of VN 1−x ᮀ x with varying x, shows that the nitrogen vacancies increase the DOS at Fermi level in WC phase, whereas they decrease the DOS in NaCl phase. And this serves as the mechanism of enhancement of the stability of the NaCl phase. Monte Carlo simulations were used for computing the finite temperature formation enthalpies of these phases as a function of nitrogen-vacancy concentration and found close agreement for NaCl͑B1͒ phase of VN 1−x ᮀ x for which measured values are available.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Cluster expansion Monte Carlo study of phase stability of vanadium nitrides

et al. 2010

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Nitrogen Partial Pressure of Stoichiometric and Nonstoichiometric Titanium, Vanadium and Niobium Nitrides and Carbonitrides

Gusev¹

1998

phys. stat. sol. (b)

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A method is proposed for calculating the nitrogen equilibrium partial pressure p N2 of stoichiometric and nonstoichiometric nitrides MN y and carbonitrides MC y N 1Ày (M Ti, Zr, Hf, V, Nb, Ta) with B1(NaCl)-type structure. Analytic forms are derived for the composition, nonstoichiometry, and temperature dependences of the nitrogen partial pressure of the afore-mentioned compounds. The partial pressure of N 2 for the MN y nitride or MC x N y carbonitrides at a given temperature T is found to be proportional to the pressure of nitrogen for MN yc nitride evaporating congruently at that temperature T. The nitrogen partial pressure p N2 yY T of titanium nitrides TiN y 0X45 y 1X0 and carbonitrides TiC x N y 0X50 x y 1X0Y 0 y 1X0, vanadium nitrides VN y 0X55 y 1X0 and carbonitrides VC x N y 0X60 x y 1X0Y 0 y 1X0, niobium nitrides NbN y 0X70 y 1X0 and carbonitrides NbC x N y 0X70 x y 1X0Y 0 y 1X0 of various compositions at temperatures of 1000 to 2400 K are calculated. The calculation results are compared with the experimental data of literature.

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Nitrides: Transition Metal Solid‐State ChemistryBased in part on the article Nitrides: Transition Metal Solid State Chemistry by Peter Ettmayer & Walter Lengauer which appeared in the Encyclopedia of Inorganic Chemistry, First Edition .

Lengauer

Eder

2005

Encyclopedia of Inorganic Chemistry

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Basic properties and properties interesting for applications of transition metal nitrides are presented in this article. Starting from crystal chemistry, bonding, and preparation, the article also briefly discusses analytical chemistry of chemical and physical nitrogen analysis and standardization as well as thermodynamics. Updated portions of phase diagrams of group 4–6 transition metals with nitrogen are presented. A substantial part is devoted to the solid‐state properties because they make nitrides interesting for application. The presentation of these properties includes hardness, thermal expansion, nitrogen diffusivity, thermal properties, electrical conductivities, superconductivities, and elastic properties. Several of these properties are given as a function of temperature and composition. The topic is closely connected to article ( see Carbides: Transition Metal Solid‐state Chemistry).

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The vanadium-nitrogen system: a review

Cited by 52 publications

References 31 publications

Cluster expansion Monte Carlo study of phase stability of vanadium nitrides

Cluster expansion Monte Carlo study of phase stability of vanadium nitrides

Nitrogen Partial Pressure of Stoichiometric and Nonstoichiometric Titanium, Vanadium and Niobium Nitrides and Carbonitrides

Nitrides: Transition Metal Solid‐State ChemistryBased in part on the article Nitrides: Transition Metal Solid State Chemistry by Peter Ettmayer & Walter Lengauer which appeared in the Encyclopedia of Inorganic Chemistry, First Edition .

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