Phase Formation of a C6 Niobium Hemicarbide from Sub-stoichiometric NbC

Ilias Bikmukhametov; Jonathan L. Priedeman; Liurukara D. Sanjeewa; Christopher R. Weinberger; Gregory B. Thompson

doi:10.1007/s11837-023-06084-y

Phase Formation of a C6 Niobium Hemicarbide from Sub-stoichiometric NbC

Ilias Bikmukhametov
, Jonathan L. Priedeman
, Liurukara D. Sanjeewa
, Christopher R. Weinberger
, Gregory B. Thompson

Research output: Contribution to journal › Article › peer-review

Abstract

The niobium hemicarbide (Nb₂C) has at least three known polymorphs: α (Pnma or Pbcn), β (P 3 ¯ 1 m) , and γ (P6₃/mmc) as a function of temperature. Identification of these phases has been notoriously difficult particularly for the lower-temperature variations (α and β) because of their long-range vacancy ordering. In the current study, an overall Nb₂C composition has been processed by hot isostatically pressing NbC and Nb powders together which did not fully homogenize. Using neutron diffraction and selected area electron diffraction, the C6 (P 3 ¯ m 1) structure was identified in the Nb₂C. The formation pathway for this phase is postulated from the high density of stacking faults observed in the NbC.

Original language	English
Pages (from-to)	4626-4635
Number of pages	10
Journal	JOM
Volume	75
Issue number	11
DOIs	https://doi.org/10.1007/s11837-023-06084-y
State	Published - Nov 2023
Externally published	Yes

Funding

G.B. T. recognizes NSF-DMR-2026760 and C.R.W. recognizes NSF-DMR-2026766 for support of this research. Stephen DiPeitro is thanked for the niobium hemicarbide sample. This research used resources at the Missouri University Research Reactor (MURR).

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title = "Phase Formation of a C6 Niobium Hemicarbide from Sub-stoichiometric NbC",

abstract = "The niobium hemicarbide (Nb2C) has at least three known polymorphs: α (Pnma or Pbcn), β (P 3 ¯ 1 m) , and γ (P63/mmc) as a function of temperature. Identification of these phases has been notoriously difficult particularly for the lower-temperature variations (α and β) because of their long-range vacancy ordering. In the current study, an overall Nb2C composition has been processed by hot isostatically pressing NbC and Nb powders together which did not fully homogenize. Using neutron diffraction and selected area electron diffraction, the C6 (P 3 ¯ m 1) structure was identified in the Nb2C. The formation pathway for this phase is postulated from the high density of stacking faults observed in the NbC.",

author = "Ilias Bikmukhametov and Priedeman, \{Jonathan L.\} and Sanjeewa, \{Liurukara D.\} and Weinberger, \{Christopher R.\} and Thompson, \{Gregory B.\}",

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doi = "10.1007/s11837-023-06084-y",

language = "English",

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TY - JOUR

T1 - Phase Formation of a C6 Niobium Hemicarbide from Sub-stoichiometric NbC

AU - Bikmukhametov, Ilias

AU - Priedeman, Jonathan L.

AU - Sanjeewa, Liurukara D.

AU - Weinberger, Christopher R.

AU - Thompson, Gregory B.

PY - 2023/11

Y1 - 2023/11

N2 - The niobium hemicarbide (Nb2C) has at least three known polymorphs: α (Pnma or Pbcn), β (P 3 ¯ 1 m) , and γ (P63/mmc) as a function of temperature. Identification of these phases has been notoriously difficult particularly for the lower-temperature variations (α and β) because of their long-range vacancy ordering. In the current study, an overall Nb2C composition has been processed by hot isostatically pressing NbC and Nb powders together which did not fully homogenize. Using neutron diffraction and selected area electron diffraction, the C6 (P 3 ¯ m 1) structure was identified in the Nb2C. The formation pathway for this phase is postulated from the high density of stacking faults observed in the NbC.

AB - The niobium hemicarbide (Nb2C) has at least three known polymorphs: α (Pnma or Pbcn), β (P 3 ¯ 1 m) , and γ (P63/mmc) as a function of temperature. Identification of these phases has been notoriously difficult particularly for the lower-temperature variations (α and β) because of their long-range vacancy ordering. In the current study, an overall Nb2C composition has been processed by hot isostatically pressing NbC and Nb powders together which did not fully homogenize. Using neutron diffraction and selected area electron diffraction, the C6 (P 3 ¯ m 1) structure was identified in the Nb2C. The formation pathway for this phase is postulated from the high density of stacking faults observed in the NbC.

UR - https://www.scopus.com/pages/publications/85170098941

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DO - 10.1007/s11837-023-06084-y

M3 - Article

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JF - JOM

IS - 11

ER -

Phase Formation of a C6 Niobium Hemicarbide from Sub-stoichiometric NbC

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