In situ synthesis of NbB2-NbC composite powders by milling-assisted carbothermal reduction of oxide raw materials

Özge Balci; Duygu Aʇaoʇullari; Didem Ovali; M. Lütfi Öveçoʇlu; Ismail Duman

doi:10.1016/j.apt.2015.06.001

In situ synthesis of NbB₂-NbC composite powders by milling-assisted carbothermal reduction of oxide raw materials

Özge Balci^*, Duygu Aʇaoʇullari, Didem Ovali, M. Lütfi Öveçoʇlu, Ismail Duman

^*Corresponding author for this work

Department of Metallurgical and Materials Engineering

Istanbul Technical University

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

29 Citations (Scopus)

Abstract

Abstract NbB₂-NbC composite powders were fabricated at reduced temperatures via the carbothermal route by mechanical milling of Nb₂O₅, B₂O₃and C powder blends. Both powder blends containing stoichiometric amounts of the reactants and those milled were subsequently annealed in a tube furnace. The effects of milling time (0, 1, 3 and 5 h) and annealing temperature (1300 and 1400°C) on both the formation and microstructure of the final products were examined. Increasing the milling time decreased the common formation temperature of the ceramic phases and contributed to the elimination of residual C from the final powders. The amount of the NbB₂phase increased and the amount of the NbC phase decreased in the composite powders by increasing the milling time and the annealing temperature. The predicted reactions and experimental results were compared, and the reaction mechanism of the Nb₂O₅-B₂O₃-C system was explained using thermochemical software, differential scanning calorimetry/thermogravimetric analysis (DSC/TGA) and X-ray diffractometry (XRD). NbB₂-based composite powders comprising NbC of approximately 600 nm in size were obtained with high purity from powder blends milled for 5 h and annealed at 1400 °C for 12 h.

Original language	English
Pages (from-to)	1200-1209
Number of pages	10
Journal	Advanced Powder Technology
Volume	26
Issue number	4
DOIs	https://doi.org/10.1016/j.apt.2015.06.001
Publication status	Published - 1 Jul 2015

Bibliographical note

Publisher Copyright:
© 2015 The Society of Powder Technology Japan.

Funding

This research investigation was financially supported by “Istanbul Technical University Scientific Research Projects” with the project number of 37812 and “The Scientific and Technological Research Council of Turkey (TÜBİTAK)” with the project number of 112M470. The authors acknowledge the State Planning Organisation ( DPT , Turkey) for purchasing the laboratory equipment utilised in this study through Research Grant 2001K120750 . Furthermore, the authors express their appreciation to Prof. Dr. Mehmet Ali Gülgün for his help with the TEM investigations.

Funders	Funder number
DPT	2001K120750
State Planning Organisation
TÜBİTAK	112M470
Türkiye Bilimsel ve Teknolojik Araştirma Kurumu
Istanbul Teknik Üniversitesi	37812

Keywords

Carbothermal reduction
Mechanical milling
Niobium boride
Niobium carbide
Reaction mechanism

Access to Document

10.1016/j.apt.2015.06.001

Cite this

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title = "In situ synthesis of NbB2-NbC composite powders by milling-assisted carbothermal reduction of oxide raw materials",

abstract = "Abstract NbB2-NbC composite powders were fabricated at reduced temperatures via the carbothermal route by mechanical milling of Nb2O5, B2O3and C powder blends. Both powder blends containing stoichiometric amounts of the reactants and those milled were subsequently annealed in a tube furnace. The effects of milling time (0, 1, 3 and 5 h) and annealing temperature (1300 and 1400°C) on both the formation and microstructure of the final products were examined. Increasing the milling time decreased the common formation temperature of the ceramic phases and contributed to the elimination of residual C from the final powders. The amount of the NbB2phase increased and the amount of the NbC phase decreased in the composite powders by increasing the milling time and the annealing temperature. The predicted reactions and experimental results were compared, and the reaction mechanism of the Nb2O5-B2O3-C system was explained using thermochemical software, differential scanning calorimetry/thermogravimetric analysis (DSC/TGA) and X-ray diffractometry (XRD). NbB2-based composite powders comprising NbC of approximately 600 nm in size were obtained with high purity from powder blends milled for 5 h and annealed at 1400 °C for 12 h.",

keywords = "Carbothermal reduction, Mechanical milling, Niobium boride, Niobium carbide, Reaction mechanism",

author = "{\"O}zge Balci and Duygu Aʇaoʇullari and Didem Ovali and {L{\"u}tfi {\"O}ve{\c c}oʇlu}, M. and Ismail Duman",

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AU - Balci, Özge

AU - Aʇaoʇullari, Duygu

AU - Ovali, Didem

AU - Lütfi Öveçoʇlu, M.

AU - Duman, Ismail

PY - 2015/7/1

Y1 - 2015/7/1

N2 - Abstract NbB2-NbC composite powders were fabricated at reduced temperatures via the carbothermal route by mechanical milling of Nb2O5, B2O3and C powder blends. Both powder blends containing stoichiometric amounts of the reactants and those milled were subsequently annealed in a tube furnace. The effects of milling time (0, 1, 3 and 5 h) and annealing temperature (1300 and 1400°C) on both the formation and microstructure of the final products were examined. Increasing the milling time decreased the common formation temperature of the ceramic phases and contributed to the elimination of residual C from the final powders. The amount of the NbB2phase increased and the amount of the NbC phase decreased in the composite powders by increasing the milling time and the annealing temperature. The predicted reactions and experimental results were compared, and the reaction mechanism of the Nb2O5-B2O3-C system was explained using thermochemical software, differential scanning calorimetry/thermogravimetric analysis (DSC/TGA) and X-ray diffractometry (XRD). NbB2-based composite powders comprising NbC of approximately 600 nm in size were obtained with high purity from powder blends milled for 5 h and annealed at 1400 °C for 12 h.

AB - Abstract NbB2-NbC composite powders were fabricated at reduced temperatures via the carbothermal route by mechanical milling of Nb2O5, B2O3and C powder blends. Both powder blends containing stoichiometric amounts of the reactants and those milled were subsequently annealed in a tube furnace. The effects of milling time (0, 1, 3 and 5 h) and annealing temperature (1300 and 1400°C) on both the formation and microstructure of the final products were examined. Increasing the milling time decreased the common formation temperature of the ceramic phases and contributed to the elimination of residual C from the final powders. The amount of the NbB2phase increased and the amount of the NbC phase decreased in the composite powders by increasing the milling time and the annealing temperature. The predicted reactions and experimental results were compared, and the reaction mechanism of the Nb2O5-B2O3-C system was explained using thermochemical software, differential scanning calorimetry/thermogravimetric analysis (DSC/TGA) and X-ray diffractometry (XRD). NbB2-based composite powders comprising NbC of approximately 600 nm in size were obtained with high purity from powder blends milled for 5 h and annealed at 1400 °C for 12 h.

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