Hf metal powder synthesis via a chemically activated combustion-reduction process

The present study demonstrates the synthesis of fine hafnium (Hf) metal powders via a chemically activated combustion synthesis (CS) approach, which develops temperatures in the range of 1000–1600 °C. The current CS approach can be employed to obtain Hf powders with a single-crystalline hexagonal cl...

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Bibliographic Details
Published in:Materials chemistry and physics 2021-04, Vol.263, p.124417, Article 124417
Main Authors: Nersisyan, Hayk, Woo, Hwa Young, Ri, Vladislav, Thanh-Nam, Huynh, Moon, Frank, MacDonald, Alister, Earner, Nicholas, Lee, Jong Hyeon
Format: Article
Language:English
Subjects:
Combustion parameters: particle size: morphology
Combustion synthesis
Hafnium
Metal powders
Oxygen content
Single crystals
Thermodynamic equilibrium
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Summary:The present study demonstrates the synthesis of fine hafnium (Hf) metal powders via a chemically activated combustion synthesis (CS) approach, which develops temperatures in the range of 1000–1600 °C. The current CS approach can be employed to obtain Hf powders with a single-crystalline hexagonal close-packed (hcp) structure in addition to high compositional uniformity and average particle sizes ranging from 0.05 to 2.0 μm. The mechanism of Hf particle formation can be understood by analyzing the process thermodynamics, including adiabatic temperatures and equilibrium reaction phases. In addition, analytical methods, including X-ray diffraction, SEM/TEM BET, FTIR, and oxygen analysis, were employed to characterize the synthesized Hf powders. Theoretical analysis was also conducted to predict the oxygen content according to Hf particle size. To the author's best knowledge, this work is the first known report demonstrating the preparation of hafnium micro- and nanopowders by the combustion synthesis method. •The combustion of HfO2+0.08KClO4+kMg systems was studied for k = 2.7–7.•Synthesis temperatures ranging from 1570 to 1000 °C were recorded.•Hf powder with particle sizes of 0.05–2.0 μm and 0.8–2.0 wt% oxygen was obtained.•Deoxidation using a Ca/Mg alloy powder produced Hf metal with less than 0.1 wt% O2.•A theoretical model, for predicting oxygen concentration in Hf particles is proposed.
ISSN:0254-0584
1879-3312
DOI:10.1016/j.matchemphys.2021.124417