Environmentally friendly chemical synthesis of intermetallic iron aluminide submicrometer particles

Yasukazu Kobayashi*, Heng Yi Teah, Nobuko Hanada

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Intermetallic iron aluminide (FeAl) in the submicrometer range is an emerging material for industrial applications due to its improved ductility and enhanced properties. In addition, preparing high-surface-area FeAl powder is highly desired due to its catalyst applications. The chemical synthesis of FeAl is feasible for mass production. However, previous synthesis methods require extensive use of toxic chemicals, organic solvents, and specialized environment-controlled facilities. To achieve a cleaner synthesis of FeAl powder with a high surface area, herein, we propose a new synthesis route. First, an Fe–Al oxide precursor, FeAl2O4, was prepared from iron and aluminum nitrates. Then, the oxide precursor was reduced to FeAl using CaH2 in molten LiCl at 600°C–700 °C. The reduction at 700 °C resulted in a single-phase intermetallic FeAl without any impurity phase, whereas at 600 °C and 650 °C, a trace of Al(OH)3 was detected under X-ray diffraction, indicating an incomplete reduction. N2 adsorption–desorption analyses and scanning and transmission electron microscopy with energy-dispersive X-ray spectroscopy confirmed the formation of submicrometer FeAl particles. The surface area of the prepared FeAl powder was as high as 88 m2/g, which is three times higher than that reported for Fe3Al nanoparticles prepared via a physical approach. We further performed a screening-level lifecycle assessment to evaluate the prospective environmental impact of the FeAl synthesis route. The cumulative energy demand and global warming potential associated with 1-kg-FeAl synthesis were 566 MJ and 41 kg CO2e, respectively, which are about half of those for existing LiAlH4-based methods. Therefore, the proposed synthesis route is promising for environmentally friendly synthesis of FeAl particles.

Original languageEnglish
Article number128264
JournalJournal of Cleaner Production
Publication statusPublished - 2021 Sept 20


  • Chemical synthesis
  • Intermetallic FeAl
  • Lifecycle assessment
  • Submicrometer particles

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • General Environmental Science
  • Strategy and Management
  • Industrial and Manufacturing Engineering


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