Open AccessCrystallographic phase formation of iron oxide particles produced from iron nitrate by liquid flame spray with a dual oxygen flow
Author(s) -
Sorvali Miika,
Honkanen Mari,
Hyvärinen Leo,
Kuisma Ritva,
Larjo Jussi,
Mäkelä Jyrki M.
Publication year - 2021
Publication title -
international journal of ceramic engineering and science
Language(s) - English
Resource type - Journals
ISSN - 2578-3270
DOI - 10.1002/ces2.10102
Subject(s) - maghemite , hematite , oxalic acid , iron oxide , citric acid , chemistry , oxygen , oxide , inorganic chemistry , materials science , analytical chemistry (journal) , chemical engineering , mineralogy , chromatography , organic chemistry , engineering
We fabricated iron oxide particles from iron(III) nitrate in a liquid flame spray synthesis. Unlike in most liquid flame spray studies, we implemented a secondary oxygen flow. The effect of the gas flow setup and two additives to the precursor solution, oxalic acid and citric acid, on the resulting particles was studied, with the focus on crystallographic phase composition. The synthesis yielded either pure maghemite or maghemite/hematite mixed phase powders. For solutions without additives, the maghemite fraction was almost linearly dependent on the equivalence ratio. The specific surface area was highest for the smallest equivalence ratios, then decreased, and increased again for the highest values. Some variation was observed between samples with equal equivalence ratios but the total oxygen flow divided differently between the two oxygen channels, a higher atomization flow promoting larger hematite fraction, and higher specific surface area. Both additives reduced the amount of hematite in the powder samples, citric acid being the more efficient one. Citric acid slightly raised the specific surface area, whereas oxalic acid dropped it in half.