Naslov
A Study of the Reduction and Reoxidation of Substoichiometric Magnetite

Autori
Gotić, Marijan ; Koščec, Goran ; Musić, Svetozar

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
EUCMOS 2008-XXIX European Congress on Molecular Spectroscopy ; Book of Abstracts / Musić, Svetozar ; Ristić, Mira ; Krehula, Stjepko - Zagreb, 2008, 234-234

ISBN
978-953-6690-76-3

Skup
EUCMOS 2008-XXIX European Congress on Molecular Spectroscopy

Mjesto i datum
Opatija, Hrvatska, 31.08.2008. - 05.09.2008

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
magnetite; maghemite; reduction; reoxidation; FE-SEM; XRD; Mossbauer spectroscopy

Sažetak
In the present work, the substoichiometric magnetite particles (Fe2.90O4)of micrometer dimensions were subjected to reduction and reoxidation at a temperature of up to 600 oC. The reduction of substoichiometric magnetite by hydrogen was performed under static conditions, whereas the reoxidation experiments were performed in a stream of oxygen. samples were characterized by FE-SEM, XRD, FT-IR and Mossbauer spectroscopy.The experimental condition for stoichiometric magnetite (Fe3O4) was obtained. It was found that Mossbauer spectroscopy is a powerful technique for monitoring the stoichiometry of magnetite, but limiting in terms of distinguishing a magnetite-maghemite mixture. FT-IR spectroscopy showed that samples, which by means of Mossbauer spectroscopy were characterised as nonstoichiometric magnetite, contained bands characteristic of magnetite and maghemite. After investigating the micrometer sized particles, all three peaks present in the XRD patterns of maghemite, but not in the XRD patterns of magnetite, at 2theta (CuKa)= 15, 24 and 26 degrees turned out clearly visible. The magnetite-to-maghemite transition mechanism will be discussed.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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