- Tytuł:
- Phase Transition of Electrooxidized $Fe_3O_4$ to γ and $α-Fe_2O_3$ Nanoparticles Using Sintering Treatment
- Autorzy:
-
Kazeminezhad, I.
Mosivand, S. - Powiązania:
- https://bibliotekanauki.pl/articles/1365306.pdf
- Data publikacji:
- 2014-05
- Wydawca:
- Polska Akademia Nauk. Instytut Fizyki PAN
- Tematy:
-
75.75.cd
61.46.Df
61.46.Bc - Opis:
- In this work, electrosynthesis of $Fe_3O_4$ nanoparticles was carried out potentiostatically in an aqueous solution of $C_4H_{12}NCl$ which acts as supporting electrolyte and electrostatic stabilizer. $γ-Fe_2O_3$ nanoparticles were synthesized by controlling oxidation of the electrooxidized $Fe_3O_4$ nanoparticles at different temperature. Finally the phase transition to $α-Fe_2O_3$ nanoparticles was performed at high temperatures using sintering treatment. The synthesized particles were characterized using X-ray diffraction, Fourier transformation, infrared scanning electron microscopy with energy dispersive X-ray analysis, and vibrating sample magnetometry. Based on the X-ray diffraction results, the transition from $Fe_3O_4$ to cubic and tetragonal $γ-Fe_2O_3$ was performed at 200C and 650°C, respectively. Furthermore, phase transition from metastable $γ-Fe_2O_3$ to stable $α-Fe_2O_3$ with rhombohedral crystal structure was approved at 800°C. The existence of the stabilizer molecules at the surface of $Fe_3O_4$ nanoparticles was confirmed by Fourier transformation infrared spectroscopy. According to scanning electron microscopy images, the average particles size was observed around 50 nm for electrooxidized $Fe_3O_4$ and $γ-Fe_2O_3$ nanoparticles prepared at sintering temperature lower than 900°C, however by raising sintering temperature above 900C the mean particles size increases. Energy dispersive X-ray point analysis revealed that the nanoparticles are almost pure and composed of Fe and O elements. According to the vibrating sample magnetometry results, saturation magnetization, coercivity field, and remnant magnetization decrease by phase transition from $Fe_3O_4$ to $Fe_2O_3$.
- Źródło:
-
Acta Physica Polonica A; 2014, 125, 5; 1210-1214
0587-4246
1898-794X - Pojawia się w:
- Acta Physica Polonica A
- Dostawca treści:
- Biblioteka Nauki
Artykuł