Dzelzs oksīda magnētisko nanodaļiņu sintēze, īpašības un pielietošanas iespējas.

Gabrene, Aļona; Juhņēviča, Inna; Sētiņa, Janīna; Mežinskis, Gundars

Different treatment and modification methods of glass surface affect their morphology and adhesive properties. The use of CeO2 suspension improves the quality of the glass surface in glass slide preparation stage significantly, which was established by the AFM results. FexOy-SiO2 system is obtained by sol-gel method. There were sol compositions obtained for α-Fe2O3 and Fe2O3 synthesis. Different acids as hydrolysis catalyst agents and additives as iron compounds were used. Fe2O3 coprecipitation from salt solutions was determining necessity of non-oxygen environment to prevent the oxidation of magnetite. Analysis of Fe2O3 based coating methods concluded that the magnetite encapsulation between two SiO2 sol layers provide better quality of the obtained coatings, compared the adding of magnetite direct to SiO2 sol. Based on results obtained from SEM analysis of Fe xOy-SiO2 sol-gel coatings it can be concluded that after high temperature treatment agglomeration of FexOy particles on the surface of coatings forms stranded iron grain chains. However, Fe2O3 powder particles had a very high agglomeration tendency which can be explained by the hydrophobic and magnetic interactions between particles. Fe-O bond vibrations region in FT-IR spectra made possible to identify magnetite, hematite and maghemite. Hematite Fe-O bond at 530 cm-1, magnetite at 590 cm-1 and 450 cm-1, maghemite at 570 cm-1 and 440 cm-1 were observed. DTA data of Fe2O3 powder has confirmed: physically bound water release at 102 °C, magnetite oxidation to form maghemite at 255 °C and transformation of maghemite to hematite at 499 °C. Literature and BET analysis based data may provide that particle sizes will not exceed 150 nm for Fe2O3 synthesized by the coprecipitation method. BET active surface area is 92, 3 m²/g.

CHEMICAL synthesis; MAGNETIC properties of iron oxides; MAGNETIC properties of nanoparticles; SURFACE chemistry; SUSPENSIONS (Chemistry); COATING processes

Material Science & Applied Chemistry, 2013, Issue 27, p11

1407-7353

Academic Journal