Thermal stability of SiO2-coated Fe3O4 nanoparticles

Our paper entitled: “Thermal stability of silica-coated magnetite nanoparticles prepared by an electrochemical method” has been accepted for publication in the journal Advanced Powder Technology published by Elsevier B.V. on behalf of the Society of Powder Technology Japan.Below are the highlights, graphical abstract and abstract of the article.

Advanced Powder Technology

Thermal stability of silica-coated magnetite nanoparticles prepared by an electrochemical method

Fauziatul Fajaroh, Heru Setyawan, Adrian Nur, I. Wuled Lenggoro

HIGHLIGHTS

1. Silica-coated magnetite nanoparticles were succesfully prepared by one-step method.
2. We investigate the thermal stability of the silica-coated magnetite nanoparticles.
3. The silica layer is stable under heating up to 550°C.
4. The silica layer can protect magnetite from being converted to other oxide species.

GRAPHICAL ABSTRACT

ABSTRACT

Magnetite nanoparticles have been prepared by electrooxidation of iron in water. Surface modifications have been conducted by coating the nanoparticles with silica by a one-step synthesis in dilute sodium silicate solution. The mean size of particles was approximately 10-30 nm for the uncoated particles and 9-12 nm for the coated particles. The results obtained from thermal gravimetric/differential thermal analysis (TG/DTA) revealed that the silica layer formed by the electrochemical method was stable and could serve as a protective layer. Annealing the nanoparticles at 550°C for 30 min converts magnetite into maghemite for the silica-coated particles, and it further converts the uncoated particles into hematite. The conversions cause the saturation magnetization to decrease for all samples.