Тип публикации: статья из журнала
Год издания: 2016
Идентификатор DOI: 10.1016/j.jallcom.2015.12.257
Ключевые слова: Thermite reactions, Reactive films, Ferromagnetic nanocomposite films, ZrO2, Chemical stability, Cobalt compounds, Crystalline materials, Ferromagnetic materials, Ferromagnetism, Nanocomposite films, Nanocomposites, Temperature, Thin films, Zirconium alloys, Ferromagnetic nanocomposites, High magnetization, Initiation temperature, Partial transformation, Secondary reactions, Synthesis and characterizations, Thermite reaction, ZrO<sub>2</sub>, Cobalt
Аннотация: Co-ZrO2 ferromagnetic nanocomposite thin films were successfully synthesized using a new thermite reaction between Zr and Co3O4 in layer geometry. The initial Zr/Co3O4 bilayers were obtained by the deposition of Zr layers onto Co3O4 films at room temperature. The process of mixing at the Zr/Co3O4 interface and synthesis of fine-crystalline Co and amorphous ZrO2 phases started at a temperature above the initiation temperature T-in similar to 250 degrees C which did not depend on the bilayer thickness. For the bilayer thickness more than 300 nm high-temperature fcc-Co and cubic c-ZrO2 ( or tetragonal t-ZrO2) phases were formed. For the bilayer thickness less than similar to 50 nm stable low-temperature hexagonal hcp-Co and monoclinic m-ZrO2 phases were also present in the reaction product. A partial transformation from Co3O4 to CoO occurred after annealing at 300 degrees C. The secondary reaction between CoO and Zr started soon after Co3O4 had been converted to the CoO phase. After annealing at 500 degrees C more than 80% of Co was reduced and the final product contained Co nanoparticles above and below the superparamagnetic critical size embedded into a dielectric ZrO2 matrix. The synthesized Co-ZrO2 nanocomposite films possessed soft magnetic behavior, high magnetization and good chemical stability. (C) 2016 Elsevier B.V. All rights reserved.
Журнал: JOURNAL OF ALLOYS AND COMPOUNDS
Выпуск журнала: Vol. 665
Номера страниц: 197-203
ISSN журнала: 09258388
Место издания: LAUSANNE
Издатель: ELSEVIER SCIENCE SA
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