부산대학교 도서관

Spinel ferrites have potential applications as gas sensors, catalysts, microwave absorbers, and they can be used for information storage systems, rechargeable lithium batteries and medical diagnostics. Alkaline steaming-assisted conversion, a new strategy, was first developed for the synthesis of pure NiFe2O4 spinel nanoparticles, and its mechanism is discussed. Ammonia, ethylenediamine, and mixtures of both were used as steaming vapor to convert the dry powder of a stoichiometric mixture of FeCl3·6H2O and NiCl2·6H2O into NiFe2O4. In this system, ethylenediamine cooperates with ammonia in the alkaline steaming vapor to convert the Ni and Fe precursors into NiFe2O4 nanoparticles. Pure NiFe2O4 nanoparticles were only obtained by the combination of alkaline ammonia and ethylenediamine. The results show that the purity of the product depends on the concentration of ethylenediamine. The crystallization and the magnetization of these NiFe2O4 nanoparticles depend on the processing temperature and duration of the steaming process. The alkaline-steaming assisted conversion strategy was further successfully extended to the synthesis of pure CoFe2O4 nanoparticles, demonstrating a broad application possibility. [ABSTRACT FROM AUTHOR]