Abstract:
Barium ferrites, particularly M-type with hexagonal molecular structure – BaFe12O19, represent important magnetic materials with applications in: wireless communication, electronic devices, microwave absorbing agents, magnetic recording media. This paper deals with the formation of barium hexaferrite via the citrate method. Starting from Ba(NO3)2, Fe(NO3)3•9H2O and citric acid monohydrate with ammonia solution addition until reaching pH=8, a precursor which self-ignites at 300 °C was obtained. After the auto-combustion reaction, a reddish brown to brown-gray powder resulted, which was annealed at different temperatures. The use of citric acid in excess and ammonia is justified in the case of barium hexaferrite formation. The results have pointed out that is possible to obtain BaFe12O19 as single phase after annealing at 800 °C/1h.
Keywords:
barium hexaferrite, citric acid, pH, auto-combustion
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