Characteristics of barium hexaferrite nanocrystalline powders prepared by a sol-gel combustion method using inorganic agent

摘要

Nanocrystalline particles of barium hexaferrite were synthesized by a sol-gel combustion route using nitrate-citrate gels prepared from metal nitrates and citric acid solutions under various Fe/Ba molar ratios of 10, 11 and 12. Sodium hydroxide was used as a pH-adjusting agent. The results revealed that the formation temperature of barium hexaferrite is influenced by Fe/Ba molar ratio; the Fe/Ba molar ratio of 12 is more favorable. For sample synthesized with a Fe/Ba molar ratio of 12, barium hexaferrite started to form at 800℃ and fully formed at 1000℃. The results also showed that the coercivity of the samples decreases as the Fe/Ba molar ratio increases from 10 to 12, whilst the saturation magnetization increases.