Topochemical Memory Effect in the Formation of Barium Hexaferrite
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The topochemical memory effect in Ba(NO3)2 : Fe2O3 = 1 : 6 reaction mixtures containing α-Fe2O3 with different particle sizes was studied at low (540–630°C; the main reaction product BaFe2O4) and high (900–930°C; the main product, BaFe12O19) reaction temperatures. The results indicate that the particle size of Fe2O3 has a significant effect on the BaFe2O4 yield in the low-temperature solid-state reaction (<585°C), in contrast to the liquid-assisted reaction (>585°C). In the subsequent high-temperature solid-state reaction (900–930°C), the BaFe12O19 yield depends on the particle size of Fe2O3 , regardless of the initial reaction temperature. It is shown that, to achieve a high BaFe12O19 yield, the process conditions should be optimized in both the low- and high-temperature stages.
KeywordsParticle Size Inorganic Chemistry Fe2O3 Barium Reaction Temperature
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