Topochemical Memory Effect in the Formation of Barium Hexaferrite.

Autor: Kulikov, F., Oleinikov, N., Murav'eva, G., Tret'yakov, Yu.
Zdroj: Inorganic Materials; Nov2002, Vol. 38 Issue 11, p1183-1185, 3p
Abstrakt: 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. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index