Magnetic properties of topochemically sintered barium hexaferrite

This communication describes the method of topochemical reaction sintering for the production of barium hexaferrite. Topochemical reaction sintering o vercomes crucial process steps that are used in the conventional wet magnet ic compaction method, such as calcination, wet grinding, and wet magnetic c ompaction, Chemical reaction sintering of the above-mentioned ferrite has b een performed in air and under vacuum. Barium hexaferrite that has been top ochemically sintered in air at a temperature of 1473 K for 60 min shows a m aximum magnetic energy product ((BH)(max)) of 6.56 kJ/m(3), whereas barium hexaferrite that has been topochemically sintered at a temperature of 1423 K for 30 min under vacuum (10(-2) mm Hg (similar to 0.133 Pa)) shows (BH)(m ax) = 7.6 kJ/m(3). The variation of the magnetic properties of the topochem ically sintered ferrites is interrelated to process variables such as tempe rature and sintering duration (time).