Ultrafine BaFe12O19 powder synthesised by mechanochemical processing

Ultrafine BaFe12O19 powder has been synthesised by a novel mechanochemical preparation method. Mechanical milling of 1.2BaCl(2) + 12FeCl(3) + 38.4NaOH led to a mixture of NaCl and iron and barium hydroxide or oxide-hydroxide. The formation of BaFe12O19 required annealing at 800 degrees C in air. A significant reduction of particle size was achieved by dilution with NaCl. High coercivity values above 5 kOe were measured for BaFe12O19 platelets of 20-100 nm in diameter and 10-20 nm thick. (C) 1998 Elsevier Science B.V. All rights reserved.