Effects of presintering temperature on structural and magnetic properties of BaMg1.8Cu0.2Fe16O27 hexagonal ferrites

W-type ferrite BaMg1.8Cu0.2Fe16O27 magnetic powders and magnets were prepared by a ceramic process. The phase identification of magnetic powders was performed by X-ray diffraction. At calcination temperatures ranging from 1200 to 1340 degrees C, the phase compositions of the magnetic powders consist of W-type hexaferrites together with small amount of impurity phases such as alpha-Fe2O3. At calcination temperatures above 1280 degrees C, single-phase W-type hexaferrites can be obtained. The microstructures of the magnets were investigated by field emission scanning electron microscopy. The particles appear in hexagonal plate-like shape and the particles are distributed homogeneously. The radial shrinkage of the magnets increases with the increase of calcination or sintering temperature. The magnetic properties of the magnets was measured by a permanent magnetic measure equipment. For high remanence, intrinsic coercivity, magnetic induction coercivity and maximum energy product, the optimized calcination temperatures is 1280 degrees C. (C) 2015 Published by Elsevier GmbH.