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W-type ferrite BaMg 1.8 Cu 0.2 Fe 16 O 27 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 °C, the phase compositions of the magnetic powders consist of W-type hexaferrites together with small amount of impurity phases such as α-Fe 2 O 3 . At calcination temperatures above 1280 °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 °C. [ABSTRACT FROM AUTHOR]

A series of W-type hexagonal ferrites with the composition Ba 1 - x Sr x Fe 2 2 + Fe 16 3 + O 27 (0≤ x ≤1) were prepared by the ceramic process in a reducing atmosphere during the whole process of pre-sintering and sintering. The phase composition, micro-morphology, and magnetic properties of the particles were investigated by XRD, SEM, and VSM. The results of XRD show that the single phase was observed in the W-type ferrites with different Sr content. The micro-morphology of the particles exhibits the uniform plane hexagonal structures of W-type ferrites with different Sr content. The coercivity ( H c ) of the particles increases with the increase of Sr content ( x ), while the saturation magnetization ( M s ) of the particles first decreases with x from 0 to 0.2, and then begins to increase when x continues to increase. [ABSTRACT FROM AUTHOR]