Powder Soft Magnetic Composites: Problems and Prospects

This work is concerned with a special class of functional materials, namely, soft magnetic alloys and composites based on them. Their main advantages and disadvantages are considered. Special attention is paid to the powder soft magnetic composites, which are a mixture of ferromagnetic powder and binder (dielectric) bound into a single conglomerate, where each powder particle is surrounded by the binder and forms a continuous dielectric phase. The main factors influencing the properties of powder soft magnetic composites are determined as follow: the choice of a ferromagnet with the required magnetic properties, the use of powder particles of the required size and shape, the use of a certain type of insulator and the method of its application, the choice of pressing conditions, and the optimal heat-treatment mode. As demonstrated, the primary method for forming the soft magnetic composites is based on the powder-metallurgy techniques. The technological process of fabrication of soft magnetic composites includes the following steps: preparation of ferromagnetic powder, mixing it with a binder, pressing, heat treatment, mechanical processing, application of a protective coating, and initial control of properties.