Hard Ferrite magnet
Since the 1950s, hard ferrite (ceramic) magnets have been widely applied because of low cost, good magnetic properties and excellent environmental stability.
Both isotropic and anisotropic hard ferrite magnets are available for UMAG. The magnetic energy products of anisotropic hard ferrite magnets are higher than that of the isotropic hard ferrite magents by up to 300%. Depending on the base materials, there are Barium Ferrite and Strontium Ferrite with higher coercive. But in recent years Barium Ferrite have been abandoned for environmental and health reasons.
After preliminary inspection, the raw materials (mainly iron oxide, strontium carbonate) are weighed, blended, pre-sintered and milled to fine powders with hexagonal crystals. For isotropic magnets, the pre-materials are milled to powders and then pressed. For anisotropic magnets there are two procedures in the production, dry press and wet press. Firstly, the raw materials are dried and then pressed in a magnetic field. Secondly, the raw materials are wet pressed under the influence of a magnetic field, then followed by sintering, finishing cleaning and magnetization. Finally the surface can be machined, marked, magnetized or coated according to customers' requirements.