Extrusion of strontium hexaferrite magnets with radial alignment using hydrothermally synthesized powder

Hydrothermally synthesized strontium hexaferrite (HT-SrM) powder was combined with an ethylvinylacetate (EVA)-paraffin wax system to give an extrudable paste from which tubular magnets were produced. Due to the very high specific surface area of the plate-like hexaferrite particles, the maximum solids loading was /spl sim/46 vol% when mixed at 120/spl deg/C. Using such pastes, a degree of radial magnetic alignment in tubular extrudates was induced by the paste flow. The extrusion parameters and the influence of die gap on the orientation of SrM particles have been investigated.