Magnetic performance enhancement in La-Ca-Co doped SrFe12O19 ferrite permanent magnets via cold isostatic pressing

Abstract

The crystallographic alignment, microstructure and magnetic properties were studied for La _0.6 Ca _0.6 Sr _0.1 Fe _12.4 Co _0.4 O _19 ferrite permanent magnets prepared with standard ceramic method. The effect of cold isostatic pressing (CIP) and sintering temperature on the structural and magnetic properties of the magnets were investigated. The CIP significantly improves the density of the green compact and final magnets, but undermines the crystallographic alignment of the magnets simultaneously. As a result, the remanence of the magnet achieves optimal value under the compromise between the increased density and the degraded alignment. Moreover, the coercivity of the magnet increases linearly with the increment of the CIP pressure due the fact that CIP processed samples bear more uniform and finer grains in favor of high coercivity. Under optimal CIP pressure and sintering temperature, the magnet obtains best magnetic properties of B _r of 0.439 T, H _cj of 396 kA m ^−1 , H _cb of 311 kA m ^−1 , and (BH) _max of 35.8 kJ m ^−3 .

Keywords

• SrFe12O19 ferrite permanent magnets
• magnetic performance
• cold isostatic pressing
• crystallographic alignment