等方性Sr-La-Nd-Pr系M型六方晶フェライト磁石の磁気特性

概要

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Experiments were carried out to investigate the effect of composite rare-earth oxide(55% La_2O_3-34% Nd_2O_3-10 Pr_6O_<11>) addition on magnetic properties of isotropic SrO・6Fe_2O_3 magnets. It was found that the magnetoplumbite structure is stabilized by addition of composite rare-earth oxide to SrO・6Fe_2O_3 compound. These Sr-La-Nd-Pr system ferrites have excellent properties as a isotropic permernent magnet and the values of (BH) max in these semisintered at 1000℃ was equivalent to those of ordinary isotropic Ba and Sr ferrites. The optimum conditions of making an isotropic magnet and some properties of a typical sample are as follows ; compotion : SrO・6Fe_2O_3 in addition .with 3wt% comopsite rare-earth oxide, semisintering condition : 1225℃×1h in O_2 gas, sintering condition : 1275℃×0.5h in O_2 gas. Magnetic and physical properties ; J_m=0.37T, J_r=0.26 T, H_<CJ>=226.8 kA/m, H_<CB>=173.5 kA/m, (BH)_<max>=11.5 kJ/m^3, T_C=447 ℃, D=5.04 Mg/m^3.