TbCu_7型構造Sm-Fe-Co-Ti-Zr系窒化化合物磁石の磁気特性(ハード磁性材料)

概要

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An experiment was carried out to examine the effect of composition, heat treatment, and nitrogenation conditions on the magnetic properties of Sm-Fe-Co-Ti-Zr nitrides with TbCu_7-type structure. The optimum preparation conditions of the compounds were as follows : composition {Sm_<10>(Fe_<0.9>Co_<0.1>)_<89.2>Ti_<0.3>Zr_<0.5>}_<83.5> N_<16.5> ; roller velocity 52m/s ; heat treatment 700℃×60min in high-purity Ar gas ; and nitrogenation condition 420℃×15h in high-purity N_2 gas. Typical magnetic properties of the obtained powders were as follows : J_r=0.96 T, H_<cJ>=811.7kA/m, (BH)_<max>=141kJ/m^3 (17.7 MGOe), and T_c=504℃. Recoil loops of the hysteresis curve and X-ray analysis showed that the sample was an exchange spring magnet. The value of (BH)_<max> of the bonded magnet prepared from {Sm_<10>(Fe_<0.9>Co_<0.1>)_<89.2>Ti_<0.3>Zr_<0.5>}_<83.5>N_<16.5> powder was 102kJ/m^3 (12.8 MGOe) when the density of the bonded magnet was 6.06 Mg/m^3. The reversible temperature coefficient of J_r was α(J_r)_<ave>.=-0.05 %/℃, and the temperature coefficient of H_<cJ> in the range from 25℃ to 125℃ obtained by linear extrapolation was α(H_<cJ>)=-0.46%/℃
社団法人日本磁気学会の論文
2005-03-01