PURPOSE: To obtain a permanent magnet which has both excellent residual magnetic flux density Br(G) and coercive force IHc(Oe) by containing silicon oxide, calcium oxide, aluminum oxide or chromium oxide and further, a main component MO in a specific ratio and by making the mol ratio of free MO + CaO and SiO2 in a definite range.
CONSTITUTION: In a weight ratio, 0.1W1.0 % silicon oxide SiO2, 0W1.2 % calcium oxide CaO and in some cases, 4 % or less aluminum oxide Al2O3 or 6 % or less chromium oxide Cr2O3 and especially, 0.1W1.5 % MO(M is Sr, Ba or Pb.) are contained. Further, the mol ratio of MO and CaO or SiO2 (MO + CaO/SiO2) generated from the difference between the stoichimetric mol ratio and the mol ratio in an actual manufacture is made in the range of 0.7W1.7. This enables obtaining a high coercive force IHc(Oe) permanent magnet together with approx. 2 % higher residual magnetic flux and reducing a time for minutely grinding required for obtaining high magnetic characteristics.
MINEGISHI MASAYOSHI
KOBAYASHI KOJI
