| 摘要 |
PCT No. PCT/JP95/00731 Sec. 371 Date Mar. 14, 1996 Sec. 102(e) Date Mar. 14, 1996 PCT Filed Apr. 14, 1995 PCT Pub. No. WO95/28718 PCT Pub. Date Oct. 26, 1995A magnetic powder containing MnBi, in which an average particle size of the magnetic powder is from 0.1 mu m to 20 mu m; a coercive force is from 3000 to 15,000 Oe at 300 K. and 50 to 1000 Oe at 80 K. when measured with applying a magnetic field of 16 KOe; an amount of magnetization is from 20 emu/g to 60 emu/g when measured at 300 K. with applying a magnetic field of 16 KOe; a degree of decrease of an amount of magnetization is 40% or less after being maintained in an atmosphere of 60 DEG C. and 90% RH for 7 days; and a content of metal bismuth (Bi) satisfies the following equation: Metal Bi/(MnBi+metal Bi)<0.5 in which "metal Bi" means a peak area assigned to the (012) plane in a X-ray diffraction pattern of Bi, and "MnBi" means a peak area assigned to the (101) plane in a X-ray diffraction pattern of MnBi, which magnetic powder is excellent in corrosion resistance, and suffers from very slight deterioration of saturation magnetization, and provides a magnetic recording medium that can prevent altering of recorded data.
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