摘要 |
PURPOSE:To manufacture a rare earth-iron-boron permanent magnet having a high energy product by improving the orientation of fine powder in moulding. CONSTITUTION:A rare earth-iron-boron ingot, having the temperature coefficient of residual magnet flux density of negative, is pulverized into fine powder of average particle diameter of 1 to 10mum and the coersive force of 7KOe. The orientation of the powder is improved by cooling it to the temperature higher than the spin rearrangement temperature and lower than 20 deg.C and by conducting a compression-molding in a magnetic field. Then, sintering and heat treatment operations are conducted, and a rare earth-iron-boron permanent magnet, having high energy, is manufactured. |