| 摘要 |
PURPOSE:To form a magnet having a relative density of 70% or more and make it possible to miniaturize electrical appliances by hot pressing powder in the shape of a thin piece without using a special biding agent. CONSTITUTION:An alloy composed of 13 atomic % Nd and/or Pr, 15 atomic % Co, 6 atomic % B, the balance being Fe, is rapidly cooled and solidified by a meltspining method and formed into powder in the shape of a thin piece having a thickness of 20 to 30 microns. This powder is housed in a space 3 formed of a non-conductive ceramics cavity 1 and a pair of conductive ceramic electrode punches 2. A pressure is applied to the pair of electrode punches, and further the space is made to a vacuum atmosphere of 10 to 10Torr. A DC voltage of 20V is applied for 60sec in a pulse width of 40msec. Thereafter, a DC current of 1.5kA is directly made to flow between the pair of electrodes for 40 to 60sec. Finally, the temperature of the powder inside the cavity reaches 700 deg.C to 750 deg.C. By cooling this powder, various magnets having different relative densities are obtained by a permeance 1 having an outer diameter of 20mm. |
