RARE-EARTH-IRON-NITROGEN-BASE MAGNET POWDER AND METHOD FOR MANUFACTURING THE SAME

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PROBLEM TO BE SOLVED : To provide a method for inexpensively manufacturing magnet powder having excellent magnetic characteristics at a yield enhanced by a reduction diffusion method by reducing the non-magnetic phase which lowers the magnetic characteristics of the rare-earth-iron-nitrogen-base magnet powder and reducing the distortion of the crystal which is the nucleus for magnetization inversion and the remaining of a-Fe. SOLUTION : The method includes steps of; mixing rare earth oxide powder, iron powder and reducing agent powder, such as an alkaline metal, at prescribed ratios : heating the mixture at 90 to 1, 180°C in an inert gaseous atmosphere; subsequently cooling the mixture down to ≤500°C, then supplying gaseous nitrogen to cause the decay of the mixture after discharging the inert gas; then supplying a gaseous mixture containing ammonia and hydrogen while keeping the mixture at ≤300°C to elevate the temperature thereof; charging the mixture into water to perform wet process treatment; removing the hydrogen having invaded the magnet alloy by the wet process treatment; and thereafter, subjecting the magnet alloy to pulverization. COPYRIGHT : (C)2007, JPO&INPIT