METHOD FOR PRODUCING IRON-BASED PERMANENT MAGNET ALLOY BY CONTROL OF CRYSTALLIZATION HEAT GENERATING TEMPERATURE

摘要

PROBLEM TO BE SOLVED: To decide the combination and ratios of rare earth elements to be added to an iron-based alloy magnet by a systematic means and to impart excellent magnet characteristics thereto.;SOLUTION: In this method for producing a fine crystal type iron-based alloy magnet having two or more metastable phases including hard magnetic phase, a stage in which an iron-based alloy containing a rare earth element R (R is Pr or Nd), a rare earth element R' having an atomic number A larger than that of the rare earth element R and a rare earth element R" having an atomic number A smaller than that of the rare earth element R is prepared, a stage in which the molten metal of the iron- based alloy is rapidly cooled, by which a rapidly cooled alloy in which the volume ratio of an amorphous phase occupies ≥90% of the whole is prepared and a heat treating stage in which the rapidly cooled alloy is heated to progress the growth of the crystals in the iron-based alloy are included. Then, by regulating the compositional ratios of R, R' and R", the crystallization heat generating temperature of one crystal phase is controlled to 585 to 615°C, and further, the crystallization heat generating temperature of the other crystal phase is controlled to 610 to 640°C, so that a fine and uniform crystal structure is formed.;COPYRIGHT: (C)2002,JPO