抄録
A new process has been developed to produce high energy bulk Pr-Fe-B magnets without the handling of any magnetic powder or powder-like ribbons. This process consists of three main steps: casting, hot-pressing and annealing, and minimizes the oxygen contamination of magnets. A typical composition of cast alloy is Pr17Fe76.5B5Cu1.5. Using this type of alloy, crystal alignment along the c axis is easily introduced by hot-pressing. Copper plays two important roles in this process: high coercivity and excellent magnetic alignment are achieved simultaneously by its addition. The magnetic properties of hotpressed Pr17Fe76.5B5Cu1.5 magnets are: Br=12.5 kG, iHc = 10.0 kOe and (BH)max=36.2 MGOe. The cast alloy of this composition also has an iHc of 7.3 kOe and a (BH)max of 9.2 MGOe after annealing at 1000°C for 24 hours. The steep rise in the initial magnetization curve indicates a nucleation controlled coercivity mechanism.
