ANNEALING-INDUCED PROPERTY IMPROVEMENTS IN 2-14-1 POWDERS PRODUCED BY INERT GAS-ATOMIZATION

摘要

A method currently under exploration for the production of rapidly-quenched isotropic powders is inert gas atomization (IGA), which offers the significant advantage over the conventional melt-quenching process that a large volume of material may be produced in a single step with equipment that is more economical to operate than that presently used. While the IGA process has been proven to produce spherical, micron-sized Fe-Nd-B powders with high coercivities, low energy products and powder nonuniformity are obstacles to further commercial development of the method. However, we have found that a brief vacuum annealing procedure raises the coercivity of the powder particles to levels comparable to that of typical commercial magnetic powder; the energy product (BH)_(max) is left at only 60-70% of that of commercial powder. We present here the investigations of the physical changes responsible for the increase in the hysteretic magnetic properties of IGA powders with annealing, and offer suggestions for the further performance improvement of this technique.