MAGNETIC HARDENING OF MELT-SPUN 2:14:1-BASED MATERIALS BY HIGH HEATING RATE AND SHORT-TIME CRYSTALLIZATION TREATMENTS

Systematic studies have been carried out about the effects of the thermal treatment parameters on melt-spun materials quenched at different cooling rates and based on the 2:14:1 hard magnetic phase. Samples of nominal compositions Dy3Nd10.2Fe79.6B6Si1.2. and Pr3Nd10.2Fe79.6B6Si1.2 were annealed at temperatures above that of crystallization of the amorphous phases present upon quenching, for times ranging from 1 to 30 min and by using different heating rates up to the annealing temperature. It is concluded that best hysteretic properties can be achieved in samples quenched at intermediate cooling rates by means of short-time thermal treatments performed by using high heating rates up to the treatment temperature. Low heating rates and long time anneals led to the deterioration of the hard magnetic behavior, due to the segregation of soft crystalline phases.