Nanocrystalline Nd/sub 6/Fe/sub 88-x/M/sub x/B/sub 6/ (M=Ti or V) magnets by rapid thermal annealing

Nanocrystalline structures were obtained by a rapid thermal annealing (RTA) process with a heating rate of 600/spl deg/C/min for a soaking time of 2 minutes for melt-spun Nd/sub 6/Fe/sub 88-x/MxB/sub 6/ amorphous alloys (M=Ti or V, x=0/spl sim/5), Exchange coupling interaction between the magnetically hard and soft phases was studied with the /spl delta/M plots. Addition of Ti or V to replace iron is effective in increasing remanence ratio, Mr/M/sub 2T/, and energy product of the modified alloys, especially that modified by V, although both saturation magnetization and remanence are decreased due to magnetic dilution. High resolution TEM studies showed that both Ti and V is effective in refining grain size of both hard and soft phases to 20-23 nm compared with 50/spl sim/52 nm for the z=0 alloy. The substitution with V results in a decrease in coercivity despite of refined grains.