Effects of Dy on magnetic properties of a-Fe/Nd/sub 2/Fe/sub 14/B type alloy

The effects of Dy content on magnetic and microstructural properties of melt-spun (Nd/sub 1-x/Dy/sub x/)4(Fe/sub 0.9/Co/sub 0.1/)/sub 86/B/sub 6/Nb/sub 3/Cu alloys have been investigated. The energy product of the alloys decreases with the increase of Dy content, while the coercivity increases up to 2.64 kOe at x=0.3. At a fixed annealing time condition, the optimum annealing temperature increases by Dy substitution, and grain coarsening occurs in the alloys with high Dy content. The deterioration of hard magnetic properties by Dy substitution is due to the decrease of exchange interaction between a-Fe and (Nd,Dy)/sub 2/Fe/sub 14/B phases by grain coarsening.