Effects of Co substitution on the magnetic and microstructural properties of melt-spun Pr/sub 7/Tb/sub 1/Fe/sub 87-x/Co/sub x/Nb/sub 0.5/Zr/sub 0.5/B/sub 4/ nanocomposites

The magnetic and microstructural properties of melt-spun Pr/sub 7/Tb/sub 1/Fe/sub 87-x/Co/sub x/Nb/sub 0.5/Zr/sub 0.5/B/sub 4/ (x = 0,10,20,30) nanocomposites have been investigated. Optimum magnetic properties are found with coercivity H/sub c/ = 6.84 kOe and (BH)/sub m/ = 11.8 MGOe in the sample of Pr/sub 7/Tb/sub 1/Fe/sub 87/Nb/sub 0.5/Zr/sub 5/B/sub 4/. For the samples with x = 10, 20, and 30, both the coercivity and the energy product decrease. The main reason for this deterioration is the decrease in the anisotropy of 2 : 14 : 1 phase and the changing morphology of (alpha)-Fe and 2 : 14 : 1 phases. Co also increases the Curie temperature of all the phases present, including the hard and soft phases.