Magnetic properties and microstructures of Fe/sub 3/B/Pr/sub 2/Fe/sub 14/B-type nanocomposite magnets with Co and Cr additions

The microstructure-property relationships of melt-spun Fe/sub 3/B/Pr/sub 2/Fe/sub 14/B-type nanocomposites micro-alloyed with Cr and Co, and the effect of the micro-alloying elements on the microstructure and magnetic properties of the nanocomposites are investigated. Increasing content of Pr enhances the coercivity at the expense of remanence and magnetic energy products in Pr/sub 4+x/Fe/sub 78-x/B/sub 18/ and Pr/sub 4+x/Fe/sub 76-x/Cr/sub 2/B/sub 18/ (x = 0, 0.5, 1) alloys. Combined additions of Cr and Co make the distribution of the grain size more uniform and further improve hard magnetic properties. The optimum magnetic properties are obtained after annealing at 628/spl deg/C and 658/spl deg/C for 10 min.