Stable magnetic powders, of 1–2µm particle size, of partially Co-substituted, Pr2Fe14−xCoxB,x⩽3, alloys together with 2–4 at% excess Pr were prepared by rapidly quenching the associated melts into thin ribbons and then mechanical attriting the ribbons in the refined particle sizes. The saturation magnetizationMs, remanent magnetizationJr, intrinsic coercivityHci and Curie temperatureTc were studied in characterizing the powders for fabricating into sintered or polymer bonded magnets. It is found that the smallx=0·4–0·8 substitution of the Co on Fe sites in this series sensitively leads to an increase in the value ofHci, by as much as 40%, with the optimum value of 21 kOe atx ∼ 0·55, together with an improvement in theTc from 292°C to 325°C, without significantly diluting theMs∼150 emu/g andJr∼8·0 kG values. The Co-substituted Pr2Fe14B alloy particles are better stable and corrosion resistant in ambient atmosphere. The results are discussed with the microstructure and comparison with the data for Nd2Fe14B powders processed under the same conditions.
Volume 42 | Issue 6
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