Regensburg 2000 – scientific programme

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AM: Magnetismus

AM 7: Dauermagnete, nanokristalline hart- und weichmagnetische Werkstoffe

AM 7.6: Talk

Monday, March 27, 2000, 16:45–17:00, H10

High coercivity of Nd-Dy-Fe-(C,B) prepared by melt spinning — •Jinbo Yang, O. Gutfleisch, A. Handstein, D. Eckert, and K.-H. Müller — IFW Dresden, Postfach 270016, 01171 Dresden

Nd₁₃Dy₂Fe₇₇C₈ and Nd₁₃Dy₂Fe₇₇C₆B₂ compounds with tetragonal Nd₂Fe₁₄B (2:14:1)-type structure have been synthesized by vacuum annealing of melt-spun ribbons. Coercivities µ_0JH_c of 1.8 T and 2.0 T, remanences B_r of 0.63 T and 0.69 T, and maximum energy products (BH)_max of 70 kJ/m³ and 89 kJ/m³ at room temperature are achieved for magnetically hard Nd₁₃Dy₂Fe₇₇C₈ and Nd₁₃Dy₂Fe₇₇C₆B₂ samples after optimum heat treatment, respectively. An even higher coercivity of 2.5 T was measured for as-quenched Nd₁₃Dy₂Fe₇₇C₆B₂ ribbons. It is found that substitution of carbon by boron accelerates the formation of 2:14:1 phase in the as-spun ribbons. The grain size and purity of the 2:14:1-type phases are the most important factors affecting the hard magnetic properties of melt-spun Nd-Fe-C based materials.