Abstract:The crystallization behavior of melt-spun Nd_8.5Fe₇₈Co₅Cu₁Nb₁B_6.5 ribbons was investigated using dynamic differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). It was found that the as-spun ribbons crystallize in two steps: at first the Nd₃Fe₆₂B₁₄+α-Fe phases are formed and subsequently Nd₃Fe₆₂B₁₄ transformed to Nd₂Fe₁₄B and α-Fe upon heating above 680℃. The effective activation energy of two crystallization peaks are 332.0kJ/mol and 470.5kJ/mol, respectively. As the wheel speed increases, the magnetic properties of the magnet change obviously. When the wheel speed is 18m/s, the best magnetic properties of the magnet was obtained after the sample was annealed at 690℃ for 8min: B_r=0.74T, _iH_c=421.7kA/m, (BH)_max=64.5kJ/m³.

Key words: nanocomposite magnet；crystallization behavior；activation energy