Interaction and Magnetic Properties of NdCeFeB Melt-Spun Ribbons

Abstract:

The alloy ingots with nominal compositions of (Nd_1-xCe_x)_2.4Fe₁₄B (x=0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared by induction melting and then melt-spun to form nanocrystalline ribbons. Phase composition, magnetic properties and microstructure were investigated. XRD results show that all melt-spun ribbons exhibit the tetragonal structure (Nd,Ce)₂Fe₁₄B phase. When Ce substitution content is more than x=0.6, CeFe₂ phase appears and CeFe₂ content increases with the increase in Ce substitution content. Remanence, remanence ratio (M_r/M_s) and lattice constant decrease while increasing Ce substitution content. A coercivity of 1.31×10⁶ A/m and the maximum energy product of 103 kJ/m³ for (Nd_0.8Ce_0.2)_2.4Fe₁₄B melt-spun ribbon are achieved. The coercivity mechanism and intergrain exchange coupling were studied. The positive δM value was observed in every sample, confirming the existence of exchange coupling interaction. The δM maximum value reaches 0.76 at the Ce substitution content x=0.2, indicating that the intergranular exchange coupling effect is the strongest, which is consistent with the varying remanence ratio. SEM observation reveals that increasing Ce substitution deteriorates the columnar crystal structure of ribbons.