Crystallization process and soft magnetic properties of nanocrystalline (Fe_(0.5)Co_(0.5))_(86) Hf_7 B_6 Cu_1 alloy used in elevated temperature applications

摘要

Nanocrystalline (Fe_(0.5)Co_(0.5))_(86) Hf_7B_6Cu_1 HITPERM alloy was investigated as the candidate of soft magnetic material for high temperature applications, compared with Fe_(86)Hf_7B_6Cu_1 NANOPERM alloy. Amorphous alloy ribbons were prepared by single-roller melt-spinning technology. Crystallization process of as-quenched ribbon was investigated using differential scanning calorimeter at different heating rates. The coercivity was determined from quasi-static hysteresis loop measured at room temperature using a computerized hysteresis loop tracer. X-ray diffraction with Cu K_α radiation was used to determine the structure. The vibrating sample magnetometer was used to measure the magnetization as a function of temperature of the nanocrystllized alloys. That Co substitution for Fe in alloy enhances the Curie temperature of amorphous alloy and the magnetization of nanocrystalline alloy at high temperature. After annealing amorphous precursor, the optimum nanocrystalline alloy obtained shows the local minimum coercivity. The coercivity increases with the increasing annealing temperature corresponding to the formation of ferromagnetic phase in the secondary crystallization.