Bao Xiaoqian

Wiedemann effect of Fe—Ga based magnetostrictive wires

(Fe83Ga17)98Cr2 wires each with a diameter of 0.7 mm are prepared by hot swaging and warm drawing from the casting rods directly, because the ductility of Fe83Ga17 alloy is improved by adding Cr element. The Wiedemann twists and dependences on magnetostrictions of Fe83Ga17 and (Fe83Ga17)98Cr2 wires are investigated. The largest observed Wiedemann twists of 245 scm−1 and 182 scm−1 are detected in the annealed Fe83Ga17 and (Fe83Ga17)98Cr2 wires, respectively. The magnetostrictions of the annealed Fe83Ga17 and (Fe83Ga17)98Cr2 wires are 160 ppm and 107 ppm, respectively. The maximum of the Wiedemann twist increases with magnetostriction increasing. However the magnetostriction is just one important factor that affects the Wiedemann effect of alloy wire, and the relationship between magnetostriction and Wiedemann effect is a complex function rather than a simple function.

Effect of Doping of Ti and C on Crystallization and Magnetic Properties of NdPrFeB Thick Melt-Spun Ribbons

Abstract Effects of Ti and C addition on crystallization process and magnetic properties of NdPrFeB thick ribbons were investigated. The results show that doping of Ti suppresses the formation of (Nd,Pr) 2 Fe 23 B 3 metastable phase and refines grains of the alloys and increases coercivity significantly. In the case of co-addition of Ti and C, the coercivity is decreased but the remanence is enhanced with increasing of C content. The magnetic properties of J r =0.88 T, H cj =618 kA/m and ( BH ) max =109.8 kJ/m 3 are achieved in the (Nd 0.4 Pr 0.6 ) 9 Fe 72 Ti 4 B 11 C 4 ribbons after optimal annealing.

Effect of titanium substitution on magnetic properties and microstructure of nanocrystalline monophase Nd-Fe-B magnets

Nd12.3Fe81.7-xTixB6.0 (x = 0.5-3.0) ribbons have been prepared by rapid quenching and subsequent annealing treatment. Effect of Ti substitution and annealing treatment on the microstructure, magnetic properties, and crystallization behavior of the ribbons was systematically investigated by the methods of differential scanning calorimeter (DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). It is found that Ti addition may increase the crystallization temperature and stabilize the amorphous phase. Ti element inhibits the grain growth during crystallization process and finally refines the microstructure. The exchange coupling interactions and magnetic properties of the ribbons increase with increasing x from 0.5 to 1 and then decrease with further increasing x ≥ 1.5. Optimum magnetic properties with (BH)max = 151.6 kJ/m3, Hci = 809.2 kA/m, Jr = 1.02 T are achieved in the Nd12.3Fe80.7Ti1B6.0 ribbons annealed at 600°C for 10 min.