Effect of Melt Temperature on the Microstructure and Magnetic Properties of Nd8.5Fe77Co5Zr3B6.5 Nanocomposite Magnet

Abstract:

Nanocomposite Nd8.5Fe77Co5Zr3B6.5 alloys were prepared by melt-spinning under different melt temperatures. The effect of melt temperature on the microstructure and magnetic properties of alloys was investigated. The results show that the melt temperature is a key factor that affects the microstructure and magnetic properties of as-quenched and also as-annealed alloys. The as-quenched alloys melt-spun at 1210 °C are composed of amorphous phase and Nd2Fe14B phase. The relative content of amorphous phase in as-quenched alloys increases as melt temperature increases. As-spun alloys with high content of amorphous phase show soft magnetic properties. Subsequent annealing of as-spun alloys initiates the formation of nanocrystalline Nd2Fe14B phase and precipitation of a small amount of soft magnetic phase. Alloys with finer microstructure and more favorable magnetic properties are obtained by crystallizing the as-quenched alloys melt spun at lower melt temperature. The as-annealed alloys melt-spun at 1210 °C shows optimum magnetic properties with an intrinsic coercivity of 559.2 kA/m, remanence of 0.98 T, and maximum energy product of 127.8 kJ/m3.