纳米晶(FeCo)78Nb6B15Cu1合金晶化过程及其磁特性研究

采用熔体快淬法制备(FeCo)78Nb6B15Cu1非晶薄带,通过DSC测试薄带的晶化特性,并据此在400,500,700和750℃进行1h退火处理。用XRD和SEM分析薄带在不同退火温度下的晶化行为,并用VSM测试薄带与粉体的静态磁参数。结果表明:对于固定成分的Hitperm合金,选择合适的退火温度,可控制晶粒大小和晶相比例。由于晶粒表面无序磁矩含量的变化,导致材料比饱和磁化强度发生变化,同时更小的纳米晶粒对降低矫顽力有利。由于淬态引入的微量结晶,薄带存在表面晶化现象,这在一定程度上会恶化材料的静态磁特性。

Crystallization Process of Nanocrystalline (FeCo)78Nb6B15Cu1 Alloy and Its Magnetic Characterization

(FeCo)78Nb6B15Cu1 amorphous ribbons were prepared by a melt-quenching method; crystallization characteristics of the ribbons were tested by DSC, and accordingly annealing at 400, 500, 700 and 750 oC for 1 h were carried out. Crystallization behavior of the ribbons at different annealing temperatures was analyzed by XRD and SEM and the static magnetic parameters of the ribbon and the powder were measured by VSM. The results show that for the Hitperm alloy with a fixed composition, a suitable annealing temperature can control the grain size and phase ratio and adjust disorder magnetic moment of the grain surface, thereby improving the specific saturation magnetization of material. Moreover, the small nano-grain is favorable for depressing the coercivity. Due to the introduction of ultracrystallite when quenching, there is crystallization on the surface of the ribbon, which will worsen the static magnetic properties of materials to a certain extent