Co基非晶软磁合金的制备与晶化动力学行为研究

采用旋铸急冷工艺在大气环境中制备出Co6.85Fe4Si10B17.5非晶合金带材.XRD分析表明:样品为完全非晶.用DiamondTG/DTA差热分析仪在高纯氩气保护下测量了非晶薄带的等温晶化动力学曲线.采用JMA方程计算出了合金的晶化动力学参数,在不同的晶化温度下,Avrami指数的值在2.11～2.58之间,晶化激活能Ec为113.67 kJ/mol.Co6.85Fe4Si10B17.5非晶合金的晶化方式是初晶型(761、791、803 K)和共晶型晶化(813 K),合金的晶化百分比与退火时间的关系曲线均为S型曲线.

Study on Preparing and Crystallization Kinetics of Melt-Spun Co-Based Soft Magnetic Amorphous Alloy

Amorphous ribbons of Co6.85Fe4Si10B17.5 were prepared by a single roller melt-spinning technique in the air atmosphere.The crystallization products were analyzed by X-ray diffraction.The crystallization kinetics of the alloys were investigated by means of differential scanning calorimetry(DSC)in the mode isothermal annealing.It is found.in the case when the isothermal kinetics was modeled by the Johnson-Mehl-Avrami equation.the Avrami exponents are calculated to be in the range of 2.11～2.58 for different isothermal temperatures.This implies that the crystallization of CO68.5Fe4Si10B17.5 amorphous alloy is governed by either diffusion or interface controlled three-dimensional growth,depending on the annealing temperature.On the basis of the Arrhenius relation.the activation energy in the isothermal process is calculated to be Ec=113.67 kJ/mol.Finally,details of the nucleation and growth behaviors during the isothermal crystallization are discussed.