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采用高真空高纯氩DSC测量了(Nd,Pr)12.8Dy0.2Fe77.4Co4.0B5.6非晶快淬薄带以及不同温度退火薄带的连续加热曲线,计算了晶化激活能、频率因子、晶化体积分数、晶化速率,研究了预退火前后薄带的晶化动力学和晶化过程。结果表明(Nd,Pr)12.8Dy0.2Fe77.4Co4.0B5.6快淬薄带在30 K/min加热速度时DSC曲线起始晶化温度865.8 K、峰值晶化温度877.2 K、晶化结束温度901.7 K,居里温度转折点581.2 K,富稀土相的初始熔化点1003.6 K。在高于峰值晶化温度或晶化结束温度退火10 min的薄带非晶完全晶化,居里温度处形成吸热峰,而低于803.0 K退火处理的薄带以及快淬薄带在相近温度处只有DSC转折点。相对于快淬薄带直接晶化的特征,在低于起始晶化温度的693.0~743.0 K退火处理的薄带晶化峰形相近;803.0 K退火处理后薄带的晶化峰的温度范围增宽:在10~40 K/min相同加热速度下其起始晶化温度均降低1.4%,晶化结束温度在加热速度20~40 K/min时达到、甚至高于快淬薄带直接晶化结束温度;在低于快淬薄带直接晶化的峰值晶化温度之前存在一个具有相同晶化速率的临界温度,在低于该临界温度时,退火薄带比快淬薄带具有较高的晶化速率、更不稳定;而在高于该临界温度,退火薄带比快淬薄带具有较低的晶化速率。
The continuous heating curves of (Nd, Pr) 12.8Dy0.2Fe77.4Co4.0B5.6 amorphous quenched ribbons and different temperature annealed ribbons were measured by high vacuum high purity argon DSC. The crystallization activation energy, frequency factor , Crystallization volume fraction and crystallization rate, the crystallization kinetics and crystallization process of the strip before and after annealing were studied. The results show that the initial crystallization temperature of DSC curve is 865.8 K and the peak crystallization temperature is 877.2 K at a heating rate of 30 K / min for the (Nd, Pr) 12.8 DyO.2Fe77.4Co4.0B5.6 quenched ribbon. The crystallization end temperature 901.7 K, the Curie temperature turning point 581.2 K, and the rare earth rich phase melting point 1003.6 K. The crystallization of the ribbon was completely crystallized at 10 min after annealing at the peak crystallization temperature or crystallization temperature, and the endothermic peak was formed at the Curie temperature. However, the annealed ribbons below 803.0 K and the quenched ribbons were close Only DSC turning point at temperature. Compared with the direct crystallization of quenched ribbon, the peak shape of ribbon annealed at 693.0 ~ 743.0 K below the initial crystallization temperature is close to that of the annealed ribbon. The temperature range of the crystallization peak of the ribbon annealed at 803.0 K Broadening: the initial crystallization temperature decreased by 1.4% at the same heating rate of 10-40 K / min, the crystallization finishing temperature reached at the heating rate of 20-40 K / min or even higher than that of the quenched ribbon direct crystal The finish temperature; before the peak crystallization temperature below the direct crystallization of the quenched ribbon, there is a critical temperature with the same crystallization rate below which the annealed ribbon has a higher value than the quenched ribbon Of the crystallization rate, more unstable; and above the critical temperature, annealed ribbon quenched ribbon has a lower crystallization rate.