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利用管式电阻炉和X射线衍射仪(XRD)实施了对恒温退火处理100、200、300和500 nm 4种粒径的微纳米铁粉热稳定特性实验研究,通过函数拟合衍射峰图谱计算其微观应变,分析退火过程中微纳米铁粉晶粒长大现象。结果表明:微观应变的大小和晶粒长大过程密切相关,随着退火温度升高,微观应变逐渐减小,晶粒尺寸增大。100、200和300 nm微纳米铁粉200℃以下晶粒长大迅速,200℃以上长大速度减小;500 nm铁粉晶粒200℃以下长大速度比较缓慢,200℃以上晶粒迅速长大。低温下大粒径铁粉热稳定性优于小粒径铁粉。
An experimental study on the thermal stability of micron-sized iron powders with different grain sizes of 100, 200, 300 and 500 nm was carried out by means of tube resistance furnace and X-ray diffraction (XRD). The thermal stability was calculated by function fitting diffraction peak pattern The micro-strain, analysis of the annealing process of micro-nano iron powder grain growth phenomenon. The results show that the microscopic strain is closely related to the grain growth. With the increase of annealing temperature, the micro-strain decreases and the grain size increases. The grain sizes of 200, 200, and 300 nm micro-nano iron powders grow rapidly below 200 ℃ and the growth rates of grains grow faster than 200 ℃. The growth speed of 500 nm iron grains below 200 ℃ is relatively slow, and the grain sizes above 200 ℃ Big. The thermal stability of large size iron powder is better than that of small size iron powder at low temperature.