【摘要】 以α Fe2O3和NiO粉体为原料,NaCl为稀释剂,利用固相机械化学反应,在高能球磨作用下合成了NiFe2O4纳米晶。采用X射线衍射分析了合成NiFe2O4的过程和不同焙烧温度对晶粒尺寸的影响,计算了前驱体热处理过程晶粒长大的活化能。研究结果表明:制备的NiFe2O4纳米晶的晶粒尺寸为20～30nm;焙烧温度越高,晶粒尺寸越大;NiFe2O4晶粒长大的表观活化能为16.7kJ/mol,这表明热处理过程的晶粒长大主要以界面扩散为主。更多还原

【Abstract】 Nanocrystalline nickel ferrite （NiFe₂O₄） was successfully synthesized by mechanochemical reaction of α-Fe₂O₃ and NiO powders in equimolar ratio with NaCl as a diluent through high energy balling. The reaction process and the effect of calcination temperature on the crystal size of the spinel NiFe₂O₄ were discussed by X-ray diffraction（XRD） technique. The mechanism for the nanocrystallite growth was primarily investigated through the calculation of activation energy. The results show that synthesized NiFe₂O₄ has a nanocrystalline structure with a crystallite size of 20～30 nm. The higher the calcination temperature, the larger the crystallite size. The activation energy for the crystal growth is evaluated to be 16.7 kJ/mol. It can be considered that the crystallite grows primarily by means of an interfacial reaction during the thermal treatment.更多还原