【摘要】 借助热膨胀仪,采用恒升温速率法研究了升温速率和添加剂MnO₂对镍铁尖晶石的初期烧结行为影响。结果表明,较低的升温速率可以使样品获得较大的线收缩,添加MnO₂,可以降低样品的开始形成烧结颈温度,加快镍铁尖晶石的致密化过程。添加MnO₂后各体系的初期烧结均由晶界扩散机制转变成了体积扩散机制,烧结过程的表观活化能均大幅下降,其中添加1.0%（质量分数）MnO₂的体系下降最为明显,从未添加时的813.9kJ/mol降到了441.9kJ/mol。更多还原

【Abstract】 The influence of heating rates and MnO₂ additives on early-stage sintering behavior to synthesize NiFe₂O₄ has been investigated.The results show that lower heating rates can produce more obvious shrinkage.Introduction of MnO₂ can shift the onset of sintering toward lower temperatures.The early-stage sintering of NiO-Fe₂O₃ system is mainly controlled by grain boundary diffusion.For MnO₂-doped samples,the early-stage sintering mechanisms are controlled by volume diffusion.The apparent activation energy of these doped samples decreased obviously,and for the 1.0wt% MnO₂-doped sample,apparent activation energy decreased from 813.9to 441.9kJ/mol.更多还原