煅烧温度对低温固相合成NiFe₂O₄纳米粉显微组织结构的影响

Effect of Calcination Temperature on the Microstructure of NiFe₂O₄ Nanopowder Synthesized by Low Temperature Solid-State Reaction

摘要: 采用低温固相合成法制备NiFe₂O₄纳米粉，重点研究煅烧温度对分析物相与形貌的影响。通过XRD、SEM和TEM对所得粉体进行表征。研究结果表明：随着煅烧温度的提升，衍射峰强度逐渐增强，衍射峰逐渐变得尖锐，粉体的结晶度变好，粉体的平均晶粒尺寸增大；NiFe₂O₄晶粒在煅烧过程中的晶粒长大活化能为14.76 kJ∙mol⁻¹，晶粒长大主要以界面扩散为主；煅烧温度提升，潜伏期变短，晶粒生长速率增大，颗粒多边形化特征明显，颗粒明显长大。

Abstract: NiFe2O4 nanopowders were prepared by low temperature solid-state reaction. The effect of calci-nation temperature on the microstructure of NiFe₂O₄ nanopowder was investigated in details. The as-obtained powders were characterized by XRD, SEM and TEM. The results show that the reflection peaks enhance and become sharper as the calcination temperature increases, indicating the improvement of crystallinity and grain size. The grain growth activation energy of NiFe₂O₄ during calcination was 14.76 kJ∙mol⁻¹, implying that the principal transmission mechanism was interfacial diffusion. As the calcination temperature increases, the incubation period shortens; the growth rate increases, the characteristic of particle polygonization becomes obvious and the grains grow up evidently.