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

NiFe2O4 nanopowders were prepared by low temperature solid-state reaction. The effect of calcination 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.