Influence of stoichiometry and calcination condition on the microstructure and phase constitution of NiFe_2O_4 powders prepared by sol-gel autocombustion method

摘要

The phase constitution and the microstructure of NiFe_2O_4 powders prepared by a sol-gel autocombustion route have been studied in this research. Amorphous gels, as-burnt powders with a varying Fe/Ni ratio and calcined powders at temperatures between 600-1000°C for 1h, were investigated by using DTA/TG, XRD and SEM techniques. The results show that different Fe/Ni ratios in the starting solution and different calcination affect the crystal size of the synthesized powder and the phase constitution. SEM micrograph also shows a particle size less than 100 nm.