SYNTHESIS OF THE NANOCRYSTALLINE NICKEL FERRITE BY A NOVEL MECHANO SOL-GEL AUTO-COMBUSTION METHOD

In this work, a novel method of mechano sol-gel auto-combustion has been developed for production of single phase nickel ferrite nano crystalline powder, consisting of a sol-gel auto-combustion synthesis followed by a high energy milling process before calcination. Sol-gel auto-combustion was carried out using a gel including citric acid as a reductant and metal nitrates as oxidants. This gel exhibited a self-propagating behavior after ignition in air. The effects of the intermediate high energy milling on the physical properties of the final product after calcination were investigated. The results showed that with a high energy milling of the sol-gel auto-combusted powders with a ball-to-powder mass ratio of 20 for 20h, the temperature of calcination for synthesis of the single phase ferrite reduced from 1000 degrees C to 700 degrees C and the size of the ferrite crystallites decreased from 72 nm to 15 nm.