Cobalt ferrite (CoFe2O4) powders with nanocrystalline sizes were produced by a combination of sol-gel auto-combustion and ultrasonic irradiation methods employing a mixture of urea, thiourea and glycine as the fuel with the corresponding metal nitrates. The pH in the starting solution affects the combustion process, and then determines the particle size of the assynthesized powder. The influence of the pH value on the gel auto-combustion and the phase composition of the synthesized powders have been studied with the help of scanning electron microscopy (SEM) observations, Fourier transform infra red (FTIR) spectroscopy and X-Ray diffraction (XRD) techniques. The synthesized powders had a particle size distribution in the range of 23-43 nm.

Keywords: Cobalt ferrite, Nanocrystalline, Sol-gel auto-combustion, Ultrasonic irradiation, pH value.