International Journal of Nano Dimension (Int. J. Nano Dimens.) Effect of pH on nanocrystalline Co-ferrite prepared using urea and thiourea fuels by combination of sol-gel auto combustion and ultrasonic irradiation methods Volume 3 (2012) Issue 2, December 2012 2024 03 01 Effect of pH on nanocrystalline Co-ferrite prepared using urea and thiourea fuels by combination of sol-gel auto combustion and ultrasonic irradiation methods 10.7508/ijnd.2012.02.007 EN Sh. Moradi Chemistry Department, North Tehran Branch, Islamic Azad University, Tehran, Iran. S. S. Madani Chemistry Department, North Tehran Branch, Islamic Azad University, Tehran, Iran. G. Mahmoudzadeh Chemistry Department, North Tehran Branch, Islamic Azad University, Tehran, Iran. M. Zhalechin Chemistry Department, North Tehran Branch, Islamic Azad University, Tehran, Iran. S. A. Khorrami Chemistry Department, North Tehran Branch, Islamic Azad University, Tehran, Iran. Journal Article 2024 03 01 The aim of this study is to evaluate the influence of pH on the synthesis of nanocrystallines cobalt ferrite by combination of sol- gel auto combustion and ultrasonic irradiation methods. Two different fuels, urea and thiourea, along with metal nitrates (oxidant) were used to prepare CoFe2O4 powders. The morphology of the resulting powders was investigated. The powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Phase pure spinel cobalt ferrite powder was obtained at pH values 6 and 7 after the calcinations at 750˚C when urea was used as the fuel; however, the samples obtained using thiourea fuel contained impurities. The average crystalline size was 21 and 37 nm, respectively, for the samples containing urea and thiourea.