Spectrothermal studies on the decomposition course of cobalt oxysalts Part I. Basic cobalt carbonate

Abstract

The thermal decomposition course of basic cobalt carbonate (BCoC),2 CoCO 3 · 3 Co( OH) 2· xH 2 O ( x=5), was characterized to the onset of formation of CoO. The thermal events encountered throughout the decomposition course were monitored by means of thermogravimetry, differential thermal analysis and differential scanning calorimetry. The intermediates obtained were characterized by infrared spectroscopy, X-ray diffractometry and scanning electron microscopy. Results showed that the genesis of CoO from BCoC occurred through four events. Basic cobalt carbonate trihydrate as an intermediate was identified and then decomposed, producing Co 3O 4 which in turn decomposed at 850 °C, giving CoO as a final product in both air and nitrogen. The morphological changes accompanying the thermal treatment of BCoC were observed and correlated with the structural modifications.