The characterization of Co xZn7-xSb2O12 spinel obtained by the pechini method

Abstract

Oxides with spinel structures have been studied for many decades as they have been used in a variety of applications like pigments and refractories. They have also been used as a model structure to evaluate the relative stability of ions in octahedral and tetrahedral sites. Zinc-antimony spinels (Zn 7 Sb 2 O 12 ) were synthesized by the Pechini method and the cation Zn 2+ was substituted by Co 2+, taking into consideration the stoichiometry of Co x Zn 7-x Sb 2 O 12 (x = 0 -7). Characterization of the thermal properties of pyrolyzed powders was carried out with a TG/DTA analyzer, and mass losses were determined as a function of the cobalt content in the resin. The powders were calcined at temperatures in the range 600 to 1000 °C and characterized by XRD, BET and IR spectroscopy. Maximum cristalinity was obtained in powders calcined at 1000 °C. Materials with x = 5 -7 revealed the presence of a secondary phase (Co, Zn)Sb 2 O 6 . Infrared analysis facilitated in the determination of the possible sites of Zn 2+ , Co 2+ and Sb 2+ ions in the lattice.

Yellow ZnxNi1−xWO4 pigments obtained using a polymeric precursor method

“…This result was observed from the TG and DTA curves, which show that zinc-rich samples displayed greater mass loss and more exothermic peaks. These findings indicate the difficulty of eliminating carbon from the samples during calcination at 350 C. The same behavior has been observed for other zinc-containing compounds [15].…”

Color and structural analysis of CoxZn7−xSb2O12 pigments

“…4). Other properties of the studied system were as well noticed to present a deviation from the Végard law, as observed in literature [14]. The (Sn 1Àx Ti x )O 2 system was also shown to disobey the Végard law, at the vicinities of the equimolar cation concentration, too [15].…”