Synthesis of MgNi2O3 and kinetics of thermal decomposition of the oxalate precursor

The thermal decomposition processes taking place in the solid state mixture of NiC2O4·2H2O–MgC2O4·2H2O (2:1 mole ratio) have been investigated in air using TG–DTG, differential scanning calorimetry (DSC) and XRD techniques. The decomposition proceeded through four well-defined steps while TG curves closely corresponded to the theoretical mass loss. The result of XRD showed the well-crystallized MgNi2O3 formed in the sample calcined at 600 °C for 2 h. The activation energies for the decompositions of NiC2O4 and MgC2O4 were calculated through the Ozawa and Kissinger–Akahira–Sunose (KAS) methods, and the possible conversion functions have been estimated through the comparative method. The activation energies for the decompositions of NiC2O4 were 151.05 kJ/mol (KAS method) and 152.6 kJ/mol (Ozawa method), and the activation energies for the decompositions of MgC2O4 were 204.74 kJ/mol (KAS method) and 205.72 kJ/mol (Ozawa method). The possible conversion function for the decomposition of NiC2O4 and MgC2O4 kept to the conversion function of “Nucleation and Growth” and “phase boundary reaction”, respectively.