Kinetics of thermal decomposition of nickel oxalate dihydrate in air

Thermal decomposition taking place in solid state complex, NiC2O4·2H2O, has been investigated in air by means of TG-DTG/DTA, DSC, XRD. TG-DTG/DTA curves showed that the decomposition proceeds through two well-defined steps with DTA peaks closely corresponding to the weight loss obtained. XRD showed that the final decomposition product of NiC2O4·2H2O was NiO. Kinetics analysis of NiC2O4·2H2O decomposition steps was performed under non-isothermal conditions. The activation energies were calculated through Friedman and Flynn-Wall-Ozawa (FWO) methods, and the most possible kinetic model function has been estimated through the multiple-linear regression method. The activation energies for the two decomposition steps of NiC2O4·2H2O were 171.1 ± 4.2 and 174.4 ± 8.1 kJ/mol, respectively.