The Influence of Mechanochemical Activation on the Properties of a Double Complex Salt [Co(NH3)6][Fe(C2O4)3]·3H2O and Its Thermolysis Products

In this work, the effect of mechanical activation (MA) on the double complex salt (DCS) [Co(NH3)6][Fe(C2O4)3]·3H2O and its thermolysis is investigated. Mechanical activation is a promising “green chemistry” method that allows improving the physicochemical properties of the DCS [Co(NH3)6][Fe(C2O4)3]·3H2O and the products of its thermal decomposition in an argon atmosphere. The conditions of the MA process and the effect of MA and passivation on the process and kinetics of DCS thermal degradation were investigated. It was shown that due to the removal of outer-sphere coordinated water and carbonation of the DCS during MA, the number of thermal degradation stages changes. It was established that passivation at 450 °C for MA times of 0 and 10 min prevents spontaneous “combustion” of the thermal degradation products of the DCS. Optimal conditions for DCS processing were determined to be 5 min of MA and heat treatment at 450 °C without passivation. Under these conditions, the yield of the CoFe intermetallic compound reaches 82.6 wt%. This optimal combination of sample production conditions allows for a reduction in MA time and the elimination of the passivation process, making the process more cost-effective and creating conditions for optimizing the production of functional materials.