Thermodynamic interpretation of the manganese-zinc ferrite synthesis by calcination of a powder mixture

摘要

The free energy of formation for Mn_(0.5)Zn_(0.5)Fe_2O_4 has been determined based on thermodynamic equilibrium of the Mn-Zn-Fe-H_2O system under conditions prevailing in the hydrothermal synthesis experimental work published recently by other authors. The equilibrium diagrams generated in this work have been used to interpret published experimentally observed results on manganese-zinc ferrite synthesis and behavior during cooling. The conclusion is that all experimental results and problems concerning the thermodynamic behavior of the system Mn-Zn-Fe-O during synthesis and cooling down are perfectly explained by the prediction of the equilibrium diagrams developed in this work. Moreover, further benefits will arise from feeding the free energy data provided here into the computational thermodynamics softwares to generate equilibrium diagrams that are not yet available involving this type of ferrite.