Phase Equilibria and Chemical Reactions in the Mn2O3–ZnO–SiO2, Mn3О4–ZnO–SiO2, and MnO–ZnO–SiO2 Systems

The subject matter of this work was the triangulation of the Mn 2 O 3 –ZnO–SiO 2 , Mn 3 O 4 –ZnO–SiO 2 , and MnO–ZnO–SiO 2 systems and the determination of phase transformations to yield Zn 2 – 2 х Mn 2 х SiO 4 solid solution. Equilibrium phase diagrams have been plotted taking into account the existence temperatures of each of the manganese oxides, phase compositions of the constituent binary systems, and checkup points, whose phase compositions helped us to determine the positions of secondary triangles. The phase compositions of reaction products of the terminal oxides and the phase transformation sequence during Zn 2 – 2 х Mn 2 х SiO 4 synthesis were monitored by X-ray powder diffraction and thermal analysis. Phase ratios in the MnO х –ZnO–SiO 2 system are caused by the charge states of manganese ions changing in response to rising temperature. The triangulation of the Mn 2 O 3 –ZnO–SiO 2 system at 800°С is determined by the ZnMn 2 O 4 –Zn 2 SiO 4 tie-line and partitions the system to the ZnO–Zn 2 SiO 4 –ZnMn 2 O 4 , Zn 2 SiO 4 –ZnMn 2 O 4 –SiO 2 , and ZnMn 2 O 4 –SiO 2 –Mn 2 O 3 simplex triangles. The Zn 2 – 2 х Mn 2 х SiO 4 solid solution with an extent limited to Zn 1.6 Mn 0.4 SiO 4 is formed at temperatures above 1000°С. The triangulation of the MnO–ZnO–SiO 2 ternary system is determined by the Zn 1.6 Mn 0.4 SiO 4 –ZnO–MnSiO 3 simplex triangle.