Phase Equilibria in the ZrO2-MgO-MnOx System

• Published in: Journal of the American Ceramic Society 2016-09, Vol.99 (9), p.3136-3145
• Main Authors: Pavlyuchkov, Dmytro, Dilner, David, Savinykh, Galina, Fabrichnaya, Olga
• Format: Article
• Language: English
• Subjects: Alloys; Differential thermal analysis; Diffractometry; Isothermal sections; Isotherms; Magnesia; magnesium oxide; Manganese compounds; Manganese oxide; manganese/manganese compounds; Oxygen partial pressure; phase diagrams; Phase equilibria; Phase transitions; Powder x-rays; Scanning electron microscopy; Solid solutions; Spinel solid solutions; spinels; Temperature intervals; Thermoanalysis; X ray diffraction analysis; zirconia; Zirconium alloys
• ISSN: 0002-7820; 1551-2916; 1551-2916
• DOI: 10.1111/jace.14327

Phase equilibria were experimentally investigated in the MgO–MnOx and the ZrO2–MgO–MnOx systems for different oxygen partial pressures by powder X‐ray diffractometry, scanning electron microscopy, and differential thermal analysis. The formation of two compositionally and structurally different β‐spinel solid solutions was observed in the MgO–MnOx system in air in the temperature interval 1473–1713 K. Isothermal sections of the ZrO2–MgO–MnOx phase diagram were constructed for air conditions (PO2 = 0.21 bar) at 1913, 1813, 1713, 1613, and 1523 K. In addition, isothermal sections at 1913 and 1523 K were constructed for PO2 = 10−4 bar. The β‐spinel and halite phases of the MgO–MnOx system were found to dissolve up to 2 and 5 mol% ZrO2. A continuous c‐ZrO2 solid solution forms between the boundary ZrO2–MnOx and ZrO2–MgO systems. It stabilizes in the ZrO2–MgO–MnOx system down to at least 1613 K in air and down to 1506 K at PO2 = 10−4 bar.