Spinel solid solutions in the systems MgAl2O4–ZnAl2O4 and MgAl2O4–Mg2TiO4

Phase relations in two binary systems MgAl2O4 –ZnAl2O4 and MgAl2O4 –Mg2TiO4 have been studied and phase diagrams for them have been constructed. Based on the data of x-ray phase and crystal-optical analyses, the formation of a continuous series of solid solutions with spinel structure between the terminal members of the systems studied has been established. In the MgAl2O4 –ZnAl2O4 system the solid solution is stable in the range from room temperature to melting temperature. In the MgAl2O4 –Mg2TiO4 system the solid solution decomposes below 1380 °C, yielding the formation of limited regions of homogeneity on the basis of MgAl2O4 and Mg2+2δ Ti1-δO4. Decomposition of the solid solution is accompanied by crystallization of MgTiO3.