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 MgAlM₂O₄ and Mg_2+2δ Ti_1–δO₄. Decomposition of the solid solution is accompanied by crystallization of MgTiO₃.