Activity—composition relations of solid solutions and stabilities of manganese and nickel titanates at 1250°C as derived from equilibria in the systems MnOCoOTiO2 and MnONiOTiO2

Equilibria between a metal phase (either cobalt or nickel), a gas phase of known oxygen pressures, and pairs of solid-solution phases in the systems MnOCoOTiO₂ and MnONiO₂ are used to calculate activity—composition relations in the solid-solution series Mn₂TiO₄Co₂TiO₄, MnTiO₃CoTiO₃, MnTi₂O₅CoTi₂O₅, Mn₂TiO₄Ni₂TiO₄ and MnTiO₃NiTiO₃, and free energies of formation of the manganese titanates Mn₂TiO₄, MnTiO₃ and MnTi₂O₅ and of nickel orthotitanate, Ni₂TiO₄.