Activity–composition relations of solid solutions and stabilities of end-member compounds in the system MgONiOTiO2 in contact with metallic nickel at 1400°C

摘要: Abstract Equilibria between metallic nickel, a gas phase of known oxygen pressures, and pairs solid-solution phases in the system MgONiOTiO 2 are used to derive activity—composition relations for solid solutions Mg TiO 4 Ni (spinel), MgTiO 3 NiTiO (geikielite) MgTi O 5 NiTi (pseudobrookite), free energies formation end-member compounds at 1400°C. The curves spinel pseudobrookite practically linear, whereas geikielite solution display slight positive deviation from linearity only stable compound NiOTiO 1400°C is NiTiO , phase, Ni NiTi unstable relative assemblages + NiO respectively. various their oxide components were determined as follows: