Fig. 5.2 a The complete phase diagram obtained by quenching from 800 C after heating in oxygen for 3 h. The red lines are boundaries to the single-phase regions, green dashed lines are tie-lines while red dashed lines are tie-lines at the outer edges of the three-phase regions. The blue dotted line represents a phase transition from the cubic rocksalt to the layered rocksalt structures. b The.. Due to its metastability, the spinel phase is usually considered as an intermediate state of the layered → rock-salt transformation. 187−189 The atomic configurations of these phases are.
In an attempt to enlarge the normal spinel phase diagram for the quaternary Li-Ni-Mn-Co-O system, the transformation at moderate temperatures (150-210 °C) of layered Li0.5(Ni1-y-zMnyCoz)O2 (R3̅m), which were obtained by an ambient-temperature extraction of lithium from Li0.5(Ni1-y-zMnyCoz)O2, into normal spinel-like (Fd3̅m) Li(Ni1-y-zMnyCoz)2O4 has been investigated.. Phase Diagram of MgO-Al2O3 System Spinel Compound Spinel is a compound with the chemical formula MgAl2O4 (or MgO-Al2O3). It is represented on the phase diagram as a single-phase field. Spinel is nonstoichiometric for compositions other than 50 mol% Al2O3-50 mol% MgO. The composition of spinel is 50 mol% Al2O3-50 mol% MgO (72 wt% Al2O3-28 wt% MgO).