LAUSR

This contribution is devoted to thermoanalytical investigation of the mechanism of the formation of solid solutions of Li1+xCrxZr2−x(PO4)3. The samples were prepared by high-temperature solid-state reaction in the reaction mixtures of (0.5 + x/2)Li2CO3–(2 − x)ZrOCl2·8H2O–(x/2)Cr2O3–3(NH4)2HPO4. Thermal behaviour of the mixtures was characterised using STA analysis (RT-1200 °C); evolution of the phase composition during heating was analysed using powder XRD analysis. It is shown that with increase in substitution degree x from 0 to 2, the mechanism of the formation of the solid solutions changes dramatically. In general, it is influenced by the content of ZrOCl2·8H2O because its interaction with (NH4)2HPO4 is the dominant feature of the thermal transformation of the mixtures. However, with decrease in ZrOCl2·8H2O content and the corresponding increase in x, the indicated process becomes less dominant. On the other hand, unreacted amount of (NH4)2HPO4 is increased and the corresponding effect of elimination of its ammonia becomes more and more prominent. The mixture with x = 2 can be characterised with typical behaviour of the mixtures of (NH4)2HPO4 with oxides or carbonates. In general, the formation of solid solutions required calcination at 1200 °C during 6–12 h.