Phase relationship in the TiO_2-Nd_2O_3 pseudo-binary system

摘要

Phase equilibria in the TiO_2-Nd_2O_3 system have been experimentally investigated via X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Four compounds Nd_2Ti_2O_7, Nd_2TiO_5, Nd_2Ti_3O_9 and Nd_4Ti_9O_(24) were confirmed to exist. The literature reported Nd_2Ti_4O_(11) was proved to be the same compound as Nd_4Ti_9O_(24), and the reported phase transformation of Nd_2Ti_4O_(11) from a structure to β at 1373 K was not detected. All the phase diagram data from both the literatures and the present work were critically reviewed and taken into account during the thermodynamic optimization of the TiO_2-Nd_2O_3 system. A set of consistent thermodynamic parameters, which can explain most of the experimental data of the TiO_2-Nd_2O_3 system, was achieved. The calculated phase diagram of the TiO_2-Nd_2O_3 system was provided.