COMPARATIVE-STUDY OF POLYMORPHIC PHASE-TRANSITION BY DIFFERENTIAL THERMAL-ANALYSIS, HIGH-TEMPERATURE X-RAY-DIFFRACTION, AND TEMPERATURE PROGRAMMED ELECTRICAL-CONDUCTIVITY MEASUREMENTS - CASE-STUDY OF MIXED IRON AND COBALT MOLYBDATE

A comparative analysis of the results, obtained by differential thermal analysis (DTA), high temperature X-ray diffraction (XRD), and temperature programmed electrical conductivity measurements (TPEC), in the study of the polymorphic transition (alpha to beta form) of a mixed ferrous and cobaltous molybdate is reported. In order to progress in the interpretation of the curves obtained using TPEC, the results obtained with these techniques, used at different heating rates, have been compared. This comparison enables one to evidence the occurrence of the phase transition on the surface and in the bulk of the sample particles.