Differentialthermoanalyse, Auswertung und Problematik

Abstract

After a short description of the differential thermal analysis (DTA), the evaluation of melting temperatures, phase transitions or other thermal effects is given for both possibilities of measurement, i. e. position of the thermcouple in/or outside the sample. Then the peak area is discussed as a function of the weight of the sample holder, the mass of the material investigated and the temperature at wich the measured thermal effect occurs. The determination of phase diagrams, of the eutectic concentration and of the solubility limit is shown as an example of the applications of the DTA-technique. Finaly the form of the general DTA-curve (base line shift, slope of the peak and «inversion wave» at the change from heating to cooling and viceversa) is described in detail, and its relation to the heat capacity, the thermal conductivity of both, sample and reference, and their change during the measurements is discussed.