New theoretical determination of latent heats from DSC curves
Résumé
Differential scanning calorimetry is a classic tool used to characterize materials, and in particular to estimate the energies involved during phase transitions. This determination of latent heat is difficult because the exploitable signal (i.e. the power absorbed/released by the sample over time) reflects the overall behavior of the sample subjected to thermal stress. It is therefore necessary to dissociate the signal/flux caused by the phase transition from the part linked to the sensible behavior (i.e. exclusively dependent on temperature). On the basis of our model, taking into account the heat transfers inside the sample, we calculate the real line to have a good delimitation of the peak giving the latent heats correctly. This method is very different from the classical using linear or not extrapolated baselines. The comparison with these determinations permits to evaluate the corresponding errors for the latent heats of melting either for pure substances or binary solutions.