An innovative encapsulation technique designed for the DSC high temperature measurements of the volatile samples is presented in this study. Stainless steel crucibles with a screwed bolt were developed for this purpose. The technique was demonstrated on the phase diagram measurement of the NaNO3-KNO3 system and the obtained results are presented in this study. Up to date two thermodynamic assessments of the NaNO3-KNO3 phase diagram have been made, one characterized by a single eutectic point with limited solubilities in the solid state in both NaNO3 and KNO3 rich corners, whereas the other version prefers a continuous solid solubility with minimum on the liquidus line. Based on our results we confirm limited solubilities in the solid state. (C) 2010 Elsevier B.V. All rights reserved.