Une méthode d’analyse thermique différentielle pour les substances volatiles à point de fusion élevé: Application au système cryolithe–alumine

Abstract

DTA has been applied to the determination of the cryolite side of the phase diagram of the system Na₃AlF₆–Al₂O₃. For this purpose a new type of sample holder has been developped permitting the analysis of volatiles substances at high temperatures. Thermograms show an eutectic peak as low as 0.5 weight % Al₂O₃. If the concentration of Al₂O₃ is plotted versus the surface of the eutectic peaks a straight line going through the origin is obtained. These results confirm the previously noted absence of solid solution of alumina in cryolite.