J. Phys. IV France 122 (2004) 197-201
Mise en évidence, synthèse et caractérisation de nouveaux composés : les chlorures doubles d'ammonium et de calcium anhydres ou hydratésR. Tenu, J. Berthet, M.A. Etoh and J.J. Counioux
Laboratoire Hydrazines et Procédés, UMR 5179, UCBL, CNRS, ISOCHEM/SNPE 22, Avenue Gaston Berger, 69622 Villeurbanne Cedex, France
The study of materials with phase change, often indicated PCM, has been developed because of their storage capacity of calorific or refrigerating energy. Their applications relate to the habitat, the transport, the protection of the electronic circuits exposed to strong variations in temperature or to the conservation of deep-frozen foods. A systematic study of the ternary system H2O-NH4Cl-CaCl2 was then undertaken at various temperatures by using different techniques like Isoplethic Thermal Analysis (I.T.A.), T.G.A., D.T.A. and X-Ray diffraction. Five invariant transformations and three new ternary compounds are observed within the temperature range -20 / 70 °C. Finally, it appears that the calcium and ammonium chlorides form a rich family of anhydrous and hydrated double salts.
© EDP Sciences 2004