The enthalpy of solution of various single-and two-phase AgI-AgBr compositions in AgNO3at 518 K has been determined using a Calvet-type twin microcalorimeter. The enthalpy (H518-H298) of melted and unmelted mixtures of AgI and AgBr of various compositions within two-phase regions of the phase diagram has also been obtained using the same calorimeter. The effect of AgBr on the temperature and enthalpy of transformation of β-Agl to α-Agl has been investigated using a Perkin Elmer Differential Scanning Calorimeter. The terminal compositions at 518 K of the two-phase region of AgI-AgBr system has been found to be AgI0.85Br0.15and AgI0.3Br0.7. The excess enthalpy, the difference in (H518-H298) values of the unmelted and melted mixtures in the two-phase region of the Agl-AgBr system, has been found to be maximum at the equivolume concentration of the two terminal phases and is suggested to be due to the generation of silver ion vacancies at the interfaces due to a space-charge layer.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry