Search Results
You are looking at 1 - 10 of 15 items for
- Author or Editor: J. Rouland x
- Refine by Access: All Content x
Representation des courbes de vaporus dans les systemes binaires a tension de vapeur non negligeable
Application au système As2Se3-As
Influence de la tension de vapeur sur une transition de phases et un equilibre peritectoide
ReprésentationT-V-x applicable au système As2Se3-As
RepresentationT-V-x des systemes binaires a tension de vapeur non negligeable
II.-Influence du volume massique sur les courbes d'ATD lors de l'étude du système NdAs-As
Congruent melting of binary compounds with non-negligible vapour pressure
I. Theoretical aspects of the congruent melting of a hydrate
Abstract
A theoretical temperature-specific volume-molar fraction (T-v-x) phase diagram of the binary systemA-H2O presenting a hydrateH with congruent melting is studied. The phase diagram is divided into two subsystems by the one-component phase diagram of the hydrateH. The eutectic invariant planes which occur in both subsystems are described. The relationships between the invariants are given. Isochoric and isoplethal theoretical sections are given. The one-component phase diagram of the hydrateH is described. It is pointed out that the triple line solid-liquid-vapour which relates the congruent melting is not necessarily perpendicular to the molar fraction axis. The means that the three phases, solid, liquid and vapour, have not necessarily the same composition. TheT-v-x representation gives an explanation to the deviation between the maximum of the melting curve and the stoichiometric composition of the hydrate which is often observed in theT-x binary diagramA-H2O.
Congruent melting of binary compounds with non-negligible vapour pressure
II. Application to the sulfaguanidine—water system
Abstract
The sulfaguanidine—water (SG-H2O) system is a binary system with non-negligible vapour pressure which presents a monohydrate. The phase diagram of this system is drawn from DTA experimental results, using the temperature-specific volume-molar fraction (T-v-x) model which was described in part I of this work. The melting of the monohydrate (SG, H2O) is found to be congruent. Isochoric sections are drawn; they make it possible to determine the limits of the two eutectic invariant planes. The composition and specific volume of the vapour phase at the eutectic equilibrium of theSG-SG, H2O subsystem are given. The triple line solid-liquid-vapour of the one-component phase diagram of the monohydrate is drawn. The experimental results are consistent with the congruent melting of the monohydrate. These results also show that the solid, liquid and vapour phase at the triple line have not the same composition.
