The phase separation of 3He—4He mixtures

✍ Scribed by D.H.N. Wansink

• Publisher: Elsevier Science
• Year: 1957
• Weight: 46 KB
• Volume: 23
• Category: Article
• ISSN: 0031-8914
• DOI: 10.1016/s0031-8914(57)95311-9

✦ Synopsis

In our paper concerning the calculation of thermodynamic quantities of 3He-4He mixtures from the vapour pressure 1) we derived the Gibbs-function of mixing zlG as a function of the 3He-concentration X at different temperatures. From such a diagram the unstable concentration regions should be found by determining the pairs of points of the AG-X curves which have a tangent in common. Because this requires the knowledge of ziG at all values of X between 0 and l, whereas our calculations yielded AG up to X = 0.07 only, we had to confine ourselves to an approximation: zIG =,0 was used as criterion for the demixing, since mixtures, for which LIG > 0, are unstable in any case. The T-X curve, obtained in this way and given in fig. 8 of the paper mentioned above, gives only a lower limit of the temperature of demixing. A better result, however, will be obtained by using the points of the AG-X diagram, for which OAG/OX = 0. The results are shown in fig. 1, which should replace the old fig. 8. The agreement with the experimental values is now rather poor.