MISCIBILITY STUDY IN THE BISMUTH-ZINC SYSTEM - EXTENSION TO THE ISOTHERMS 425 AND 500-DEGREES-C OF THE TERNARY-SYSTEM BI-SB-ZN

The miscibility curve of the system Zn-Bi has been studied by using ca lorimetric analysis and isothermal solubility measurements. A thermody namical equation of this curve has been established and the critical p oint co-ordinates have been calculated: T-c = 595 degrees C, W-Bi = 0. 363. The compositions of the invariant solutions and the temperatures of the three-phase equilibria have been stated precisely. The reaction enthalpies of the monotectic (Delta H = 90 +/- 4 J g(-1)) and the eut ectic (Delta H = 53 +/- 1 J g(-1)) transformations have been determine d. In the ternary system Zn-Bi-Sb, the miscibility gap has been comple tely delimited at two temperatures. At 425 degrees C, the one-phase li quid field is very reduced, but at 500 degrees C, a liquid solution ca n be obtained whatever the ratio bismuth/zinc in the alloy.