Фазовая диаграмма системы Al-S

К оглавлению: Другие диаграммы (Others phase diargams)


Al-S (Aluminum-Sulfur) R.C. Sharma and Y.A. Chang The assessed Al-S phase diagram is based essentially on the work of [74For] between 0 to 60 at.% S, but between 60 to 100 at.% S it is hypothetical. Two intermediate phases, AlS and Al2S3, exist in the Al-S system. Pure Al melts at 660.452 C. Pure S, in the solid state, exists in two allotropic forms: (aS), stable up to 95.5 C, and (bS), stable from 95.5 C to its melting point of 115.22 C. There was no systematic work on the determination of the Al-S phase diagram prior to the work of [74For]. [74For] determined the phase diagram between Al and Al2S3 and found AlS to be stable between 1010 and 1060 C. At 1010 C, AlS decomposed to liquid Al and Al2S3, and at 1060 C it melted to two liquids, L1 and L2. A eutectic reaction was found at xs = 0.56 and 1040 C where the liquid L2 decomposed to AlS and Al2S3. Al2S3 is found in two allotropic forms: aAl2S3, stable up to 1000 C, and gAl2S3, stable from 1000 C to its melting point at 1100 C [52Fla]. [74For] found that Al2S3 can dissolve excess Al and reported the composition of Al2S3 at the eutectic point (1040 C) to be ~59 at.% S. Two additional high-pressure modifications of Al2S3 are reported in the literature. [70Don] reported a tetragonal modification with a structure similar to that of bIn2S3 when Al2S3 was subjected to pressures of 2 to 65 kbar at 1000 to 1200 C. [73Ran] reported a cubic modification of Al2S3 at 40 kbar and 400 C. 52Fla: J. Flahaut, Ann. Chim. (Paris), 7, 632-696 (1952) in French. 70Don: P.C. Donohue, J. Solid. State Chem., 2, 6-8 (1970). 73Ran: K.J. Range and H.J. Huebner, Z. Naturforsch., 28, 353-355 (1973) in German. 74For: T. Forland, J. Gomez, S.K. Ratkje, and T. Ost., Acta Chem. Scand., A, 28, 226-228 (1974). Published in Bull. Alloy Phase Diagrams, 8(2), Apr 1987. Complete evaluation contains 2 figures, 4 tables, and 17 references. Special Points of the Al-S System