Фазовая диаграмма системы As-Cr

К оглавлению: Другие диаграммы (Others phase diargams)


As-Cr (Arsenic-Chromium) M. Venkatraman and J.P. Neumann No determinations of the Cr-As phase diagram have been carried out at elevated temperatures, so the solid-liquid phase equilibria in this system are not known. Only the solid-state phase equilibria involving the various intermediate phases have been studied; they are indicated in the partial assessed Cr-As phase diagram. The following phases have been reported [14Die, 38Now, 60Yuz, 65Hol, 73Jei, 75Ber, 76Ber] for the Cr-As system: Cr3As, Cr2As, Cr5As3, Cr3As2, Cr4As3, CrAs, Cr2As3, and CrAs2. The existence of most of these phases is firmly established, but the phase relationships in the range from 35 to 45 at.% As require clarification. The existence of Cr2As3, which was reported in only one investigation [14Die], is highly questionable. The compounds generally are synthesized by direct reaction of Cr and As powders in evacuated sealed silica tubes between 600 and 1000 C. The homogeneity ranges of most intermediate phases are small. The solubility of As in the (Cr) terminal solid solution is appreciable. [ 38Now] indicates a solubility of ~2 at.% As, which is in accord with the value of 3 at.% As at 800 C and 6 at.% As at 1100 C reported by [65Hol]. The magnetic behavior of the intermediate phases in the Cr-As system is very complex and has been the subject of numerous investigations, including [60Yuz] and [65Hol]. 14Die: T. Dieckmann and O. Hanf, Z. Anorg. Allg. Chem., 86, 291-295 (1914) in German. 38Now: H. Nowotny and O. Arstad, Z. Phys. Chem. B, 38(6), 461-465 (1938) in German. 60Yuz: M. Yuzuri, J. Phys. Soc. Jpn., 15(11), 2007-2012 (1960). 65Hol: L. Hollan, P. Lecocq, and A. Michel, Compt. Rend. (Paris), 260, 2233- 2234 (1965) in French. 73Jei: W. Jeitschko and P.C. Donahue, Acta Crystallogr. B, 29, 783-789 (1973). 75Ber: R. Berger, Acta Chem. Scand. A, 29, 641-646 (1975). 76Ber: R. Berger, Acta Chem. Scand. A, 30, 363-369 (1976). Submitted to the APD Program. Complete evaluation contains 1 figure, 2 tables, and 40 references. 1