Фазовая диаграмма системы Ag-Ba

К оглавлению: Другие диаграммы (Others phase diargams)

Ag-Ba (Silver-Barium) M.R. Baren The assessed phase diagram for the Ag-Ba system is based on the only reported phase diagram study [30Wei]. The points shown in this diagram were based entirely on thermal analysis data. Because the Ba used in this work contained 1.9% Sr and 0.15% N and had a melting point of 629 C (compared to the most recently accepted value of 727 C [88Itk]), it is likely that most of this diagram is highly uncertain, particularly for alloy compositions containing more than 50 at.% Ba. [30Wei] suggested the existence of the following intermediate compounds: Ag4Ba, Ag5Ba3, and Ag3Ba2. Ag4Ba and Ag3Ba2 formed congruently from the melt at 729 C and 848 C, respectively. Ag5Ba3 formed peritectically at 797 C. However, the composition of this peritectic phase is questionable [Hansen]. Using X-ray diffraction, [50Heu] determined the crystal structure of a compound Ag5Ba. This phase would replace the compound Ag4Ba [Hansen]. [81Mer], also using X- ray diffraction, determined the structure of single crystals of AgBa to be orthorhombic of the FeB structure. More work is needed in the Ag-Ba system to ascertain the phase boundaries in the Ag-rich region, to determine if the compounds Ag4Ba and Ag3Ba2 exist, and to determine the compounds and phase boundaries for alloy compositions greater than 50 at.% Ba. Editor's note: The Ag2Ba compound (oI12,Imma) was reported by [70Bru]. 30Wei: F. Weibke, Z. Anorg. Chem., 193, 296-310 (1930). 50Heu: T. Heumann, Nachr. Akad. Wiss. Gottengen Math-Physik Kl., 2, 1-6 (1950). 70Bru: G. Bruzzone, Atti. Acad. Naz. Lincei Cl. Sci. Fis. Mat. Natur., Rend., 48, 235-241 (1970) in Italian. 81Mer: F. Merlo and M.L. Fornasini, Acta Crystallogr., B37, 500-503 (1981). 88Itk: V.P. Itkin and C.B. Alcock, Bull. Alloy Phase Diagrams, 9(2), 98-99 ( 1988). Submitted to the APD Program. Complete evaluation contains 1 figure, 2 tables, and 5 references. 1