Фазовая диаграмма системы Ag-Zr

К оглавлению: Другие диаграммы (Others phase diargams)


Ag-Zr (Silver-Zirconium) I. Karakaya and W.T. Thompson The assessed, partially calculated phase diagram for the Ag-Zr system was obtained by thermodynamic modeling. Estimates were used together with the known thermodynamic properties of pure Ag [87Kar], aZr, and bZr [77Bar]. Small ranges of solubilities for the compounds were not introduced in the modeling. The equilibrium phases are the liquid, L; the Ag-rich fcc (Ag) solid solution; Zr-rich bcc (bZr) and cph (aZr) solid solutions; and two tetragonal intermediate phases with the approximate compositions AgZr and AgZr2. The Ag-rich solid solution was reported to have very limited Zr solubility ( about 0.1 at.% at 900 C [48Rau, 69Pra]). A detailed investigation [58Bet] of the Ag-Zr system in the region 64 to 100 at.% Zr showed considerable (20 at.%) Ag solubility in (bZr) at the peritectic temperature. Although the Ag solubility in (aZr) was reported as 1.1 at.% at the eutectoid, this concentration was found to decrease as the level of iodide impurity in Zr increased [58Bet]; at 0.05 at.% iodide the Ag solubility dropped to 0.1 at.%. A systematic study of the Ag-Zr system is required to resolve uncertainties surrounding the peritectic reactions, the Ag solubility in (aZr), the liquidus near (bZr), and the range of solubility for the intermediate phase AgZr. 48Rau: E. Raub and M. Engel, Z. Metallkd., 39, 172-177 (1948) in German. 52Kar: N. Karlsson, Acta Chem. Scand., 6, 1424-1430 (1952). 58Bet: J.O. Betterton, Jr. and D.S. Easton, Trans. AIME, 212, 470-475 (1958). 62Nev: M.V. Nevitt and J.W. Downey, Trans. AIME, 224, 195-196 (1962). 69Pra: N.L. Pravoverov and Yu.G. Kolonin, Russ. Metall., 2, 154-155 (1969). 77Bar: I. Barin, O. Knacke, and O. Kubaschewski, Thermochemical Properties of Inorganic Substances, Springer-Verlag, Berlin (1977). 87Kar: I. Karakaya and W.T. Thompson, Bull. Alloy Phase Diagrams, 8(4), 326- 334 (1987). Submitted to the APD Program. Complete evaluation contains 2 figures, 4 tables, and 10 references. Special Points of the Ag-Zr System