Фазовая диаграмма системы Au-Th

К оглавлению: Другие диаграммы (Others phase diargams)

Au-Th (Gold-Thorium) H. Okamoto, T.B. Massalski, and D.E. Peterson The assessed Au-Th phase diagram is based on [43Rau] for the composition range 0 to 20 at.% Th and on [86Pal] for the composition range 20 to 80 at.% Th. All of the data points shown were obtained by thermal analysis. The diagram differs significantly from the previously assessed diagram [86Oka] regarding the number of intermetallic compounds and the melting point of AuTh2. Six compounds occur in the Au-Th system: (1) Au51Th14, isomorphous with Ag51Gd14; ( 2) the Al-B2-type Au2Th; (3) Au4Th3, isomorphous with Pu3Pd4; (4) CrB-type AuTh; (5) Au2Th3, with (probably) cubic symmetry; and (6) CuAl2-type AuTh2. No solid solubility has been detected. [47Rau] considered the Au-Th system analogous to the Ag-Th system, consisting of three intermetallic phases, Au3Th, Au2Th, and AuTh2, as it appeared in [ 86Oka]. Because of inconsistency with thermodynamic modeling, [86Oka] pointed out the possibility of undiscovered phases existing between Au2Th and AuTh2. The additional three phases found by [86Pal] in this region may not have been detected previously because of low-temperature instability. Based on the new information provided by [86Pal], the thermodynamic modeling of the Au-Th system given in [86Oka] was updated. 43Rau: E. Raub and M. Engel, Z. Elektrochem., 49, 487-493 (1943) in German. 47Rau: E. Raub and M. Engel, Metallforschung, 2, 115-119 (1947) in German. 61Bro: A. Brown, Acta Crystallogr., 14, 860-865 (1961). 72Har: E.E. Havinga, H. Damsma, and P. Hokkeling, J. Less-Common Met., 27, 169- 186 (1972). 86Oka: H. Okamoto, T.B. Massalski, and D.E. Peterson, Bull. Alloy Phase Diagrams, 7(16), 528-531 (1986). 86Pal: A. Palenzona and S. Cirafici, J. Less-Common Met., 124, 245-249 (1986). Published in Phase Diagrams of Binary Gold Alloys, 1987, and Bull. Alloy Phase Diagrams, 7(6), Dec 1986. Complete evaluation contains 2 figures, 3 tables, and 9 references. 1