Фазовая диаграмма системы Ni-Th

К оглавлению: Другие диаграммы (Others phase diargams)


Ni-Th (Nickel-Thorium) C.J. Santandrea and D.E. Peterson The assessed Th-Ni phase diagram is based on [48Hor] and [72Tho]. Thermal analysis points of [48Hor] were used in establishing phase boundaries. [47Wil] and [48Hor] indicated essentially no solid solubility of Ni in (Th). The terminal solubility of Th in (Ni) was reported by [44Hes] to be less than 0.003 at.% at room temperature and less than 0.013 at.% at 1000 C. [65Tho] and [72Tho] found that alloys of lower Ni content survived short-term anneals, but oxidized in air during long-term anneals at low temperatures; consequently, the assessed diagram in the 50 to 65 at.% Ni range is established only down to 1000 C. [72Tho] showed that a compound designated ThNix exists at 63.5 at.% Ni. Because both the ThNi-ThNix eutectic at 60 at.% Ni and the peritectic reaction ThNi2 + L = ThNix at 63.5 at.% Ni occur at about the same temperature (1037 с 12 C), the peritectic temperature in the assessed diagram must be placed above the eutectic temperature. [72Tho] also suggested that due to its appearance, ThNix undergoes a phase transformation or a eutectoidal decomposition to ThNi + ThNi2 at a temperature below 1000 C ( assumed in the assessed diagram). Alloys in the 65 to 96 at.% Ni range are more resistant to air oxidation and have been studied down to 800 C. The Th2Ni17-(Ni) eutectic and the peritectic reaction of ThNi5 + L = Th2Ni17 occur at 1300 to 1325 C according to [72Tho]. An accurate value for the melting point of ThNi5 has not been measured. [48Hor] reported 1530 C, which is accepted in this assessment. 44Hes: W. Hessenbruch and L. Horn, Z. Metallkd., 36, 145-146 (1944). 47Wil: H.A. Wilhelm, O.N. Carlson, and A.I. Snow, ISC-6, 76-77 (1947). 48Heu: T. Heumann, Nachr. Akad. Wiss. Gottingen, Math. Phys. Klasse, 1, 21-26 ( 1948) in German. 48Hor: L. Horn and C. Basserman, Z. Metallkd., 39, 272-275 (1948) in German. 65Tho: J.R. Thomson, J. Nucl. Mater., 15(1), 88-94 (1965). 72Tho: J.R. Thomson, J. Less-Common Met., 29, 183-188 (1972). 83For: H.L. Fornasini, Acta Crystallogr. C, 39, 846-947 (1983). 84And: A.F. Andresen, H. Fjellvag, and A.J. Maeland, J. Less-Common Met., 103, 27-31 (1984). Published in Phase Diagrams of Binary Nickel Alloys, 1991 and Bull. Alloy Phase Diagrams, 9(4), Aug 1988. Complete evaluation contains 1 figure, 4 tables, and 19 references. Special Points of the Ni-Th System