Фазовая диаграмма системы Bi-Cr

К оглавлению: Другие диаграммы (Others phase diargams)

Bi-Cr (Bismuth-Chromium) M. Venkatraman and J.P. Neumann No comprehensive investigations of the binary Cr-Bi system were found in the literature. However, the assessed (tentative) phase diagram is based on the exploratory thermal analysis and metallographic studies of [07Wil] and the solubility measurements of solid Cr in liquid Bi of [55Wee]. The diagram is characterized by the absence of intermediate phases and by extensive immiscibility in the liquid state and essential immiscibility in the solid state. According to the limited data of [07Wil], the liquid miscibility gap extends at the monotectic temperature (~1553 C) from 5 to at least 50 at.% Bi. The monotectic temperature observed by [07Wil] was approximately the same as the melting temperature of the Cr used by [07Wil]. Because the adopted melting temperature of Cr (1863 C [Melt]) is about 300 C higher than the melting temperature of the Cr used by [07Wil], it is possible that the true monotectic temperature is actually higher than is shown in the assessed diagram. No determinations of the boundaries of the liquid miscibility gap above the monotectic temperature were carried out because of the high vapor pressure of Bi, 1 bar at 1564 C for pure Bi (IPTS-68) [Hultgren,E]. The type of the invariant three-phase equilibrium at ~271 C involving L2, (Cr) , and (Bi) is not known; the temperature of this equilibrium was found by [ 07Wil] to be (within the precision of the measurements) the same as the melting temperature of Bi, reported as 268 C. This value was adjusted in the assessed diagram to the adopted melting temperature of pure Bi (271.442 C [ Melt]). 07Wil: R.S. Williams, Z. Anorg. Allg. Chem., 55, 1-33 (1907) in German. 55Wee: J.R. Weeks, C.J. Klamut, M. Silberberg, W.E. Miller, and D.H. Gurinsky, Proc. Int. Conf. Peaceful Uses Atomic Energy, Vol. 9, United Nations, New York, 341-355 (1955). 82Boe: F.R. de Boer, R. Boom, and A.R. Miedema, Physica, 113B, 18-41 (1982). Published in Bull. Alloy Phase Diagrams, 9(3), Jun 1988. Complete evaluation contains 2 figures, 2 tables, and 7 references. Special Points of the Cr-Bi System