Фазовая диаграмма системы B-Nd

К оглавлению: Другие диаграммы (Others phase diargams)

B-Nd (Boron-Neodymium) P.K. Liao and K.E. Spear As with most RE-boride systems, little experimental work has been performed on the equilibria for the Nd-B system. The assessed phase diagram is from [76Spe]. The liquidus curves were estimated by correlating the melting behavior of the Nd-B phases with those in other RE-boride systems. The equilibrium phases are ( 1) the liquid, L; (2) the terminal solid solutions, bcc (bNd) and dcph (aNd); ( 3) the terminal solid solution, rhombohedral (bB); and (4) four intermediate compounds, Nd2B5, NdB4, NdB6, and NdB66. (bB) and both (Nd) solid solutions have negligible composition ranges. The melting behavior of the Nd borides and their respective melting temperatures are largely estimated in the assessed diagram [76Spe]. The value of 2540 C listed by [65Sam] for NdB6 is in good agreement with the melting temperature predicted by [76Spe]. The homogeneity ranges of Nd borides are small except perhaps for NdB6. [76Spe, 77Spe] discuss the rather wide homogeneity ranges for a number of REB6 phases. A significant effort has gone into investigating these ranges and the hexaboride defect structures; all available experimental data indicate that the hexaboride is stoichiometric at its metal-rich phase boundary, and becomes B-rich by the formation of up to approximately 30% metal vacancies [76Spe, 77Spe]. 59Eic: H.A. Eick and P.W. Gilles, J. Am. Chem. Soc., 81, 5030-5032 (1959). 64Bli: G. Bliznakov and P. Peshev, J. Less-Common Met., 7, 441-446 (1964). 65Gie: R.F. Giese, Jr., J. Economy, and V.I. Matkovich, Z. Krist., 122, 144- 147 (1965). 65Sam: G.V. Samsonov, High-Temperature Compounds of Rare Earth Metals with Nonmetals, Consultants Bureau, New York, 1-100 (1965). 68Mor: O.A. Mordovin and E.N. Timofeeva, Russ. J. Inorg. Chem., 13(12), 1627- 1629 (1968). 70Car: J.-O. Carlsson and T. Lundstrom, J. Less-Common Met., 22, 317-320 (1970) . 72Fis: Z. Fisk, A.S. Cooper, P.H. Schmidt, and R.N. Castellano, Mater. Res. Bull., 7(4), 285-288 (1972). 76Spe: K.E. Spear, Phase Diagrams: Materials Science and Technology, Vol. 4, Academic Press, New York, 91-159 (1976). 77Cal: B. Callmer, Acta Crystallogr. B, 33, 1951-1954 (1977). 77Spe: K.E. Spear, Boron and Refractory Borides, V.I. Matkovich, Ed., Springer- Verlag, New York, 439-456 (1977). Submitted to the APD Program. Complete evaluation contains 1 figure, 3 tables, and 16 references. Special Points of the Nd-B System