Фазовая диаграмма системы La-Nb

К оглавлению: Другие диаграммы (Others phase diargams)


La-Nb (Lanthanum-Niobium) H. Okamoto The assessed phase diagram for the La-Nb system is adopted primarily from [ 73Sav], which appears to be based on the thermal, X-ray, metallographic, hardness, and electrical resistivity measurements of [59Sav]. The addition of Nb increases the melting point of gLa by 5 to 7 C, forming the peritectic reaction L + (Nb) = (gLa) at 885 C [59Sav]. Apparently, [73Sav] modified the peritectic temperature to 925 C to be consistent with the melting point of gLa (918 C [Melt]). The purity of La used by [59Sav] may have been low, as suggested by the considerable (~40 C) disagreement in the melting point of La. Therefore, the type and temperature of the transition from (gLa) to (bLa) in the assessed diagram (eutectoid at 840 C [59Sav]) must be confirmed. The L2 = L1 + (Nb) monotectic temperature is 2400 C [59Sav]. An uncertainty of с20 C was added by [73Sav]. 59Sav: E.M. Savitskii, V.F. Terekhova, and I.V. Burov, Zh. Neorg. Khim., 4(6), 1462-1463 (1959) in Russian; TR: Russ. J. Inorg. Chem., 4(6), 658 (1959). 73Sav: E.M. Savitskii and Yu.V. Efimov, Redkozemel'n. Met., Splavy Soedineniya, Nauka, Moscow, 310-316 (1973) in Russian. Submitted to the APD Program. Complete evaluation contains 1 figure, 2 tables, and 2 references. 1