Фазовая диаграмма системы Er-Tl

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Er-Tl (Erbium-Thallium) S. Delfino, A. Saccone, A. Palenzona, and R. Ferro The assessed phase diagram for the Er-Tl system is based on [87Del] and [87Sab] . The assessed diagram has five intermediate phases (Er5Tl3, Er5Tl3+x, ErTl, Er3Tl5, and ErTl3) and two eutectic reactions. Metallography results suggest a homogeneity range of about 1 at.% for Er5Tl3 and Er3Tl5. ErTl, Er3Tl5, and ErTl3 form peritectically at 1240, 900, and 850 C, respectively. Only Er5Tl3 melts congruently at 1420 C. The formation mechanism of Er5Tl3+x, whose powder photograph showed clear similarities with that of the Ba5Pb3-type structure, was not determined by [87Del]. [87Sab] suggested a stoichiometry nearer to 5:4 for this phase, but did not identify the powder photograph of this phase and its crystal structure. [87Sab] suggested a peritectoidal formation of the phase at 1192 C (this effect was also observed at 1190 C by [87Del], who attributed it to a solid state transformation of ErTl). The composition proposed by [87Del] and the formation mechanism suggested by [87Sab] have been accepted in this assessment. The maximum solid solubility of Tl in (Er) is estimated at about 6 at.% Er at the 1100 C eutectic temperature. The solid solubility of Er in (bTl) and (aTl) is assumed to be negligible. Thermodynamic and magnetic properties of Er-Tl alloys as well as general properties of RE-Tl alloys have been discussed by [88Sac]. 87Del: S. Delfino, A. Saccone, G. Cacciamani, and R. Ferro, Z. Metallkd., 78, 344 (1987). 87Sab: N.A. Sabirzyanov, S.P. Yatsenko, and V.I. Kononenko, Izv. Akad. Nauk. SSSR, Met., 6, 168 (1987). 88Sac: A. Saccone, S. Delfino, and R. Ferro, J. Less-Common Met., 143, 1 (1988) . Submitted to the APD Program. Complete evaluation contains 1 figure, 1 table, and 5 references. 1