Фазовая диаграмма системы Li-Pt

К оглавлению: Другие диаграммы (Others phase diargams)

Li-Pt (Lithium-Platinum) J. Sangster and A.D. Pelton The assessed Li-Pt phase diagram is based on the work of [80Loe]. Few liquidus data are available [80Loe], obtained by DTA at compositions below 40 at.% Pt. Reaction of the alloys with the container above 1100 C prevented the measurement of liquidus data at higher temperatures. Because of the experimental difficulties, the sparseness of the results, and the lack of confirmation from other authors, most of the assessed diagram is shown by dashed lines. The Li-rich eutectic was reported to be at 169 C. On the assumption of zero solubility of Pt in solid (Li), a eutectic composition of ~2.0 at.% Pt may be calculated. On the basis of one thermal arrest at 290 C, [80Loe] proposed the existence of Li5Pt. Similar evidence for Li5Pd was obtained by the same authors [77Loe], who also presented X-ray evidence for Li5Pd. Hence, Li5Pt is tentatively shown in the assessed diagram, but its stoichiometry and even its existence remain in doubt. Thermal arrests at 313 C were attributed to the compound Li15Pt4, suggested [80Loe] by analogy to the compound Li15Pd4, whose structure was determined by X-ray diffraction [77Loe]. Because of the reactivity of the specimens, no X-ray or metallographic studies of Li15Pt4 were obtained. Li2Pt has been prepared by direct combination of the elements in an iron [ 68Fer] or corundum [75Bro] container and also through a LiH + Pt reaction [ 75Bro]. The compound has been identified by X-ray [68Fer] and neutron [75Bro] powder diffraction. A peritectic decomposition temperature of 955 C has been assigned to this compound [80Loe]. LiPt has been synthesized by a LiH + Pt reaction and identified by neutron diffraction [75Bro]. LiPt2 was prepared by direct combination of the elements in molybdenum [60Nas] or tantalum [80Loe] containers and identified by X-ray powder diffraction [60Nas, 80Loe]. A compound prepared at high temperature by the reaction of Li2CO3 with Pt [62Bro] was tentatively identified from X-ray measurements as LiPt7. The stoichiometry was confirmed by neutron diffraction work [85Bro]. The solid solubility of Li in (Pt) is appreciable [80Loe, 81Loe]. At 1600 C, the solubility limit is about 6 at.%, according to high-temperature X-ray analysis. At 600 C, the limit is 1.8 at.%, also from X-ray analysis. At or near room temperature, the limit is still about 1.8 at.%, as determined by extrapolation of electrical resistivity and magnetic susceptibility data [ 80Loe]. 60Nas: C.P. Nash, F.M. Boyden, and L.D. Whittig, J. Am. Chem. Soc., 82(23), 6203-6204 (1960). 62Bro: W. Bronger and W. Klemm, Z. Anorg. Allg. Chem., 319(1-2), 58-81 (1962) in German. 68Fer: R. Ferro, R. Capelli, S. Delfino, and G. Centineo, Atti Accad. Naz. Lincei, Sci. Fis. Mat. Nat. Rend., 45(6), 564-566 (1968) in Italian. 75Bro: W. Bronger, B. Nacken, and K. Ploog, J. Less-Common Met., 43(1-2), 143- 146 (1975) in German. 77Loe: O. Loebich and C.J. Raub, J. Less-Common Met., 55(1), 67-76 (1977) in German. 80Loe: O. Loebich and C.J. Raub, J. Less-Common Met., 70(1), P47-P55 (1980) in German. 81Loe: O. Loebich and C.J. Raub, Platinum Met. Rev., 25(3), 113-120 (1981). 85Bro: W. Bronger, G. Klessen, and P. Muller, J. Less-Common Met., 109(1), L1- L2 (1985) in German. Submitted to the APD Program. Complete evaluation contains 1 figure, 3 tables, and 10 references. Special Points of the Li-Pt System