Фазовая диаграмма системы Ir-Os

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Ir-Os (Iridium-Osmium) H. Okamoto The assessed Ir-Os phase diagram is based on the work of [64Rei]. The estimated maximum error in the solidus temperature is с35 C. The liquidus boundaries are schematic. The equilibrium phases are (1) the liquid, L; (2) the fcc terminal solid solution, (Ir); and (3) the cph terminal solid solution, (Os). From investigations using the natural ore "osmiridium," [32Zvy1] and [32Zvy2] concluded that wide mutual homogeneity ranges of (Ir) and (Os) exist. However, the solubility limit and lattice parameter data of (Ir) and (Os) obtained in studies by many investigators were uncertain due to varying amounts of impurity elements (mainly Pt, Rh, and Ru with Ru up to 19.1% [32Zvy1]) contained in the ore. The melting point of Ir is 2447 C [Melt]. Addition of a few percent of Os in (Ir) increases the melting point by several hundred degrees Celsius [ 32War]. The (Ir) solvus is nearly vertical below 2400 C, occurring at about 42 at.% Os [64Rei]. [54Vac] indicated that the (Ir) solvus occurs at <39 at.% Os. The superconducting transition temperature of Ir-Os alloys indicated that the (Ir) solvus is at about 50 at.% Os [63Geb]. The values given by [54Vac] and [63Geb] are for nonequilibrium states according to [64Rei]. The L + (Os) = (Ir) peritectic temperature is about 2660 C [64Rei]. The melting point of Os is 3033 C [Melt]. The (Os) solvus is nearly vertical below 2600 C, occurring at about 63 at.% Os [64Rei]. Data obtained by [54Vac] indicated that a 79.2 at.% Os alloy is two phase. This alloy is apparently in a nonequilibrium state, because the superconducting transition temperature measurements demonstrated that a two-phase 70 at.% Os alloy becomes single phase after annealing at 1000 C for 10 days [63Geb]. 32War: H.V. Wartenberg, H. Werth, and H.J. Reusch, Z. Elektrochem., 38, 50 ( 1932) in German. 32Zvy1: O.E. Zvyagintsev, Z. Kristallogr., 83, 172-186 (1932). 32Zvy2: O.E. Zvyagintsev and B.K. Brunovskiy, Z. Kristallogr., 83, 187-192 ( 1932). 38Zvy: O.E. Zvyagintsev, Compt. Rend. Acad. Sci, USSR, 18, 295-297 (1938). 54Vac: H.C. Vacher, C.J. Bechtoldt, and E. Maxwell, Trans. AIME, 200(1), 80 ( 1954). 63Geb: T.H. Geballe, Phys. Rev., 129(1), 182-183 (1963). 64Rei: R.D. Reiswig and J.M. Dickinson, Trans. AIME, 230(4), 469-472 (1964). 67Rud: P.S. Rudman, J. Less-Common Met., 12(1), 79-81 (1967). Submitted to the APD Program. Complete evaluation contains 1 figure, 2 tables, and 12 references. 1