Фазовая диаграмма системы Ge-Pt

К оглавлению: Другие диаграммы (Others phase diargams)


Ge-Pt (Germanium-Platinum) H. Okamoto The assessed Ge-Pt phase diagram is based on the thermal, metallographic, and X-ray investigations of [87Oya], who clarified the uncertainties remaining in the phase diagram after the previous report by [66Jai]. The most significant change is that the melting reaction of GePt2 was shown as congruent in [66Jai], whereas it is a peritectic reaction in [87Oya]. The equilibrium phases are (1) the liquid, L; (2) the diamond cubic terminal phase, (Ge); (3) orthorhombic CaCl2-type Ge2Pt, (4) orthorhombic Ge3Pt2, (5) orthorhombic MnP-type GePt; (6) orthorhombic Ge2Pt3; (7) hexagonal Fe2P-type GePt2; (8) monoclinic GePt3; and (9) the fcc terminal phase, (Pt). The solubility of Pt in (Ge) must be very small, because the segregation coefficient (ratio of the initial slopes of liquidus to solidus) is 5 <291> 10- 6 [54Dun]. The maximum solubility of Ge in (Pt) is 6.6 at.% at the L + (Pt) = GePt3 peritectic temperature of 951 C [87Oya]. The peritectic melting point of Ge2Pt3 is 820 C [87Oya] ([66Jai] stated it to be at 807 C). [87Oya] could not confirm the polymorphic transformation in Ge2Pt3, which was observed by [66Jai] at 675 C. A tetragonal SiU3-type phase, metastable GePt3, forms on extremely rapid cooling (-106 C/s) of Ge-Pt alloy melts containing 76 to 78 at.% Pt [80Ell]. The relative stability of this phase at high temperatures is unknown. 50Pfi: H. Pfisterer and K. Schubert, Z. Metallkd., 41(10), 358-367 (1950) in German. 53And: K. Anderko and K. Schubert, Z. Metallkd., 44(7), 307-312 (1953) in German. 54Dun: W.C. Dunlap, Jr., Phys. Rev., 96(1), 40-45 (1954). 60Bha: S. Bhan and K. Schubert, Z. Metallkd., 51(6), 327-339 (1960) in German. 66Jai: K.C. Jain and S. Bhan, Trans. Indian Inst. Met., 19, 49 (1966). 68Eng: I. Engstrom and H.L. Pfeifer, Acta Chem. Scand., 22(10), 3137-3145 ( 1968). 75May: H.W. Mayer and K. Schubert, Z. Metallkd., 66(7), 437 (1975) in German. 76Hei: S. Heinrich and K. Schubert, J. Less-Common Met., 45(1), 125-135 (1976) in German. 78Sch: K. Schubert, Z. Kristallogr., 148, 221-236 (1978). 80Ell: M. Ellner and B. Predel, J. Less-Common Met., 76, 181-197 (1980) in German. 81Ell: M. Ellner, J. Less-Common Met., 78, P21-P32 (1981) in German. 87Oya: Y. Oya and T. Suzuki, Z. Metallkd., 78(4), 295-300 (1987). Submitted to the APD Program. Complete evaluation contains 1 figure, 4 tables, and 14 references. Special Points of the Ge-Pt System