Фазовая диаграмма системы Bi-Pd

К оглавлению: Другие диаграммы (Others phase diargams)

Bi-Pd (Bismuth-Palladium) H. Okamoto The assessed phase diagram for the Bi-Pd system is taken primarily from [57Zhu] (which superseded [53Zhu]) for 50 to 100 at.% Pd, [59Bra] for 0 to 50 at.% Pd, and [79Sar] near Bi2Pd5, with review of the data of [61Sch]. The equilibrium phases are: (1) the liquid, L; (2) the rhombohedral terminal solid solution, (Bi); (3) tetragonal MoSi2-type high-temperature phase, bBi2Pd; (4) monoclinic aBi2Pd, stabl e below 380 C; (5) orthorhombic high- temperature phase, bBiPd; (6) monoclinic aBiPd, stable below 210 C; (7) high- temperature g phase with a significant (>5 at.%) homogeneity range; (8) monoclinic Bi2Pd5; (9) orthorhombic Bi12Pd31, stable in a limited temperature range between 605 and 550 C; (10) bBiPd3 with unknown structure and stable above ~800 C; (11) orthorhombic low-temperature phase, aBiPd3; and (12) the fcc terminal solid solution (Pd). The solubility of Pd in (Bi) does not exceed 0.1 at.% at 245 C [59Bra]. The g phase has a fairly extensive solubility range (~60 to 70 at.% Pd) [57Zhu] . In the composition range of the g phase, however, [53Sch] reported the existence of a NiAs-type high-temperature phase (Bi3Pd5) and a low-temperature phase with a lower symmetry. To clarify the disagreement between [ 53Sch] and [57Zhu], [58Zhu] investigated variously heat-treated alloys with nominal Bi3Pd5 composition and confirmed the eutectoidal breakdown of g. More recent work of [79Sar], however, showed Bi12Pd31 and Bi2Pd5 coexisting with high- and low-temperature forms of "Bi3Pd5" below 605 C. These contradictory observations cannot be compromised. Therefore, the g phase region in the assessed diagram is tentative. No attention has been paid to the validity of a very wide (~20 at.%) solubility range of (Pd) speculated by [53Zhu]. Because the initial slope of ( Pd) liquidus at 100 at.% Pd coincides with the ideal liquidus assuming no solid solubility of Bi in (Pd), the homogeneity range of (Pd) is probably very much narrower than 20 at.%. 42Bur: S.V. Burr and M.A. Peacock, Univ. Toronto Studies, Geol. Ser., (47), 19- 31 (1942). 53Khe: D.M. Kheiker, G.S. Zhdanov, and N.N. Zhuravlev, Zh. Eksp. Teor. Fiz., 25, 621-627 (1953) in Russian. 53Sch: K. Schubert, K. Andelko, M. Kluge, H. Beeskow, M. Ilschner, E. Dorre, and P. Esslinger, Naturwissenschaften, 40, 269 (1953) in German. 53Zev: L.S. Zevin, G.S. Zhdanov, and N.N. Zhuravlev, Zh. Eksp. Teor. Fiz., 25, 751-754 (1953) in Russian. 53Zhu: N.N. Zhuravlev and G.S. Zhdanov, Zh. Eksp. Teor. Fiz., 25, 485-490 ( 1953) in Russian. 54Zhd: G.S. Zhdanov, Tr. Inst. Kristallogr., Akad. Nauk SSSR, 10, 99-116 (1954) in Russian. 56Zhu: N.N. Zhuravlev and G.S. Zhdanov, Izv. Akad. Nauk. SSSR, Ser. Fiz., 20, 708-713 (1956) in Russian; TR: Bull. Acad. Sci. USSR, Phys. Ser., 20, 645-649 ( 1956). 57Zhu: N.N. Zhuravlev, Zh. Eksp. Teor. Fiz., 32(6), 1305-1312 (1957) in Russian; TR: Sov. Phys. JETP, 5(6), 1064-1072 (1957). 58Zhu: N.N. Zhuravlev, Kristallografiya, 3, 503-504 (1958) in Russian; TR: Sov. Phys. Crystallogr., 3, 506 (1958). 59Bra: J. Brasier and W. Hume-Rothery, J. Less-Common Met., 1(2), 157-164 ( 1959). 61Sch: D.G. Schweitzer and J.R. Weeks, Trans. ASM, 54, 185-200 (1961). 68Sch: K. Schubert, S. Bhan, T.K. Biswas, K. Frank, and P.K. Panday, Naturwissenschaften, 55, 542-543 (1968) in German. 73Cab: L.J. Cabri, D.C. Harris, and R.I. Gait, Can. Mineralog., 11(5), 903-912 (1973). 79Bha: Y.C. Bhatt and K. Schubert, J. Less-Common Met., 64(2), P17-P24 (1979) in German. 79Sar: N. Sarah and K. Schubert, J. Less-Common Met., 63(2), P75-P82 (1979) in German. Submitted to the APD Program. Complete evaluation contains 1 figure, 3 tables, and 19 references. Special Points of the Bi-Pd System