Gd-Si (Gadolinium-Silicon)
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Supplemental Literature Review: Section III
Gd-Si (Gadolinium-Silicon) H. Okamoto
The Gd-Si phase diagram in [Massalski2] was updated by [1995Oka] according to [1991Ere]. Intermediate compounds existed in this diagram were Gd5Si3, Gd5Si4, GdSi, Gd2Si3 (dimorphic), and GdSi2 (dimorphic). The asymmetry and inflection in the GdSi liquidus were thought to be unlikely [1995Oka]. Figure 1 shows the Gd-Si phase diagram proposed by [2007Hua] based on experimental investigations and Table 1 Phase (bGd) (aGd) Gd5Si3 Gd5Si4 GdSi bGd3Si5 aGd3Si5 bGdSi2 aGdSi2 (Si)
thermodynamic modeling. Additional information on polymorphic transitions is shown with dashed lines. The most significant change from [1991Ere] diagram is that Gd3Si5 exists instead of Gd2Si3. The problems of the asymmetry and inflection in the GdSi liquidus have been solved in this new phase diagram. According to [2007Hua], GdSi2 may have an observable width because the polymorphic transition temperatures are different on either side of this phase, as
Gd-Si crystal structure data Composition, at.% Si
Pearson symbol
Space group
Strukturbericht designation
Prototype
0 0 37.5 44.4 50 62.5 62.5 66.7 66.7 100
cI2 hP2 hP16 oP36 oP8 oI112 hP3 tI12 oI12 cF8
Im3m P63/mmc P63/mcm Pnma Pnma Imma P6/mmm I41/amd Imma Fd 3m
A2 A3 D88 … B27 … C32 Cc … A4
W Mg Mn5Si3 Ge4Sm5 FeB … AlB2 ThSi2 … C (diamond)
Fig. 1 Gd-Si phase diagram
Journal of Phase Equilibria and Diffusion Vol. 30 No. 2 2009
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Section III: Supplemental Literature Review in [1991Ere], although [1991Ere] reported the transition at much lower temperatures (500 to 425 C). Table 1 shows Gd-Si crystal structure data References 1991Ere: V.N. Eremenko, K.A. Meleshevich, Yu.I. Buyanov, and P.S. Martenyuk, Phase Diagram of the Gadolinium-
214
Silicon System, Ukr. Khim. Zh., 1991, 57(10), p 1047-1094 in Ukrainian: TR: Soviet Prog. Chem., 1991, 57(10), p 3642 1995Oka: H. Okamoto, Comment on Gd-Si (Gadolinium-Silicon), J. Phase Equilib., 1995, 16(2), p 198-199 2007Hua: M. Huang, D.L. Schlage, F.A. Schmidt, and T.A. Lograsso, Experimental Investigation and Thermodynamic Modeling of the Gd-Si System, J. Alloys Compd., 2007, 441, p 94-100
Journal of Phase Equilibria and Diffusion Vol. 30 No. 2 2009
