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Section III: Supplemental Literature Review

Au-Ga (Gold-Gallium) H. Okamoto

The Au-Ga phase diagram in [Massalski2] was redrawn from [1987Mas], which was primarily based on [1966Coo]. This phase diagram was thermodynamically analyzed by [2010Liu] and [2011Wan]. The most significant difference between them was that the former took solubility range of some intermediate phases into account, whereas the latter assumed that all intermediate phases were line compounds. The result of [2010Liu] is shown with solid lines in Fig. 1 because of general agreement with [1966Coo] for the entire

Table 1 Phase (Au) a¢ bAu7Ga2 aAu7Ga2 bAu2Ga aAu2Ga AuGa AuGa2 (Ga)

composition range. However, result of [2011Wan] agrees better with [1966Coo] for the (Au) liqudus and solidus, which are shown with dashed lines in Fig. 1. Thermodynamic calculation done by [1987Mas] agreed with [2010Liu]. This area of the phase diagram requires further clarification because of this discrepancy. Table 1 shows Au-Ga crystal structure data taken from [2007Vil]. The nomination of Au2Ga and Au7Ga2 phases in Fig. 1 is based on this table. The composition

Au-Ga crystal structure data Composition, at.% Ga

Pearson symbol

Space group

Strukturbericht designation

Prototype

0 to 12.2 13 to 13.7 20.2 to 22.1 20.9 to 23.1 30.5 to 32 30 to 31.8 50 66.7 100

cF4 hP4 hP27 o** … oC24 oP8 cF12 oC8

Fm3m P63/mmc P62m … … Cmc21 Pnma Fm3m Cmca

A1 A3¢ … … … … B31 C1 A11

Cu aLa … … … … MnP CaF2 Ga

Weight Percent Gallium 0

10

20

30

40

50

60

70

80

90 100

1200

2010Liu 2011Wan

1064.43°C 1000

L

800

600

α'

491°C

461°C 12.2

400

423°C 348°C

(Au)

349°C

282°C 9

βAu7Ga2

200

410°C 375

54.6 349 33.6

346°C 286°C

274°C

βAu 2Ga 30°C

αAu7Ga2

0

454°C

αAu2Ga

29.7741°C

(Ga)

-200 0

Au Fig. 1

174

10

20

30

40

50

60

70

80

90

Atomic Percent Gallium

Au-Ga phase diagram

Journal of Phase Equilibria and Diffusion Vol. 34 No. 2 2013

100

Ga

Supplemental Literature Review: Section III range of each phase corresponds to the calculated result of [2010Liu]. References 1966Coo: C.J. Cooke and W. Hume-Rothery, The Equilibrium Diagram of the System Gold-Gallium, J. Less-Common Met., 1966, 10, p 42-51 1987Mas: T.B. Massalski and H. Okamoto, The Au-Ga (GoldGallium) System, Phase Diagrams of Binary Gold Alloys,

H. Okamoto and T.B. Massalski, Eds., ASM International, Materials Park, OH, 1987, p 111-118 2007Vil: P. Villars and K. Cenzual, Pearson’s Crystal Data CD ROM, ASM International, Materials Park, OH, 2007 2010Liu: J. Liu, C. Guo, C. Li, and Z. Du, Thermodynamic Assessment of the Au-Ga System, J. Alloys Compd., 2010, 508, p 62-70 2011Wan: J. Wang, V.J. Liu, L.B. Liu, H.Y. Zhou, and Z.P. Jin, Thermodynamic Assessment of the Au-Ga Binary System, CALPHAD, 2011, 35, p 242-248

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