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JPEDAV (2007) 28:489 DOI: 10.1007/s11669-007-9129-3 1547-7037
ASM International

Au-Pr (Gold-Praseodymium) H. Okamoto

The Au-Pr phase diagram in [Massalski2] was redrawn from [1987Gsc]. This phase diagram was derived by thermodynamic modeling by assuming systematic changes in thermodynamic parameters of related phases in the goldrare earth systems. Table 1 Phase (Au) Au6Pr Au51Pr14 Au36Pr17 Au2Pr Au4Pr3 cAuPr bAuPr aAuPr AuPr2 (bPr) (aPr)

[1997Sac] determined the Au-Pr phase diagram by means of X-ray powder diffraction, optical and scanning electron microscopy, electron prove microanalysis and differential thermal analysis. Data points are shown Fig. 1. Two new phases, Au36Pr17 and Au4Pr3, were discovered. Solid lines in Fig. 1 show the Au-Pr phase diagram thermodynamically assessed by [2004Du] based on the data obtained by [1997Sac]. Table 1 shows Au-Pr crystal structure data.

Au-Pr crystal structure data Composition, Pearson at.% Pr symbol 0 to 1.6 14.3 21.5 32.1 33.3 42.9 50 50 50 66.7 98.5 to 100 99.5 to 100

cF4 mC28 hP65 tP106 oI12 ... cP2 oC8 oP8 oP12 cI2 hP4

Space group

Struktur bericht designation Prototype

Fm3m C2/c P6/m I4/nmm Imma ... Pm3m Cmcm Pnma Pnma Im3m P63/mmc

A1 ... ... ... ... ... B2 Bf B27 C23 A2 A3¢

Cu Au6Pr Ag51Gd14 Au36Nd17 CeCu2 ... CsCl CrB FeB Co2Si W aLa

References 1987Gsc: K.A. Gschneidner Jr., F.W. Calderwood, H. Okamoto, and T.B. Massalski, The Au-Pr (Gold-Praseodymium) System, in Phase Diagrams of Binary Gold Alloys., H. Okamoto and T.B. Massalski, Eds., ASM International, Metals Park, OH, 1987, p 228-232 1997Sac: A. Saccone, D. Maccio, M. Giovannini, and S. Delfino, The Praseodymium-Gold System, J. Alloys Compounds, 1997, 247, p 134-140 2004Du: Z. Du, C. Guo, and D. Lu¨, Thermodynamic Assessment of the Au-Pr System, J. Alloys Compounds, 2004, 364, p 117120

Weight Percent Praseodymium 10

0

20

30

40

50

60

70

80

90

100

1500 1420°C γAuPr

1997Sac

1320°C

1300 41.3

1250°C

1210°C

L

1100°C

1100 1064.43

1050

1090°C

1000°C

(βPr)

Au36Pr17

13 900°C

Au6Pr

(Au)

500

Au51Pr14

700

760°C 90 98.5

750°C 70.1

931°C 795°C

610°C

AuPr2

790°C

βAuPr

7.6

1.6

Au4Pr3

900

Au2Pr

Temperature,°C

1180°C

84.3

(α Pr)

440°C

α ΑuPr 300 0

Au

10

20

30

40

50

60

70

80

90

Atomic Percent Praseodymium

100

Pr

Fig. 1 Au-Pr phase diagram

Journal of Phase Equilibria and Diffusion Vol. 28 No. 5 2007

489