Comment on Ir-Si (Iridium-Silicon)

S u p p l e m e n t a l L i t e r a t u r e R e v i e w : S e c t i o n HI Comment on Fe-Y (Iron-Yttrium) H. O k a m o t o [93Li] measured the solubility of Y in ((xFe) by EPMA. Specimens were annealed at 600, 700, 800, and 880 ~ for 1440, 720,480, and 240 h, respectively. The experimental results are given in Table 1 and can be represented by the relationship: lnX(at.% Y) =-2363.7/T(K) - 5.892 + 0.060. Table 1 Solubility of Y in (IxFe) Temperature, ~ Cited Reference Solubility, a t . % Y 8 8 0 ....................................................... 0.038 800 ....................................................... 700 ....................................................... 600 ....................................................... 0.029 0.025 0.018 93Li: L. Li and Z. Xhing,Acta Metall. Sin., 29(3), A136-A141 (1993) in Chinese. Comment o n Ir-Si ( I r i d i u m - S i l i c o n ) H. O k a m o t o [93A11] investigated the Ir-Si phase diagram on the Si-rich side by means of x-ray powder diffraction, density, DTA, metallography, EPMA, and electrical resistivity. A partial diagram is given in Fig. 1. In this diagram, the liquidus has been modified slightly near the congruent melting point of IrSi. [93All] observed a polymorphic transformation in IrSi 3 on the Ir-rich side of stoichiometry (72.5 at.% Si). Since three crystallographic forms of IrSi 3 have been reported [82Eng, 62Fin], this transformation is believed to be the [3 to T transformation, and it occurred at approximately 975 ~ This temperature is within the 900 to 1000 ~ range earlier reported by [82Eng] for the transformation. The Ix to [~transformation temperature is unknown. Ir2Si 3 [70Eng] and IrSi 2 [60Bha] were not observed. No Ir-Si phase diagram was given in [Massalski2]. Cited References 57Kor: W.L. Korst, L.N. Finnie, and A.W. Searcy, J. Phys. Chem., 61, 1541-1543 (1957). 57Rei: G. Reinacher, Rev. Met., 54, 321-336 (1957) in French. 60Bha: S. Bhan and K. Schubert, Z Metallkd., 51, 327-339 (1960) in German. 62Fin: L.N. Fin nie, J. Less-Common Met., 4(1 ), 24-34 (1962). 70Eng: L Engstrom and E Zackrisson, Acta Cher~ Scand., 24(6), 21092116(1970). 82Eng: I. Engstrom and E. Zdansky, Acta Chem. Scand. A, 36(3), 857858(1982). 87Eng: I. Engstrom, T. Lindsten, and E. Zdansky, Acta Che~ Scand. A, 41,237-242 (1987). 93AIh C.E. Allevato and C.B. Vming, J. Alloy. Compd., 200, 99-105 (1993). Although not shown in Fig. 1, the (Ir)-rich eutectic point is at 9.5 at.% Si and 1470 ~ [57Rei]. The Ir3Si 2 ~ Ir2Si + IrSi eutectoid temperature is between 750 and 500 ~ [60Bha]. Ir-Si Crystal Structure Data Phase Composition, at.% Si Pearson symbol Space group Strukturbericht designation Prototype Reference (Ir) ............................... 0 cF4 Frn3m A1 Cu ... Ir3Si ............................. 25 tl16 14/mcm DO c SiU 3 [60Bha] 160Bha] Ir2Si ............................. 33.3 oP12 Prima C23 CozSi Ir3Si2 ........................... 40 hP6 P631mmc B8~ Ni2In [60Bha] IrSi .............................. 50 oP8 Pnma B31 MnP [57Kor] Ir4Si5 ........................... 55.6 mPl 8 P21/m ... Rh4Si 5 [70Eng] Ir3Si4 ........................... 57.1 oP28 Pnma ... Rh3Si 4 [70Eng] P 2 i/c Ir3Si5 ........................... 62.5 mP64 ylrSi3 ........................... 72.5 o** . . . . . . . . . [82Eng] [3IrSi3 .......................... 72.5 m** . . . . . . . . . [82Engl 75? hP8 P63mc . e F8 Fd3m A4 ~IrSi3 .......................... (Si) .............................. 1O0 . . . . Joumal of Phase Equilibria Vol. 16 No. 5 1995 . . . . . . . C(diamond) [87Eng] [62Fin] ... 473 Section HI: S u p p l e m e n t a l Literature Review Weight P e r c e n t Siticon 50 ' 1800 ' i .... ..... i . . . . . . I 60 , , [ I 80 70 " ' I . 9 0 100 ,I, ,I, 1707 ~ x N x 1600 N ~x xX 1408 ~ " 1414 ~ 1400 j~ / 80.5• 1315 ~ I 9 f J L 1260 ~ ~ ~ / 1200 " 1222~ (si 1000 975~ . . . . . . 800 50 60 70 Atolnic ] 9 , 80 Perc:eul . . . . . . . . . . . 9c} . . . . . 100 ~iiicon ~i Fig. 1 Si-rich side of Ir-Si phase diagram. C o m m e n t on Mg-Zn (Magnesium-Zinc) H. O k a m o t o The Mg-Zn phase diagram in [Massalski2] was redrawn from [88C1a]. [92Aga] calculated a Mg-Zn phase diagram (see [94Oka]). In the calculated diagram, the "Mg7Zn3 '' phase of the [88C1a] diagram, which was included in the [Massalski2] compilation, was replaced by Mg51Zn20 (28.1 at.% Zn) to be in accord with the observation of [81Hig]. [94God] determined the partial Mg-Zn phase diagram, which is shown in Fig. I and is in good agreement with [92Aga]. The formation of Mg2Zn u was suppressed due to a nucleation problem when DTA measurements were made on cooling at 2 ~ The metastable L ~ MgZn 2 + (Zn) eutectic is shown with dashed lines in Fig. 1. 474 Cited References 81Hig: I. Higashi, N. Shotani, M. Uda, T. Mizoguchi, and H. Katoh, J. Solid State Chen~,36, 225-233 (1981). 88Cla: J.B. Clark, L. Zabdyr, and Z. Moser, Phase Diagrams of Binary Magnesium Alloys, ASM Intemational, Metals Park, OH, 353-364 (1988). 92Aga: R. Agarwal, S.G. Fries, H.L. Lukas, G. Petzow, E Sommer, T.G. Chart, and G. Effenberg,Z Metallkd., 82 (4), 216-223 (1992). 94God: T. Godecke and F. Sommer, Z Metallkd., 85(10), 683-691 (1994) in German. 94Oka: H. Okamoto,J. Phase Equilibria, 15(1), 129-130 (1994). Journal of Phase Equilibria Vol. 16 No. 5 1995  (...truncated)