Фазовая диаграмма системы Si-Zr

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Si-Zr (Silicon-Zirconium) H. Okamoto The assessed phase diagram for the Si-Zr system is based primarily on [76Koc], with review of the experimental data of [53Lun], [54Kie], [62Erm], and [68Bru]. The data of [76Koc] are accepted as the experimental basis for the liquidus in the assessed diagram. The liquidus temperatures between 10 and 60 at.% Zr are significantly higher than those given in previous diagrams, which were based primarily on [53Lun] and [54Kie]. The liquidus data of [76Koc] obtained by thermal analysis are preferred to those of [54Kie] obtained by using an optical method. The composition of the Zr-rich eutectic reaction, 91.2 at.% Zr, is accepted from [53Lun]. The eutectic temperature is 1570 [76Koc], 1575 с 5 [68Bru], or 1610 C [53Lun]. The former appears to be defined better. No solubility of Zr in (Si) was detected [51Joh]. The solubility is considerably less than 5 wt.% (1.6 at.%) Zr [53Lun]. There has been confusion regarding Si2Zr3 since [53Lun] reported its existence. [57Dau] and [61Sch] confirmed the existence of Si2Zr3 by determining its crystal structure. The peritectic formation temperature is 2215 C [76Koc], in good agreement with 2210 C [53Lun]. On the other hand, [68Bru] considered Si2Zr3 to melt congruently at 2325 с 25 C. Although the melting temperatures of Si4Zr5 and Si2Zr3 are in disagreement, the liquidus trends observed by [ 68Bru] and [76Koc] in this composition range are alike. Si3Zr5 exists in a limited temperature range between 2180 and 1745 C [76Koc] . According to [56Bre], impurity elements such as oxygen, carbon, and nitrogen stabilize Si3Zr5. Consequently, Si5Zr6 (Si4Zr5?), Si2Zr3, SiZr2, and SiZr4 ( SiZr3?) are disproportionated when impure Zr is used. This impurity problem was probably the reason why [54Kie] observed Si3Zr5 as the most dominant phase in the Si-Zr system, with the highest congruent melting temperature at 2250 C, although Si3Zr5 was not detected by [53Lun]. It is assumed in this evaluation that SiZr3 is the same as "SiZr4", which was previously reported by numerous investigators. The reason for the absence of this phase in some studies may be the stabilization of Si3Zr5, caused by the presence of very small amounts of impurity [56Bre, 61Sch]. Alternatively, [ 60Aro] proposed that "SiZr4" is stable only in a restricted temperature range. "SiZr4" is not stable below 1200 C [62Sch] or above 1500 C [68Bru]. The solid solubility of Si is less than 1.6 [49She] or less than 0.6 [53Lun] at.%. The solubility of 9 at.% at 1000 C reported by [52Rob] may be too high. A thermal arrest corresponding to the (bZr) <259> (aZr) eutectoid transformation was observed at 870 с 5 C [52Rob]. For this type of reaction, the temperature is too high with respect to the allotropic transformation temperature of pure Zr at 863 C. [53Lun] could not determine whether the reaction is eutectoid or peritectoid type. Therefore, the invariant temperature in the assessed diagram is shown at 863 C. The solid solubility of Si in (aZr) is less than 0.3 at.% [53Lun]. 28Sey: H. Seyfarth, Z. Kristallogr., 67, 295-328 (1928) in German. 49She: S.M. Shelton, U.S. At. Energy Comm., AF-TR-5932 (1949); Met. Abstr., 21, 869 (1954). 51Joh: W.R. Johnson and M. Hansen, U.S. Air Force Tech. Rep. 6383 (1951); Met. Prog., 63(2), 105-109 (1953). 52Rob: A.H. Roberson and E.T. Hayes, Trans. ASM, 44, 536 (1952). 53Lun: C.E. Lundin, D.J. McPherson, and M. Hansen, Trans. ASM, 45, 901-914 ( 1953). 53Sch: H. Schachner, H. Nowotny, and R. Machenschalk, Monatsh. Chem., 84(4), 677-685 (1953) in German. 54Kie: R. Kieffer, F. Benesovsky, and R. Machenschalk, Z. Metallkd., 45(8), 493-498 (1954) in German. 54Sch: H. Schachner, H. Nowotny, and H. Kudielka, Monatsh. Chem., 85(5), 1140- 1153 (1954) in German. 56Bre: L. Brewer and O. Krikorian, J. Electrochem. Soc., 103, 38-51 (1956). 57Dau: C.H. Dauben, J. Electrochem. Soc., 104(8), 521-523 (1957). 60Aro: B. Aronsson, Ark. Kemi., 16, 379-423 (1960). 61Sch: O. Schob, H. Nowotny, and F. Benesovsky, Monatsh. Chem., 92(6), 1218- 1226 (1961) in German. 62Erm: S.V. Ermakov and B.M. Tsarev, Radiotekh. Elektron., 7, 2101-2104 (1962) in Russian. 62Sch: O. Schob, H. Notwotny, and F. Benesovsky, Planseeber. Pulvermetall., 10, 65-71 (1962) in German. 66Pfe: H.V. Pfeifer and K. Schubert, Z. Metallkd., 57, 884-888 (1966) in German. 68Bru: C.E. Brukl, Tech. Rep. AFML-TR-65-2, Wright-Patterson Air Force Base, OH (1968). 76Koc: Yu.A. Kocherzhinskii, O.G. Kulik, and E.A. Shiskin, Akad. Nauk Ukr. SSR, Metallofiz., 64, 48-52 (1976) in Russian. Published in Bull. Alloy Phase Diagrams, 11(5) Oct 1990. Complete evaluation contains 1 figure, 3 tables, and 56 references. 1