Фазовая диаграмма системы Co-Si

К оглавлению: Другие диаграммы (Others phase diargams)


Co-Si (Cobalt-Silicon) K. Ishida and T. Nishizawa The assessed phase diagram for the Co-Si system is based on the data of [ 34Vog], [37Has], [73Kos], and [90Eno], with review of the data of [37Kos], [ 64Zel], [70Kre], and [72Fro]. The equilibrium phases are (1) the liquid, L; (2) the Co-rich fcc terminal solid solution, (aCo); (3) the Co-rich cph terminal solid solution, (eCo), with a maximum solubility of 18.4 at.% Si at the eutectic temperature of 1204 C [73Kos]; (4) the tetragonal phase, Co3Si, stable between 1193 and 1214 C; (5) Co2Si, with two modifications: low- temperature orthorhombic a, stable below about 1320 C, and high-temperature b, with an unknown structure, stable between 1238 C and the congruent melting temperature of 1334 C; (6) the cubic intermediate phase CoSi, stable to the congruent melting temperature of 1460 C; (7) the cubic phase CoSi2, stable to the congruent melting temperature of 1326 C; and (8) the cubic solid solution, (Si), with negligible solid solubility of Co. [63Luo] reported that (aCo) solid solution up to 13 at.% Si was obtained by rapid quenching from the melt, which is within the solubility limit of (aCo). The formation and transformation behaviors of Co3Si and aCo2Si are complex and are quite different on heating and cooling, mainly due to the suppression of the formation of Co3Si. The metastable eutectic reaction L = (aCo) + aCo2Si at about 1192 C was found by [72Boo] and was supported by [74Boo] and [75Liv], while [73Kos] did not detect this reaction. According to [73Joh], Co3Si transforms ultimately to a eutectoid structure of aCo2Si and the Co-rich solid solution, but the reaction has only been observed to proceed via a transition phase with an orthorhombic structure not distinguished from that of aCo2Si. This phase appears to form by a massive transformation. [73Kos] found the metastable ordered phase with D019 structure in a composition of about 8 at.% Si at temperatures below ~570 C. The tetragonal phase Co2Si3, formed at pressures >4 GPa and at temperatures between 500 and 750 C, is metastable under ordinary conditions. After annealing at 700 C, it decomposes into the aCoSi2 and CoSi phases [82Lar]. Laser irradiation of thin Co films on single crystalline Si was studied by [ 79Gur]. In the case of 0.1 mm Co film, Co2Si, CoSi, and CoSi2 were formed. CoSi2 films on (111) Si substrates were obtained by solid phase epitaxy [80Sai] and the evaporation of Co onto Si [82Sor]. CoSi2, CoSi, Co2Si, and Co4Si were obtained by solid-state reaction at 800 C in thin bilayers of amorphous Si and Co evaporated on SiO2 substrates. The crystal structure of Co4Si could not be determined [86Apr]. The ferromagnetic coercivity of the unaligned structure near the eutectic composition of the Co-23 at.% Si alloy was reported to be from 68 to 297 Oe [ 73Joh], whereas that of the aligned eutectoid was lower than 36 Oe [75Liv]. 34Vog: R. Vogel and K. Rosenthal, Arch. EisenhЃttenwes., 12, 689-691 (1934) in German. 37Has: U. Haschimoto, J. Jpn. Inst. Met., 1, 135-143 (1937) in Japanese. 37Kos: W. K”ster and E. Schmid, Z. Metallkd., 29, 232-233 (1937) in German. 63Luo: H. Luo and P. Duwez, Can. J. Phys., 41, 758-761 (1963). 64Zel: L.P. Zelenin, F.A. Siderenko, and P.V. Geld, Izv. V.U.Z. Tsvetn. Metall. , 7(2), 146-151 (1964) in Russian. 70Kre: R.P. Krentsis, V.Y. Zinovyev, L.P. Andreyeva, and P.V. Geld, Fiz. Met. Metalloved., 29(1), 118-123 (1970) in Russian; TR: Phys. Met. Metallogr., 29(1) , 122-127 (1970). 72Boo: J.V.D. Boomgaard and F.M.A. Carpay, Acta Metall., 20, 473-476 (1972). 72Fro: A.A. Frolov, Y.V. Putintsev, F.A. Sidorenko, P.V. Geld, and R.P. Krentsis, Izv. Akad. Nauk SSSR, Neorg. Mater., 8, 468-471 (1971) in Russian; TR: Inorg. Mater., 8, 408-411 (1972). 73Joh: R.E. Johnson, H.W. Rayson, and W. Wright, Acta Metall., 21, 1471-1477 ( 1973). 73Kos: W. K”ster, H. Warlimont, and T. Godecke, Z. Metallkd., 64, 399-405 ( 1973) in German. 74Boo: J.V.D. Boomgaard and F.M. Carpay, Scr. Metall., 8, 23-26 (1974). 75Liv: J.D. Livingston, Acta Metall., 23, 521-527 (1975). 79Gur: G.J.V. Gurp, G.E.J. Eggermont, Y. Tamminga, W.T. Stacy, and J.R.M. Gijsbers, Appl. Phys. Lett., 35, 273-275 (1979). 80Sai: S. Saitoh, H. Ishiwara, and S. Furukawa, Appl. Phys. Lett., 37, 203-205 (1980). 82Lar: V.I. Larchev and S.V. Popova, J. Less-Common Met., 84, 87-91 (1982). 82Sor: Y. Sorimachi, H. Ishiwara, H. Yamamoto, and S. Furukawa, Jpn. J. Appl. Phys., 21, 752-756 (1982). 83Nis: T. Nishizawa and K. Ishida, Bull. Alloy Phase Diagrams, 4(4), 387-390 ( 1983). 86Apr: G. Aprilesi, E. Mazzega, M. Michelini, and F. Nava, J. Appl. Phys., 60, 310-317 (1986). 90Eno: H. Enoki, K. Ishida, and T. Nishizawa, J. Less-Common Met., 160, 153- 160 (1990). Submitted to the APD Program. Complete evaluation contains 2 figures, 9 tables, and 37 references. Special Points of the Co-Si System