Фазовая диаграмма системы Ag-Co

К оглавлению: Другие диаграммы (Others phase diargams)


Ag-Co (Silver-Cobalt) I. Karakaya and W. T. Thompson The condensed phases of the Ag-Co system are almost immiscible [Hansen]. The assessed phase diagram is qualitatively identical to that of [Hansen], but it takes into account more recent phase boundary data [70Ber, 76Bur]. It was drawn from thermodynamic optimization calculations. The solid solubility of Co in fcc (Ag), determined from magnetic property measurements [30Tam] by dissolving small amounts of Co in liquid Ag, was found to fall in the range of 0.0007 to 0.0013 at.% Co. A more recent diffusion investigation [70Ber] places the Co solubility between 0.0002 and 0.009 at.% Co in the temperature range 600 to 940 C. The approximate Co solubility in liquid Ag at 1450 C was taken as 3.3 at.% from analysis of equilibrated then quenched specimens [76Bur]. The reported solid solubilities of Ag in high-temperature fcc (aCo) are in conflict. Although up to 1.5 at.% of Ag solubility was reported [37Has] at temperatures above 460 C, even a 0.1 at.% Ag alloy was reported to be heterogeneous [52Kos]. Following [52Kos], no solid solubility is shown in the assessed diagram. From X-ray studies of Ag-Co alloys quenched at cooling rates of about 105 to 106 C/s, it was found that up to 1.5 at.% Co could dissolve in solid Ag [ 83Nin]. The onset of ferromagnetism of amorphous Ag-Co film at low Co concentrations ( less than 15 at.%) was attributed to the high Co moment. A steep concentration dependence of Curie temperature (40 C/at.%) in amorphous alloys containing 15 to 20 at.% Co has been observed [75Hau]. The Curie temperature for pure Co is reported to lie between 1094 and 1131 C [83Nis]. 30Tam: G. Tammann and W. Oelson, Z. Anorg. Chem., 186, 257-288 (1930) in German. 37Has: U. Haschimoto, Nippon Kinzoku Gakkai-Shi, 1, 177-190 (1937) in Japanese. 52Kos: W. Koster and E. Horn, Z. Metallkd., 43, 333-334 (1952) in German. 70Ber: J. Bernardini, A. Combe-Brun, and J. Cabane, Scr. Metall., 4 985-990 ( 1970) in French. 75Hau: J.J. Hauser, Phys. Rev. B, 12, 5120-5165 (1975). 76Bur: B.P. Burylev and V.D. Ivanova, Russ. J. Phys. Chem. 50, 1286-1288 (1976) . 83Nin: Y. Ning, Acta Metall. Sin., 19, A346-A353 (1983) in Chinese. 83Nis: T. Nishizawa and K Ishida, Bull. Alloy Phase Diagrams, 4, 387-390 (1983) . Published in Bull. Alloy Phase Diagrams, 7(3), Jun 1986. Complete evaluation contains 4 figures, 3 tables, and 12 references. 1