Фазовая диаграмма системы Co-Pd

К оглавлению: Другие диаграммы (Others phase diargams)


Co-Pd (Cobalt-Palladium) K. Ishida and T. Nishizawa The assessed Co-Pd phase diagram is based on [36Gru], with review of the data of [35Gru], [61Boz], [67Bag], and [68Bag]. The equilibrium phases are (1) the liquid, L; (2) the fcc solid solutions (aCo,Pd), with complete solubility at all compositions; and (3) the Co-rich cph solid solution, (eCo). The equilibrium between (aCo) and (eCo) is unknown, but it is estimated from the data on the (aCo) = (eCo) transformation temperatures that the allotropic phase boundary is lowered by the addition of Pd. The martensitic transformation temperatures of (aCo) = (eCo) on heating and cooling were measured by [35Gru] and [70Kra]. The Ms point is lowered, but the reverse temperature As is raised by the addition of Pd. The allotropic phase boundary, T0 = (Ms + As)/2, is lowered. This suggests that Pd stabilizes the ( aCo) phase rather than the (eCo) phase. Electron diffraction studies on vapor-deposited thin films of Co-Pd alloys revealed two types of ordered phases. One type is the L12 (AuCu3-type) structure found in the composition range between 60 and 90 at.% Pd; the order-disorder transition temperature is estimated to be about 830 C for the 80 at.% Pd alloy. The other type has the L10 (CuAu-type) structure with a narrow region of composition around 50 at.% Pd [72Mat]. These phases are metastable because the bulk samples with compositions Co3Pd, CoPd, and CoPd3 showed no trace of the corresponding superlattice reflections. Magnetic properties of the Co-Pd system have been studied extensively by [ 35Gru], [36Gru], [61Boz], [67Bag], [67Tak], [68Bag], [69Boe], and [69Whe]. Ferromagnetism exists in solution up to 0.1 at.% Co, where the Curie temperature is -266 C [61Boz]. 35Gru: G. Grube and O. Winkler, Z. Elektrochem., 41, 52-60 (1935) in German. 36Gru: G. Grube and H. Kastner, Z. Elektrochem., 42, 156-160 (1936) in German. 61Boz: R.M. Bozorth, P.A. Wolff, D.B. Davis, V.B. Compton, and J.H. Wernick, Phys. Rev., 122, 1157-1160 (1961). 67Bag: D.M.S. Bagguley, W.A. Crossley, and J. Liesegang, Proc. Phys. Soc., 90, 1047-1058 (1967). 67Tak: T. Takahashi and M. Shimizu, J. Phys. Soc. Jpn., 23, 945-948 (1967). 68Bag: D.M.S. Bagguley and J.A. Robertson, Phys. Lett. A, 27, 516-517 (1968). 69Boe: B.M. Boerstoel, G.J. Nieuwenhuys, and G.J. van Den Berg, Phys. Lett. A, 29, 526-527 (1969). 69Whe: J.C.G. Wheeler, J. Phys. C, 2, 135-146 (1969). 70Kra: W. Krajewski, J. Kruger, and H. Winterhager, Cobalt, 48, 120-128 (1970) in German. 72Mat: Y. Matsuo, J. Phys. Soc. Jpn., 32, 972-978 (1972). 83Nis: T. Nishizawa and K. Ishida, Bull. Alloy Phase Diagrams, 4(4), 387-390 ( 1983). Submitted to the APD Program. Complete evaluation contains 3 figures, 5 tables, and 15 references. 1