Фазовая диаграмма системы Au-Ho

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Au-Ho (Gold-Holmium) K.A. Gschneidner, Jr., F.W. Calderwood, H. Okamoto, and T.B. Massalski No complete phase diagram based on experimental data is available for the Ho- Au system. The Ho-rich half of this system resembles the Dy-Au system, but because one more intermetallic compound is formed in the Au-rich half of this system, that section of the Ho-Au phase diagram differs from the Dy-Au diagram. Seven intermetallic compounds have been reported in the Ho-Au system. The Ho- rich compound, Ho2Au, was reported by [71Mcm] to have the orthorhombic Co2Si- type structure. The low-temperature form of dimorphic HoAu has the orthorhombic CrB-type structure [71Mcm], and the high-temperature form has the cubic CsCl-type structure [61Dwi]. [71Mcm] found that the b = a transformation in HoAu occurs at 1610 с 10 C, and the b form melts at 1698 с 10 C. No data were found on the melting temperature of any Ho-Au compound other than Ho-Au. HoAu2 crystallizes with the tetragonal MoSi2-type structure, and an orthorhombic structure of the Cu3Ti-type has been reported for HoAu3. [71Mcm] observed that Ho is the heaviest lanthanide metal to form a Ho14Au51 compound with the hexagonal Gd14Ag51-type structure. HoAu6 crystallizes in a tetragonal unit cell. [65Wun] investigated the solid solubility of Ho in (Au) and reported it to be a maximum of 3.92 at.% at the eutectic temperature of 810 C. 61Dwi: A.E.Dwight, ANL-6516, Argonne National Laboratory, Argonne, IL (1961). 65Wun: W.J. Wunderline, B.J. Beaudry, and A. Palenzona, J. Less-Common Met., 25, 135 (1971). 71Mcm: O.D. McMasters, K.A. Gschneidner, Jr., G. Bruzzone, and A. Palenzona, J. Less-Common Met., 25, 135 (1971). Published in Phase Diagrams of Binary Gold Alloys, 1987. Complete evaluation contains 2 figures, 2 tables, and 19 references. 1