Thermodynamic models for Ge-Pd system using calculation of phase diagram(Calphad)are proposed to solve the problem that the experimentally determined Ge-Pd phase diagram is hard to be extrapolated to multi-component system. Different thermodynamic models are employed for different kinds of phases. Because there is no solubility of Pd in pure Ge
Gibbs energy function of pure element from Scientific Group of Thermal Europe is employed for Ge
the solid solution model is used to describe liquid and Pd solid solution
the line compound model is employed to describe stoichiometric phases GePd
GePd
2
and Ge
8
Pd
21
and th
e sublattice model is used for non-stoichiometric phases Ge
9
Pd
25
GePd
3
α-GePd
5
and β-GePd
5
. Thermodynamic parameters are optimized by using the experimental data of mixing entropy and enthalpy of liquid
invariant reaction temperature and composition
hence a set of reliable thermodynamic models are obtained. The calculation results based on these models consist with most of experimental data. These models can be extrapolated to multi-component systems
and provide support to the thermodynamic database construction
composition design and preparation optimization of Ge-based multi-component systems.
MACHAC P, MACHOVIC V. Raman spectroscopy of Ge/Pd/GaAs contacts [J]. Microelectronic Engineering, 2004, 71(2): 177-181.
HOU Linggui, LIU Peng, CHEN Zhiwen, et al. Annealing-dependent growth and nonlinear electrical properties of fractal Ge nanojoints based on Pd matrix [J]. Materials Letters, 2014, 115(2): 29-33.
OKAMOTO H. The Ge-Pd system [J]. Journal of Phase Equilibria, 1992, 13(4): 410-413.[8] KHALAFF K, SCHUBERT K. Constitution of the Pd-Ge system [J]. Zeitschrift Fuer Metallkunde, 1974, 65(5): 379-382.
CASTANET R, CHASTEL R. Thermodynamic behaviour of Pd-Si, Pd-Ge and Pt-Ge molten alloys [J]. Zeitschrift Fuer Metallkunde, 1987, 78(2): 97-102.
LBIBB R, CASTANET R. Thermodynamic investigation of Pt-Ge and Pd-Ge binary alloys [J]. Journal of Alloys and Compounds, 1992, 189(1): 23-29.
CHANG Y A, CHEN Shuanglin, ZHANG Fan, et al. Phase diagram calculation: past, present and future [J]. Progress in Materials Science, 2004, 49(3/4): 313-345.
LUO A A. Material design and development: from classical thermodynamics to CALPHAD and ICME approaches [J]. Calphad, 2015, 50: 6-22
ÅGREN J. 材料基因组与相图计算 [J]. 科学通报, 2013, 58(35): 3633-3637.
ÅGREN J. The materials genome and CALPHAD [J]. Chinese Science Bulletin, 2013, 58(35): 3633-3637.
LI Yiwei, CHANG Keke, DU Yong. Calculation of phase diagram and its application [J]. Materials Science and Engineering of Powder Metallurgy, 2012, 17(1): 1-9.
JIANG Min, LI Hongxiao, HAO Shiming. Recent developments and applications of cluster variation method(CVM)[J]. Journal of Materials and Metallurgy, 2010, 9(3): 193-197.
WOPERSNOW W, SCHUBERT K. Kristallstruktur von Pd25Ge9 [J]. Journal of the Less-Common Metals, 1975, 41(1): 97-103.
HILLERT M. The compound energy formalism [J]. Journal of Alloys and Compounds, 2001, 320(2): 161-176.
Computherm Company Limited. Software package for multi-component phase diagram calculation [CP]. Madison, WI, USA: CompuTherm Company Limited, 2014.