摘要
New experimental measurements of the phase diagram and the mixing enthalpy of liquid phase along with the previous experimental data were used in a reassessment of the Ni–Ga system. A set of self-consistent thermodynamic parameters of the Ni–Ga system is obtained using the calculation of phase diagram (CALPHAD) technique, and the available phase diagram and thermodynamic data are reproduced well within experimental error limits. Some noticeable improvements are obtained in the present work compared with the previous assessment: (1) the calculated Ga-rich liquidus is more reasonable; (2) Ni<sub>3</sub>Ga<sub>7</sub> is adopted as the most Ga-rich compound rather than NiGa<sub>4</sub>; (3) the Ni<sub>5</sub>Ga<sub>3</sub> phase is treated as the nonstoichiometric compound with consideration of its narrow homogeneity range; (4) the phase transformation between B8<sub>1.5</sub>_Ni<sub>3</sub>Ga<sub>2</sub> and Ni<sub>13</sub>Ga<sub>9</sub> is considered instead of treating them as Ni<sub>3</sub>Ga<sub>2</sub> phase simply; (5) the latest experimental data of mixing enthalpy for the liquid phase are adopted. The present study can be used as a basis for the development of a thermodynamic database of the Ni-based semiconductor alloy systems.
New experimental measurements of the phase diagram and the mixing enthalpy of liquid phase along with the previous experimental data were used in a reassessment of the Ni–Ga system. A set of self-consistent thermodynamic parameters of the Ni–Ga system is obtained using the calculation of phase diagram (CALPHAD) technique, and the available phase diagram and thermodynamic data are reproduced well within experimental error limits. Some noticeable improvements are obtained in the present work compared with the previous assessment: (1) the calculated Ga-rich liquidus is more reasonable; (2) Ni<sub>3</sub>Ga<sub>7</sub> is adopted as the most Ga-rich compound rather than NiGa<sub>4</sub>; (3) the Ni<sub>5</sub>Ga<sub>3</sub> phase is treated as the nonstoichiometric compound with consideration of its narrow homogeneity range; (4) the phase transformation between B8<sub>1.5</sub>_Ni<sub>3</sub>Ga<sub>2</sub> and Ni<sub>13</sub>Ga<sub>9</sub> is considered instead of treating them as Ni<sub>3</sub>Ga<sub>2</sub> phase simply; (5) the latest experimental data of mixing enthalpy for the liquid phase are adopted. The present study can be used as a basis for the development of a thermodynamic database of the Ni-based semiconductor alloy systems.
基金
financially supported by the National Natural Science Foundation of China(Nos.50934011 and51274034)
the Fundamental Research Funds for the Central Universities(No.FRF-SD-12-010A)
