熔融CaCl2-MgCl2体系的粘度

用旋转柱体法系统测量了CaCl2-MgCl2熔融盐体系的粘度,考察了熔融CaCl2-MgCl2体系粘度随温度和组成的变化关系.比较了实验测得的数据与文献报道值,根据熔融盐体系粘度变化规律对熔融体系结构进行了推断.实验测得熔融物体系粘度随温度升高而明显降低,由于所用试剂含有少量杂质,与文献报道的纯CaCl2和MgCl2的粘度值相比,实验测得值出现偏差.熔融CaCl2-MgCl2混和体系的粘度明显要比纯物质的粘度大,这说明在熔融条件下,CaCl2-MgCl2体系生成了体积较大的配合物粒子,增加了熔体粘度.在不同的温度条件下,由于有不同组成的配合物生成,体系粘度最大值对应了不同熔体组分.     

Thermodynamic evaluation of phase equilibria in NaNO3-KNO3 system

The binary phase diagram of NaNO₃-KNO₃ was studied by differential scanning calorimetry (DSC) and high-temperature x-ray diffractometry. The solid solutions in the intermediate concentration phase appeared to be a mixture of the NaNO₃-based solid solutions and KNO₃-based solid solutions. This behavior below the solidus suggests that NaNO₃-KNO₃ might well be regarded as a system with limited solid solubilities instead of a continuous series of solid solutions. The temperatures for the solidus and liquidus have been determined with consideration of limited terminal solid solutions. Two models, the Henrian solution and regular solution theory for NaNO₃-based phase and the KNO₃-based phase, respectively, were used to reproduce the solidus and liquidus of the phase diagram. The results are in good agreement with the DSC data. The thermodynamic properties for the NaNO₃-based and KNO₃-based solid solutions have been derived from an optimization procedure using the experimental data. The calculated phase diagram and optimized thermodynamic parameters are thermodynamically self-consistent. Thus, the limited solid solution model seems to be more consistent with the phase diagram obtained by DSC than the continuous solid solution model.     

Thermodynamic study of phase equilibria in the Pb-Bi-Hg system

Thermodynamic modeling of the Pb-Bi-Hg ternary system was done with the help of the calculation phase diagram (CALPHAD) method. This work included a thermodynamic characterization of the three binary borders: the parameters relating to the Pb-Bi system were taken from the literature, whereas those of Pb-Hg and Bi-Hg systems were determined during this study, and were primarily based on particular calorimetric measurements. Some differential scanning calorimetry (DSC) data for the ternary system allowed us to verify the existence of a ternary compound with a composition close to Pb_0.45Bi_0.35Hg_0.2 and the presence of two peritectic invariants. With these results, it was possible to carry out the assessment of the ternary interaction parameter of the liquid phase.     

Thermodynamic study of phase equilibria in the Pb-Sn-Sb system

A thermodynamic analysis of the phase equilibria in the Pb-Sn-Sb ternary system was conducted. A regular solution approximation based on a two-sublattice model was adopted to describe the Gibbs energy of formation of the individual phases in the binary and ternary systems. In the case of some component binary systems, the effect of pressure also was considered. Experimental data obtained by differential thermal analysis (DTA) and electron probe microanalysis (EPMA) in the present study, along with literature data on phase boundaries and thermochemical properties, form the basis for the evaluated thermodynamic parameters used in the calculation. Calculated and experimental phase boundaries agree fairly well. Present address: Kawasaki Steel Corporation, Chiba 260, Japan.     

Thermodynamic study of phase equilibria in the Ni-Si-B system

A thermodynamic analysis of the phase equilibria in the Ni-Si-B ternary system was conducted. A regular solution approximation based on a sublattice model was adopted to describe the Gibbs energies for the individual phases in the binary and ternary systems. A set of thermodynamic parameters for the individual phases was evaluated from literature data on phase boundaries and thermochemical properties. The optimized parameters reproduced the experimental data, for the most part, satisfactorily. However, in the calculated isothemal section at 850 °C, phase equilibria between the fcc phase and Ni₆Si₂B or Ni₃Si(β ₁) and Ni₆Si₂B were found instead of the experimentally observed equilibria between Ni₃Si(β ₁) and Ni₃B or Ni₅Si₂(γ) and Ni₃B. Further, in the primary crystal surface for the fcc phase, the calculated liquidus temperatures were higher than the reported values by approximately 80 °C. Therefore, it is considered that the fcc phase evaluated in the Ni-Si system by Lindhólm and Sundman is too stable.     

Thermodynamic study of phase equilibria in the Pb-Bi-Hg system

Thermodynamic modeling of the Pb-Bi-Hg ternary system was done with the help of the calculation phase diagram (CALPHAD) method. This work included a thermodynamic characterization of the three binary borders: the parameters relating to the Pb-Bi system were taken from the literature, whereas those of Pb-Hg and Bi-Hg systems were determined during this study, and were primarily based on particular calorimetric measurements. Some differential scanning calorimetry (DSC) data for the ternary system allowed us to verify the existence of a ternary compound with a composition close to Pb_0.45Bi_0.35Hg_0.2 and the presence of two peritectic invariants. With these results, it was possible to carry out the assessment of the ternary interaction parameter of the liquid phase.     

Thermodynamic study of phase equilibria in the Ni-Si-B system

A thermodynamic analysis of the phase equilibria in the Ni-Si-B ternary system was conducted. A regular solution approximation based on a sublattice model was adopted to describe the Gibbs energies for the individual phases in the binary and ternary systems. A set of thermodynamic parameters for the individual phases was evaluated from literature data on phase boundaries and thermochemical properties. The optimized parameters reproduced the experimental data, for the most part, satisfactorily. However, in the calculated isothemal section at 850 °C, phase equilibria between the fcc phase and Ni₆Si₂B or Ni₃Si(β ₁) and Ni₆Si₂B were found instead of the experimentally observed equilibria between Ni₃Si(β ₁) and Ni₃B or Ni₅Si₂(γ) and Ni₃B. Further, in the primary crystal surface for the fcc phase, the calculated liquidus temperatures were higher than the reported values by approximately 80 °C. Therefore, it is considered that the fcc phase evaluated in the Ni-Si system by Lindhólm and Sundman is too stable.     

Thermodynamic properties and phase equilibria in the Si-B system

The vapor composition and thermodynamic properties of Si-B alloys with boron content from 1.5 up to 100 at.% were investigated in the temperature interval of 1522 to 1880 K by Knudsen effusion mass spectrometry. Thermodynamic functions of the SiB₆ and SiB _n borides, primary solid solutions, and liquid solution were obtained. The thermodynamic functions of the Si-B melt were approximated by the ideal associated-solutions model under the assumption that only one complex, SiB₃, existed. The established thermodynamic functions of the melt and of the SiB₆ and SiB _n compounds were used for computation of the phase diagram of the Si-B system. Good agreement with the available experimental data was obtained.     

Thermodynamic properties and phase equilibria in the silicon-phosphorous system

Knudsen effusion mass spectrometry and a static method were used to study the vapor composition and the thermodynamic properties of the Si-P melt with the phosphorous content from 0.09 to 26.5 at.% in the temperature range 1507 to 1831 K. A representative file of experimental data comprising about 100 values of phosphorus activity at various concentrations and/or temperatures was obtained. The thermodynamic characteristics as functions of temperature and concentration were approximated by the ideal associated-solution model under the assumption that SiP and Si₂P complexes exist in the melt. The boundaries of the region of liquid phase stability on the phase diagram were computed, and agreement with the available experimental information was obtained.     

Thermodynamic properties and phase equilibria in the silicon-phosphorous system

Knudsen effusion mass spectrometry and a static method were used to study the vapor composition and the thermodynamic properties of the Si-P melt with the phosphorous content from 0.09 to 26.5 at.% in the temperature range 1507 to 1831 K. A representative file of experimental data comprising about 100 values of phosphorus activity at various concentrations and/or temperatures was obtained. The thermodynamic characteristics as functions of temperature and concentration were approximated by the ideal associated-solution model under the assumption that SiP and Si₂P complexes exist in the melt. The boundaries of the region of liquid phase stability on the phase diagram were computed, and agreement with the available experimental information was obtained.     

Thermodynamic properties and phase equilibria in the Cr-P system

A Knudsen effusion method with mass-spectrometric analysis of gaseous phase has been applied to investigate the thermodynamic properties of the chromium phosphides (1341 to 1704 K) and Cr-P liquid alloys (1664 to 1819 K). Simultaneously, DSC has been used to measure heat capacities of chromium phosphides Cr₃P and Cr₁₂P₇ in the temperature range of113 to 873 K. The entropies of formation of chromium phosphides calculated according to the second and third laws of thermodynamics agree within the limits of experimental error. The Gibbs energies of formation of the phosphides from solid Cr and P₂ gas have been approximated with the following equations (in J/mol): A_fG⁰(Cr₃P) = −(244 112 ±2800) + (70.95 ±1.80)T ΔG⁰(Cr₁₂2P₇) = −(1563 678 ±15 350) + (440.6 ±9.90)T Thermodynamic properties of liquid solutions have been described with the ideal associated-solution model assuming that CrP, Cr₂P, Cr₃P, and Cr₃P₂ complexes exist in the melt. The phase diagram computed with the help of the thermodynamic data agrees with the published information.     

Thermodynamic properties and phase equilibria in the Si-B system

The vapor composition and thermodynamic properties of Si-B alloys with boron content from 1.5 up to 100 at.% were investigated in the temperature interval of 1522 to 1880 K by Knudsen effusion mass spectrometry. Thermodynamic functions of the SiB₆ and SiB _n borides, primary solid solutions, and liquid solution were obtained. The thermodynamic functions of the Si-B melt were approximated by the ideal associated-solutions model under the assumption that only one complex, SiB₃, existed. The established thermodynamic functions of the melt and of the SiB₆ and SiB _n compounds were used for computation of the phase diagram of the Si-B system. Good agreement with the available experimental data was obtained.     

Thermodynamic calculation of phase equilibria of the Bi-Sn-Zn system

A thermodynamic assessment of the Bi-Sn-Zn ternary system was carried out by considering the experimental data including the phase equilibria and thermodynamic properties on the basis of the CALPHAD method. A set of optimized thermodynamic parameters has been obtained, which leads to a very good fit between calculation and experiments. In particular, the thermodynamic calculations in the Sn-rich portion are presented in view of the recent progress in Pb-free solder alloys.     

Thermodynamic calculation of phase equilibria of the Bi-Sn-Zn system

A thermodynamic assessment of the Bi-Sn-Zn ternary system was carried out by considering the experimental data including the phase equilibria and thermodynamic properties on the basis of the CALPHAD method. A set of optimized thermodynamic parameters has been obtained, which leads to a very good fit between calculation and experiments. In particular, the thermodynamic calculations in the Sn-rich portion are presented in view of the recent progress in Pb-free solder alloys.     

Cu-Ni-Sn三元系相平衡的热力学计算

基于Cu-Ni-Sn三元系的相平衡和热力学的实验信息,采用亚正规溶体模型描述液相和fcc相的Gibbs自由能,为了预测该体系中bcc相的A2-B2有序-无序转变,bcc相的Gibbs自由能采用双亚点阵模型进行描述.利用CALPHAD(相图计算)方法评估了Cu-Ni-Sn三元系各相的热力学参数,计算的富Cu侧相图和热力学性质与实验数据比较一致.并对该三元系中bcc相的A2-B2有序-无序转变及fcc相的溶解度间隙进行了计算.这些计算结果对利用析出强化以及Spinodal分解开发高强度和高导电性的新型Cu基合金的组织设计具有一定的指导意义.     

Thermodynamic evaluation of the phase equilibria and glass-forming ability of the Ti−Be system

The glass-forming ability of Ti−Be alloys is of great interest. Experimental and theoretical evaluations of the glass-forming ability of this binary alloy show that the formation of a metastable TiBe phase with a CsCl-type B2 structure controls the glass-forming ability in this system. However, there is no information on the thermochemical properties of metastable TiBe for the quantitative evaluation of the glass-forming ability using Davies-Uhlmann kinetic formulations. We have carried out a thermodynamic analysis using experimental phase diagram data and the energy of formation of the stoichiometric compounds from ab initio calculations. Furthermore, the Gibbs energy of formation for the body-centered cubic (bcc) phase was evaluated over the entire composition range by applying the cluster expansion method (CEM) to the total energy of some bcc-based ordered structures obtained from ab initio calculations. For the bcc phase, the two-sublattice formalism, (Ti, Be)_0.5(Ti,Be)_0.5, was adopted to describe the A2/B2 transformation. A good agreement between the calculated values and experimental phase equilibria was obtained. Evaluation of the glass-forming ability was also attempted utilizing the thermodynamic quantities obtained from the phase diagram assessment. The calculated glass-forming ability agrees well with the experimental results. This paper was presented at the International Symposium on User Aspects of Phase Diagrams, Materials Solutions Conference and Exposition. Columbus, Ohio, 18–20 October, 2004.     

Thermodynamic analysis and phase equilibria calculations of the ga-in-sb system

Aquasi sub-subregular solution model is used to describe the tbermodynamic properties of the liquid phase in the ternary Ga-In-Sb system. The ternary compound, (Ga_yJn_i-y)Sb, is considered a regular solid solution of the stoichiometric compounds, GaSb and InSb. Previous data on the thermodynamic properties and phase equilibria in the Ga-In-Sb system are used to obtain optimum values of the model parameters. Using optimized model parameters, phase equilibria and thermodynamic properties of Ga-In-Sb are calculated and compared with the previous experimental data. Present address: India Hard Metals Ltd., 58 Motilal Gupta Road, Calcutta 700 008, India     

Thermodynamic analysis and phase equilibria calculations of the ga-in-sb system

Aquasi sub-subregular solution model is used to describe the tbermodynamic properties of the liquid phase in the ternary Ga-In-Sb system. The ternary compound, (Ga_yJn_i-y)Sb, is considered a regular solid solution of the stoichiometric compounds, GaSb and InSb. Previous data on the thermodynamic properties and phase equilibria in the Ga-In-Sb system are used to obtain optimum values of the model parameters. Using optimized model parameters, phase equilibria and thermodynamic properties of Ga-In-Sb are calculated and compared with the previous experimental data. Present address: India Hard Metals Ltd., 58 Motilal Gupta Road, Calcutta 700 008, India     

Thermodynamic evaluation of phase equilibria in NaNO3-KNO3 system

The binary phase diagram of NaNO₃-KNO₃ was studied by differential scanning calorimetry (DSC) and high-temperature x-ray diffractometry. The solid solutions in the intermediate concentration phase appeared to be a mixture of the NaNO₃-based solid solutions and KNO₃-based solid solutions. This behavior below the solidus suggests that NaNO₃-KNO₃ might well be regarded as a system with limited solid solubilities instead of a continuous series of solid solutions. The temperatures for the solidus and liquidus have been determined with consideration of limited terminal solid solutions. Two models, the Henrian solution and regular solution theory for NaNO₃-based phase and the KNO₃-based phase, respectively, were used to reproduce the solidus and liquidus of the phase diagram. The results are in good agreement with the DSC data. The thermodynamic properties for the NaNO₃-based and KNO₃-based solid solutions have been derived from an optimization procedure using the experimental data. The calculated phase diagram and optimized thermodynamic parameters are thermodynamically self-consistent. Thus, the limited solid solution model seems to be more consistent with the phase diagram obtained by DSC than the continuous solid solution model.     

Thermodynamic evaluation of phase equilibria in the CaCl2-MgCl2-CaF2-MgF2 system

The phase diagram of the CaCl₂-CaF₂-MgCl₂-MgF₂ reciprocal ternary system was calculated thermodynamically from available data on the common-ion binary subsystems and from available data on the CaCl₂-MgF₂ join. This join is very nearly quasibinary and divides the system into two quasiternary systems: the CaCl₂-MgF₂-CaF₂ system with a ternary eutectic calculated at 724 +-5 °C and the CaC₂-MgF₂-MgCl₂ system with a ternary eutectic calculated at 561 +-5 °C.