Thermodynamic Optimization of TmCl3-ACl （A = Na, K, Rb, Cs）Phase Diagrams

As well known, molten salt electrolysis was wide ly used for the production of rare earth metals andtheir alloys. And, phase diagrams are the most impor tant data for fused electrolytes. Dealing with the bina ry phase diagrams relating to rar…     

Thermodynamic description of Sn-Y and Mg-Sn-Y systems

The thermodynamic optimization of the Sn-Y and Mg-Sn-Y systems was critically carried out by means of the CALPHAD（CALculation of PHAse Diagram） technique. In the Sn-Y system, the solution phases（liquid, bcc, bct and hcp） were described by the substitutional solution model. The compound Sn3Y5, which has a homogeneity range, was treated as the formula（Sn, Y）3（Sn, Y）2Y3 by a three-sublattice model in accordance with the site occupancies. In the Mg-Sn-Y system, the liquid phase was treated as the formula（Mg, Sn, Y, Mg2Sn） using an associated solution model, and bcc, bct and hcp were treated as the formula（Mg, Sn, Y）. The compound Sn3Y5 was treated as the formula（Sn, Y, Mg）3（Sn, Y, Mg）2Y3. The ternary compound MgSnY was treated as stoichiometric compound. A set of self-consistent thermodynamic parameters of the Mg-Sn-Y system was obtained. The projection of the liquidus surfaces and the reaction scheme of the Mg-Sn-Y system were predicted.     

Phase diagram of Er-Sn-Te system for diluted magnetic semiconductor developments

Phase diagrams of the RE (rare earth)-IV-VI systems are very important for the design of rare earth doped diluted magnetic semiconductors (DMSs), but related information is very limited. In this work, ...     

Thermodynamic Assessment of DyCl3-MCl （M= Na, K, Rb, Cs） Systems

Using the CALPHAD （Calculation of Phase Diagram） technique, the DyCl3-MCl （M = Na, K, Rb, Cs） systems were optimized and calculated. The modified quasi-chemical model in the pair approximation for short-range ordering was used to describe the Gibbs energies of the liquid phase in these systems. From the measured phase diagram data and experimental thermodynamic properties, a series of thermodynamic functions were optimized base on an interactive computer-assisted analysis. The optimized parameters and the experimental data were thermodynamically self-consistent. The optimized results were discussed.     

Thermodynamic optimization and calculation of phase diagrams of YbCl3-MCl (M=Na, K, Rb, Cs)

YbCl3-MCl (M = Na, K, Rb, Cs) systems were optimized and calculated using the CALPHAD (CALculation of PHAse Diagram) technique. The modified quasi-chemical model in the pair-approximation for short-range ordering was used to describe the Gibbs energies of liquid phase in the systems. On the basis of the measured phase diagram data and experimental thermodynamic properties, a series of thermodynamic functions were optimized and calculated through an interactive computer-assisted analysis. Furthermore, some reasonable discussions on the thermodynamic parameters for these strong interaction binary systems were carried out. The results showed that the optimized parameters and experimental data are thermodynamically self-consistent.     

Thermodynamic optimization and calculation of phase diagrams of YbCl3-MCl （M=Na,K, Rb,Cs）

YbCl3-MCl （M = Na, K, Rb, Cs） systems were optimized and calculated using the CALPHAD （CALculation of PHAse Diagram） technique. The modified quasi-chemical model in the pair-approximation for short-range ordering was used to describe the Gibbs energies of liquid phase in the systems. On the basis of the measured phase diagram data and experimental thermodynamic properties, a series of thermodynamic functions were optimized and calculated through an interactive computer-assisted analysis. Furthermore, some reasonable discussions on the thermodynamic parameters for these strong interaction binary systems were carded out. The results showed that the optimized parameters and experimental data are thermodynamically self-consistent.     

Phase Equilibria in the AI-Nd-Sb System at 500℃

The Al-Nd-Sb phase diagram over the whole concentration region at 500℃ has been determined with the use of powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive analysis. A new ternary compound~Al6Nd28Sb66 (space group Imm2, a=1.5191(1)nm, b=1.9914(2)nm, c=0.4377(1)nm) with La6MnSb15-type has been found.     

Isothermal section of Gd-Sm-Co ternary system at 773 K

The isothermal section of the phase diagram of the Gd-Sm-Co ternary system at 773K was investigated by X-ray powder diffraction(XRD),differential thermal analysis(DTA),optical microscopy and scanning electron microscopy(SEM) techniques.The result shows that the isothermal section consists of 12 single-phase regions,16 two-phase regions and 5 three-phase regions.Five pairs of corresponding compounds of Gd-Co and Sm-Co systems,i.e.,Gd2Co17 and Sm2Co17,Gd2Co7 and Sm2Co7,GdCo3 and SmCo3,GdCo2 and SmCo2,Gd3Co and SmCo form continuous series of solid solutions.The maximum solid solubility of Sm in Gd 4Co3 and Gd12Co7 were about 7.2 at.% and 47.8 at.% Sm,respectively.The maximum solid solubility of Gd in Sm5Co19 and Sm5Co2 were about 4.7 at.% and 7.6 at.% Gd,respectively.The binary compounds Sm9Co4,GdCo5 and SmCo5 were not observed at 773K.No ternary compound was found.     

Experimental investigation on phase equilibria of Ce-Sn-Zn system at 400℃

The Ce-Sn-Zn alloys were prepared by furnace melting. The isothermal section of the Ce-Sn-Zn system at 400 oC over the whole composition range was established by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). A new ternary compound, CeSn 2 Zn 2 , was discovered in the present work. This compound adopted CaBe 2 Ge 2 structure type (space group P4/nmm) with the lattice parameters of a=0.4455 (9) nm and c=1.0348 (1) nm. The existence of previously known ternary compounds, CeSnZn and Ce 2 SnZn 3 , were confirmed, too. The maximum solubility of Zn in CeSn 3 was determined to be 12.7 at.%.     

Phase equilibria in Nb-Y-Si ternary system at 873 K

The isothermal section of the Nb-Y-Si ternary system at 873 K was investigated over the whole concentration range mainly by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive analysis (EDX). This isothermal section consisted of 10 single-phase regions, 17 two-phase regions, and 8 three-phase regions. The existence of the binary compounds, i.e., Y 5 Si 3 , Y 5 Si 4 , YSi, Y 3 Si 5 , YSi 2 , Nb 5 Si 3 and NbSi 2 at 873 K was confirmed. On the basis of XRD patterns, the structure types of Y 5 Si 4 , Y 3 Si 5 and YSi 2 were discussed. No ternary compound and no detectable solid solubility in the binary compounds were found.     

Phase relationship of Dy-Fe-Mn system at 773 K

Rare-earth intermetallic compounds formed in many R-Fe-Mn（R=rare-earth element） systems exhibit excellent properties. In order to understand the existence and stability of the compounds in the system and further search for the potential application of R-Fe-Mn alloys in various aspects, it is necessary to investigate the phase relations of the Dy-Fe-Mn ternary system. A total of 96 samples of the Dy-Fe-Mn alloys were prepared by arc-melting and examined by metallographic analysis, X-ray diffraction（XRD）, scanning electron microscopy（SEM） and energy dispersive spectroscopy（EDS） techniques. The phase relationship of the Dy-Fe-Mn system at 773 K was determined. It was found that the isothermal section was characterized by intermediate solid solutions based on the substitutions of Fe/Mn atoms and the large extensions of the binaries into the ternary domains. The solid solubilities of the third element in the binary compounds and the phase boundaries were also determined by XRD technique using the phase disappearing method combined with the lattice parameter method and SEM/EDS technique. Two pairs of corresponding binary compounds in the Dy-Fe and Dy-Mn systems（DyFe2 and DyMn2, Dy6Fe23 and Dy6Mn23） formed a continuous series of solid solution at 773 K, respectively.     

Phase equilibria calculation of LaI3-MI （M=Na, K, Cs） binary systems

The Gibbs energies of liquid phases in the LaI3-MI (M=Na, K, Cs) systems were described by the modified quasi-chemical model. From the measured phase equilibrium data of these binary systems, a set of thermodynamic functions were optimized by using the CAL-PHAD technique. The enthalpy of mixing and the interaction parameter of the liquid phase were predicted from known data for the LaI3-MI systems.     

Isothermal Section of Er-Mn-Nd Ternary System at 773 K

The isothermal section of the Er-Mn-Nd ternary system at 773 K was investigated mainly by X-ray powder diffraction with the aid of differential thermal analysis. The 773 K isothermal section of the ternary system consists of 9 single-phase regions, 14 two-phase regions, and 6 three-phase regions. At 773 K, the maximum solid solubility of Er in Nd and Nd in Er is about 20%（atom fraction） Er and 26%（atom fraction） Nd, respectively. Er6Mn23 and Nd6Mn23 form a continuous solid solution. The homogeneity range of δ phase extends from about 38% （atom fraction） Er to 43% （atom fraction） Er. No ternary compounds were observed at 773 K in this system.     

LiBr-TbBr3体系相图热力学评估

采用CALPHAD技术热力学评估、计算了LiBr-TbBr3体系在整个成分范围内的平衡相图,其中组元LiBr和TbBr3的热力学性质分别采用SGTE热力学数据库和作者近期的评估结果,LiBr-TbBr3体系的热力学数据则通过对已有相图、热力学实验数据的精确评估优化获得.计算结果与实验数据的比较表明,本工作建立的热力学数据能够很好地解释现有实验结果、具有较好的物理意义.     

RECl3-SrCl2-LiCl三元系相图计算

基于对9个侧边二元系RECl₃-SrCl₂、RECl₃-LiCl、SrCl₂-LiCl(其中RE:La、Ce、Pr、Nd)热力学数据和实验相图信息的优化、评估,以及三元系相关热力学性质的分析,计算并讨论了RECl₃-SrCl₂-LiCl系列4个三元系相图。     

Isothermal section of Nd-Zr-Si ternary system at 773 K

Phase diagram is an important basis for materials research and materials application.The phase relations of the Nd-Zr-Si ternary system at 773 K were investigated by X-ray powder diffraction analysis,metallographic analysis and scanning electron microscopy with en-ergy dispersive analysis.The isothermal section of the phase diagram of the Nd-Zr-Si ternary system at 773 K was determined.The isother-mal section of the system consisted of 13 single-phase regions,23 two-phase regions and 11 three-phase regions.The homogeneity range of α-NdSix was from 63 at.% to 66 at.% Si(with x=1.70-1.94).The maximum solid solubilities of Nd in Zr-Si binary compounds and Zr in the Nd-Si binary compounds were observed less than 1 at.% at 773 K.     

Preparation of BaMgAl10O17 ：Eu^2＋ and Its Phase Behavior in Microemulsion System

BaMgAl10O17 ： Eu^2＋ （BAM） was prepared in the microemulsion system and its phase behavior was studied. There exists a small region in the reverse microemulsion system where the dispersed particles are of spherical form. In this way, BAM blue phosphor with good dispersion can be synthesized. The microemulsion phase diagrams of the pseudo-ternary system （Triton X-100/cosuffactant-oil-BAM brine） were first established intuitively by the dilution method. The microstructure of microemulsions was determined through eyeballing, conductance technique, and polar optical microscopy. Its phase behavior is affected by various factors, such as temperature （room temperature, 30, 40 ℃）, oil, surfactants, and cosurfactants in microemulsions. According to the phase diagrams, the microemulsion system of Triton X-100/1-hexanol-hexane-BAM brine was chosen to prepare the precursor. The BAM phosphor can be obtained via sintering the precursor at a comparatively low temperature. The phosphors were characterized by XRD and vacuum ultraviolet （VUV） spectra.     

Preparation of BaMgAl10O17∶Eu2+ and Its Phase Behavior in Microemulsion System

BaMgAl10O17∶Eu2 (BAM) was prepared in the microemulsion system and its phase behavior was studied. There exists a small region in the reverse microemulsion system where the dispersed particles are of spherical form. In this way, BAM blue phosphor with good dispersion can be synthesized. The microemulsion phase diagrams of the pseudo-ternary system (Triton X-100/cosurfactant-oil-BAM brine) were first established intuitively by the dilution method. The microstructure of microemulsions was determined through eyeballing, conductance technique, and polar optical microscopy. Its phase behavior is affected by various factors, such as temperature (room temperature, 30, 40 ℃), oil, surfactants, and cosurfactants in microemulsions. According to the phase diagrams, the microemulsion system of Triton X-100/1-hexanol-hexane-BAM brine was chosen to prepare the precursor. The BAM phosphor can be obtained via sintering the precursor at a comparatively low temperature. The phosphors were characterized by XRD and vacuum ultraviolet (VUV) spectra.     

Solution and Thermodynamic Studies on Binary and Ternary Complexes of Lanthanides

The interactions of La(Ⅲ), Pr(Ⅲ), Nd(Ⅲ), Sm(Ⅲ), Eu(Ⅲ), Gd(Ⅲ), Dy(Ⅲ), and Yb(Ⅲ) with cytosine, 5-bromocytosine, 5-azacytosine and 5-flurocytosine as primary ligands (L) and guanine (A) as secondary ligand for both binary (1:1) as well as ternary (1:1:1) systems were investigated by potentiometric equilibrium measurements at 25, 35 and 45 ℃ in aqueous solution (ionic strength, μ=0.1 mol·dm-3 NaNO3). The stability constants of the binary (1:1) and ternary (1:1:1) metal-ligand complexes follow the following order La＜Pr＜Nd＜Sm＜Eu＞Gd＜Dy＞Yb. Results also indicate that the ternary lanthanide complexes of La(Ⅲ), Pr(Ⅲ), Nd(Ⅲ), Sm(Ⅲ), Eu(Ⅲ), Gd(Ⅲ), Dy(Ⅲ), and Yb(Ⅲ) are more stable than corresponding binary lanthanide complexes. The enthalpy (Δhof) and entropy (Δsof) changes for the formation of binary and ternary complexes were calculated from temperature coefficient data. The ΔΔSof values are positive for all the metal ligand systems. The negative ΔΔHof values indicate the extra stability of the ternary complexes by the exothermic enthalpy changes (ΔΔSof=ΔTSof-ΔBSof and ΔΔHof=ΔTHof-ΔBHof where ΔTSof, ΔTHof and ΔBSof, ΔBHof are the entropy and enthalpy values associated with the ternary and binary complexes, respectively). It was also proposed that the guanine is bonded to metal ions through N1/C6=O and N7 whereas cytosine and its derivatives are bonded through N3 atoms in ternary complexes.