Al2O3-V2O5体系的热力学优化

在对Al₂O₃-V₂O₅体系相图、热力学数据以及晶体结构数据进行综述与评估的基础上，采用相图计算方法对Al₂O₃-V₂O₅体系进行热力学优化.液相采用修正的似化学模型进行描述，利用对近似处理液相中存在的短程有序.将液相模型的最大短程有序设置在AlVO₄处，将VO₄3-当作液相中V₂O₅的基本组成单元.体系中AlVO₄相看作线性化合物.计算结果很好的重现了选定的实验数据，获得了一套合理、可靠、自洽的模型参数用来描述体系中各相的热力学性质，为Al₂O₃负载V₂O₅型催化剂催化性能的提高打下坚实的基础.      

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.     

熔盐相图计算的现状和展望

本文简要阐明了相图计算的原理和主要数值计算方法。相图计算的关键之一是确定体系中各相的过剩摩尔自由能,因而侧重评述了预示熔盐溶液相的过剩摩尔自由能的理论模型和几何方法及其进展。指出了计算的意义和局限性,阐明了理论计算相图与实验测定相结合是构筑熔盐相图的最佳方法。     

Calculation of the PrCl_3-CaCl_2-MgCl_2 Phase Diagram

Based on the thermodynamically self-consistent analysis and optimization of three sub-binary systems ofthe ternary system PrCl_3-CaCl_2-MgCl_2,the thermodynamics of this ternary system has been studied.UsingHillert model and taking MgCl_2 as an asymmetric component,the PrCl_3-CaCl_2-MgCl_2 phase diagram hasbeen calculated.The agreement between calculated and measured compositions and temperatures at deflectingpoints on liquidus is good.The system is a simple eutectic one with a eutectic point at 26.0mol% PrCl_3,41.5mol% CaCl_2,32.5mol% MgCl_2;560℃(calculated)and 26.0mol% PrCl_3,39.4mol% CaCl_2,34.6mol%MgCl_2;546℃(measured),respectively.     

Calculation of the Heat of Formation:Ternary Alloy System

A semi-empirical calculation of the heat of formation was applied to ternary system:La-Fe-Al,Fe-Ni-V and Cu-Pd-Si.The calculated values were compared with the experimental ones andthe coincidence was satisfactory.This method is helpful to predict the stabilities of ternary compounds andsolid solubility.     

A Study of the Specific Heats of the Compounds in the Sm_2O_3-BaO-CuO System

By means of X-ray diffraction and adiabatic scanning calorimeter,the specific heatsof five compounds in the Sm_2O_3-BaO--CuO system,such as Sm_2BaO_4,Sm_2CuO_4,BaCuO_4,Sm_2BaCuO_5,SmBa_2Cu_3O_(7-x),from -150℃ to 800℃ have been measured.It is found that the specific heats ofthese compounds increase smoothly with the increase of temperature.     

RECl_3-CaCl_2-MgCl_2(RE:La、Ce、Pr和Nd)三元相图

优化评估了RECl_3-CaCl_2(RE:La、Ce、Pr和Nd),RECl_3-MgCl_2和CaCl_2-MgCl_2九个侧边二元系相图和热力学性质,运用Hillert不对称模型,以MgCl_2为不对称组元计算了RECl_3-CaCl_2-MgCl_2系列三元系相图,并简要讨论了不对称组元的选取原则。     

YCl_3－AECl_2（AE＝Mg，Ca，Sr，Ba）二元相图的研究

用差热分析法测定了ＹＣｌ_３一ＳｒＣｌ_２体系二元相图，并用Ｘ时线衍射法验证了该二元体系中新相的生成。使用ＣＡＬＰＨＡＤ技术评估和优化了ＹＣｌ_３一ＡＥＣｌ_２（ＡＥ＝Ｍｇ，Ｃａ，Ｓｒ，Ｂａ）系列四个二元相图和热力学性质，取得了热力学性质和相图自相一致的结果。     

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.     

Ta-Ni和Nb-Ni的熔盐电化学表面合金化及合金性质的研究

在850—1050℃含有Ta或Nb离子的氟化物熔盐中,用电化学表面合金化的方法制备了Ta-Ni和Nb-Ni二元合金,分析表明合金层的成分是均匀的TaNi_3和NbNi_3化合物.利用恒电流间隙滴定技术(Galvanostatic Intermittent Titration Technique)证实了Ta-Ni二元系存在Ta_2Ni,TaNi,TaNi_2和TaNi_3四种化合物,测定了其生成电位和自由能;Nb-Ni二元系仅生成、NbNi和NbNi_3二种化合物.在熔盐电化学表面合金化的过程中,表面合金层的厚度与时间呈抛物线关系.测定了Ta-Ni和Nb-Ni合金中Ta和Nb的扩散系数,并建立了扩散系数随温度变化的Arrhenius方程