Electrochemical determination of Gibbs free energy of formation of magnesium ferrite

作     者：Ling Wang Huizhu Zhou Yanruo Hong Girish M Kale 

作者机构：School of Chemical Engineering and Biotechnology Hebei Polytechnic University Tangshan 063009 China Materials Science and Engineering School University of Science and Technology Beijing Beijing 100083 China School of Process Environmental and Materials Engineering Department of Mining and Mineral Engineering University of Leeds Leeds LS2 9IT UK 

出 版 物：《Journal of University of Science and Technology Beijing》 (北京科技大学学报（英文版）)

年 卷 期：2007年第14卷第4期

页      面：361-364页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：the National Natural Science Foundation of China (No.50572024) the Education Ministry Foundation for Returning Overseas Scholar of China 

主　　题：magnesium ferrite electrochemical cell Gibbs free energy of formation solid electrolyte 

摘      要：The standard Gibbs free energy of formation of magnesium ferrite was determined by means of two types of solid state electrochemical cells： one using MgZr4（PO4）6 （MZP） as the solid electrolyte and the other using CaF2 as the solid electrolyte. The first cell was operated in the range of 950 to 1100 K. The second cell was operated in the range of 1125 to 1200 K. The reversibility of the cell EMFs was confirmed by microcoulometric titration. The Gibbs energy changes of magnesium ferrite relative to component oxides were calculated based on EMF measurements and are given by following expressions, respectively： AG1 = -3579-15 T （J/mol） and AGⅡ =6258-24.3 T （J/mol）. The results obtained from two different cells are consistent with each other. The results also are in agreement with Rao＇ s and Tretjakov＇s data in the measured temperature range. When the Gibbs free energies of formation of MgO and Fe203 were substituted in the reaction, the Gibbs free energies of formation of MgFe204 was obtained in two temperature ranges and the for mations are shown as follows： AG 1Formation =-1427394＋360.5 T （J/mol） and AGⅡ Formition =-1417557＋351.2 T （J/mol）.