An Attempt was Made to Establish the Heat of Formation of Al₈Mg₅, AlMg and Al₃Mg₄

Abstract

For this purpose,the authors made use of the direct method,namely the oxidation method by means of the isothermal bombcalorimeter. By this method,one can obtain the heat of formation of the oxide of Al-Mg alloys,viz Al oxides (Al₂O₃):381.0 kcal/mol.Mg oxide(MgO):13.89 kcal/mol and the same values for Al-Mg Alloys(Al 5∼95%) are shown in Fig. 3. Then,the heat of combustion of the mixture of Al & Mg, was measured. From these data,the heat of formation of the compounds of Al-Mg binary system calculated and the results were obtained as follows : 120 cal/formation of Al₈Mg₅; −45 cal/formation AlMg,and −100 cal/formation of Al₃Mg₄.