Thermodynamics of the Iron-Nickel-Oxygen System at 1000°C

Abstract

The isothermal section of the Fe-Ni-O system at 1000~ has been defined by determining the compositions and structures of the equilibrated solid phases. Wustite can coexist with Fe-Ni alloys containing up to 79.6 a/o (atomic per cent) Ni. The three-phase field wustite-spinel-alloy consists of wustite con-taining 0.51 a/o Ni, spinel containing 0.6 a/o Ni, and an alloy containing 79.6 a/o Ni. The three-phase field, spinel-nickel oxide-alloy, consists of nickel ferrite, nickel oxide containing 6.5 a/o Fe, and an alloy containing 99.5 a/o Ni. Tie lines in the spinel-alloy field were investigated in detail. Wustite-nickel oxide solid solutions exhibited nonideal behavior. The properties of the Fe-Ni-O system at high temperatures where the iron-nickel alloys occur in the form of austenitic solid solution have not been inten-sively investigated. Brabers and Birchenall (1) deter-mined the equilibrium compositions of wustite, spinel oxide, and alloys containing up to 60 w/o (weight per cent) Ni at 1050~ The latest available results ob-tained for temperatures in the range 70O~176 are those reported by Viktorovich and Lisovskii (2) and