Interação tensão-oxidação: caso da oxidação do ferro pelo vapor d'água.

Abstract

This work presents the study on the oxidation of pure iron at temperatures their correlation with the resulting tensions. The samples in the form of rectangular platelets of 15 x 5 mm and with thicknesses of 1 and 2 mm were oxidized under atmospheres of argon or oxygen and water vapor. Experiment temperatures ranged from 850 to 950øC in a time range of 20 to 50 minutes. The obtained products were characterized by X-ray diffraction, optical microscopy and scanning electron microscopy. The results showed that in all cases the layer was composed of three oxides: wustita (FeO), magnetite (Fe304) and hematite (Fe203). To perform the voltage calculation, the oxidized sample was chosen at 950 ° C (Ar / H2O) because it has a more adherent layer and at the same time a finer granulometry. The results revealed that the oxide layer was subjected to a compressive stress.