Resumo

MARULANDA, José Luddey; CASTANEDA, Saúl Isaac  e  PEREZ, Francisco Javier. Study microstructure and composition of oxidation in steam at 700 and 750°C of austenitic steels AISI 304, 316 and 317. Rev.fac.ing.univ. Antioquia [online]. 2013, n.67, pp.98-111. ISSN 0120-6230.

We have investigated the oxidation of austenitic stainless steelsAISI SAE: 304, 316 and 317, at temperatures of 700 to 750°C in an atmosphere approaching 100% of steam, and in a time range of 10 to 1000h of exposure. The purpose is to check the quality of austenitic steels and studying the morphology, composition and structure of the phases of the layers formed on the oxide scale samples by scanning electron microscopy (SEM), X-ray analysis energy dispersive (EDAX) and X-ray Diffraction (XRD), respectively. Just as well, has been performed at different times, a systematic study ofThermogravimetry of the samples oxidized, which was observed that the AISI 304 steel had the lowest mass gain and the AISI 316 steel had the higher mass gain respect to the three steels of the work. Additionally we carried out a theoretical study of thermodynamic simulation of steam oxidation of three steels, under the same experimental conditions and by the Thermo-calc program. In the oxidized steels have been checked the presence of oxide phase structures such as Fe₂O₃, the protective mixed spinels Fe₃O₄ and Cr₂NiO₄, and mixed oxides of type (Cr_xFe_y)₂O₃, (Fe,Cr,Mn)₃O₄ and Ni₆MnO₈. Finally, it was discusses a possible mechanism of formation of oxide layers of the samples tested.

Palavras-chave : Water steam oxidation; high temperature oxidation; austenitic stainless steels; thermogravimetry; thermodynamic simulation of oxidation.

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