Avaliação microestrutural da liga FeCr após exposição a alta temperatura em atmosfera N2-4%H2

Abstract

The aim of this work was to evaluate the microstructure changes occurred in the alloys FeCr, FeCrY, FeCrAl and FeCrAlY after exposition of 48h at 1000°C in a N2-4%H2 atmosphere, often used in steel sintering furnaces in industries. The characterization was performed in a scanning electron microscopy coupled with dispersive energy analysis, and X-ray diffraction. It was observed the formation of chromium oxide and chromium nitride in the FeCr and FeCrY alloys in the bulk of the sample as internal oxidation. FeCrAl alloy presented chromium and aluminum oxide and nitride at the surface and in the bulk of the alloy. FeCrAlY alloy formed a -alumina layer in the surface that maintained at the alloy protected from further oxidation.