Influence of Selenium on the Internal Oxidation of Fe–Si–Al–C Alloy

Abstract

The effect of selenium on the oxidation of Fe–Si–Al–C alloy during decarburization at 840°C in wet hydrogen was studied. Selenium was found to change the morphology of internal oxides of an Fe–Si–Al–C alloy. The long penetrating internal oxides of Si and Al in the alloy containing 0.034 at.% Se demonstrate an obvious preferential growth perpendicular to the steel substrate. FEG-SEM/EDX was performed to analyze the scale and the subscale. It was assumed that columnar morphology of internal oxides could be induced by selenium surface segregation. Therefore, in-situ AES analysis using a resistive heating of specimen in UHV was used to obtain more accurate data on temperature dependence of selenium surface segregation in silicon steel. Additionally, the kinetics of the selenium surface segregation was investigated in-situ during annealing at 840°C in the ultra-high vacuum chamber of a field-emission Auger electron spectrometer.