Anomalous oxidation of Fe–Si alloys under a low oxygen pressure at 800 °C

Abstract

Abstract:The oxidation of three 9,13

Effects of Cr Addition and a Magnetron Sputtered Film on the Oxidation-Sulfidation Behavior of Fe-xCr-5Si Alloys in H2-CO2-H2S Mixture at 800°C

“…Moreover, a continuous and protective external oxide scale could form on this alloy even when it was exposed to a sulfur-free gas mixture providing the same oxygen pressure (P O2 = 10 −20 atm). 45 The situation for the cast ternary Fe-5Cr-5Si alloy is actually borderline between a protective and a non-protective behavior, as evidenced by the presence of two different types of scale over the surface of corroded samples as well as by the rather protective kinetic behavior. However, for this alloy the surface areas not protected by the presence of a mixed oxide layer directly in contact with the alloy form mixtures of an FeS matrix containing a dispersion of isolated particles of the two oxides, which are not effective in producing a significant reduction of the corrosion kinetics.…”

Effect of Annealing Time on Oxides Phases and Morphology along Oxidized Depth of Fe-3%Si Steel during Decarburization

“…The diffusion coefficients of silicon and oxygen atoms in steel matrix were shown in Eq. (4): 22,23) ... (4) Where, n si was the mole fraction of silicon in the steel. In a given volume unit of Fe-3%Si steel, the volume fraction of silicon atoms was lower than that of iron atoms.…”

Effect of Surface Oxidation on Decarburization of a Fe-3%Si Steel during Annealing

“…Mole fraction of oxygen dissolved in steel at the alloy/ gas interface and diffusion coefficients of oxygen, silicon and carbon in the steel. 18,19) Symbol Unit Equation O sum increases with increasing temperature from 1 083 K to 1 103 K, but decreases with further increasing temperature to 1 123 K, suggesting that the total oxygen concentration consumed in the oxidation reactions does not increase continuously with increasing annealing temperature when annealing time is short. When reaction time increases from 2 min to 3 min, however, O sum increases continuously with increasing temperature from 1 083 K to 1 123 K. The calculation results are shown in Fig.…”