The Oxidation Properties of an Iron‐1.5 wt.% Silicon Alloy in Carbon Dioxide‐Carbon Monoxide Atmospheres at 1000°C

Abstract

An investigation is reported on the growth and structure of the scale formed on a ferritic Fe‐1.5 wt.% Si alloy exposed to carbon‐dioxide‐carbon monooxide atmospheres at 1000°C. The amorphous silica film on the metallographically polished specimens crystallized to β‐cristobalite. Wustite and fayalite developed within nodules which grew laterally to cover the alloy surface. Oxygen diffusion into the underlying alloy led to precipitation of silica as α‐tridymite. This internal oxidation zone was sufficiently depleted of silicon for its transformation to an austenitic phase. A fully developed scale was composed of an external wustite layer and an inner wustite‐fayalite conglomerate layer, interspersed with discontinuous fayalite bands. A model and a reaction sequence are advanced to account for the form of the oxidation curves and the reaction rate constants in terms of surface reaction steps similar to those for wustite formation on pure iron in these atmospheres.

Tunable plasmonic resonance of gallium nanoparticles by thermal oxidation at low temperatures

“…The linear model describes well ultralight metals, such as potassium and sodium, that forms porous and non-protective oxides. The parabolic (also known as Tammann-Pilling-Bedworth law) [56] and cubic models are most commonly observed in heavy metals such as iron, copper and nickel at high temperature regimes [57]. This model is based on the diffusion of ions through the oxide.…”