Modeling of Trilayered Oxide Thermally Grown on 441 Ferritic Stainless Steel at 900 °C in Synthetic Air

Abstract

Ferritic stainless steel (AISI 441) oxidation was studied at 900 °C in synthetic air. At short time of oxidation (3 min), the oxide scale is comprised of chromia including some MnCr 2 O 4 nodules (of a few tens of nanometers in diameter) and exhibits n-type conduction. Later, after 10 h, a trilayered morphology was observed with an internal equiaxed chromia, an intermediate columnar chromia and a top covering spinel layer. A model for oxide scale growth has been developed in this paper, taking into account all experimental observations and earlier studies.