Dynamic Breakdown of Passive Films on Stainless Steel During in Situ Thermal Oxidation

Abstract

The outstanding corrosion resistance of stainless-steel results from the presence of a thin passive oxide film on the metal surface. Environmental transmission electron microscope was used in a modern atomic-scale in situ initial oxidation analysis process to reveal the microstructural and elemental variation. An amorphous oxide layer was the main oxide at temperatures below 500 °C, oxidation pits formed between 500 and 700 °C, and a porous structure formed when the temperature surpassed 700 °C. The protective passive films on the oxide/alloy interface were damaged by priority structural oxidation and prompted further alloy failure. The study provides direct experimental data beyond that of traditional research.

Keywords: Stainless steels, In situ, TEM, Oxidation, Microstructure