High-temperature corrosion and carburization behaviour of austenitic stainless steels in impurity-added CO 2 environments

Abstract

The corrosion and carburization behaviour of four austenitic stainless steels were evaluated in CO 2 and CO 2 +impurities (CH 4 , CO and O 2 ) at 600 degrees C. Exposure to CO 2 , CO 2 +CH 4 , and CO 2 +CO environments showed poor corrosion resistance, especially in 316 grades with the spallation of Cr 2 O 3 layer and breakaway corrosion. Conversely, materials showed improved corrosion resistance in CO 2 +O 2 environment with thin Cr 2 O 3 layer. TEM analysis of 316LN revealed carbon-accumulated layer at the Cr 2 O 3 - matrix interface for highly corrosive environments. The degradation of Cr 2 O 3 adherency is correlated with the carbon-accumulated layer, resulting from the high carbon activity in CO 2 , CO 2 +CH 4 , and CO 2 +CO environments.