Corrosion of stainless steel in a coal gasification plant

Abstract

A corrosion study was performed on the commercially available austenitic stainless steel used in the piping materials of a coal gasification pilot plant. Thermodynamic Ellingham– Pourbaix stability diagrams were constructed to provide insight into the mechanism of the observed corrosion behavior. The thermodynamic inference on the corrosion mechanism was supplemented with the morphological, compositional, and microstructural analyses of the corroded samples using scanning electron microscopy and energy-dispersive x-ray spectroscopy analyses. Corrosion products with conspicuous surface rupture were observed after 139 h exposure to the corrosive environment, which were attributed to the chlorination/oxidation into thin (spalled) oxides.