Effects of Cr Addition and a Magnetron Sputtered Film on the Oxidation-Sulfidation Behavior of Fe-xCr-5Si Alloys in H₂-CO₂-H₂S Mixture at 800°C

Abstract

The corrosion behavior of two cast Fe-xCr-5Si (x = 0, 5 at.%) alloys has been studied at 800°C in H2-CO2-H2S mixture. The addition of 5 at.% Cr improved the corrosion resistance of the Fe-5Si alloy by forming a protective scale of mixed Cr2O3 and SiO2 at the bottom of a non-uniform scale. The corrosion resistance of the cast Fe-5Cr-5Si alloy was further improved by a magnetron-sputtered film of identical composition that promoted the formation of a protective scale of a Cr2O3-SiO2 mixture at the coating/alloy interface. The mechanisms of forming the protective scales are examined and analyzed.

Investigation on Oxidation Behavior of Super304H and HR3C Steel in High Temperature Steam from a 1000 MW Ultra-Supercritical Coal-Fired Boiler

“…According to Ellingham-Richardson diagram [23], the Gibbs free energy (∆G θ ) formed by Fe 2 O 3 in the alloy was higher than that of Cr 2 O 3 . Therefore, Cr 2 O 3 preferentially generated on the matrix surface during the oxidation process.…”