Oxidation behavior of ferritic stainless steels in simulated automotive exhaust gas containing 5 vol.% water vapor

• Published in: Materials chemistry and physics 2018-02, Vol.205, p.508-517
• Main Authors: Wei, L.L., Chen, L.Q., Ma, M.Y., Liu, H.L., Misra, R.D.K.
• Format: Article
• Language: English
• Subjects: Alloying effects; Alloying elements; Cerium; Chromium; Chromium steels; Exhaust gases; Ferritic stainless steel; Ferritic stainless steels; Gravimetric analysis; Kinetics; Oxidation; Oxide coatings; Rare earth element; Reaction kinetics; Scale (corrosion); Scanning electron microscopy; Simulation; Spallation; Structural steels; Tungsten; Water vapor; X-ray diffraction
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2017.11.051

In this study, the effect of alloying elements, cerium (Ce) and tungsten (W), on the oxidation behavior of medium chromium ferritic stainless steel in simulated automotive exhaust gases containing 5 vol.% H2O was studied in the temperature range of 950–1100 °C for 5 h. The oxidation kinetics and oxide film characteristics were analyzed by means of thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM) and elemental probe micro-analyzer (EPMA). The growth rate of oxidation and oxidation mass gain were significantly decreased on the addition of Ce. A dense, uniform, and thin oxide scale formed on Ce-containing steels. The steel containing Ce and ∼0.5 wt% W displayed similar oxidation behavior compared to the steel containing only Ce. A large number of cracks and pores existed in the oxide film and oxide/metal interface leading to the spallation of oxide film, when the addition of W reached ∼1.0 wt%. •Ce and W were added in Fe-Cr alloy to improve its high temperature performance.•Oxidation kinetics displayed significantly different with adding Ce and W at 950–1100 °C.•The property of oxide film was obvious improved with adding ∼0.05 wt% Ce in steel.•Laves phase and porous SiO2 caused the oxide film spalling when adding ∼1.0 wt% W.