The Influence of Oxide-Scale Microstructure on KCl(s)-Induced Corrosion of Low-Alloyed Steel at 400 °C
Journal article, 2018

The high-temperature corrosion of low-alloyed steels and stainless steels in the presence of KCl(s) has been studied extensively in the last decades by several authors. The effect of KCl(s) on the initial corrosion attack has retained extra focus. However, the mechanisms behind the long-term behavior, e.g., when an oxide scale has already formed, in the presence of KCl(s) are still unclear. The aim of this study was to investigate the effect of the microstructure of a pre-formed oxide scale on low-alloyed steel (Fe–2.25Cr–1Mo) when exposed to small amounts of KCl(s). The pre-oxidation exposures were performed at different temperatures and durations in order to create oxide scales with different microstructures but with similar thicknesses. After detailed characterization, the pre-oxidized samples were exposed to 5%O2 + 20%H2O + 75%N2 (+KCl(s)) at 400 °C for 24, 48, and 168 h and analyzed with scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and focused ion beam. The microstructural investigation indicated that Cl-induced corrosion is a combination of oxide thickness and microstructure, and the breakaway mechanism in the presence of KCl(s) is diffusion-controlled as porosity changes prior to breakaway oxidation were observed.

Low-alloyed steels

High-temperature corrosion

Pre-oxidation

Cl-induced corrosion

Author

Mercedes Andrea Olivas Ogaz

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry

Johan Eklund

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry

Amanda Persdotter

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry

Mohammad Sattari

Chalmers, Physics, Materials Microstructure

Jesper Liske

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry

Jan-Erik Svensson

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Torbjörn Jonsson

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry

Oxidation of Metals

0030-770X (ISSN) 1573-4889 (eISSN)

Subject Categories

Materials Chemistry

Metallurgy and Metallic Materials

Corrosion Engineering

Infrastructure

Chalmers Materials Analysis Laboratory

DOI

10.1007/s11085-018-9881-2

More information

Latest update

6/24/2019