Use of Microanalysis to Better Understand the High-Temperature Corrosion Behavior of Chromium Exposed to Multi-Oxidant Environments
- 46 Downloads
The corrosion behavior of metals and alloys at high temperatures in complex multi-oxidant environments is of a great interest for achieving extended service performances and improved operation efficiencies. In this basic study, the scaling reactions of pure chromium in several multi-oxidant gas mixtures were assessed. The environments studied are similar to those that exist in low-NOx burner and coal gasification atmospheres, which are very reducing and favor sulfidation and carburization, together with possible formation of Cr2O3. The effect of sulfur on chromia-scale growth kinetics was also considered. Isothermal exposures were done for up to 100 h at 871 °C (1600 °F), and comparison was made to similar exposures to air. Exposed samples were characterized in detail using some combination of X-ray diffraction and electron beam scattering and spectroscopic techniques. It was found that chromia scales formed in mixed gases containing water vapor grew much faster and had a finer grain structure than those formed in dry air. Both inward growth and outward growth of the chromia scale were inferred for the mixed-gas conditions. The effect of a high carbon potential in the gas on the scaling behavior is also discussed.
KeywordsMixed gas Chromia Sulfidation Carburization Water vapor
The authors would like to thank Prof. Gerald Meier for helpful discussions and Dr. Sahar Farjami for technical assistance on EBSD sample preparation and microscopy.
- 11.J. A. Kneeshaw, The corrosion behavior of Fe–Cr–Ni alloys in complex high temperature gaseous atmospheres containing the reactants oxygen, sulphur and carbon. Doctoral Dissertation, Loughborough University, 1987.Google Scholar
- 13.R. A. Perkins, in DOE, EPRI, GRI, NBS, Third Annual Conference on Materials for Coal Conversion and Utilization, October 10-12, 1978.Google Scholar
- 15.A. D. Smigelskas and E. O. Kirkendall, Transactions of AIME 171, 1947 (130).Google Scholar
- 22.D. R. Gaskell, An Introduction to Transport Phenomena in Materials Engineering, (Macmillan, New York, 1992).Google Scholar
- 23.D. R. Poirier and G. H. Geiger, Transport Phenomena in Materials Processing, (The Minerals, Metals & Materials Society, Warrendale, 1994).Google Scholar
- 25.D. J. Young, High Temperature Oxidation and Corrosion of Metals, (Elsevier, Oxford, 2008).Google Scholar
- 35.R. G. Olsson and E. T. Turkdogan, Metallurgical Transactions 5, 1974 (21).Google Scholar
- 38.C. Wagner, Zeitschrift für Elektrochemie 63, 1959 (772).Google Scholar
- 47.J. L. Meijering, in Advances in Materials Research, 5th ed, ed. H. Herman (Wiley-Interscience, New York, 1971).Google Scholar