Performance of Al-rich oxidation resistant coatings for Fe-base alloys

B. A. Pint

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Diffusion aluminide coatings have been evaluated as a strategy for improving the oxidation resistance of austenitic and ferritic-martensitic (FM) steels, particularly in the presence of steam or water vapor. The objective was to evaluate the strengths and weaknesses of these coatings and quantify their performance and lifetime. Long-term diffusion and oxidation experiments were conducted to study the behavior of various model diffusion coatings and produce a better data set for lifetime predictions. The key findings are that (1) thin coatings (<50μm) with relatively low Al contents appear to be more effective because they avoid high thermal expansion intermetallic phases and have less strain energy to nucleate a crack; and (2) the low Al reservoir in a thin coating and the loss of Al due to interdiffusion are not problematic because the low service temperatures of FM steels (≤600°C) and, for austenitic steels at higher temperatures, the phase boundary between the ferritic coating-austenitic substrate inhibits Al interdiffusion. Unresolved issues center on the effect of the coating on the mechanical properties of the substrate including the reaction of N in the alloy with Al.

Original languageEnglish
Title of host publicationAdvances in Materials Technology for Fossil Power Plants - Proceedings from the 6th International Conference
Pages839-849
Number of pages11
StatePublished - 2011
Event6th International Conference on Advances in Materials Technology for Fossil Power Plants - Santa Fe, NM, United States
Duration: Aug 31 2010Sep 3 2010

Publication series

NameAdvances in Materials Technology for Fossil Power Plants - Proceedings from the 6th International Conference

Conference

Conference6th International Conference on Advances in Materials Technology for Fossil Power Plants
Country/TerritoryUnited States
CitySanta Fe, NM
Period08/31/1009/3/10

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