Metallic catalytic converters for automotive emission control is becoming an important application for heat resistant alloys as more design opportunities are realized. The service conditions and design of metallic catalytic converters require the alloy to be highly oxidation resistant at gauges typically at 50 microns or less. For conventional heat resistant alloy design the goal is to form a well adherent scale on the alloy surface to protect the alloy matrix from being oxidized. However, the thin gauge results in a limited supply of alloying elements that can form the protective scale on the surface. The alloy chemistry has to be optimized to have the minimum oxidation while maintaining processing characteristics. Furthermore, the ratio of scale thickness to foil gauge is significant and the stress state between them introduces measurable permanent distortion of the foil. In this study, the effect of alloying elements on the oxidation behavior of commonly used Fe-Cr-Al alloys was quantified by the oxidation weight gain and length change measurements.

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