High-temperature oxidation corrosion alumina-forming alloys

The constmction material of metallic monoliths are alloys of iron, about 15-20 wL % chromium and 5 wt.% aluminium (Fecralloy). The unique feature of these alloys is the formation of a thin alumina layer (0.5 pm) on their outer surface when treated at temperatures above 850 °C [130]. Long alumina whiskers are formed at temperatures of around 900 °C and an oxidation time of greater than 12h (see Figure 10.6). This alumina layer then acts as an adhesion layer for the catalyst coating. On top of this, the alumina layer protects the alloy from corrosion, which allows the operation of ultra-thin Fecralloy foils at high temperatures. 

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