Effect of Y on the corrosion behavior of Fe22Cr5Al3Mo alloy in 500 °C super-heated steam

Fe22Cr5Al3Mo-xY (x = 0, 0.15%, mass fraction) alloys were fabricated and corroded in 500 degrees C/10.3 MPa superheated steam using a static autoclave. The results show that the oxide films present a four-layer structure consisting of Fe oxide, Cr oxide, mixed oxide region, and Al oxide from outside to inside. There is alpha-(Fe, Cr) in Al2O3 layer near the oxide/metal interface. The addition of Y can delay the formation of the large iron oxide particles and increase the ratio of Cr2O3 film thickness to the thickness of the flat oxide film area, thus improving the corrosion resistance of the alloys.

Automated summary

The results show that Fe22Cr5Al3Mo-xY alloys formed a four-layered oxide film structure in the superheated steam environment, consisting of Fe oxide, Cr oxide, mixed oxide region, and Al oxide. Near the oxide/metal interface, there was the presence of alpha-(Fe, Cr) in the Al2O3 layer. The addition of Y element delayed the formation of large iron oxide particles and increased the ratio of Cr2O3 film thickness to the thickness of the flat oxide film area, thus improving the corrosion resistance of the alloys.