High-temperature oxidation resistance of FeCrAl alloys with small amounts of yttrium in oxygen-water vapor (47 vol%)

Abstract

High-temperature oxidation resistance of FeCrAl alloys with small amounts of yttrium was studied in oxygen-water vapor (47 vol%) up to five cycles (one cycle = 18ks) at 1573K, by mass gain measurements, the amount of spalled oxide, X-ray diffraction, scanning electron microscopy, and field emission-transmission electron microscopy-energy dispersive spectroscopy. Oxide films on FeCrAl, FeCrAl0.1Y and FeCrAl0.2Y alloys spalled, however, those of on FeCrAl0.5Y alloy showed good oxide adherence during cyclic oxidation. Oxides on all the alloys were mainly found as α-Al₂O₃, and oxides on the alloys with yttrium were α-Al₂O₃ and Y₃Al₅O₁₂. Oxide adherence of FeCrAl0.5Y alloy was mainly improved by the keying effect of Y₃Al₅O₁₂ pegs at the oxide⁄alloy interface.