High-temperature oxidation performance of a new alumina-forming Ni–Fe–Cr–Al alloy in flowing air

A new type of alumina-forming Ni–Fe–Cr–Al-based alloy (HAYNES® HR-224™ alloy) has been recently developed for aggressive oxidizing environments. This paper evaluates cyclic oxidation resistance of newly developed HR-224 alloy and its comparative performance to selected alumina- and chromia-forming heat-resistant alloys in flowing air at 982 °C and 871 °C. The HR-224 alloy outperformed several chromia-forming alloys owing to its ability to form and maintain a continuous, slow-growing, and adherent alumina scale. In fact, results indicated that HR-224 alloy exhibits comparable oxidation resistance to one of the most oxidation resistant alumina-forming Ni–Cr–Al-based 214® alloy. Moreover, in this paper, growth kinetics of alumina scale in these two alumina-forming alloys is discussed in detail. Among chromia-formers, Ni–Cr based alloys with low Fe contents exhibited excellent oxidation resistance.