Assessment of a High-Throughput Methodology for the Study of Alloy Oxidation using AlxFeyNi1-x-y Composition Gradient Thin Films.

The high-temperature oxidation of multicomponent metal alloys exhibits complex dependencies on composition, which are not fully understood for many systems. Combinatorial screening of the oxidation of many different compositions of a given alloy offers an ideal means for gaining fundamental insights into such systems. We have previously developed a high-throughput methodology for studying AlxFeyNi1-x-y alloy oxidation using ∼100 nm thick composition spread alloy films (CSAFs). In this work, we critically assess two aspects of this methodology: the sensitivity of CSAF oxidation behavior to variations in AlxFeyNi1-x-y composition and the differences between the oxidation behavior of ∼100 nm thick CSAFs and that of bulk AlxFeyNi1-x-y alloys. This was done by focusing specifically on AlxFe1-x and AlxNi1-x oxidation in dry air at 427 °C. Transitions between phenomenologically distinguishable types of oxidation behavior are found to occur over CSAF compositional ranges of <2 at. %. The oxidation of AlxFe1-x CSAFs is found to be very similar to that of bulk AlxFe1-x alloys, but some minor differences between CSAF and bulk behavior are observed for AlxNi1-x oxidation. On the basis of our assessment, high-throughput studies of CSAF oxidation appear to be an effective method for gaining fundamental insights into the composition dependence of the oxidation of bulk alloys.