2025/11/12 by Cameron. Crabb, Crabb, Cameron., Zachary Kloenne +11
Engineering · #Advanced Materials Characterization Techniques #FOS: Physical sciences #High Temperature Alloys and Creep #High-Temperature Coating Behaviors #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.2511.09678
openalex publication_date 2025/11/12 · openalex created_date 2025/11/15 · openalex updated_date 2026/07/28
Understanding how protective oxide scales evolve over time is necessary for improving the long term resistance of superalloys. This work investigates the time-dependent oxidation behavior of an ingot-processable Co/Ni-based superalloy oxidized in air at 800~^\circC for 20, 100, and 1000~h . Mass-gain and white-light interferometry measurements quantified oxidation kinetics, surface roughness, and spallation, while high-resolution STEM-EDX characterized oxide morphology and nanoscale elemental partitioning. Atom probe tomography captured the key transition regions between the chromia and alumina scales, and X-ray diffraction was used to identify a gradual transition from NiO and (Ni,Co)-spinel phases to a compact, dual phase chromia and alumina-rich scale. The oxidation rate evolved from near-linear to parabolic behavior with time, consistent with diffusion-controlled growth once a continuous Cr2O3/α-Al2O3 scale formed. These observations help link kinetics, structure and chemistry, showing how an originally porous spinel layer transforms into a dense, adherent chromia + alumina scale that provides long-term protection in wrought Co/Ni-based superalloys.