SKM 2023 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 22: Mechanical Properties and Alloy Design: Porous and Nanostructured Materials
MM 22.5: Vortrag
Dienstag, 28. März 2023, 15:15–15:30, SCH A 118
Study of the oxidation mechanism of Cr2AlC MAX phase through nanoscale analysis of alumina scale formation — •Anicha Reuban1,2, Jesus Gonzalez-Julian1,2, Ivan Povstugar1, Andrey Litnovsky1, and Christian Linsmeier1 — 1Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — 2Institute of Mineral Engineering, RWTH Aachen University, 52074 Aachen, Germany
In a Concentrated Solar Power (CSP) plant, the receiver must withstand temperatures >800 ∘C, be resistant to oxidation by air and/or corrosion by molten salts and maintain its properties over time. MAX phases, which are ternary carbides and nitrides with a unique combination of ceramic and metallic properties, are candidate materials for the receiver. In this work, the oxidation mechanism of the alumina-forming MAX phase Chromium Aluminium Carbide (Cr2AlC) is studied. The samples are oxidized in a thermogravimetric analyzer (TGA) at 1000 ∘C and 1200 ∘C in humid air. The oxide scale is characterized using XRD, FIB-SEM, EDX and STEM. The alpha alumina layer formed consists of needle-like grains on top, with larger grains at the bottom, below which is a layer of chromium carbide. The elemental distribution across grain boundaries and interfaces of various regions of the oxide scale, carbide and bulk material are being analyzed with Atom Probe Tomography (APT), since these are possible pathways for the diffusion of aluminium and oxygen ions to form the oxide layer. The effect of dissolved chromium in the oxide scale and the segregation of impurities such as iron and silicon to interfaces is examined.