Exploring the Depths of Corrosion: A Novel GE-XANES Technique for Investigating Compositionally Complex Alloys

Abstract

In this study, we propose the use of nondestructive, depth-resolved, element-specific characterization using grazing exit X-ray absorption near-edge structure spectroscopy (GE-XANES) to investigate the corrosion process in compositionally complex alloys (CCAs). By combining grazing exit X-ray fluorescence spectroscopy (GE-XRF) geometry and a pnCCD detector, we provide a scanning-free, nondestructive, depth-resolved analysis in a sub-micrometer depth range, which is especially relevant for layered materials, such as corroded CCAs. Our setup allows for spatial and energy-resolved measurements and directly extracts the desired fluorescence line, free from scattering events and other overlapping lines. We demonstrate the potential of our approach on a compositionally complex CrCoNi alloy and a layered reference sample with known composition and specific layer thickness. Our findings indicate that this new GE-XANES approach has exciting opportunities for studying surface catalysis and corrosion processes in real-world materials.

Atomic spectrometry update: review of advances in the analysis of metals, chemicals and materials

“…A second paper also explored the corrosion process, this time of nickel-based materials . 58 These authors used the non-destructive technique of grazing exit-X-ray absorption near edge structure (GE-XANES) spectroscopy for the task. The experimental setup was described in full, with the instrumentation comprising a GE-XANES instrument equipped with a pnCCD detector.…”

Machine learning for efficient grazing-exit x-ray absorption near edge structure spectroscopy analysis: Bayesian optimization approach

“…For instance, thin film transistors (TFTs) in electronics utilize layered structures for enhanced charge transportation and flexibility [1], while thin-film photovoltaic devices in renewable energy employ strategic layering for optimized light absorption and electron-hole separation [2]. Similarly, the study of layered corrosion in compositionally complex alloys provides crucial insights into material degradation processes [3,4]. Numerous examples, including those mentioned above and others, highlight the crucial role of layered structures in a wide range of research and application areas [5][6][7][8][9][10][11].…”

“…Depending on the grazing exit angle of the fluorescence radiation, the information depth of the experiment can vary from tens to hundreds of nanometers. Such adaptability is important for the analysis of thin films, corrosion layers, and interfaces in layered materials, where the complex relationship between structure and properties at the nanoscale is critical [4].…”

“…Increasing this distance, increases the angular resolution but decreases the detected intensity by a factor proportional to the square of the distance (D 2 ) and as a result, experiment times are extended. For greater XRF intensity, the sample-detector distance can be reduced, but this reduces angular resolution and can lead to overlapping fluorescence signals from layered materials due to variance in emission angles from different depths [4].…”

“…The emission angle of the XRF mainly depends on the complex refractive index, and when different oxidation states are analyzed, the angular intensity profiles of layers with different states are close to each other. To resolve the angular intensity profiles of the different layers in such a scenario, good angular resolution is required [4].…”