An in-situ ToF-LEIS and AES study of near-surface modifications of the composition of EUROFER97 induced by thermal annealing. (March 2022)

• Record Type: Journal Article
• Authors: Shams-Latifi, Jila; Ström, Petter; Pitthan, Eduardo; Primetzhofer, Daniel
• Is Part Of: Nuclear materials and energy. Volume 30(2022)
• Publication Date: 2022-03
• Subjects: EUROFER97 -- ToF-LEIS -- AES -- In-situ -- Annealing -- Segregation -- Diffusion; Nuclear energy -- Periodicals; Nuclear fuels -- Periodicals; Nuclear reactors -- Materials -- Periodicals; Radioactive substances -- Periodicals; 621.4833
• DOI: 10.1016/j.nme.2022.101139
• Languages: English
• ISSNs: 2352-1791

Abstract

Highlights: Surface segregation of W, Ta, Cr, O and S in annealed EUROFER97 was observed. Time-of-flight low energy ion scattering and Auger electron spectroscopy were applied. Monte-Carlo simulations were performed using the TRBS code. Simulations show a W + Ta enriched layer of 1 ± 0.3 nm after first annealing to 675 °C. Abstract: Surface segregation and diffusion of W, Ta, Cr, O and S after thermal annealing of EUROFER97 were studied in-situ . The sample was prepared by polishing, annealing up to 300°C and 3 keV Ar sputtering. In-situ measurements with time-of-flight low energy ion scattering using 8 keV Ne ions and Auger electron spectroscopy were carried out close to room temperature after each annealing, in sequence, to 425°C, 675°C, 400°C, 675°C, 900°C, and 925°C. Surface segregation/diffusion of chromium and tungsten and/or tantalum can be observed in the ion scattering spectra. The segregation of sulfur was clearly observed in Auger electron spectroscopy. The energy converted time-of-flight low-energy ion scattering spectrum after the first annealing to 675°C was compared to Monte-Carlo simulations using the TRBS code. The most compatible simulation indicates a layer enriched in W + Ta of 1 ± 0.3 nm featuring 0.0276 combined relative concentration of tungsten and tantalum to total metal content which is considerably higher than the bulk value of 0.0042.