Enhanced XRF Methods for Investigating the Erosion-Resistant Functional Coatings

Mihail Lungu,Cosmin Dobrea,Ion Tiseanu

doi:10.3390/coatings9120847

Abstract

The development of erosion-resistant functional materials usable as plasma facing first wall components (PFC) is crucial for increasing the lifetime of future fusion reactors. Generally, PFCs have to be quality checked and characterized regarding their composition, before integrating them into the fusion reactor vessel. Enhanced X-ray fluorescence (XRF) methods represent an effective alternative to conventional analysis methods for the characterization of refractive metallic coatings on large areas of fusion materials. We have developed and applied XRF methods as fast and robust methods for the characterization of the thickness and composition uniformity of complex functional coatings. These coatings consist of tungsten included in multilayer configuration and deposited on low or high Z substrates. We have further developed customized calibration protocols for quantifying the element composition and layer thickness of each investigated sample. The calibration protocols are based on a combination of standard samples measurements, Monte Carlo simulations, and fundamental parameter theoretical calculations. The calibrated results are discussed considering a selection of relevant PFC samples. The deposition uniformity was successfully investigated for different PFC-relevant tiles and lamella shaped samples with W layers below and over the W L-line saturation thickness. Also, the 2D thickness mapping capability of the XRF method was demonstrated by studying the plasma post-erosion pattern.

Highlights

It is widely known that tungsten (W) is well suited as a possible candidate for plasma facing materials, because of its many properties, such as its low retention of reactor fuel, high melting point, and low sputtering yield [1]
Macro-X-ray fluorescence (XRF) Analysis Assisted by Monte Carlo (MC) Simulations for W L-Lines Investigation on plasma facing component (PFC)-Like Lamellae
The low energy XRF method assisted by MC simulations was applied to PFC relevant lamellae configured with thin W and Mo multi-layers with a W substrate, deposited using the combined magnetron sputtering with ion implantation (CMSII) technique

Summary

Introduction

It is widely known that tungsten (W) is well suited as a possible candidate for plasma facing materials, because of its many properties, such as its low retention of reactor fuel, high melting point, and low sputtering yield [1]. In contrast to a destructive analysis approach, non-destructive techniques such as X-ray fluorescence are more effective when investigating the plasma facing component (PFC) relevant samples. Such methods are applied as quality assurance tools, resulting in future improvements of layer deposition techniques [3,4]. The XRF method is considered an important tool with applicability in domains such as the environment [5], food [6], and metallurgy [7]. The key advantages of XRF-based methods are expressed as follows: fast measuring, require no consumables, and are highly versatile [5]

Methods

Results

Conclusion