Resonant Laser Induced Breakdown Spectroscopy for quantitative elemental depth profile analysis of WTa coating

This work reports on the procedure of Resonant-LIBS, in which ablation and subsequent excitation is achieved by fine-tuning an Optical Parametric Oscillator (OPO) laser to the resonant transition of tungsten (W I) at 255.14 nm and analyzing the optical emission spectroscopy results. Compared to conventional LIBS, the ablation rate is significantly reduced in the resonant regime, resulting in finer resolution of depth profiles. This reduction in ablation rate can be attributed to a process called Resonance Laser Ablation (RLA) where a part of the laser energy is employed for ablation, while the rest is dedicated to resonant excitation. The sample under consideration is a WTa-coated (7μm) Mo substrate prepared by a dual magnetron sputtering system. These efforts are motivated by the need for improvement in quantitative depth analysis of W-based Plasma-Facing Components (PFC). Particularly to target the undesirable surface modifications due to the interaction with H isotopes in fusion plasma, such as fuel retention or erosion/deposition

Surface, Structural, and Mechanical Properties Enhancement of Cr2O3 and SiO2 Co-Deposited Coatings with W or Be

Direct current (DC) and radio frequency (RF) magnetron sputtering methods were selected for conducting the deposition of structural materials, namely ceramic and metallic co-depositions. A total of six configurations were deposited: single thin layers of oxides (Cr2O3, SiO2) and co-deposition configurations (50:50 wt.%) as structural materials (W, Be)—(Cr2O3, SiO2), all deposited on 304L stainless steel (SS). A comprehensive evaluation such as surface topology, thermal desorption outgassing, and structural/chemical state was performed. Moreover, mechanical characterization evaluating properties such as adherence, nano indentation hardness, indentation modulus, and deformation relative to yielding, was performed. Experimental results show that, contrary to SiO2 matrix, the composite layers of Cr2O3 with Be and W exhibit surface smoothing with mitigation of artifacts, thus presenting a uniform and compact state with the best microstructure. These results are relevant in order to develop future dense coatings to be used in the fusion domain

Deposition, Morphological, and Mechanical Evaluation of W and Be-Al2O3 and Er2O3 Co-Sputtered Films in Comparison with Pure Oxides

Compact and defect-free high melting point oxide strengthened metallic matrix configurations are promising to resolve the hydrogen permeation and brittleness issues relevant to the fusion research community. Previous studies on oxide addition to metallic matrix demonstrated a mitigation in brittleness behavior, while deposition techniques and material configurations are still to be investigated. Thus, here, we report the structural, morphological, and mechanical characterization of metal-oxides thin layers co-deposited by radio frequency (RF)and direct current (DC) magnetron sputtering. A total of six configurations were deposited such as single thin layers of oxides (Al2O3, Er2O3) and co-deposition configurations as metal-oxides (W, Be)—(Al2O3, Er2O3). The study of films roughness by atomic force microscopy (AFM) method show that for Al2O3 metallic-oxides is increased to an extent that could favor gaseous trapping, while co-depositions with Be seem to promote an increased roughness and defects formation probability compared to W co-depositions. Lower elastic modulus on metal-oxide co-depositions was observed, while the indentation hardness increased for Be and decreased for W matrix configurations. These outputs are highly relevant for choosing the proper compact and trap-free configuration that could be categorized as a permeation barrier for hydrogen and furtherly studied in laborious permeation yield campaigns