Tungsten coatings under high thermal loads in JET and Magnum-PSI

Ruset, C.; Maier, H.; Grigore, E.; Matthews, G. F.; Temmerman, G. De; Widdowson, A.; Contributors, Jet‐Efda

doi:10.1088/0031-8949/2014/t159/014025

Cited by 7 publications

(1 citation statement)

References 12 publications

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“…The coatings deposition produced on PFCs have to protect them from high heat flux plasm particles in order to improve their performance in long pulse operations. However, some materials are eroded as high heat flux strike with wall components and redeposited as an impurity on PFCs which changed the surface composition . Moreover, the exposure of PFCs to high‐energy particles fluxes changes the surface crystallinity and causes the change in ablation threshold value.…”

Section: Introductionmentioning

confidence: 99%

Depth profiling of tungsten coating layer on CuCrZr alloy using LIBS approach

Imran

Sun

Liu

et al. 2018

Surface & Interface Analysis

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Laser induced breakdown spectroscopy (LIBS) was employed to find the depth profile of W-coated CuCrZr alloy. Cathodic arc deposition method was applied to produce tungsten coating on the CuCrZr alloy. The LIBS measurements were carried out by using a Nd:YAG laser at its fundamental wavelength (1064 nm) with various fluences.The spectral intensity emitted from laser induced plasma of the coating material was investigated for both elemental and depth-profile analyses in terms of linear correlation coefficient. Other surface characterization techniques (scanning electron microscopy and energy dispersive X-ray) were also used to determine morphology and elemental composition. It is observed that nonuniform radial energy distribution of Gaussian laser beam caused gradual decay of spectral lines of the coating and rise of substrate lines. The results indicate that the spectral intensity from W coating was higher than that from the bulk material at same laser fluence. The high-resolution in-depth profile was achieved at low fluence. This study demonstrates that LIBS is a promising technique for the depth-profiling analysis of W coating of EAST-like material and can be used to determine the material erosion and impurity deposition on plasma facing components. KEYWORDS cathodic arc deposition, CuCrZr alloy, depth profile, LIBS, W-coating 1 | INTRODUCTION Metallic coatings for various applications, like plasma facing material, wear and corrosion resistance, and protection against erosion, have great importance and are in a high demand both in technology and industry. 1 Many types of coating are used to improve mechanical, optical, thermal, electrical, chemical, and magnetic properties of the substrate. Many applications in industry require in-depth characterization of coated layers with thickness from nanometre to tens of micrometre. 2 The plasma facing components (PFCs) used in fusion devices have to operate under highly aggressive environment. The coatings deposition produced on PFCs have to protect them from high heat flux plasm particles in order to improve their performance in long pulse operations. However, some materials are eroded as high heat flux strike with wall components and redeposited as an impurity on PFCs which changed the surface composition. 3-5 Moreover, the exposure of PFCs to high-energy particles fluxes changes the surface crystallinity and causes the change in ablation threshold value. In EAST tokamak, the ITER-like W mono-blocks were used in upper divertor target. The divertor baffle and dome were made of W/CuCrZr (W plates on CuCrZr alloy). 6,7 A reliable technique is required to measure the depth profile of erosion and impurity deposition on surface modification which could perform in the tokamak-like environment for in-situ analysis and give the entire information of elemental composition.Laser induced breakdown spectroscopy (LIBS) is a promising multi-element analytical technique for in-situ analysis of the chemical composition of components inside the vacuum vessel of fusion devices. [8][9][10...

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Section: Introductionmentioning

confidence: 99%

Depth profiling of tungsten coating layer on CuCrZr alloy using LIBS approach

Imran

Sun

Liu

et al. 2018

Surface & Interface Analysis

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Tungsten coatings repair: An approach to increase the lifetime of plasma facing components

Diez

Firdaouss

Richou

et al. 2019

Fusion Engineering and Design

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Global erosion and deposition patterns in JET with the ITER-like wall

Baron-Wiechec

Widdowson

Alves

et al. 2015

Journal of Nuclear Materials

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A set of Be and W tiles removed after the first ITER-like Wall campaigns (JET-ILW) from 2011-2012 has been analysed. The results indicate that the primary erosion site is in the main chamber (Be) as in previous carbon campaigns (JET-C). In particular the limiters tiles near the mid-plane are eroded probably during the limiter phases of discharges. W is found at low concentrations on all plasma-facing surfaces of the vessel indicating deposition via plasma transport initially from the W divertor and from main chamber W-coated tiles;there are also traces of Mo (used as an interlayer for these coatings). Deposited films in the inner divertor have a layered structure, and every layer is dominated by Be with some W and O content.

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Tungsten coatings under high thermal loads in JET and Magnum-PSI

Cited by 7 publications

References 12 publications

Depth profiling of tungsten coating layer on CuCrZr alloy using LIBS approach

Depth profiling of tungsten coating layer on CuCrZr alloy using LIBS approach

Tungsten coatings repair: An approach to increase the lifetime of plasma facing components

Global erosion and deposition patterns in JET with the ITER-like wall

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