Optimisation and characterisation of tungsten thick coatings on copper based alloy substrates

Riccardi, B.; Montanari, Roberto; Casadei, Maria Antonietta; Costanza, Girolamo; Filacchioni, G.; Moriani, Andrea

doi:10.1016/j.jnucmat.2006.02.069

Cited by 49 publications

(37 citation statements)

References 10 publications

(13 reference statements)

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“…The specific coating characteristics, i.e., morphology, structure, integrity and mechanical properties, were then thoroughly investigated [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Laser Pulse Effects on Plasma-Sprayed and Bulk Tungsten

Montanari

Pakhomova

Pizzoferrato

et al. 2017

Metals

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Tungsten (W) is considered a promising plasma-facing material for protecting the divertor of the ITER (International Thermonuclear Experimental Reactor). The effects on W of transient thermal loads of high energy occurring in a tokamak under operative conditions have been simulated through a single laser pulse delivered by an Nd:YAG laser. Bulk and plasma-sprayed (PS) samples have been submitted to tests and successively examined via SEM (scanning electron microscopy) observations. In both types of materials, the laser pulse induces similar effects: (i) a crater forms in the spot central area; (ii) all around the area, the ejection and the movement of molten metal give rise to a ridge; (iii) in a more external area, the surface shows plates with jagged boundaries and cracks induced by thermal stresses; (iv) the pores present in the original material become preferred ablation sites. However, the affected surface area in PS samples is larger and asymmetric if compared to that of bulk material. Such a difference has been explained by considering how microstructural characteristics influence heat propagation from the irradiated spot, and it was found that grain size and shape play a decisive role.

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“…The specific coating characteristics, i.e., morphology, structure, integrity and mechanical properties, were then thoroughly investigated [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Laser Pulse Effects on Plasma-Sprayed and Bulk Tungsten

Montanari

Pakhomova

Pizzoferrato

et al. 2017

Metals

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“…Figure 1(a) manifests the complex shape of the interface layers: the material appears compact and no macro-porosity is observed. However, a residual porosity is present as assessed in a previous work [4] because the density measured by a water picnometer is 17.8 g cm −3 (∼92% of the bulk density).…”

Section: Resultsmentioning

confidence: 92%

“…[2 -4] The microstructural and mechanical properties of this coating were extensively investigated and the results demonstrated its good characteristics. [4,5] The present work was undertaken to study the chemical distribution in the layered interface and in the coating. Particular attention was paid to ascertain the presence of Ni in the external layer of W because this element has a high activation due to neutron flux and even a low quantity may be detrimental in fusion applications for the remarkable amount of produced radioactivated material.…”

Section: Introductionmentioning

confidence: 99%

Composition of plasma‐sprayed tungsten coatings on CuCrZr alloy

Kačiulis

Mezzi

Montanari

et al. 2010

Surface & Interface Analysis

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Mock-ups for the International Thermonuclear Experimental Reactor(ITER) were manufactured by depositing W coatings on tubular substrates of CuCrZr alloy via plasma spraying. An appropriate interlayer (of Ni, Al and Si) was optimised to increase the adhesion of W on the Cu alloy and to provide a soft interface with intermediate thermal expansion coefficient for better thermo-mechanical compatibility.\ud The distribution of chemical elements in the layered interface and in the coating was investigated by energy dispersive spectroscopy (EDS), XPS and AES in the as-preparedmaterial and after heat treatment of 24 h at 823 K. Moreover, the external Wlayer was examined by inductively coupled plasma emission spectrometry(ICP-ES).\ud The results showed that the as-prepared material does not exhibit macro-porosity. The layers forming the interface do not exhibit any long-range diffusion of the chemical species from layer to layer during the deposition process. The heat treatment does not seem to cause long-rangemigration of Al and Ni into theWcoating.\ud The presence of Ni (0.4wt%) in the as-deposited externalWlayer as shown by ICP-ES is only due to the low purity (commercial grade) of W powders used in spraying operations. It can be eliminated by using W powders of higher purity in the deposition process

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“…It consists of a layer of pure Ni (thickness~200 μm) directly on the CuCrZr substrate followed by a stratification of thinner layers (thickness~30 μm) obtained by spraying grading mixtures of Al-12% Si, Ni-20% Al, Ni-20% Al and W powders. A detailed description is given in [94,95].…”

Section: Case Studymentioning

confidence: 99%

Experimental Techniques to Investigate Residual Stress in Joints

Montanari¹,

Fava²,

Barbieri³

2018

Residual Stress Analysis on Welded Joints by Means of Numerical Simulation and Experiments

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Residual stress arising from welding processes is matter of great concern in industrial practice since it can affect geometry, mechanical behavior and corrosion resistance of components. In order to evaluate residual stress in welded joints and optimize postwelding heat treatments, a lot of work has been devoted to the improvement of measurement methods with increasing sensitivity and accuracy. The chapter presents and discusses some of the experimental techniques commonly used today to determine residual stress in welds and describes recent results and advancements. Destructive (sectioning, contour, hole-drilling, instrumented indentation) and nondestructive (Barkhausen noise, ultrasonic, X-ray and neutron diffraction) methods are illustrated to highlight the specific characteristics, advantages and drawbacks.

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Optimisation and characterisation of tungsten thick coatings on copper based alloy substrates

Cited by 49 publications

References 10 publications

Laser Pulse Effects on Plasma-Sprayed and Bulk Tungsten

Laser Pulse Effects on Plasma-Sprayed and Bulk Tungsten

Composition of plasma‐sprayed tungsten coatings on CuCrZr alloy

Experimental Techniques to Investigate Residual Stress in Joints

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