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Mock-ups of thermal shields for international thermonuclear experimental reactor (ITER) have been manufactured by depositing 5-mm-thick W coatings on a CuCrZr alloy (ELBRODUR®). Coatings, made by controlled atmosphere plasma spray technique, have low porosity and excellent thermal fatigue resistance under high heat flux. Their structure has been investigated by scanning electron microscopy (SEM), scanning tunnel microscopy (STM), energy dispersion spectroscopy (EDS) and inductively coupled plasma (ICP) analysis. In spite of the remarkable thermo-mechanical properties of coatings, the present work evidenced some flaws (small cracks, unmolten W particles and presence of Ni in the external layers). Quality of coatings may be improved by strictly controlling purity and granulometry of sprayed W powders and some process parameters.

The structure and the preservation state of artistic heritage and archaeological findings have been studied by the analysis of the heat diffusion process in the sample. The investigations have been performed by non-invasive time resolved infrared thermography (IRT). Thickness maps, buried defects detection, inhomogeneity and corrosion analysis, as well as the quality check of welding and reinforcements elements, have been performed on the studied samples.

The precipitation hardened CuCrZr alloy has been used in the past as a structural material for actively cooled plasma facing components of nuclear reactors (Tore Supra and JET) and selected as the heat sink material for divertor parts of the future International Thermonuclear Experimental Reactor (ITER) [1]. Because of its high melting point and good thermal conductivity, W is a promising material to use as protection (armour) for thermal shields made of CuCrZr. However, W-Cu joining is really challenging for the high thermal expansion mismatch between W and Cu alloys (alpha(Cu) approximate to 4 alpha(W)), the high elastic modulus and brittleness of W. Important requirements for high quality W-armours are low porosity and low impurity content. For realizing the joints, plasma spraying (PS) has been used for its simplicity, the possibility to cover complex and extended surfaces and the relatively low cost. An appropriate interlayer was optimized 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. It was possible to manufacture mock-ups for ITER by depositing up to 5-mm thick W-coatings on tubular substrates of CuCrZr (Fig.1), which were able to sustain a remarkable number of thermal fatigue cycles under high heat flux (up to 5 MW/m(2)) [2-4]. Microstructural and mechanical characterization confirmed the good properties [4,5].

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. 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-prepared material and after heat treatment of 24 h at 823 K. Moreover, the external W layer was examined by inductively coupled plasma emission spectrometry (ICP-ES). 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-range migration of Al and Ni into the W coating. The presence of Ni (0.4 wt%) in the as-deposited external W layer 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.

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. 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-prepared material and after heat treatment of 24 h at 823 K. Moreover, the external W layer was examined by inductively coupled plasma emission spectrometry(ICP-ES). 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-range migration of Al and Ni into the W coating. The presence of Ni (0.4 wt%) in the as-deposited external W layer 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.

Un diagnostic thermographique, une methode non destructrice et applicable in situ, a ete appliquee pour la premiere fois a l'analyse des structures et a l'etat de conservation de quelques reliures de parchemin datant du 17eme et du 18eme siecles. Grâce a cette technique il a ete possible, sans desassembler les echantillons, d'obtenir des informations sur quelques details de structure, comme la position et la taille des accolures et des fils ainsi que la connexion entre la reliure et le corps d'ouvrage. D'autre part, il a ete possible de recueillir des informations relatives a l'etat de conservation du volume a partir des observations faites sur les endroits endommages et en analysant les modifications de certaines proprietes physiques du parchemin mal conserve. Enfin, on a demontre comment, grâce a la thermographie, il est possible de representer de facon cartographique la variation d'epaisseur du parchemin moderne.