Abstract: Tungsten has been decided as the plasma facing material (PFM) for some high heat flux regions of the divertor in the International Thermo-Nuclear Experimental Reactors (ITER). In this paper, our efforts concentrated on the functionally gradient W/Cu coating fabricated on the oxygen free copper by atmosphere plasma spraying under the inert gases protection. The functionally gradient W/Cu coatings were designed to relieve the thermal stress during the spraying processes. For comparison, the tungsten coatings were also deposited directly onto the copper substrates by the same technology. XRD, SEM and EDS were applied to identify the phases, morphologies and compositions of these coatings. Tensile tests were performed to measure the bonding strength between the coatings and the substrates. Furthermore, water quenching and high heat loading experiments using a pulse laser beam were also carried out to estimate the thermal shock properties of these coatings.

Abstract: Molybdenum has many prominent properties, such as high melting point, good thermal properties, and low erosion rate and so on, which make it promising candidate materials for plasma facing materials in the next fusion reactor. In this paper, Molybdenum coatings were deposited onto the oxygen-free copper substrates by atmospheric plasma spraying. The spraying parameters had been carefully selected. Different interlayers were induced between the substrate and the coating. SEM and XRD were used to investigate the photographs and compositions of these coatings. The micro-hardness and bonding strength were also tested. Thermal behaviors of the coatings were evaluated by thermal shock tests. The coatings with interlayers showed better resistance of thermal shock but lower bonding strength compared to coatings that without interlayers.

Abstract: Several kinds of ceramic powders including SiC, TiO2 and Al2O3 were selected as fillers blending with epoxy resin, curing agent and other additives to prepare a heavy-duty and anti-wear coating. The effects of filler sort, powder size, dispersion homogeneity on the coating properties were investigated. The results showed that the wear resistance and corrosion resistance of the coating could be improved significantly after meliorating the dispersion of the ceramic particles in epoxy resin. Other mechanical properties were also studied in order to support the view on the positive effect of the nano-particles in the epoxy coating.

Abstract: A new resistance sintering method under ultra high pressure has been developed for fabrication of Mo/Cu (functional graded material) FGM. The consolidation was carried out under pressure of 8GPa, and input power of 15kW for 50s. The relative density of the FGM specimen was upwards 98% and the composition distribution was nearly the same as designed one. The micro-hardness and bend strength were measured to evaluate the sintering effects. The densification effect and microstructure of these FGM samples were investigated and the sintering mechanism was discussed.

Abstract: This paper reports some new progresses on layered and graded coatings for plasma facing materials in fusion devices in Laboratory of Special Ceramics and Powder Metallurgy (LSCPM), University of Science and Technology Beijing (USTB), China. They included tungsten coatings made be various particle sizes of initial feedstock and interlayers and boron carbide graded coatings. All the coatings were fabricated on the oxygen free copper by plasma spraying. The microstructures and properties were investigated for PFM. Water quenching and high heat loading experiments were also carried out to estimate the thermal performance of these coatings.

Abstract: Tungsten coatings with different interlayers onto the oxygen-free copper substrates were fabricated by atmosphere plasma spraying. The effects of different interlayers of NiCrAl, NiAl and W/Cu on bonding strength were studied. SEM, EDS and XRD were used to investigate the photographs and compositions of these coatings. The tungsten coatings with different initial particle sizes resulted in different microstructures. Oxidation was not detected in the tungsten coating, but in the interlayer, it was found by both XRD and EDS. The tungsten coating deposited directly onto the copper substrate presented higher bonding strength than those with different interlayers.

Abstract: Tungsten has the highest melting point among all metal, which makes it withstand thermal shock and erosion in high temperature environments. In this study, Tungsten coatings were sprayed onto the oxygen-free copper substrates by plasma spraying using inert gases protection. XRD, SEM and EDS were used to identify the phases, morphologies and compositions of the coatings. Vickers micro-hardness and bonding strength of the tungsten coatings were also measured. The results revealed that the hardness distribution of the tungsten coatings was different along the thickness direction. The tungsten coating without any interlayer showed higher bonding strength than that of the other two coatings with NiCrAl and W/Cu interlayers, respectively.

Abstract: Molybdenum has many prominent properties, such as high melting point, good thermal properties, low erosion rate and so on, which make it promising candidate materials for plasma facing materials in the next fusion reactor. In the present work, molybdenum coatings were deposited onto the oxygen-free copper substrates by atmospheric plasma spraying. Different interlayers were introduced between the coatings and substrates. SEM, EDS and XRD were used to investigate the photographs and compositions of these coatings. The bonding strength of the coatings was tested to investigate the effect of interlayers on adhesion of the coatings at room temperature and it was found that the coating without interlayers showed the highest bonding strength. Water quenching method was used to evaluate the adhesion of the coatings under thermal cycling conditions and the results showed that the molybdenum coating with two interlayers possessed of the highest resistance of thermal cycling wrack.