Heat load and deuterium plasma effects on SPS and WSP tungsten

Abstract Tungsten is a prime choice for armor material in future nuclear fusion devices. For the realization of fusion, it is necessary to address issues related to the plasma–armor interactions. In this work, several types of tungsten material were studied, i.e. tungsten prepared by spark plasma sintering (SPS) and by water stabilized plasma spraying (WSP) technique. An intended surface porosity was created in the samples to model hydrogen/helium bubbles. The samples were subjected to a laser heat loading and a radiation loading of deuterium plasma to simulate edge plasma conditions of a nuclear fusion device (power density of 108 W/cm2 and 107 W/cm2, respectively, in the pulse intervals up to 200 ns). Thermally induced changes in the morphology and the damage to the studied surfaces are described. Possible consequences for the fusion device operation are pointed out.

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MICROSTRUCTURE AND MICROHARDNESS EVALUATION FOR NiCrAlY MATERIALS MANUFACTURED BY SPARK PLASMA SINTERING AND PLASMA SPRAYING

Acta Polytechnica CTU Proceedings ◽

10.14311/app.2020.27.0013 ◽

2020 ◽

Vol 27 ◽

pp. 13-17

Author(s):

Iosif Hulka ◽

Radek Mušálek ◽

František Lukáč ◽

Jakub Klečka ◽

Tomáš Chrástka

Keyword(s):

Spark Plasma Sintering ◽

Inductively Coupled Plasma ◽

Thermal Spraying ◽

Protective Atmosphere ◽

Feedstock Powder ◽

Inductively Coupled ◽

Plasma Sintering ◽

Water Stabilized Plasma ◽

Spark Plasma ◽

Phase Characterization

NiCrAlY deposited by different thermal spraying methods is commonly used as the bond coat material in thermal barrier coatings (TBCs). In the present study, two experimental coatings were deposited by hybrid water stabilized plasma (WSP-H) and radio frequency inductively coupled plasma (RF-ICP) using the same feedstock powder. Spark plasma sintering (SPS) was used to manufacture a compact NiCrAlY from the same feedstock powder as a reference material. Microstructure, internal oxidation, phase characterization and quantification of the mechanical behaviour in terms of microhardness were studied. The investigations clearly showed microstructural and mechanical differences between the NiCrAlY samples manufactured by different plasma technologies. The results confirmed that SPS and RF-ICP provide dense structures with no oxides due to the fabrication under protective atmosphere and similar mechanical properties. Thus, RF-ICP may be used for deposition of very dense coatings with microstructure and hardness comparable to compacted materials prepared by SPS.

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Effect of Mixing Modes and Nano Additives on the Densification and Sintering Behavior of Tungsten Material Under Spark Plasma Sintering

Journal of Cluster Science ◽

10.1007/s10876-017-1268-z ◽

2017 ◽

Vol 28 (5) ◽

pp. 2905-2917 ◽

Cited By ~ 3

Author(s):

Nguyen Van Minh ◽

Gopalu Karunakaran ◽

Yury Konyukhov

Keyword(s):

Spark Plasma Sintering ◽

Sintering Behavior ◽

Plasma Sintering ◽

Spark Plasma ◽

Nano Additives ◽

Tungsten Material

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Enhanced thermoelectric properties of N-type polycrystalline In4Se3-x compounds via thermally induced Se deficiency

Functional Materials Letters ◽

10.1142/s1793604714500258 ◽

2014 ◽

Vol 07 (03) ◽

pp. 1450025 ◽

Cited By ~ 2

Author(s):

Ran Zhao ◽

Yu-Tian Shu ◽

Fu Guo

Keyword(s):

Thermoelectric Properties ◽

Thermal History ◽

Thermal Processing ◽

Carrier Mobility ◽

Figure Of Merit ◽

Thermally Induced ◽

Plasma Sintering ◽

Spark Plasma ◽

Se Deficiency ◽

Surface Morphologies

In 4 Se 3-x compound is considered as a potential thermoelectric material due to its comparably low thermal conductivity among all existing ones. While most studies investigated In 4 Se 3-x thermoelectric properties by controlling selennium or other dopants concentrations, in the current study, it was found that even for a fixed initial In / Se ratio, the resulting In / Se ratio varied significantly with different thermal processing histories (i.e., melting and annealing), which also resulted in varied thermoelectric properties as well as fracture surface morphologies of In 4 Se 3-x polycrystalline specimens. Single phase polycrystalline In 4 Se 3-x compounds were synthesized by combining a sequence of melting, annealing, pulverizing, and spark plasma sintering. The extension of previous thermal history was observed to significantly improve the electrical conductivity (about 121%) and figure of merit (about 53%) of In 4 Se 3-x polycrystalline compounds. The extended thermal history resulted in the increase of Se deficiency (x) from 0.39 to 0.53. This thermally induced Se deficiency was observed to associate with increasing carrier mobility but decreasing concentration, which differs from the general trend observed for the initially adjusted Se deficiency at room temperature. Unusually large dispersed grains with nanosize layers were observed in specimens with the longest thermal history. The mechanism(s) by which previous thermal processing enhances carrier mobility and affect microstructural evolution are briefly discussed.

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