Tungsten particles fabrication by a microjet discharge

Abstract

As a consequence of interaction of a microjet discharge with the tungsten electrodes, tungsten material is released to plasma, and tungsten particles, of submicron size, are formed. The obtained particles were analyzed to establish a correlation of their morphology, size distribution and chemical composition with the discharge configuration and distance to collector. Experimental conditions were identified leading to spherical tungsten particles.

Hybrid Nanostructures Obtained by Transport and Condensation of Tungsten Oxide Vapours onto CNW Templates

“…The presence of the WO 3 doublet is observed at 35.14 eV (W4f7/2) and 37.25 eV (W4f5/2) with a contribution of 54.88%. The WO 2 doublet is observed at 32.83 eV (W4f7/2) and 34.90 eV (W4f5/2) with a contribution of 44.74% [ 17 , 39 , 40 ]. W metallic doublet is still present after oxidation at 31.35 eV (W4f7/2) and 33.72 eV (W4f5/2), but with a small contribution of just 0.39%.…”

“…Regarding the W4f region, the WO 2 doublet is observed at 32.12 eV (W4f7/2) and 34.23 eV (W4f5/2) with a contribution of 30.54%. The presence of the WO 3 doublet is observed at 35.14 eV (W4f7/2) and 37.32 eV (W4f5/2) with a contribution of 42.68% [ 17 , 39 , 40 ]. Moreover, due to the higher atomic percentage of nitrogen, the WN chemical doublet is present at 32.93 eV (W4f7/2) and 35.3 eV (W4f5/2), with a contribution of 26.78% [ 41 ].…”

Material Erosion and Dust Formation during Tungsten Exposure to Hollow-Cathode and Microjet Discharges

“…(a) (b) The microjet discharge [50] (MD) setup (Figure 1b) comprises two parts. In a quartz tube of 20 mm diameter is enclosed the plasma source, where the RF electrode is a tungsten bar of 1.5 cm length and 5 mm diameter, and the grounded electrode is a disk-shaped plate nozzle.…”

“…For example, in the case of tungsten, the exposure of surfaces to heating and He plasma showed the fuzz appearance, in conditions created in Tokamaks [44], Pilot PSI experiments [45], by simultaneously exposure to heat by laser and He plasma [46], but also in normal laboratory hollow cathode discharges [47]. Similarly, particle formation (droplets, debris, nanoparticles) is a common phenomenon in magnetron sputtering and plasma jets [48][49][50], in spite of the fact that plasma configurations are very different for Tokamak plasmas. So, laboratory scale experiments are meaningful even if the conditions are apparently very different, just because they emphasize the similar behaviors of materials.…”

“…In this paper, we study the interactions between plasma and tungsten surfaces in order to investigate the erosion/melting/vaporization phenomena, and as a direct consequence, the dust occurrence. Special generating systems were designed and used, namely a hollow cathode (HC) [47] and a microjet discharge (MD) [50]. The experiments were made with helium and argon gas, in order to investigate soft and hard damages of the exposed tungsten surfaces.…”