ON TUNGSTEN SPRAYING USING INDUCTIVELY COUPLED PLASMA SYSTEM – FIRST RESULTS

1 KLEČKA Jakub
Co-authors:
1,2 MUŠÁLEK Radek 1 VILÉMOVÁ Monika 1 LUKÁČ František
Institutions:
1 Institute of Plasma Physics CAS, v.v.i., Department of Materials Engineering, Za Slovankou 3, 182 00 Prague, Czech Republic, EU, klecka@ipp.cas.cz
2 Department of Materials, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Trojanova 13, 120 00 Praha 2, Czech Republic, EU
Conference:
26th International Conference on Metallurgy and Materials, Hotel Voronez I, Brno, Czech Republic, EU, May 24th - 26th 2017
Proceedings:
Proceedings 26th International Conference on Metallurgy and Materials
Pages:
1321-1326
ISBN:
978-80-87294-79-6
ISSN:
2694-9296
Published:
9th January 2018
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
41 views / 7 downloads
Abstract

Thanks to its unique properties such as high melting point and density, tungsten and tungsten-based alloys are commonly used in a wide range of applications. Among others, these materials are promising candidates for the plasma facing components in the future fusion reactors. One of considered ways of production of these parts is plasma spraying. There are however several limitations for conventional gas stabilized torches, mainly in plasma enthalpy (i.e. the ability to efficiently melt tungsten particles in considerable feed rates) and susceptibility of tungsten to oxidation (which complicates spraying in oxidizing open-air atmosphere). The radio frequency inductively coupled plasma torch (RF-ICP) is a unique system which can potentially overcome both these problems and can be used for efficient tungsten spraying. The tungsten powder, which can be finer than the one used for the conventional systems, is fed axially into the hot plasma core; both factors lead to a more efficient melting of the particles. The deposition is performed in a chamber with controlled atmosphere of inert gas or decreased pressure, the oxidation is therefore suppressed. In this first study carried out with the newly commissioned RF-ICP system TekSpray 15 (Tekna), samples of tungsten coatings on graphite substrates were prepared. The X-ray diffraction and SEM images of the free surfaces and cross-sections were obtained, documenting high purity of the deposits and appropriate flattening of the splats leading to a dense coating microstructure. The effect of substrate preheating on the microstructure, porosity and hardness was also studied.

Keywords: Radio frequency inductively coupled plasma torch, Tungsten, Plasma facing components, Plasma spraying
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