On tungsten spraying using inductively coupled plasma system - First results

0498210 - ÚFP 2019 RIV CZ eng C - Conference Paper (international conference)
Klečka, Jakub - Mušálek, Radek - Vilémová, Monika - Lukáč, František
On tungsten spraying using inductively coupled plasma system - First results.
METAL 2017: 26th International Conference on Metallurgy and Materials: abstracts. Ostrava: Tanger Ltd., 2017, s. 1321-1326. ISBN 978-80-87294-73-4.
[26th International Conference on Metallurgy and Materials. Brno (CZ), 24.05.2017-26.05.2017]
R&D Projects: GA ČR(CZ) GA17-23154S
Institutional support: RVO:61389021
Keywords : Radio frequency inductively coupled plasma torch * tungsten * plasma facing components * plasma spraying
OECD category: Materials engineering

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.
Permanent Link: http://hdl.handle.net/11104/0290604