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Composition of plasma‐sprayed tungsten coatings on CuCrZr alloy
Author(s) -
Kaciulis S.,
Mezzi A.,
Montanari R.,
Ucciardello N.,
Volterri R.
Publication year - 2010
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.3302
Subject(s) - materials science , tungsten , alloy , coating , x ray photoelectron spectroscopy , inductively coupled plasma , metallurgy , layer (electronics) , plasma , analytical chemistry (journal) , composite material , chemical engineering , chemistry , physics , chromatography , quantum mechanics , engineering
Mock‐ups for the International Thermonuclear Experimental Reactor(ITER) were manufactured by depositing W coatings on tubular substrates of CuCrZr alloy via plasma spraying. An appropriate interlayer (of Ni, Al and Si) was optimised to increase the adhesion of W on the Cu alloy and to provide a soft interface with intermediate thermal expansion coefficient for better thermo‐mechanical compatibility. The distribution of chemical elements in the layered interface and in the coating was investigated by energy dispersive spectroscopy (EDS), XPS and AES in the as‐prepared material and after heat treatment of 24 h at 823 K. Moreover, the external W layer was examined by inductively coupled plasma emission spectrometry(ICP‐ES). The results showed that the as‐prepared material does not exhibit macro‐porosity. The layers forming the interface do not exhibit any long‐range diffusion of the chemical species from layer to layer during the deposition process. The heat treatment does not seem to cause long‐range migration of Al and Ni into the W coating. The presence of Ni (0.4 wt%) in the as‐deposited external W layer as shown by ICP‐ES is only due to the low purity (commercial grade) of W powders used in spraying operations. It can be eliminated by using W powders of higher purity in the deposition process. Copyright © 2010 John Wiley & Sons, Ltd.