[Article] Towards conductive alumina-carbon composites coatings developed by plasma electrolytic oxidation of aluminium with dispersed carbon nanoparticles.
The present study reports on the influence of the concentration in carbon black nanoparticles dispersed in electrolyte on their incorporation through alumina coatings elaborated by plasma electrolytic oxidation with the ultimate goal to achieve electrical percolation of the incorporated carbon nanoparticles.
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Abstract
This collaborative work involves the IJL groups « plasmas – surfaces – processes » and « carbon-based materials » within the project CAMFRE (ANR21-CE08-0029) that aims at growing conductive alumina based composite layers for the connector industry.
Incorporation of carbon-based nanoparticles into ceramic coatings during plasma electrolytic oxidation (PEO) is promising for the synthesis of new composite layers on lightweight metals. Specifically, the present study focuses on the incorporation of carbon black (CB) nanoparticles into PEO alumina layers. For this purpose, PEO of aluminium is performed in silicate-based electrolytes containing various concentrations of dispersed carbon black nanoparticles (from 0 to 6 g⋅L-1). The influence of this concentration on the microstructure of the achieved PEO coatings is investigated by combining complementary characterization techniques (scanning electron microscopy, X-ray diffraction and Raman spectroscopy). Results show that using concentrations up to 6 g⋅L-1 tend to limit the morphological inhomogeneity between the edges and the centre of the treated samples. Moreover, the addition of carbon black nanoparticles results in a sponge-like outermost sublayer covering larger areas of the surface with abilities to host a higher amount of these nanoparticles. It is also evidenced that CB nanoparticles do not suffer any further structural degradation during their incorporation. In addition, cross-checked results show that the presence of dispersed CB nanoparticles slightly affect the coating average growth rate. As for potential future applications, the electrical volume conductivity of grown carbon-alumina composite coatings is also measured.
Authors :
Lucas Magniez, Corentin Da Silva Tousch, Sébastien Fontana, Sébastien Cahen, Julien Martin, Claire Hérold, Gérard Henrion
References :
L. Magniez, C. Da Silva Tousch, S. Fontana, S. Cahen, J. Martin, C. Hérold, G. Henrion, Surface and Coatings Technology 473 (2023) 129990.
DOI :