Atmospheric plasma process to produce nanocomposite coatings for protecting metal parts against corrosion

Context

Corrosion is a challenge for a sustainable society. It is a question of understanding and improving the lifespan of our metallic and alloy structural materials. Recent advances in the design of coatings have attempted to synergistically combine different modes of corrosion protection within a single coating system, with the goal to extending the lifetime of the protected structural components and to provide protection against challenging corrosive environments [1]. Polymer nanocomposites, composed of a polymer matrix in which nanofillers are dispersed, can be used to produce protective coatings with remarkable properties, particularly in terms of their anti-corrosion and mechanical behavior [1,2]. Nanocomposite coatings can form a very adherent and protective layer on steel but also to other metals like aluminum-based alloys, which is essential to receive the organic coating (epoxy or siloxane coatings) deposited on top. This intermediate layer can replace the traditional chromate or phosphate treatment which in the case of the former is highly toxic and carcinogenic and in the case of the latter leads to water eutrophication if wastewater treatment is ignored. Therefore, environmentally friendly cold atmospheric plasma treatment processes with effective corrosion preventive properties are urgently required for both academic research and industrial applications.

Objectives and preliminary results

The aim of this thesis is to develop and optimize nanocomposite coatings for the protection of metals against corrosion using the atmospheric plasma process. The aim will be to explore the properties of the coatings obtained, in terms of adhesion, homogeneity and corrosion resistance, while studying the influence of plasma process parameters (power, chemical composition, treatment time, etc.) on the quality of the coatings.

The ambitious goal of this research project is to go from the process to the material and up to the demonstration of the industrial application. The proposed methodology is as follows i) optimization of the introduction of a colloidal solution of siloxane precursor containing different nanofillers into the plasma discharge. The objective is to achieve a homogeneous and controlled dispersion of the nanofillers in the coatings. In-situ plasma diagnostics using optical emission spectroscopy will be used to qualify the efficiency and reproducibility of the precursor introduction into the discharge. ii) deposition of different nanocomposite chemistries obtained from different siloxane precursors (different chain length and Si/C ratio) and combined with different nanofillers, iii) characterization of physico-chemical and electrochemical properties of nanocomposites coatings by electrochemical impedance spectroscopy (EIS), ATR-FTIR, SEM and Raman.

Preliminary results [3,4] have shown an improvement in the corrosion performance of plasma polymerized hexamethyldisiloxane (pp-HMDSO) with 1wt.% of graphene as compared to pp-HMDSO alone, and the mechanical properties were studied for the first time on very thin coatings (500 nm) but further siloxane and nanofiller chemistries, and process improvements need to be conducted to gain a better understanding of anticorrosion properties. Even though the scope of this project is oriented to protection corrosion applications, we also aim to understand the deposition process as well as the durability and tribological properties of the nanocomposite coatings and the evolution of their anticorrosion protection properties after applying different mechanical solicitations.

References

[1] R.  Ding, W. Li, X. Wang , T. Gui, B.  Li , P. Han,  H. Tian, A. Liu,  X. Wang , X.  Liu,  X.  Gao,  W. Wang, L.  Song, A brief review of corrosion protective films and coatings based on graphene and graphene oxide, Journal of Alloys and Compounds 764 (2018) 1039-1055.

[2]  R. V. Dennis, V. Patil, J. L.Andrews, J. P. Aldinger, G.D. Yadav and S. Banerjee, Hybrid nanostructured coatings for corrosion protection of base metals: a sustainability perspective, Mater. Res. Express 2 (2015) 32001.

[3] A. Anagri, A. Baitukha, C. Debiemme-Chouvy, T.Lucas, J. Pulpytel, T.T.M. Tran, S.Tabibian, F. Arefi-Khonsari, Nanocomposite coatings based on graphene and siloxane polymers deposited by atmospheric pressure plasma. Application to corrosion protection of steel, Surf. Coat. Technol. (2019) 377(15), 124928

[4] A. Anagri, E. Zgheib, J. Pulpytel, T.T. M. Tran , A. Alhussein, F. Arefi-Khonsari, Nanoindentation characterization of nanocomposites coating based on graphene and siloxane matrix deposited by dielectric barrier discharge plasma. Surface and Interfaces (2022), 32, 102093

L’UMR 8235 de Sorbonne Université/CNRS mène ses travaux en Electrochimie dans le contexte de la Physico-Chimie et de la Réactivité aux interfaces. Les domaines concernés sont la corrosion et son inhibition, les traitements de surface, le stockage et la conversion de l’énergie.

Master's degree (or equivalent) in Materials Science or Chemical Engineering.

Knowledge of materials, thin films, plasma processes and electrochemistry would be highly appreciated.