Corrosion performance of a benzoxazine type resin loaded with nanoparticles and applied on aluminium alloys

Corrosion performance of a benzoxazine type resin loaded with nanoparticles and applied on aluminium alloys
A. Renaud1, Y. Paint2, L. Bonnaud2, M. Poorteman1, P. Dubois2, M. Olivier1,*

1 Department of Materials Science, Materials Engineering Research Center (CRIM), University of Mons, Place du Parc 20, B-7000 Mons, Belgium
2 Laboratory of Polymeric and Composite Materials, Center of Innovation and Research in Materials and Polymers (CIRMAP), Materia Nova research Center & University of Mons, Place du Parc 20, B-7000 Mons
* +32(0)65/37.44.31, marjorie.olivier@umons.ac.be

Aluminium alloys are widely used in aircraft applications, especially series 2xxx (Cu) and 7xxx (Zn). Those alloys offer improved mechanical properties, compared to pure aluminium, but are strongly sensitive to corrosion. In order to protect aluminium pieces from aggressive environments, one or several barrier layers are usually applied onto the metal surface. The application of an organic coating is one of the most common ways to elaborate such a protective barrier. Thermoset polymers, and more particularly epoxy resins, are widely used for these applications because of their good performance. Nevertheless, new classes of resins with comparable or even better properties are under development. In particular, polybenzoxazines appear to be good candidates for replacing epoxy polymers because of their high thermal and chemical resistances, their low water uptake and an almost zero shrinkage during cross-linking steps.
Recently, ParaPhenlyleneDiAmine (pPDA)-based benzoxazines applied on aluminium substrates as passive protection layers [1] have shown promising properties. However, high stresses generated during curing of these organic coatings can induce premature failure with successive corrosion propagation once aggressive species have reached the metal surface.
In this work, different nanoparticles (cerium and zinc oxide) have been incorporated in a pPDA-based benzoxazine resin, aiming at improving corrosion protection, as reported in recent papers [2, 3]. Different amounts of nanoparticles have been dispersed in pPDA-based benzoxazine formulations and applied on 1050 and 2024-T3 aluminium substrates. The morphology of obtained coatings has been characterised using Scanning Electron Microscopy (SEM) combined with Energy-Dispersive X-ray spectroscopy (EDX). The nanoparticle impact on the thermo-mechanical properties of the resin has been investigated using Differential Scanning Calorimetry (DSC) and DiElectric Analysis (DEA). Finally, the corrosion performance of the coatings has been evaluated using Electrochemical Impedance Spectroscopy (EIS) in order to understand the behaviour of obtained systems.

[1] M. Poorteman, A. Renaud, J. Escobar, L. Dumas, L. Bonnaud, P. Dubois, M-G. Olivier - Thermal curing of para-phenylenediamine benzoxazine for barrier coating applications on 1050 aluminum alloys, Progress in Organic Coatings 97 (2016) 99-109
[2] R.V. Lakshmi, S.T. Aruna, S. Sampath - Ceria nanoparticles vis-à-vis cerium nitrate as corrosion inhibitors for silica-alumina hybrid sol-gel coating, Applied Surface Science 393 (2017) 397-404
[3] D. Álvarez, A. Collazo, X.R. Nóvoa, C. Pérez - Assessment of ZnO nanoparticles as anticorrosive pigment in hybrid sol-gel films, Progress in Organic Coatings 96 (2016) 3-12