Multifunctional Protective Coatings of RE-ZnO Nanocomposite Deposited on Metallic Alloys ^†

The use of nanocomposite materials in various strategic industries has gained great extent due to the excellent protection ability on various substrates. In the manufacture of nanocomposites with multifunctional performances, it is necessary to take into account the selection of the main components (polymer matrix-RE and dispersed phase-ZnO), the characteristics and properties of each component, the compatibility and the impact of the interface between them, the synthesis technology, and the application domain. The study of substrates based on metallic alloys is a representative selection criterion, considering the compatibility between the nanocomposites and substrates, so that the whole assembly can be applied in many industrial sectors [1,2,3].

This paper focuses on the possibility of depositing RE-ZnO nanocomposites films on the surface of the alloy and examining the influence of the particles in the matrix and the effect of composite coating on the metal alloys. The incorporation of the ZnO nanoparticles into the epoxy resin was realized by ex-situ synthesis, and in order to increase the compatibility degree between the two components, the dispersion of the ZnO powder in the afferent matrix solvent was made in the beginning phase. The RE-ZnO samples were deposited on the aluminum alloy substrate, after its previous preparation, followed by the final heat treatment at 100 °C.

From the optical analysis of the nanocomposite film, a high degree of dispersion of the ZnO phase in RE and a good adhesion to the metal alloy substrate were found. The morphological analysis confirms the uniform relative distribution of the powder in the matrix, the particle size being about 35–80 nm. Structural analysis using FTIR and EDX highlights the total incorporation of ZnO nanoparticles into the RE matrix. The contact angle of the nanocomposite film indicates the improvement of the hydrophobic character by increasing the angle around 100 °C.

Based on the obtained results, the developed nanocomposites can be deposited by various substrates with applicability in different environmental fields.