Synthesis of organic-inorganic 3D-nanocontainers for smart corrosion protection of friction stir welded AZ31B magnesium alloy-titanium dissimilar joints

Abstract

The joining of different light metals through friction stir welding (FSW) is gaining interest as a method to decrease weight and improve fuel efficiency. However, to ensure durability, these welded metals may require surface treatments to protect against corrosion or wear. This study presents a novel approach for the simultaneous delivery of two distinct corrosion inhibitors to Ti-Mg dissimilar PEO treated joints on demand. The research focuses on the synthesis, characterization, and application of cerium@polystyrene (Ce@PS) nanocontainers, which are loaded with 8-hydroxyquinoline (8-HQ) to enhance corrosion protection. The synthesis involves several key steps, including the formation of a cerium-based outer layer around polystyrene nanospheres, the selective removal of the polystyrene core to create a porous structure, and the subsequent loading of the 8-HQ inhibitor. Structural and compositional analyses, conducted using scanning transmission electron microscopy (STEM) and energy-dispersive X-ray spectroscopy (EDS), confirmed the successful incorporation of 8-HQ within the nanocontainers. Additionally, Fourier-transform infrared spectroscopy (FTIR) provided detailed information about the chemical composition of the organic materials throughout the synthesis process. Thermal decomposition analysis verified the successful fabrication and stability of the dual-shell nanocontainers.

Corrosion tests on Ti-Mg joints treated with plasma electrolytic oxidation (PEO) coatings and loaded nanocontainers demonstrated significantly improved corrosion resistance compared to untreated joints. This research highlights the potential of dual-shell nanocontainers, containing both organic and inorganic inhibitors, to offer prolonged corrosion protection, particularly against galvanic corrosion in dissimilar joints. The findings suggest that these synthesized nanocontainers hold promise for various industrial applications, particularly in the context of friction stir welded (FSW) Ti-Mg dissimilar joints, providing valuable insights for the development of advanced materials designed to mitigate corrosion.