Darya Snihirova

Hydroxyapatite microparticles as feedback-active reservoirs of corrosion inhibitors.

This work contributes to the development of new feedback-active anticorrosion systems. Inhibitor-doped hydroxyapatite microparticles (HAP) are used as reservoirs, storing corrosion inhibitor to be released on demand. Release of the entrapped inhibitor is triggered by redox reactions associated with the corrosion process. HAP were used as reservoirs for several inhibiting species: cerium(III), lanthanum(III), salicylaldoxime, and 8-hydroxyquinoline. These species are effective corrosion inhibitors for a 2024 aluminum alloy (AA2024), used here as a model metallic substrate. Dissolution of the microparticles and release of the inhibitor are triggered by local acidification resulting from the anodic half-reaction during corrosion of AA2024. Calculated values and experimentally measured local acidification over the aluminum anode (down to pH = 3.65) are presented. The anticorrosion properties of inhibitor-doped HAP were assessed using electrochemical impedance spectroscopy. The microparticles impregnated with the corrosion inhibitors were introduced into a hybrid silica-zirconia sol-gel film, acting as a thin protective coating for AA2024, an alloy used for aeronautical applications. The protective properties of the sol-gel films were improved by the addition of HAP, proving their applicability as submicrometer-sized reservoirs of corrosion inhibitors for active anticorrosion coatings.

Smart composite coatings for corrosion protection of aluminium alloys in aerospace applications

Abstract Several new concepts to design and fabricate self- healing materials have emerged over the last few years, all presenting advantages and disadvantages. Among these, smart coatings have been considered as extremely promising for several applications, including for corrosion protection purposes. Smart coatings show great potential in what concerns the increased lifetime of metallic structures and reduction of the corrosion-related maintenance costs. This chapter reviews existing self-healing strategies for developing new and more efficient coatings for corrosion protection of aluminium alloys used in aeronautical applications.