Unravelling corrosion degradation of aged aircraft components protected by chromate-based coatings

Despite extensive research, eliminating hexavalent chromium-based inhibitors from aerospace coatings remains challenging due to a lack of understanding of coating degradation during aircraft service. This study addresses the issue by investigating the protective mechanisms and aging processes of chromate-containing coatings on aircraft...

Passive film formation and corrosion resistance of laser-powder bed fusion fabricated NiTi shape memory alloys

Electrochemical tests and surface analysis measurements were performed to study the corrosion behavior in a 0.9 wt.% NaCl solution at 37 °C of three NiTi shape memory alloys fabricated by laser-powder bed fusion (L-PBF). The passive film characteristics and corrosion resistance of L-PBF NiTi showed different features as a function of their...

Smart protective coatings with self‐sensing and active corrosion protection dual functionality from pH-sensitive calcium carbonate microcontainers

Herein, we report the development of a self-sensing and active corrosion protection coating which incorporates pH-sensitive multilayer chitosan/alginate-covered CaCO₃ microcontainers containing 1,10-phenanthrolin-5-amine (APhen). The microcontainers can respond to pH variation to release APhen which serves not only as a corrosion...

Li leaching from Li carbonate-primer: Transport pathway development from the scribe edge of a primer/topcoat system

Depletion depths of inorganic components from a scribe edge in a polyurethane primer containing Li₂CO₃, MgO, BaSO₄ and TiO₂ beneath a topcoat, were determined using a range of techniques including SEM/EDS and proton induced X-ray and γ-ray emission spectroscopies. SEM of sections cut using an ion...

Multifunctional ZrB₂-rich Zr_1-xCr_xB_y thin films with enhanced mechanical, oxidation, and corrosion properties

Refractory transition-metal (TM) diborides have high melting points, excellent hardness, and good chemical stability. However, these properties are not sufficient for applications involving extreme environments that require high mechanical strength as well as oxidation and corrosion resistance. Here, we study the effect of Cr addition on the...

Durable lubricant-infused anodic aluminum oxide surfaces with high-aspect-ratio nanochannels

Recently, lubricant-infused surfaces (LIS) have emerged as a prominent class of surface technology for antifouling, anti-icing and anticorrosion applications. However, long-term corrosion exposure and mechanical damages may deteriorate the practical performance of LIS during application. In this study, a robust LIS was fabricated by the...

Li leaching from lithium carbonate-primer: An emerging perspective of transport pathway development

Studies of Li depletion in sections of a Li ₂ CO ₃ -primer comprising a polyurethane binder, MgO, TiO ₂ , BaSO ₄ in addition to Li ₂ CO _3, were performed using a combination of particle induced γ-ray and X-ray emission spectroscopies along with SEM/EDS analysis. A mixture of...

Compositional study of a corrosion protective layer formed by leachable lithium salts in a coating defect on AA2024-T3 aluminium alloys

Organic primer coatings loaded with environmentally harmful Cr(VI) corrosion inhibitive pigments still play an important role in corrosion protection of aluminium alloys for the aerospace industry. A potential “green” alternative coating system has recently been developed, loaded with lithium salt corrosion inhibitors. Under exposure to...

The use of odd random phase electrochemical impedance spectroscopy to study lithium-based corrosion inhibition by active protective coatings

In this work, the study of the time-dependent behaviour of lithium carbonate based inhibitor technology for the active corrosion protection of aluminium alloy 2024-T3 is presented. Odd random phase electrochemical impedance spectroscopy (ORP-EIS) is selected as the electrochemical tool to study the corrosion protective properties of a model...

Particle induced gamma and X-ray emission spectroscopies of lithium based alloy coatings

Lithium based inhibitors in aerospace coatings are seen as excellent replacements for their chromium counterparts which are both carcinogenic and heavier. However, Li is generally difficult to detect and following changes in its distribution due to corrosion is impossible with many standard techniques. Combining MeV Particle Induced Gamma and...

Modified hydrotalcites as chloride scavengers and inhibitor release agents for improved corrosion protection of reinforced concrete

Owing to the unique molecular structure and high ion exchange capacity, hydrotalcites are believed to have a potential to be modified and tailor-made as an active corrosion protective component of reinforced concrete. In this paper, two types of modified hydrotalcites (MHT-pAB and MHT-NO2) were tested both in alkaline solution and mortar for...