Materials and Corrosion-werkstoffe Und Korrosion最新文献

Patch repair is one of the most adopted methods for repairing distressed reinforced concrete (RC) roof slabs. Galvanic anodes in the patch repair area can overcome the formation of incipient anodes and extend the service life of the repair work. This experimental study evaluates the protection criterion to assess the performance of galvanic anodes in patch repair regions. The potential and the current distribution in the RC slabs were monitored for 440 days. As per EN ISO 12696: 2022, the 100-mV depolarisation potential criterion is not applicable for galvanic anodes embedded in the patch repair region. Alternatively, this paper explores the use of output current from the anode (anodic current) as a parameter to assess the performance of the galvanic anode. The reducing trend of corrosion current density values of steel rebar in the repair region over a period indicates the performance of galvanic anodes, and this was also validated using numerical simulation.

Coating microdamage and interfacial corrosion are inevitable for the metal/coating system during service, leading to the premature failure of the equipment and posing significant safety hazards. However, challenges remain regarding the achievement of early detection of corrosion and the visual monitoring of damage. Herein, a novel polymeric coating system exhibiting robust capabilities for corrosion sensing and visualization has been developed through the combination of meticulously designed nanosensors. These nanosensors were synthesized utilizing a zeolitic imidazolate framework that is infused with phenanthroline (Phen) corrosion probes. The onset of metal corrosion at the interface of coating damage can be promptly sensed and reflected by an apparent orange-red color, attributing to the formation of Phen-Fe²⁺ coordinates. The impermeability and corrosion resistance of the epoxy coating have been greatly improved through introducing the synthesized nanosensors. This straightforward yet powerful strategy based on elaborate nanosensors, offering a new perspective for design of multifunctional and long-life protective materials.

This study evaluates the effectiveness of CeO₂ nanoparticles (NPs) as corrosion inhibitors for A1008 low carbon steel and compares their performance with cerium nitrate inhibitors. Several parameters, including inhibitor concentration, solution temperature, and immersion duration, were considered in the assessment. All experiments were carried out in a 3.5% NaCl solution. Electrochemical and surface analysis techniques were used to characterize the samples. The results demonstrated that both CeO₂ NPs and cerium nitrate effectively prevent corrosion at optimal concentrations during short and long immersion periods, with adsorption primarily governed by physical mechanisms. Moreover, Ce³⁺ ions exhibited higher corrosion resistance compared to CeO₂ NPs, particularly at elevated temperatures and over extended exposure times. The incorporation of both ceria NPs and Ce³⁺ ions into the protective layer enhanced the durability of carbon steel surfaces by reducing nodule formation and promoting a more homogeneous surface, largely free of corrosion products.

Surface mechanical attrition treatment (SMAT) enhances the strength and corrosion resistance of aluminum alloys, but corrosion behavior across the resulting gradient structure remains unclear. In this study, gradient-structured 7075 aluminum alloy was fabricated via SMAT and exposed to cyclic wet/dry corrosion under simulated marine atmospheric conditions. Electrochemical impedance spectroscopy, polarization testing, and morphology analysis revealed layer-specific corrosion responses across the nanostructured surface layer (NSL), refined structure layer (RSL), deformed grain zone (DG), and original grain matrix (OG). The NSL showed excellent resistance, with minimal pitting and cracking, due to refined second phases, dense grain boundaries, and residual compressive stress. In contrast, the OG suffered severe localized corrosion with pits over 13 μm. Polarization resistance confirmed a hierarchy of NSL > RSL > DG > OG in early stages, while DG developed the most protective film over time. These results clarify gradient-induced corrosion behavior and inform marine-grade aluminum alloy design.

The austenitic stainless steel 15-15Ti is a promising cladding material for Lead-cooled Fast Reactors (LFRs), yet it suffers severe corrosion in liquid Lead-Bismuth Eutectic (LBE), especially under low-oxygen conditions. In this study, 15-15Ti steel was exposed to oxygen-controlled LBE ( ~ 10⁻⁷ wt% O) at 500°C for up to 2000 h. Surface and cross-sectional analyses using SEM, EDX, and XRD revealed a duplex oxide scale: a protective inner FeCr₂O₄ spinel and a porous outer Fe₃O₄ layer. With time, the outer layer cracks and delaminates, enabling LBE penetration and selective dissolution of Fe and Ni. A Cr-enriched spinel persists but cannot prevent degradation. Based on these results, a four-stage corrosion model is proposed, capturing the transition from oxidation-dominated behavior to dissolution-driven attack. This study provides new insights into corrosion kinetics of 15-15Ti steel in LBE and underscores the need to preserve oxide integrity for long-term performance in LBE-cooled systems.