Carbon nanotube-reinforced waterborne epoxy zinc-rich coatings were developed by modifying waterborne epoxy zinc-rich formulations with varying amounts of carbon nanotubes (CNTs), to improve the coatings’ corrosion resistance and their protection for Q355b steel in environments rich in chlorides. A detailed investigation of the microstructural changes in the coatings prior to and following corrosion was conducted through FTIR, SEM, XRD, and XPS analytical techniques. The effectiveness of these innovative coatings in providing corrosion protection for Q355b steel in chloride conditions was assessed via electrochemical corrosion methodologies and neutral salt spray testing. The results indicate that an increase in the CNT concentration led to an initial enhancement in the corrosion resistance of the coatings, followed by a decrease, with optimal performance noted at 0.3 wt.% CNTs. During the electrochemical evaluations, the open circuit potential (OCP) of the coating containing 0.3 wt.% CNTs remained stable below the critical threshold of −0.78 V for an extended period, indicating sustained cathodic protection. In comparison to the coatings with CNT concentrations (wt.%) of 0.1, 0.5, 0.7, and 1.0, the coating with 0.3 wt.% CNTs demonstrated the lowest corrosion current density, measured at 0.0322 µA/cm². Further validation of its exceptional corrosion resistance was provided by the 240 h neutral salt spray tests. This performance can be linked to the capability of the CNTs to improve electrical conductive connectivity between the zinc particles and the Q355b steel substrate beneath them, subsequently enhancing both the cathodic protection of the coating and its physical shielding effectiveness.

The coagulation cascade triggered by the contact between blood and the surface of implantable/interventional devices can lead to thrombosis, severely compromising the long-term safety and efficacy of medical devices. As an alternative to systemic anticoagulants, surface anticoagulant modification technology can achieve safer hemocompatibility on the device surface, holding significant potential for clinical application. This article systematically elaborates on the latest research progress in the surface anticoagulant modification of blood-contacting materials. It analyzes and discusses the main strategies and their evolution, spanning from physically inert carbon-based coatings and heparin-based drug-functionalized surfaces to hydrophilic/hydrophobic dynamic physical barriers, biologically signaling regulatory coatings, and bio-integrative/regenerative endothelium-mimicking surfaces. The advantages and limitations of the respective methods are outlined, and the potential for synergistic application of multiple strategies is explored. A special emphasis is placed on current research hotspots regarding novel anticoagulant surface technologies, such as hydrogel coatings, liquid-infused surfaces, and 3D-printed endothelialization, aiming to provide insights and references for developing long-term, safe, and hemocompatible cardiovascular implantable devices.

In this paper, we investigated the effects of the matrix and precipitates in Cr-Ni-Mo-V rotor steel on its mechanical properties after water quenching and tempering (450–700 °C). The results indicate that the microstructure and mechanical properties of the steel can be significantly adjusted by changing the tempering temperature. An excellent combination of tensile strength (1028.608 MPa) and elongation (19%) was obtained upon tempering at 650 °C. This is attributed to the martensite lath with a high dislocation density, solid solution strengthening and the strengthening effect of spherical Mo₂C and VC particles. At a tempering temperature of 550 °C, the precipitation and development of rod-shaped Fe₃Mo₃C resulted in a considerable drop in strength. At 650 °C, the dissolution of Fe₃Mo₃C and dispersion precipitation of Mo₂C and VC led to a large rise in strength. At 700 °C, the coarsening of Mo₂C and VC, together with the recrystallization of the martensite lath, resulted in a loss in strength. Meanwhile, as the tempering temperature was increased from 450 °C to 700 °C, the tensile fracture characteristics of Cr-Ni-Mo-V rotor steel gradually changed from cleavage fractures to dimple fractures.

Corrosion inhibitors play a crucial role in the corrosion protection of rebars in reinforced concrete structures under harsh service conditions. However, conventional corrosion inhibitors often suffer from low efficiency and environmental concerns. This study investigates a low-cost and environmentally friendly lotus leaf extract (LLE) as a corrosion inhibitor and examines its effects on carbon steel rebar corrosion under various conditions. The structure and composition of LLE were characterized using SEM, FTIR, and LC-MS. The effects of LLE on rebar corrosion behavior under different environmental conditions were investigated using electrochemical tests, Mott–Schottky analysis, and XPS. The main findings indicate that LLE is rich in polar chemical bonds and functional groups, which facilitate adsorption and film formation on the rebar surface. In a 3.5% NaCl solution, rebar corrosion is primarily influenced by the solution pH, and low concentrations of LLE exhibit effective corrosion inhibition. In a simulated concrete pore solution, higher concentrations of LLE promote the formation of a passivation film in a chloride-alkaline environment. Studies on pre-passivated rebar indicate that LLE effectively protects the passivation film, with the optimal LLE concentration for passivation film protection and adsorption film quality being 0.5 wt%. This study contributes to the application and development of novel LLE-based corrosion inhibition technology for carbon steel rebar.

A new type of corrosion-resistant alloyed-steel rebar, Cr10MoV, was researched using techniques such as corrosion electrochemistry, X-ray computed tomography, and zero resistance ammeter to systematically study the macro-cell corrosion behavior and corrosion resistance of alloyed-steel rebar in mortar and concrete samples induced by chloride ion concentration in the marine environment. The macro-cell corrosion characteristics and development patterns induced by chloride ion concentration in alloyed-steel rebar were preliminarily revealed. In the macro-cell corrosion system of rebar mortar samples induced by 29 times chloride ion concentration, the corrosion current density of the alloyed-steel rebar combination stabilizes at 1.6–2.4 μA/cm², which is only one-third of that of the carbon-steel rebar combination, while the dissimilar steel rebar combination stabilizes at 0–0.4 μA/cm². Alloyed-steel rebar and carbon-steel rebar are configured in high concentration and low concentration chlorine salt areas, respectively. With the help of high corrosion resistance, the long-term stable corrosion resistance of alloyed-steel rebar is ensured. The potential difference between carbon-steel rebar and alloyed-steel rebar is reduced to weaken the driving force of macro-cell corrosion. It is a useful way to inhibit the macro-cell corrosion of dissimilar steel rebar and ensure the high corrosion resistance and durability of marine reinforced concrete structures.

The service of reinforced concrete structures (RCSs) in harsh coastal environments is often threatened by chloride corrosion. The penetration of chloride ions through concrete pores into the steel/concrete interface will cause the depassivation and corrosion of steel rebars, which will lead to the deterioration and failure of RCSs durability. It is important to repair and protect the corrosion damage of existing concrete structures and ensure their high durability, and the high performance of repairing and protecting materials is crucial. In this paper, a novel cement-based protective coating material with low porosity, high impermeability and chloride-corrosion resistance was designed and prepared by introducing polypropylene fiber and high-performance cement into commercial cement-based protective materials through the double modification strategy of fiber-toughening and substrate-enhancing, in order to provide a reliable corrosion protection solution for the high durability and long life of RCSs under chloride erosion environment. Based on this, the microstructure and pore structure of the double-modified coating material was systematically analyzed by SEM, XRD, X-CT and other characterization methods. The impermeability and chloride corrosion resistance of this material were scientifically evaluated, and the protection mechanism was systematically discussed. The results show that the impermeability of the double-modified coating material is about 2.8 times higher than that of the untreated mortar. At the same time, the corrosion current density was significantly reduced to 8.60 × 10⁻⁷ A·cm⁻², which was about 86% lower than that of the untreated sample (6.11 × 10⁻⁶ A·cm⁻²). The new cement-based coating material optimized by double-modification effectively inhibits the formation and propagation of microcracks in the protective coating through the bridging effect of fibers. At the same time, the regulation of cement hydration products and the densification of pore structure are realized by adjusting the composition of cement matrix. Based on the above two aspects of microstructure improvement, the chloride-corrosion protection performance of the novel cement-based protective coating material has been greatly improved.