Search Results (22)

Vehicle fleet renewal policies promoting NEVs aim to decarbonize transportation but inadvertently alter urban atmospheric corrosivity, threatening the durability of infrastructure coatings. This study investigated the cross-system impacts of vehicle trade-in subsidies on the degradation of protective coatings. We developed a coupled framework integrating a Mixed Logit model for fleet evolution, dynamic Life Cycle Assessment for tracking acidic precursors (SO₂, NO_x), and an Environmental Corrosion Risk Index. Using established Dose–Response Functions, we quantified the lifespan depletion of a standard epoxy zinc-rich primer and polyurethane topcoat system. Our results indicate that aggressive subsidies induce a transition to heavy NEVs, triggering an “emission inversion” that spikes upstream grid acidic emissions. This localized acidification significantly accelerates chemical degradation, reducing the effective service life of infrastructure coatings by 1.3–2.3 years and necessitating premature, costly recoating. We identify a Pareto-optimal subsidy window (8000–10,500 CNY) that effectively balances decarbonization targets with coating preservation. In conclusion, sustainable urban policies must incorporate surface engineering and material durability metrics to prevent emission shifts from compromising the physical integrity of transportation infrastructure. Full article

To tackle the long-standing issue of inadequate corrosion protection in waterborne coatings, this study innovatively incorporates hollow glass microspheres (HGB) into waterborne epoxy zinc-rich primers through physical blending, constructing a dual-layer synergistic anticorrosion system comprising an HGB-modified primer and a zirconium phosphate/urushiol titanium polymer (UTPCZrP)-modified waterborne epoxy topcoat. Optimal performance is achieved with 2 wt% HGB addition: the dual-layer coating retains favorable physicochemical and mechanical properties while enhancing anticorrosion performance by 1–2 orders of magnitude, boasting an impedance of 3.2 × 10⁶ Ω, a corrosion rate as low as 5.71 × 10^–6 mm/year, 99.98% protection efficiency (stable after 25-day immersion), and 720 h salt spray resistance without corrosion diffusion. This method exhibits universality in waterborne polyurethane (WPU) and polyester (WPE) systems, yielding impedance values of 3.57 × 10⁶ Ω and 2.7 × 10⁶ Ω, respectively, with over 90% improved anticorrosion performance and long-term stability. By optimizing components and synergistic system design, this work significantly enhances waterborne coatings’ anticorrosion efficiency, reduces raw material costs, and provides a scalable technical pathway for high-performance, eco-friendly anticorrosion coatings. Full article

Conventional anticorrosive coatings suffer from limitations of low solid content and rigorous surface pretreatment, posing environmental and cost challenges in field applications. In this study, a novel high-solid-content (>95%) epoxy-polysiloxane (Ep-PSA) ceramic metal coating was prepared that enables low-surface-treatment application. The originality lies in the synergistic combination of nano-sized ceramic powders, high-strength metallic powders, polysiloxane resin (PSA), and solvent-free epoxy resin (Ep), which polymerize through an organic–inorganic interpenetrating network to form a dense shielding layer. The as-prepared Ep-PSA coating system chemically bonds with indigenous metal substrate via Zn₃(PO₄)₂ and resin functionalities during curing, forming a conversion layer that reduces surface preparation requirements. Differentiating from existing high-solid coatings, this approach achieves superior long-term barrier properties, evidenced by |Z|_0.01Hz value of 9.64 × 10⁸ Ω·cm², after 6000 h salt spray exposure—four orders of magnitude higher than commercial 60% epoxy zinc-rich coatings (2.26 × 10⁴ Ω·cm², 3000 h salt spray exposure). The coating exhibits excellent adhesion (14.28 MPa) to standard sandblasted steel plates. This environmentally friendly, durable, and easily applicable composite coating demonstrates significant field application value for large-scale energy infrastructure. Full article

To evaluate the slip resistance of high-strength bolted friction-type connections subjected to different corrosion-protection treatments, calibration tests were performed on six representative faying-surface conditions: sand-blasted (uncoated), epoxy zinc-rich primer, waterborne inorganic zinc-rich coating, alcohol-soluble inorganic anti-corrosion anti-slip primer, a complete multi-layer protective coating system, and cold galvanizing. Fifteen test groups comprising 45 tensile specimens were examined to determine slip factors, which were then compared with values recommended in domestic and international design standards. The results show that sand-blasted surfaces (W type) exhibit stable slip factors of μ = 0.43–0.45; alcohol-soluble inorganic primer surfaces (S type) provide the highest slip resistance with μ = 0.49–0.51, representing an increase of approximately 13%–18% compared with sand-blasted surfaces; and cold-galvanized surfaces (D type) achieve favourable performance with μ ≈ 0.44. Waterborne inorganic zinc-rich surfaces (A type) yield μ ≈ 0.33, corresponding to a reduction of about 25%, and are suitable for non-slip-critical connections. In contrast, epoxy zinc-rich primers (C type) and complete multi-layer coating systems (X type) present lower slip factors of μ = 0.26–0.28 and μ ≈ 0.23, corresponding to reductions of approximately 35%–45% and about 50%, respectively, indicating that the X-type treatment is unsuitable for slip-critical applications. The influence of bolt diameter is limited, with slip-factor variations within 5%–8% under the same surface condition, and no statistically significant effect confirmed by two-way ANOVA. These findings provide a quantitative experimental basis for the design, classification, and future standardization of friction-type bolted connections with coated faying surfaces. Full article

This study explored the preparation of the rare earth complex phosphor Eu(PTA)_1.5phen, which was used to modify zinc-rich protective coatings. The methods employed in this study included FTIR spectroscopy, SEM, EDS, EIS, fluorescence spectroscopy, XRD, and XPS to examine the impact of varying concentrations of Eu(PTA)_1.5phen on Fe³⁺ sensing, fluorescence quenching, and the performance of the coating. The results showed that Eu(PTA)_1.5phen exhibits excellent fluorescence properties, with a maximum emission intensity of 1.8 × 10⁸ and a quantum yield of 89.26%. Fluorescence quenching by Fe³⁺ allows for the quantification of steel corrosion. Corrosion tests revealed that adding Eu(PTA)_1.5phen enhanced the compactness of the zinc-rich coatings. The optimal performance was obtained when using 3 wt.% Eu(PTA)_1.5phen, leading to a corrosion current density of 6.76 × 10⁻⁷ A/cm². The XRD and XPS analyses indicated that introducing Eu³⁺ does not influence the corrosion products present in the coating. This research showed that zinc-rich coatings enhanced with rare earth fluorescence not only safeguarded the steel substrate but also allow for the real-time tracking of Fe³⁺ concentrations in both the coating and the substrate. This approach offers a method for timely and effective corrosion prevention and corrosion identification, providing new insights for the development of advanced protective coatings and practical applications. Full article

Coating systems used for anticorrosion protection usually consist of a primer, intermediate layers, and topcoats. Zinc-rich primers, which serve as cathodic and barrier protection, are widely used for the corrosion protection of steel structures. Due to the fact that the functioning of the above-mentioned coatings is related to the conduction of galvanic current, these types of coatings are highly pigmented with zinc (up to 80 wt% in the dry coating). This may result not only in a deterioration of the performance of the coating system but also have a negative impact on the environment. Taking the above into account, solvent-based and water-based organic epoxy primers with zinc content reduced to approximately 50% have been developed. Zinc pigments of different shapes and with different surface treatments were used in the primers, as well as pigments without chemical treatment but with the addition of nanoparticles. It was found that, depending on the type of zinc pigment, both the developed solvent-based and water-based primers demonstrate good protective properties comparable to traditional zinc-rich coatings. Water-based paints tend to absorb more moisture compared to solvent-based systems, but their water uptake reversibility is limited. Moreover, the organic treatment of zinc flakes helps to improve this water uptake reversibility, improving the mechanical properties of coatings. Full article

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. Full article

The cathodic protection provided by epoxy coating/epoxy zinc-rich coatings on defective areas under atmospheric and immersion conditions was studied via a Q235 wire beam electrode (WBE), scanning electron microscopy, X-ray diffraction, and surface morphology analysis. The results showed that the cathodic protection processes under the two test conditions displayed significant differences. The effective protection time of the defective area under the atmospheric condition was 1.7 times that under the immersion condition. Compared with the immersion condition, zinc particles in zinc-rich coatings under the atmospheric condition exhibited higher cathodic protection efficiency. The possible activation mechanism of zinc particles under the two conditions was elucidated. Full article

To improve the corrosion inhibition of zinc-rich epoxy (ZRE) composite coatings and shed light on the influence of the spatial structure of graphene fillers on the coatings’ performance, three-dimensional graphene (3DG) and a conventional graphene sheet (G) were used to modify the ZRE composite paint, respectively. The effect of introducing the 2D G fillers on the anti-corrosion behavior of ZRE was studied comprehensively, and its optimal content was determined to be 0.5 wt%. Interestingly, it was found that, comparing with 2D graphene sheets, the corrosion resistance of the ZRE coating could be enhanced more significantly with incorporating even less 3DG. With introducing only 0.1 wt% 3DG, the corrosion current intensity of the resulting 3DG/ZRE coating was reduced to be about 1/10 that of the G/ZRE coating with the same graphene content and 27% of that of the optimized G/ZRE. The corrosion products of the coating were analyzed with the XRD technique. The results indicated that, in contrast to neat ZRE coating, Zn₅(CO₃)₂(OH)₆ was absent from the corroded 3DG/ZRE coating, confirming its improved long-term anti-corrosion performance. The porous interconnected framework and high crystallinity of 3DG could contribute to not only its facilely mixing with epoxy resin, but also its effective incorporation into the conductive network of zinc micro-flakes, thus enhancing the corrosion resistance of its ZRE coating at a lower content. The innovative technology to improve the anti-corrosion performance of the ZRE coatings via using the 3D graphene fillers should be capable to be extended to other 2D fillers, such as MXenes. Full article

Deteriorating concrete structures are repaired to restore their load-carrying capacity and enhance their appearance. As part of the repair procedure, the corroded reinforcing steel bars are cleaned by sandblasting, and a protective coating is applied to protect them from further corrosion. Generally, a zin-rich epoxy coating is used for this purpose. However, there have been concerns about the performance of this type of coating in protecting the steel due to the formation of galvanic corrosion, thus necessitating the need for developing a durable steel coating. In this study, the performance of two types of steel coatings, namely a zinc-rich epoxy and cement-based epoxy resin coating, was investigated. The performance of the selected coatings was evaluated by conducting both laboratory and field experiments. In the field studies, the concrete specimens were exposed to a marine exposure site for more than five years. The salt spray and accelerated reinforcement corrosion studies indicated that the performance of the cement-based epoxy coating was better than the zinc-rich epoxy coating. However, there was no visible difference between the performance of the investigated coatings in the reinforced concrete slab specimens placed in the field. It is suggested to use cement-based epoxy coatings as steel primers based on the field and laboratory data developed in this study. Full article

Atmospheric pressure plasma (AP) treatment, using an open-air jet of ionized CO_2, N₂, or air, was applied to AZ91D Mg alloy surfaces to investigate its effects on primer coating adhesion and corrosion resistance. The CO₂ and air AP treatments formed an O- and C-rich surface layer (Mg-O-C) consisting of agglomerated nanoparticles and pits with a depth of a few microns and increasing the surface roughness by 6–8 times compared with the reference 600 grit-finished surface. Then, three commercial primers, zinc phosphate (ZnP), chromate-containing epoxy, and MIL23377, were applied on the treated surfaces to evaluate the corrosion resistance associated with the coating adhesion. Microscopic analysis demonstrated stronger interlocking between the primer layer and the nano-/microrough Mg-O-C surface compared to the untreated (600 grit-finished) surfaces, indicating improved coating adhesion and corrosion resistance. Crosscut tests of the MIL23377 primer on the CO₂ and air AP-treated surfaces showed the highest level of adhesion, ASTM class 5B. Salt spray corrosion tests showed that after 8 days of exposure, the primer coatings on air AP-treated surfaces had corrosion areas that were more than four times smaller than that of the 600 grit-finished surface. The N₂ AP treatment showed similar adhesion enhancement. The preliminary operation expenses for AP treatment using CO₂, N₂, and air were estimated at USD 30.62, USD 35.45, and USD 29.75 (from an air cylinder)/USD 0.66 (from an air compressor) per m², respectively. Full article

In this research, methods of increasing the corrosion resistance of reinforced concrete were experimentally investigated. The study used silica fume and fly ash at optimized percentages of 10 and 25% by cement weight, polypropylene fibers at a ratio of 2.5% by volume of concrete, and a commercial corrosion inhibitor, 2-dimethylaminoethanol (Ferrogard 901), at 3% by cement weight. The corrosion resistance of three types of reinforcements, mild steel (STt37), AISI 304 stainless steel, and AISI 316 stainless steel, was investigated. The effects of various coatings, including hot-dip galvanizing, alkyd-based primer, zinc-rich epoxy primer, alkyd top coating, polyamide epoxy top coating, polyamide epoxy primer, polyurethane coatings, a double layer of alkyd primer and alkyd top coating, and a double layer of epoxy primer and alkyd top coating, were evaluated on the reinforcement surface. The corrosion rate of the reinforced concrete was determined through results of accelerated corrosion and pullout tests of steel-concrete bond joints and stereographic microscope images. The samples containing pozzolanic materials, the corrosion inhibitor, and a combination of the two showed significant improvement in corrosion resistance by 7.0, 11.4, and 11.9 times, respectively, compared to the control samples. The corrosion rate of mild steel, AISI 304, and AISI 316 decreased by 1.4, 2.4, and 2.9 times, respectively, compared to the control sample; however, the presence of polypropylene fibers reduced the corrosion resistance by 2.4 times compared to the control. Full article

At present, the common protection technology of power-transmission and transformation equipment is mainly coating protection and hot-dip zinc protection. However, due to the low adhesion of epoxy zinc-rich coating, and the poor compatibility with top paint, environmental pollution, complex processing, high energy consumption and other defects of the hot-dip zinc process, its development is limited. In view of the above deficiencies, new anti-corrosion coating materials and processes were investigated in this study. Zinc coatings and Al-Zn coatings were prepared on the C45 steel matrix by hot-spraying and cold-spraying processes. The macro appearance, micromorphology and phase composition analysis of the coatings were evaluated. The adhesion of the coating to the substrate after the salt-spray test was tested. The results showed that the hot dip zinc coating and hot spray zinc coating had obvious cracking after the salt-spray test. The surface structure of cold-sprayed Al-Zn coating was relatively dense after the salt-spray test. The critical load of the cold-sprayed Al-Zn coating after the salt-spray test was higher than that of the other two coatings. The corrosion resistance to salt spray of cold-sprayed Al-Zn coating was demonstrated to be better than the hot-dip zinc coating, and thus has great application prospects. Full article

Zinc-rich primers are among the most promising organic coating systems for improving the corrosion resistance of metals in the marine environment. However, the high zinc content results in poor coating adhesion, high cost, insecurity and pollution. To decrease the zinc dust content, the carbonaceous and polymer conductive additives carbon black (CB), conductive graphite (CG), multiwalled carbon nanotubes (MWCNT) and polyaniline (PANI) were introduced to partially replace the zinc dust in the primers. A comparative study of the anticorrosion performance of epoxy zinc-rich primer (ZRP) is presented herein to systematically discuss and elaborate on the effects of the different conductive additives. There were no blisters, rust or corrosion products presented on the coatings of the CB-modified series due to the good dispersion and conductivity of nanosized CB clusters, while the zinc corrosion products covered the surface of the MWCNT-modified series samples, which was attributed to the excessive electrical conductivity resulting in high consumption of zinc powder. The lamellar CG provided an additional blocking barrier for the coatings based on the maze effect. The transition from the intrinsic state to the doped state of PANI resulted in corrosion protection for the coatings depending on the cathodic and barrier function. The experimental results suggested that the formula with 2 wt.% CB and 67 wt.% zinc dust had the most promising anticorrosion properties, which was also demonstrated by the high R_ct and low CPE_dl values calculated according to the equivalent electrical circuit analyses. Full article

In this study, liquid polysulfide rubber was modified by silane coupling agent. New kinds of anti-corrosion coatings with salt spray resistance and strong adhesion to the steel substrate were obtained using the modified liquid polysulfide rubber, bimetallic filler, carbon nanotubes, and epoxy resin. Infrared and nuclear magnetic resonance confirmed the preparation of new modified liquid polysulfide rubber through coupling reaction between the epoxy group of silane compound and the sulfide group of the liquid polysulfide rubber. A 1440 h neutral salt spray test showed the coating to be completely free of rust and blisters. The corrosion diffusion width of the scribed area was only 1.7 mm. In addition, in a 3.5% by weight NaCl solution, the coating shows no blistering and no corrosion phenomena compared with zinc-rich epoxy paints (the added zinc content was only 28.6%). These tests confirmed that the new coating had a dense microstructure, strong adhesion to the steel substrate, good corrosion resistance, and anti-blister performance. The performance indicates that the coatings have potential for use in the atmosphere and underwater, which provides a better choice for long-term protection of marine projects such as ships, wharves, offshore platforms, and wind power structures. Full article