Protective Coatings Research Articles

Protective Properties of Silane Composite Coatings Modified with Poly(3,4-ethylenedioxythiophene) with Heteropolyacid on X20Cr13 and 41Cr4 Steel

This paper describes the methodology of the preparation and analyses of the structure and anticorrosion properties of silane coatings modified with poly(3,4-ethylenedioxythiophene) (PEDOT) with phosphododecamolybdic acid (PMo12). Protective coatings, consisting of vinyltrimethoxysilane (VTMS), PEDOT powder with PMo12 admixture (at different concentrations), and ethanol, were deposited on X20Cr13 and 41Cr4 steels by immersion. The physicochemical properties of these silane coatings (e.g., surface morphology, thickness, roughness, and adhesion to the substrate) were elucidated using a digital microscope, a Fourier transform infrared spectrophotometer with attenuated total reflectance, and various electrochemical diagnostic techniques. Protective properties were assessed in acidified sulfate solutions with and without chloride ions (pH 2). Experimental results have shown that this coating displayed the effective protection of steel against general and pitting corrosion, stabilized the corrosion potential in the passive state, and provided barrier protection.

Elastic Base with Protective Coating and Initial Stresses Under Action of Moving Load

Elastic Base with Protective Coating and Initial Stresses Under Action of Moving Load

Bibliographic Study Regarding Renewable Energy: Infrared Reflective Layer Made of Al<sub>2</sub>O<sub>3 </sub>Using HVOF Process

This bibliographic research explores the field of renewable energy by exploiting the potential of the High Velocity Oxygen Fuel Deposition (HVOF) method, an advanced thermal spray coating technology. HVOF involves propelling powder particles at remarkable speeds onto material surfaces, providing a means of applying protective coatings. This study explores the versatility of HVOF in creating protective coatings tailored for renewable energy applications. Specifically, the main coating targeted is the infrared reflective coating, made using alumina powders renowned for their exceptional attributes such as high strength, hardness, corrosion resistance and heat resistance, making them ideal for various components used in the renewable energy sector.

Effect of Combining Fungal and Flame-Retardant Coatings on the Thermal Degradation of Spruce and Beech Wood Under Flame Loading

Compliance with fire safety standards for wood is crucial for its application in the internal applications of buildings. This article focuses on monitoring the quality of protective coatings for wood under thermal loading conditions. The examined samples of spruce (Picea abies L. Karst.) and beech wood (Fagus sylvatica L.) were treated with selected fungicidal coatings based on dimethylbenzyl ammonium chloride. Following this, they were soaked in a ferric phosphate-based flame-retardant solution. Additionally, a portion of the samples was treated solely with the flame retardant. The effectiveness of the protective coatings was assessed through experimental thermal loading of the prepared samples. The testing method adhered to according to selected standards, which evaluate the ignitability of building materials when subjected to a small flame source. The experimental results, including the mass loss, mass loss rate, and time–temperature curves of the thermally loaded samples, demonstrated a significant influence of the selected coatings on thermal degradation. Notably, the fungicidal coating exhibited protective properties. Samples treated only with the flame retardant showed higher mass losses compared to those treated first with the fungicidal coating followed by the retardant. Additionally, differences were observed between the wood types, with beech samples exhibiting greater mass losses and higher mass loss rates than spruce.

Comparative flank wear and produced chips types analysis of CNMG 120408 indexable cutting inserts after machining hardened 1.6582 steel

IntroductionThe marking of interchangeable cutting inserts according to ISO 6987 does not include the know-how of cutting tool manufacturers in the design of chip-breakers or the application of coatings. These small differences have a key effect on the efficiency and service life of cutting tools and result in qualitative and quantitative differences in production, which is related to the reduction or increase in costs associated with the appropriate choice of cutting tool. The design of the inserts also affects the shape and size of the chips produced, which is important to monitor for a safe machining process and subsequent waste management. This research deals with the effect of selected factors on the tool life and the form of the chips produced.MethodsIndexable cutting inserts of the type CNMG 120408 from three different manufacturers were tested for their lifetime under identical cutting conditions (vc = 80 m s−1, ap = 1.5 mm, f = 0.3 mm·ot−1) on steel 1.6582 hardened to 40–44 HRC. These inserts are made of sintered tungsten carbide in a cobalt binder, coated with Al2O3 and TiCN layers. During machining, the wear of the main flank was continuously measured until the critical wear rate VBmax = 0.3 mm was reached. At the same time, the produced chips were continuously collected and analyzed in terms of their shape and size. The number of chips produced per 100 g of chips was calculated to obtain an analogous value indicating the total chip collection in terms of waste management. The SEM was used to identify both the types of coating layers present on the investigated inserts and the types of wear observed after reaching critical wear.ResultsThe longest lifetime was achieved by the PM 4325 insert coated by 11.5 ± 1.2 µm TiCN layer and 5.3 ± 0.3 µm Al2O3 layer with a time T = 19.5 min. The chips produced were in the forms of arch connected and arch loose and the average chip length was 27.9 ± 7.6 mm. The number of chips per 100 g produced by the PM 4325 was 1,494 ± 401 pieces, which was the lowest count of chips within the experiment (which is not optimal). The MP3 -WPP20S insert coated by 17.8 ± 0.4 µm TiCN layer and 15.1 ± 0.3 µm Al2O3 layer achieved lifetime T = 17.4 min even though it has twice the thickness of the coating compared to PM 4325. Produced chips in the forms of arch connected, arch loose and tubular short shape and the average chip length was 34.1 ± 5.5 mm, which was the worst chip length result within the experiment in terms of chip evaluation. The number of chips per 100 g produced by MP3 -WPP20S was 1,520 ± 401 pieces. The E-M GRADE T9325 insert coated by 7.2 ± 0.5 µm TiCN layer and 5.1 ± 0.2 µm Al2O3 layer achieved the shortest lifetime with a time T = 10.8 min. The chips produced were arch loose in shape, with an average chip length of 8.2 ± 0.7 mm. The number of chips per 100 g produced by the E-M GRADE T9325 was 2,392 ± 259 pieces, achieving the best result in the experiment in terms of chips produced. The achieved results are correlated with different combinations of thicknesses of Al2O3 and TiCN protective coatings revealed by SEM analysis.Discussion/ConclusionTogether with the geometrical nuances of the design of the different manufacturers, factor of combinations of coatings thicknesses has an influence on the variation of the wear progress and the achievement of a specific lifetime value of the cutting inserts. The experiment concludes that the thickness of the coating layers alone does not have a direct effect on the overall lifetime of the tool, and the approximate lifetime of the cutting edge cannot be predicted based on the parameters of the coating layers. When choosing a cutting tool, the manufacturer should carry out a test series for the specific material to be machined, despite the declaration of the composition and thickness of the coating layers. The analysis of the produced chips led to the conclusion that the wafers with a thinner coating layer, especially the Al2O3 layer, formed better chips in terms of their shape and size due to the different heat distribution during machining.

Identifying and Prioritizing Hazardous Chemicals in Construction Metal Structure Coating Systems: A Roadmap for Data-Driven Disease Prevention.

Occupational exposure as a painter was classified by the International Agency for Research on Cancer (IARC)as a Group 1 carcinogen (carcinogenic to humans) in 1989. Chemical agents responsible for cancers and other illnesses among industrial painters are not well-documented. The goal of this systematic review and synthesis was to document the chemistries of metal structure coating systems, summarize data gaps on occupational exposures and health effects among painters, and identify and prioritize hazardous chemicals to guide future exposure and occupational health studies, and ultimately disease prevention efforts. We reviewed coating products approved by the Northeast Protective Coating Committee (NEPCOAT) for use in steel bridges in New England, with a special focus on Part B of these reactive chemical systems, and related literature on exposures and health effects. From the review of safety datasheets (SDS), we identified 61 unique CAS numbers belonging to different Part B chemical groups of isocyanate- and epoxy-based formulations, including amine hardeners, solvents, nanomaterials, and other additives. The list of identified ingredients contained 14 potent sensitizers, two IARC Group 1 known carcinogens, and 7 IARC Group 2B possible carcinogens. Cancers of the lungs, urinary bladder, liver, kidneys, and gastrointestinal system, allergic contact dermatitis, lung fibrosis, and asthma were some possible disease endpoints. Existing occupational exposure studies focused on solvent exposures, while exposure and biomonitoring studies of amine hardeners and other ingredients of concern in these formulations are lacking. The list of chemicals of concern identified here, including sensitizers and carcinogens, can serve as a basis for analytical method development and field exposure assessment studies. A national multi-pronged strategy to reduce chemical exposures and health risks among construction painters is warranted, including research on exposure monitoring and reduction efforts, longitudinal epidemiological studies, and product reformulation.

Bimetal-Driven Nucleotide Nanosheets for Spontaneously Enhanced Antibacterial and Protective Coatings

Bimetal-Driven Nucleotide Nanosheets for Spontaneously Enhanced Antibacterial and Protective Coatings

Enhancement in Corrosion Resistance of Low-Carbon Steel via Surface Modification

This research investigated the corrosion resistance of surface layers on low-carbon steel exposed to a chloride environment at room temperature. This study systematically evaluated the effects of varying pack compositions, coating temperatures, and application durations on the characteristics of the deposited coatings. The potentiodynamic polarization corrosion test was employed to assess the wet corrosion behavior of the specimens. Elemental compositions and microstructural features were analyzed using energy-dispersive X-ray spectroscopy (EDX) in conjunction with scanning electron microscopy (SEM), providing insights into phase distribution. The chromizing, titanizing, and chromotitanizing treatments were conducted at temperatures of 900 °C, 1000 °C, and 1100 °C, respectively, with varying coating times. X-ray diffraction analysis revealed a complex arrangement of elements and compounds within the coatings, including Cr, Ti, Cr1.9Ti, FeTi, Al2O3, Cr2O3, TiO2, Cr1.36Fe0.52, and (Ti0.86)3.58. The study found that as the deposition duration increased, the coating thickness increased, comprising a thin inner layer and a substantially thicker outer layer. This layered structure resulted from the outward diffusion of Fe atoms and the inward diffusion of Cr and Ti atoms. Electrochemical analysis in a 3.5% NaCl aqueous solution indicated a marked enhancement in the corrosion resistance of the coated specimens compared to their uncoated counterparts. The potentiodynamic polarization tests confirmed that the protective coatings significantly reduced the corrosion rate, with performance influenced by both the temperature and duration of the deposition process. These findings highlighted the potential of tailored coating techniques to improve the durability and performance of low-carbon steel in corrosive environments.

Design of dual-functional Mg/Al layered double hydroxide for smart protective coatings

Although corrosion inhibitors are often added to protective coatings to hinder the corrosion at defect sites, the normal inhibiting pigments are prone to uncontrollable leaching of the active component, leading to fast exhaustion of anti-corrosion properties. Moreover, the protective coatings hide the corrosion, making it difficult to detect the initial degradation processes on the steel. Therefore, it is desirable to develop “self-healing” and “corrosion-sensing” smart solutions for long-term protection and early detection of the onset of corrosion. Herein, we demonstrate the intercalation of corrosion inhibitors and corrosion sensors into layered double hydroxides via an anionic-exchange process and surface modifications with rhodamine B derivative RB2. Electrochemical measurements showed that adding 8 wt% Mg/Al LDH-MoO42−-RB2 pigment in dry paint film provides the epoxy coating with self-healing ability in the event of microcracks for up to 120 h of exposure in salt spray chamber. In addition, pinkish spots were observed near the scribed line at 120 h of salt spray exposure, demonstrating that the added corrosion sensor provided early detection of corrosion upon exposure to Fe3+ ions. The results of this study will aid in reducing the risk of corrosion through self-healing and allow for the detection of corrosion for maintenance purposes, especially in the oil and gas industry.

Effect of argon and nitrogen environments on the structure and properties of protective cermet coatings based on titanium borides obtained by electric arc surfacing

The aim of this work was to enhance the mechanical and tribological properties of an alpha titanium substrate by forming a protective cermet coating on its surface. In this study, protective cermet coatings based on titanium borides were prepared by electric arc surfacing in a protective environment. Two types of protective environment were investigated during the surfacing process: (i) inert (argon) and (ii) reactive (nitrogen). The characteristic zones of the deposited layer were established depending on the environment used, and the coating-substrate transition zone was thoroughly examined. It was demonstrated that the formation of the transition zone results from the mutual diffusion of the molten material of the electrode material and the substrate. For the first time, the formation of TiB2-TiN eutectic in the form of whiskers 4-20 μm wide and 100-300 μm long distributed in the matrix of the Ti(B,N)x solid solution was established when forming a protective cermet coating in a nitrogen environment. The presence of this TiB2-TiN eutectic led to a significant increase in the hardness of the coating, up to 4.4 times, from 350 to 1530 HV. Tribological tests of surfacing coatings were conducted, and both 2D and 3D profiles of the wear grooves are presented, providing insight into the wear mechanism. It was found that the wear resistance of the cermet coating obtained in a nitrogen environment increased by 5.2 times, while in an argon environment it increased by 3.1 times as compared to the substrate without the protective cermet coating. The results indicate the potential of the developed protective cermet coatings for use in abrasive operating conditions.

Mathematical Modeling of Complex-Shape Forming of Ultrafine-Grained Ti Alloy and Subsequent Deposition of Protective High-Entropy Coatings

Mathematical Modeling of Complex-Shape Forming of Ultrafine-Grained Ti Alloy and Subsequent Deposition of Protective High-Entropy Coatings

Eco-friendly corrosion inhibition of steel using phenolic compounds from Cynara syriaca

This study evaluates the corrosion inhibition performance of the n-butanol (n-BuOH) fraction derived from Cynara syriaca on mild steel in acidic environments. The n-BuOH fraction achieved up to 94 % inhibition at 500 ppm, as assessed through gravimetric analysis, potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). Key phenolic compounds, including kaempferol, naringenin, myricetin, chlorogenic acid, and quercetin, were identified by UPLC-MS/MS. These compounds form stable flavonoid-metal complexes, as confirmed by UV–Vis spectroscopy. FT-IR and SEM-EDS analyses revealed the formation of protective coatings and interactions with the steel surface. Polarization curves indicate that the n-BuOH fraction acts as a mixed-type inhibitor, predominantly affecting the anodic reaction. The inhibition efficiency decreased from 93.89 % to 73.43 % with increasing temperatures. Thermodynamic analysis showed an increase in activation energy (Ea = 58.20 kJ/ mol) and a positive ΔH value of 56.17 kJ/mol, which can be attributed to the increased thickness of the double layer, enhancing the activation energy of the corrosion process. A Gibbs free energy (ΔG0ads) value of −25.48 kJ/mol confirms that the adsorption process is spontaneous and involves both physisorption and chemisorption. pKa analysis identified specific adsorption sites. This research underscores the potential of the n-BuOH fraction as a novel, eco-friendly corrosion inhibitor, offering valuable insights for sustainable corrosion control strategies.

Preparation and Characterization of Graphene and Carbon Nanotube Hybrid Polydimethylsiloxane Composites for Protective Coating Applications

In this work, the synergistic effect of graphene nanosheets (GNs), as well as multiwalled carbon nanotubes (MWCNTs), as reinforcing agents of polydimethylsiloxane (PDMS) was investigated, in order to explore the possibilities of designing composite materials, tailored for use in the field of coatings, which might be, in fact, a very interesting application. It was shown that the addition of GNs and MWCNTs in PDMS matrices significantly improves the thermal stability of the obtained nanocomposites, especially those reinforced exclusively with GNs. The tensile tests indicated that strength increased for all the examined composites. It was also observed that the Young’s moduli had an increasing trend, with the exception of the composites containing only GNs, while those reinforced solely with MWCNTs exhibited the best performance. The O2 permeability measurements revealed that the highest reduction in the permeability was observed in GN-MWCNT/PDMS composite membranes, in comparison to those reinforced only with graphene or carbon nanotubes. Dielectric relaxation spectroscopy showed that all the examined composites, and especially those of MWCNTs, possess electrical conductivity, apart from the samples reinforced exclusively with graphene. The electromagnetic shielding effectiveness was also improved at higher filler loadings, which is more evident in composites reinforced with MWCNTs. It was concluded that the improved properties of the above studied hybrid composites make them suitable for protective coating applications.

Electrochemical interaction behaviors between adjacent zinc-rich coating defects on steel structures under immersion and wet–dry environments

This study investigates the corrosion mechanism of carbon steel beneath zinc-rich coating (ZRC) defects to understand the mutual interference of carbon steel in atmospheric environments. First, electrochemical impedance spectroscopy (EIS) was conducted to determine the self-corrosion behavior of carbon steel under ZRC defects. Subsequently, a macrocell current tests were conducted under immersion and wet–dry environments to evaluate the electrochemical interaction effects at the location of coating defects. The results indicate that the electrochemical interactions between the ZRC defects are influenced by the sacrificial anode effect of Zn. Further, the interaction mechanisms between the steel substrates beneath the organic and inorganic ZRC defects were analyzed. The findings provide deeper insight into the behavior of steel structures in atmospheric environments, offering potential improvements in the design of protective coatings for infrastructure longevity.

Effect of CaO deposit on the oxidation kinetics of CoCrAlY alumina forming alloys

MCrAlY (M = Ni and/or Co) alloys are commonly utilized as protective coatings for a variety of metallic substrates, including Ni- and Co-based superalloys due to their outstanding resistance to corrosion and oxidation in harsh environmental conditions. In such environments, external deposits have the potential to compromise the oxidation behavior of these alloys. This work assesses the oxidation kinetics of three different CoCrAlY alloys that can form alumina, with and without CaO deposits. Thermal gravimetric analysis experiments were carried out at 1100 °C for 50 h in dry-air conditions. It was observed that the presence of CaO deposits resulted in an accelerated oxidation rate and hindered the formation of alpha-alumina. Upon exposure to CaO, the examination of cross-sections revealed the formation of varying layers of calcium aluminates through the chemical reaction between Al2O3 and CaO. The characterized alloys exhibited a significant increase in oxidation rate during the initial stage, and therefore, an analysis at short oxidation times (9 min) is included in this study. These results indicate the formation of calcium chromate and suggest a potential link to the content of the gamma phase, which could be responsible for the accelerated oxidation during the early oxidation stages.

Revolutionizing polymethyl methacrylate toughness: Achieving 190% improvement with nanocellulose reinforcement while maintaining optical clarity

Polymethyl methacrylate (PMMA) is widely used in applications requiring high transparency and durability, such as optical lenses and protective coatings. However, its inherent brittleness limits its application in high-impact environments. This study investigates the incorporation of cellulose nanocrystals (CNCs) into PMMA to significantly enhance its toughness without compromising its optical clarity. By reinforcing PMMA with CNCs, the nanocomposites exhibited a remarkable 190% increase in toughness while maintaining 90% optical transparency. The innovation lies in achieving a balance between toughness and transparency through controlled CNC dispersion within the PMMA matrix, which minimizes excessive bonding that could lead to brittleness. Proper CNC dispersion was achieved through in-situ polymerization, allowing the nanocrystals to interact with the polymer matrix through van der Waals forces rather than covalent bonds. This approach reduces stress concentration and mitigates the formation of defects in the polymer matrix, ultimately leading to a tougher, more flexible material. In addition to enhancing mechanical properties, this study underscores the importance of controlling CNC content to preserve the intrinsic optical transparency of PMMA. These findings open new possibilities for CNC-reinforced PMMA in advanced applications that demand high mechanical performance coupled with excellent optical properties, extending its use in fields such as medical devices, protective coatings, and transparent structural materials.

O IMPACTO DE MANIFESTAÇÕES PATOLÓGICAS DO CONCRETO NA DURABILIDADE E SEGURANÇA DAS ESTRUTURAS

This study analyzes the impact of pathological manifestations in reinforced concrete, emphasizing their effects on the durability and safety of structures. Common issues such as cracks, reinforcement corrosion, and spalling were investigated, along with their main causes, including design flaws, improper execution, poor maintenance, and adverse environmental conditions. Through a theoretical approach based on an extensive literature review, this research aimed to understand the origins and consequences of these pathologies and propose solutions to mitigate them. The findings reveal that pathological manifestations not only compromise structural integrity but also increase repair and maintenance costs throughout the service life of buildings. Aggressive environments, such as coastal zones or regions with significant temperature variations, were identified as aggravating factors, accelerating concrete deterioration and raising the risk of structural failures. Preventive measures, such as the use of high-quality materials, regular inspections, and protective coatings, proved essential to minimize the impacts of these pathologies. Furthermore, adopting proper practices during the design and execution stages significantly contributes to extending the service life of structures and ensuring user safety. In conclusion, pathological manifestations in concrete represent a critical challenge for civil engineering, requiring special attention from the initial construction phases to periodic maintenance. This study highlights the importance of combining technical knowledge with the implementation of best practices to preserve the functionality, safety, and aesthetic value of structures. It also underscores the need for future practical studies to further evaluate the effectiveness of various prevention and repair techniques, fostering sustainable development in the construction industry.

Fabrication of Hydrophilic Organosilicon Coatings and Study of Their Resistance to Factors Accompanying Corona Discharge

Modern power industry widely uses high-voltage overhead lines to transport electricity, which are characterized by problems of corona discharge and leakage currents, especially in rain and snow conditions. One approach to solve these problems is to create protective coatings that can reduce corona in adverse weather conditions. This paper presents a study of a hydrophilic organosilicon coating based on aminopropyltriethoxysilane and PEG-400 for aluminum wires. Studies conducted to assess the resistance of the coating to prolonged contact with water, UV radiation and an ozone-saturated atmosphere have shown that the hydrophilicity of the coating increases under effect of these factors, which improves its anti-corona properties. Thus, durability under operating conditions open prospects for use of the developed coating in the energy sector.

Protective coatings forming on the surface of fuel rod by high-speed laser cladding

Protective coatings forming on the surface of fuel rod by high-speed laser cladding

From Fossil to Bio-Based AESO–TiO2 Microcomposite for Engineering Applications

Environmental issues and the reduction of fossil fuel resources will lead to the partial or total substitution of petroleum-based materials with natural, raw, renewable ones. One expanding domain is the obtaining of engineering materials from vegetable oils for sustainable, eco-friendly polymers for different applications. Herein, the authors propose a simplified and green synthesis pathway for a thermally curable, acrylated and epoxidized soybean oil matrix formulation containing only epoxidized soybean oil, acrylic acid, a reactive diluent (5%) and just 0.15 mL of catalyst. The small amount of reactive diluent significantly reduced the initial system viscosity while eliminating the need for adding solvent, hardener, activator, etc. Both the thermally cured composite with a 2% TiO2 microparticle filler and its pristine matrix were comparably characterized in terms of structural, thermal, morphological, dielectric and wettability by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetry, scanning electron microscopy, broadband dielectric spectrometry and contact angle measurements. The 2% filler in the composite generated superior thermal stability via lower mass loss (48.89% vs. 57.14%) and higher degradation temperatures (395 °C vs. 387 °C), increased the glass transition temperature from −20 °C to −10 °C, rendered the microcomposite hydrophobic by increasing the contact angle from 88° to 96° and enhanced dielectric properties compared to the pristine matrix. All investigations recommend the microcomposite for protective coatings, capacitors, sensors and electronic circuits. This study brings new contributions to green chemistry and sustainable materials.