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In the process of high temperature service, the mechanical properties of cutting tools decrease sharply due to the peeling of the protective coating. However, the mechanism of such coating failure remains obscure due to the complicated interaction between atomic structure, temperature, and stress. This dynamic evolution nature demands both large system sizes and accurate description on the atomic scale, raising challenges for existing atomic scale calculation methods. Here, we developed a deep neural network (DNN) potential for Ti–N binary systems based on first-principles study datasets to achieve quantum-accurate large-scale atomic simulation. Compared with empirical interatomic potential based on the embedded-atom-method, the developed DNN-potential can accurately predict lattice constants, phonon properties, and mechanical properties under various thermodynamic conditions. Moreover, for the first time, we present the atomic evolution of the fracture behavior of large-scale rocksalt-structure (B1) TiN systems coupled with temperature and stress conditions. Our study validates that interatomic brittle fractures occur when TiN stretches beyond its tensile yield point. Such simulation of coating fracture and cutting behavior based on large-scale atoms can shed new light on understanding the microstructure and mechanical properties of coating tools under extreme operating conditions. [ABSTRACT FROM AUTHOR]

PVD technologies, including vacuum arc evaporation and DC-magnetron sputtering, have been utilized in industrial settings since the early 1980s for depositing protective coatings. These coatings encompass a range of materials such as metal nitrides, carbonitrides, oxides, oxynitrides, and DLC, serving diverse applications such as cutting and forming tools, automotive components, and decoration. Vacuum arc evaporation generates a highly energized and ionized particle flux toward the substrate, while "classical" gas-ion-dominated direct current magnetron sputtering (DCMS) has limitations in generating ionized and energetic species of the sputtered target material. The development of High-Power Impulse Magnetron Sputtering (HiPIMS) has exhibited significant potential in addressing DCMS's limitations by enabling the production of highly energetic particles. This innovation, with its industrial applicability for protective coatings, was introduced around 2010. This paper aims to provide an industrial perspective on HiPIMS, serving as a guide for scientists and engineers in comprehending and implementing HiPIMS solutions. It covers historical context and fundamental characteristics. Basic features as well as state-of-the-art configurations of PVD systems are also described. Graphical representations of experimental results illustrate HiPIMS features, including operational modes, deposition rate effects, thickness uniformity, and sustainability, particularly in terms of energy efficiency. The discussion focuses on the application prospects, advantages, and constraints of industrially applied HiPIMS protective coatings, emphasizing cutting and forming tools, within the context of the findings presented. [ABSTRACT FROM AUTHOR]

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 TiB 2 -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 TiB 2 -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. [ABSTRACT FROM AUTHOR]

High temperature corrosion and slag deposition significantly reduce the thermal efficiency and lifespan of biomass-fired boilers. Surface modification with protective coatings can enhance boiler performance and prevent commercial losses due to maintenance and damage. This review focuses on the development of corrosion-resistant coatings (CRCs) and anti-slagging coatings (ASCs) over the past decade. CRCs are explored through thermal spray processes that include arc spray, atmospheric plasma spray (APS), high-velocity oxygen fuel (HVOF), detonation gun (D-gun™), and cold spray. Studies on alloys, ceramics, and ceramic–metal composites are summarised, highlighting the high temperature corrosion prevention mechanisms and discussing new coating materials. ASCs are reviewed in the context of advancements via thermal spray and slurry spray methods. The mechanisms for slag reduction, testing methods to evaluate ASC effectiveness, and the necessary architecture for preventing slag deposition are examined. A lab-based rig simulating fly ash deposition onto water-cooled coating coupons for anti-slagging investigations is also presented. Further research is needed to develop and evaluate materials for ASCs effectively. [ABSTRACT FROM AUTHOR]

Silicon nitride ceramic (Si 3 N 4) for industrial applications is conventionally manufactured with sintering additives, and the properties of Si 3 N 4 change significantly based on the contents of these additives. In this study, we investigate the effects of laser shock peening (LSP) on Si 3 N 4 sintered with varying ratios of sintering additives. The Si 3 N 4 samples were sintered with a mixture of Y 2 O 3 , MgO, and SiO 2 sintering additives at 5, 7, 9, and 11 wt%. A Nd:YAG laser (wavelength = 532 nm, maximum pulse energy = 1.4 J, repetition rate = 10 Hz, pulse duration = 8 ns, beam diameter = 11 mm, top-hat profile) was used to irradiate the Si 3 N 4 samples. The samples were coated with a protective layer (100 μm thick aluminum foil) and a water layer to confine plasma. LSP of Si 3 N 4 with 5 % sintering additives resulted in a slight change in surface hardness but a 77 % decrease in surface compressive residual stress. In contrast, LSP of Si 3 N 4 with 11 % sintering additives led to a simultaneous increase in surface hardness (7.3 %) and surface compressive residual stress (67 %), indicating a significant difference in the effectiveness of LSP depending on the ratio of sintering additives. Additionally, the surface of Si 3 N 4 with 11 % sintering additives showed evidence of grain refinement after LSP. It was demonstrated that the bending strength of Si 3 N 4 with 11 % sintering additives increased by 15.2 %, and the depth of the fracture origin was significantly deepened. [ABSTRACT FROM AUTHOR]

Corrosion protection of metals is essential for a wide range of technological applications, and coating metal surfaces with protective materials is a commonly employed method to achieve this. Among these, TiO 2 coatings are extensively used due to their excellent photocatalytic properties, their applications in sensing and solar cells, and enhancing the corrosion and wear resistance of metal surfaces. Recent advancements have focused on the incorporation of carbide particles, such as B 4 C, to further improve the performance of TiO 2 coatings. In this study, TiO 2 coatings containing 0–3.25 wt% B 4 C were applied to a 316 L stainless steel substrates using the sol-gel method. The coatings were characterized by XRD and SEM-EDS analyses, and their wear and corrosion properties were evaluated using ball-on-disc wear tests and corrosion tests in NaCl solutions. The results demonstrated that lower concentrations of B 4 C led to improved wear resistance, likely due to the formation of a durable tribolayer, while higher concentrations reduced the wear resistance, attributed to increased oxidation and the formation of brittle phases. Corrosion resistance was enhanced in coatings containing 0.25 wt% and 1.25 wt% B 4 C, which can be attributed to the formation of protective B 2 O 3 phases. However, at higher B 4 C concentrations, the corrosion rate increased, primarily due to the presence of cracks in the coating structure. Overall, the addition of 0.25 wt% B 4 C to the TiO 2 coating significantly improved wear and corrosion resistance, indicating its potential as an effective additive for protective coatings. [ABSTRACT FROM AUTHOR]

Manufacturing technology has been refined and described for the fabrication of honeycomb-based bioresorbable networks for temporal bone replacement applications. Two novel techniques, digital light processing and investment casting, were utilized to produce customized, shape-optimized cellular constructs with additional orifices promoting tissue ingrowth during osteo-regeneration. For this purpose, a conventional magnesium casting alloy (AZ91) was chosen. Numerical simulations were conducted to predict the compressive behavior of the proposed biodegradable lightweight scaffolds. Spatial castings were adjusted to possess mechanical properties comparable to the ones of cortical or trabecular bones. Two kinds of protective coatings (plasma electrolytic oxidation and organic ones based on natural polyphenols from tea extract) were deposited and characterized. They can be utilized to control the degradation rate during exploitation to achieve a predictable implant lifespan. The elaborated layers aim to mitigate the rapid corrosion of magnesium substrates by prolonging their bioresorption time and thus expanding their applicability in osseointegration. To evaluate this assumption, immersion tests in phosphate-buffered saline were performed, showing better chemical resistance of PEO coating and as-cast sample (for both mass gain by below 1%), and visible increase in mass of sample coated with organic coating (increase by almost 5%). Compressive strength results from numerical approach were further validated by experimental compression tests, showing that PEO coating deteriorated compressive strength by almost 3%, and organic coating improved it by over 9%. Results achieved in numerical approach were better than expected for stiffer sample, and slightly lower for the one with bigger pores. [ABSTRACT FROM AUTHOR]

A natural nano-edible coating based on fish gelatin-rosemary essential oil was developed for the preservation of blunt snout bream (Megalobrama amblycephala) fillets. The results showed that the coating treatment effectively maintained the texture stability of the fish fillets, including appearance and water-holding capacity, significantly delayed lipid and protein oxidation, and inhibited microbial growth. On day 10, compared to the CK group, the TVB-N and TVC of the CT decreased by 41.46% and 31.36%, respectively. Proteomics was used to reveal the biochemical mechanisms affecting fish quality characteristics. Bioinformatics analysis of differential abundant proteins (DAPs) showed that the effects of the coating were related to the cellular process, skeleton structure, and enzymatic activity. Meanwhile, 65 DAPs which related to quality changes were further screened out, and most DAPs showed upregulation in coated fish fillets compared to the control, including myosin heavy chain, myosin-7, T-complex protein 1, isocitrate dehydrogenase (NADP (+)), 40S ribosomal protein, and HSPs, while Prdx-6 showed downregulation. It is believed that the coating delayed and prevented the generation of microbial degradation products and reduced the damage to the protein structure by suppressing microbial growth and protease activity, thereby stabilizing texture properties of refrigerated fish fillets. The shelf life of fillets during storage at 4 °C was significantly extended by at least 30%. The study provides an innovative method for the fish preservation and a theoretical basis for the protective effect of the coating on protein structures at the molecular level. [ABSTRACT FROM AUTHOR]

Durability is still a critical factor that limits solid oxide cell (SOC) technology industrialization. In order to maintain a good level of performance for the overall targeted lifetime of about 40 kh, the oxidation of the interconnects made of ferritic stainless steel and Cr volatilization from this material to the cell electrodes have to be restricted. CeCo-based coatings were applied by PVD HiPIMS on AISI441 alloy. Their ability to reduce the thickness of the poorly conductive formed oxide and improve Cr retention was studied at sample scale by measurements of weight gain and Cr content by ICP-OES after 5000 h of exposure in ambient air at 700 and 800 °C. In the testing conditions, post-test characterization by SEM/EDX showed that oxide scale thickness was reduced when coatings were applied compared to bare AISI441 steel. Moreover, the strong oxide scale spallation observed at 800 °C with bare AISI441 steel was avoided. Cr volatilization was also strongly decreased. Post-test SEM/EDX and ToF–SIMS characterization of a short stack integrating coatings on the air side in some repeat units (RU) confirmed the limited Cr diffusion in the strontium doped lanthanum manganite (LSM) contact layer when the coating is present after 5200 h of solid oxide electrolysis cell operation (SOEC). [ABSTRACT FROM AUTHOR]

Conductivity chromium‐free conversion coatings on aluminum substrates were achieved by utilizing Na2SnO3 and Mo/Ti solutions. The composition and morphology of the coatings were characterized using XPS, SEM, EDS, AFM, and Raman spectroscopies. The corrosion behavior of the coatings in 3.5‐wt% NaCl solution was investigated through a dynamic potential polarization method and EIS analysis. Mott–Schottky and UV–Vis analyses were used to determine the semiconductor properties of the coatings, including carrier concentration and band gap. The results revealed that the main components of the coating were Al2O3, SnO2, MoO3, and MoO2 and the coating presented a double‐layer structure, including a transition layer close to the substrate and a compact layer on the surface. The coating also exhibited the properties of a p‐type semiconductor. The electrical contact resistance value of adding Na2SnO3 decreased from 0.4331 to 0.1343 Ω/in2 (in 200 psi), while the band gap decreased from 2.281 to 2.232 eV. [ABSTRACT FROM AUTHOR]

Ni–P has been widely used as a protective coating for many substrates. The corrosion resistance of Ni–P in neutral solutions such as NaCl, or acidic electrolytes such as HCl and H2SO4, has been extensively studied. However, the corrosion behavior of Ni–P coatings in caustic media, such as KOH, has received much less attention. Typically, corrosion behavior is studied through the use of electrochemical methods with corrosion rates determined from corrosion currents and potentials measured from Tafel curves. In this work, the corrosion rates of Ni–P coatings, with P concentrations varying from 2 to 11 wt%, in highly alkaline KOH (11 M) are obtained directly through electron microscopy measurements of cross sections and subsequent correlation with electrochemical data. Phosphorus concentration affects the corrosion rate; corrosion rate increases with increasing P content, peaks out at about 6–8 wt% P, and then decreases with any further increase in P content. This behavior is correlated to internal stress levels developed in the coatings. [ABSTRACT FROM AUTHOR]

Stellite 6 is a superalloy primarily composed of cobalt, known for its exceptional resistance to corrosion and wear at elevated temperatures. The current investigation involved the application of a co-based Stellite 6 coating on SS 304 boiler heat exchanger steel using HVOF technology. The objective was to boost surface wear resistance against elevated temperature. Protective coatings are widely employed across various industries to enhance resistance to erosion and wear of engineering components. The corrosion behavior of coated and uncoated steel was assessed under various conditions, including impact velocity, impact angle, and time duration, using a high-temperature air-jet erosion tester. Microploughing, cracking cutting, and hard phase pull-outs were all erosion processes seen in the coatings. Among the samples that were tested, it was observed that the Stellite 6 coating applied on SS 304 exhibited the lowest erosion rate. This study aims to facilitate the selection and optimization of coating materials suitable for applications in industry that require enhanced resistance against erosion wear under high-temperature conditions. [ABSTRACT FROM AUTHOR]

Multifunctional robust protective coatings that combine biocompatibility, antifouling and antimicrobial properties play an essential role in reducing host reactions and infection on invasive medical devices. However, developing these protective coatings generally faces a paradox: coating materials capable of achieving robust adhesion to substrates via spontaneous deposition inevitably initiate continuous biofoulant adsorption, while those employing strong hydration capability to resist biofoulant attachment have limited substrate binding ability and durability under wear. Herein, we designed a multifunctional terpolymer of poly(dopamine methyacrylamide-co-2-methacryloyloxyethyl phoasphorylcholine-co-2-(dimethylamino)-ethyl methacrylate) (P(DMA-co-MPC-co-DMAEMA)), which integrates desired yet traditionally incompatible functions (i.e., robust adhesion, antifouling, lubrication, and antimicrobial properties). Direct normal and lateral force measurements, dynamic adsorption tests, surface ion conductance mapping were applied to comprehensively investigate the nanomechanics of coating-biofloulant interactions. Catechol groups of DMA act as basal anchors for robust substrate deposition, while the highly hydrated zwitterion of MPC provides apical protection to resist biofouling and wear. Moreover, the antimicrobial property is conferred through the protonation of tertiary amine groups on DMAEMA, inhibiting infection under physiological conditions. This work provides an effective strategy for harmonizing demanded yet incompatible properties in one coating material, with significant implications for the development of multifunctional surfaces towards the advancement of invasive biomedical devices. Multifunctional robust protective coatings have been widely utilized in invasive medical devices to mitigate host responses and infection. However, modified surface coatings often encounter a trade-off between robust adhesion to substrates and strong hydration capability for antifouling and antimicrobial properties. We propose a universal strategy for surface modification by dopamine-assisted co-deposition with a multifunctional terpolymer of P(DMA-co-MPC-co-DMAEMA) that simultaneously achieves robust adhesion, antifouling, and antimicrobial properties. Through elucidating the nanomechanics with fundamentally understanding the interactions between the coating and biomacromolecules, we highlight the role of DMA for substrate adhesion, MPC for biofouling resistance, and DMAEMA for antimicrobial activity. This approach presents a promising strategy for constructing multifunctional coatings on minimally invasive medical devices by tuning interfacial molecular asymmetricity to reconcile incompatible properties within one coating. [Display omitted] [ABSTRACT FROM AUTHOR]

Atomic layer deposition (ALD) can be used to fabricate protective coatings including moisture barrier layers for organic light emitting diodes, anticorrosion layers for photoelectrodes, and plasma-resistant coating for semiconductor manufacturing equipment, which necessitates the deposition of large and thick ALD films via batch ALD. However, batch ALD for the fabrication of large-area and thick coatings exhibits nonideal film growth, a phenomenon that cannot solely be explained by transient concentration distribution within the deposition chamber. This paper describes the application of precursor "exposure" (in the unit of Langmuir, or Pa s), defined as the integral of concentration over time, as a metric to assess the growth per cycle (GPC) distribution under nonideal ALD conditions, demonstrating that the local GPC correlates well with the cumulative precursor exposure at that site. Consequently, this measure can effectively predict the nonuniformity (NU) distribution of film thickness and facilitate the determination of optimal operating conditions that ensure maximal uniformity of exposure. Under this condition, the intrafilm NU of ALD-grown Al2O3 film (nominal thickness 300 nm) was reduced to 1.2%, and the interfilm NU is diminished to as low as 3.3%. These values represent reductions of 40% and 45%, respectively, compared to the NU levels observed under nonideal conditions (insufficient trimethylaluminum, TMA exposure downstream). The plasma etch rate of ALD-deposited films is merely 4.3 nm/min, representing a reduction of one-half compared to films deposited under nonideal conditions (9.8 nm/min) with overload TMA exposure downstream leading to chemical vapor deposition-like reactions. [ABSTRACT FROM AUTHOR]

Many next‐generation materials for Li‐ion batteries are limited by material instabilities. To stabilize these materials, ultrathin, protective coatings are needed that conduct both lithium ions and electrons. Here, we demonstrate a hybrid chemistry combining molecular layer deposition (MLD) of trimethylaluminum (TMA) and p‐hydroquinone (HQ) with oxidative molecular layer deposition (oMLD) of molybdenum pentachloride (MoCl5) and HQ to enable vapor‐phase molecular layer growth of poly(p‐hydroquinone) (PHQ)—a mixed electron and lithium ion conducting polymer. We employ quartz crystal microbalance (QCM) studies to understand the chemical mechanism and demonstrate controlled linear growth with a 0.5 nm/cycle growth rate. Spectroscopic characterization indicates that this hybrid MLD/oMLD chemistry polymerizes surface HQ monomers from the TMA‐HQ chemistry to produce PHQ. The polymerization to PHQ improves air stability over MLD TMA‐HQ films without crosslinking. Electrochemical measurements on hybrid MLD/oMLD films indicate electronic conductivity of ~10−9 S/cm and a Li‐ion conductivity of ~10−4 S/cm. While these coatings show promise for Li‐ion battery applications, this work focuses on establishing the coating chemistry and future studies are needed to examine the stability, structure, and cycling performance of these coatings in full Li‐ion cells. [ABSTRACT FROM AUTHOR]

ABSTRACT The potential capabilities of the x‐ray spectral analysis method and the efforts of many researchers have ensured its widespread use in industry and scientific research. X‐ray fluorescence analysis (XRF) is one of the non‐destructive methods widely used to determine the chemical composition of automobile catalysts, solar panels, coins, jewelry, and so forth. In recent years, the problems of studying gold and silver objects of artistic value have attracted great interest. This paper presents a review of work on determining the chemical composition and thickness of single‐layer and multi‐layer coatings of artifacts and other objects of study with surfaces of complex configuration using the ratio of the intensities of characteristic x‐ray radiation of α‐ and β‐lines. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) have garnered extensive attention owing to their excellent biocompatibility, elevated specific surface area, and facile functionalization, as well as their diverse methods of preparation. In recent times, CDs have been applied for anti‐corrosion and obtained some significant results. In this work, the preparation methods of CDs are first briefly introduced, and the relative merits of different approaches are highlighted. Subsequently, the application of CDs in the realm of corrosion inhibitors is discussed, and the corrosion inhibition effects and mechanism of nitrogen‐doped CDs, nitrogen and sulfur‐co‐doped CDs, as well as CDs functionalized with other elements and nitrogen‐co‐doped are summarized. Finally, the application of CDs and functionalized CD‐modified coatings for anti‐corrosion and their protective mechanism is analyzed in detail. This review summarizes recent progress in research related to CDs and heteroatom‐doped CDs in anti‐corrosion applications and anticipates the prospects and applications of CDs in corrosion protection. With their unique properties and versatile applications, CDs are expected to assume a progressively pivotal role in the advancement of cutting‐edge corrosion protection technologies. [ABSTRACT FROM AUTHOR]

ABSTRACT To control mango postharvest deterioration, an edible coating based on pectin, glycerol, and oregano essential oil (OEO) was developed using a three‐step process involving optimization, validation, and comparison with a commercial fungicide. An extreme vertices mixture design approach was initially used to optimize the pectin, glycerol, and OEO concentrations in the coating formulation. We evaluated the impact of the coating components on the respiration rate, quality parameters, and anthracnose disease of mangoes. The optimal coating composition was 3.91% (w/v) pectin, 0.57% (w/v) glycerol, and 0.52% (w/v) OEO, with a desirability value of 0.8998. Model validation demonstrated that the measured values for all parameters fit the prediction interval of 95%, and the relative error varied between 0.88% and 12.28%. Validation experiments of the optimal coating compared to untreated mango and mango treated with a commercial fungicide showed that the optimal coating delayed ripening and effectively controlled the incidence of anthracnose for 18 days at 14°C and 85% relative humidity. [ABSTRACT FROM AUTHOR]

The long-term operation of intermediate temperature-solid oxide fuel cells (IT-SOFCs) could be significantly influenced by the stability of the interconnect itself, especially, its oxidation resistance under the cathode environment. To effectively prevent Cr-volatilization and improve the interconnector performance, application of highly dense and stable protective coatings over the interconnector is indispensable. In this work, Ni-Co-based alloy protective coatings doped with Fe and Cu were applied onto the 441 interconnector via a novel high-speed laser cladding technology. The microstructure evolution, phase composition, oxidation resistance, electrical conductivity and mechanical properties of the coated steels were investigated at different oxidation stages at 800 °C. It was found that the Ni 33.8 Co 34 Fe 32.2 -coated steel shows the best oxidation resistance and electrical properties. The oxidation rate (k p) and ASR of Ni 33.8 Co 34 Fe 32.2 -coated steel is respectively 4.44 × 10−13 g2 cm−4 s−1 and 25.55 mΩ cm2, significantly lower than the uncoated steel and Ni 44.6 Co 44.7 Cu 10.7 -coated steel at the end of 1000-h test cycle. The resultant conductivity of the Ni 44.6 Co 44.7 Cu 10.7 and Ni 33.8 Co 34 Fe 32.2 -coated steels is approximately 7.8 and 4.1 S cm−1, respectively, which could meet the requirement for SOFC stacks. In addition, the nano-hardness of the Ni 33.8 Co 34 Fe 32.2 and Ni 44.6 Co 44.7 Cu 10.7 -coated steels was found to be 8.3 GPa and 8.8 GPa, respectively, through nanoindentation testing. The improved surface hardness is attributed to grain refinement and increased oxide content on the coating surface. The results indicated that the Ni-Co-based alloy coatings effectively improved the long-term stability and mechanical property of the 441 interconnector under the SOFC cathode environment. [Display omitted] [ABSTRACT FROM AUTHOR]

A series of Ce4+-doped Pr 2 Zr 2 O 7 ceramics were produced using a solid reaction method to utilize novel ceramic materials as potential candidates for thermally protective coatings. The effects of Ce4+ doping on the phase composition and mechanical, infrared radiative, and thermophysical properties were studied in detail. The results indicated the good phase stability and sintering resistance of the Pr 2 (Zr 1−x Ce x) 2 O 7 ceramics. Moreover, Ce4+-doped Pr 2 Zr 2 O 7 bulk materials exhibited higher infrared emissivity (0.904) at wavelengths of 3–5 μm and 1000 °C for Pr 2 (Zr 0.5 Ce 0.5) 2 O 7) owing to the introduction of impurity energy levels. Pr 2 (Zr 0.7 Ce 0.3) 2 O 7 exhibited an appropriate average coefficient of thermal expansion of 12.4 × 10−6 K−1 and a low thermal conductivity of 1.14 W m−1 K−1 at 1000 °C, owing to the reduction of lattice energy and the presence of more oxygen vacancies and substitution atoms. [ABSTRACT FROM AUTHOR]

Epoxy-nanomaterials offer a promising solution to combat corrosion threatening civil infrastructure. To examine the impact of nano silica on corrosion resistance, varying amounts of nano silica, ranging from 0.0 to 3 wt%, were introduced into the epoxy matrix. Mechanical properties were studied through studying the dog-bone tensile strength and tribological aspects were assessed through mass loss abrasion tests. Corrosion resistance performance was studied using electrochemical impedance spectroscopy (EIS) and salt spray tests. Nano structure of the coated specimens was studied after salt spray tests using SEM-EDX analysis. Micro Chromatography (M-Ct) technique was employed to investigate the pore formation in the epoxy matrix. Besides, atomic force microscopy (AFM) was introduced to study surface roughness. The test results displayed a notable improvement (5–10 %) in tensile strength upon the introduction of nano silica. Taber tester results showed a reduction in mass loss with the addition of nano silica. Electrochemical impedance spectroscopy (EIS) studies further established a significant increase in corrosion resistance, having an impedance of 12 GOhm.cm2 for epoxy matrix samples containing 2.5 % nano silica after a 768-h salt spray test. SEM-EDX analysis revealed the absence of iron content in the epoxy matrix reinforced with uniformly distributed nano silica. Surface roughness assessments illustrated that nanolaminates contributed to an increase in overall roughness, minimizing surface irregularities in the epoxy matrix. Micro-CT scanning results proposed a decrease in epoxy matrix porosity upon the addition of nano silica. AI based prediction model helped to understand the relationship between surface roughness and corrosion. In summary, the experimental findings suggest valuable insights for future advancements in the development of protective coatings for worldwide civil infrastructures. [ABSTRACT FROM AUTHOR]

Rare earth ytterbium monosilicate (Yb 2 SiO 5) is one of the most ideal candidates for environmental barrier coatings. In this paper, Yb 2 SiO 5 coating was successfully fabricated by atmospheric plasma spraying technology. The effect of main gas flow rate and spraying powder composition on the microstructure and phase composition of Yb 2 SiO 5 coating were systematically investigated to solve the volatilization of SiO 2 during plasma-spraying process. The results showed that Yb 2 SiO 5 coating was relatively dense with the less internal defects under the main gas flow rate of 35 L/min, and the main gas flow rate from 30 L/min to 40 L/min had no significant effect on the melting effect of spraying powder and the porosity of coating. Yb 2 SiO 5 coating was composed of Yb 2 O 3 , Yb 2 SiO 5 two crystal phases and amorphous phase. The phase composition of coating was not affected by the change of main gas flow rate. After heat-treatment at 1400 °C for 20 h, Yb 2 SiO 5 crystal phase precipitated from the coating, and the content of Yb 2 SiO 5 phase reached 74.29 mol%, and the remaining phase was Yb 2 O 3 phase. The Yb 2 SiO 5 -25.71 mol% SiO 2 coating was still dense, the content of Yb 2 SiO 5 crystal phase was up to 97.76 mol% after heat-treatment, and the content of Yb 2 Si 2 O 7 phase was only 2.24 mol%, indicating that excessive addition of a certain amount of SiO 2 could compensate for the volatilization of SiO 2 , so as to prepare Yb 2 SiO 5 coating with approximate stoichiometric ratio. [ABSTRACT FROM AUTHOR]

Sustainably enhancing condensation heat transfer performance is a major challenge in thermal management and energy systems, since typical condensation enhancement methods (i.e. , dropwise condensation with low surface energy coatings) have limited lifetime/durability, restricted compatibility with working fluids, and sustainability concerns due to the coating composition (e.g. , fluorinated compounds). The robust and scalable capillary-enhanced filmwise condensation mode presented in this work demonstrates high heat transfer coefficients for water and low surface tension liquids condensing in a porous wick. Thin porous wicks offer the highest enhancements in heat transfer, however such thin porous wicks have thickness-dependent permeability, and the effective liquid thickness of the wick depends on the shape of the liquid-vapor interface. In this study, we leverage a spatially-discretized porous media model to characterize the effect of the wick thickness on condensation heat transfer performance. The model uses a spatially-varying permeability that depends on the local liquid-vapor interface shape/curvature and the resulting effective wick thickness. We apply this model to investigate the correlation between the heat transfer enhancement and various geometric factors, which enables the design of optimal porous structures for relevant phase-change application. We also predict favorable enhancement in condensation performance with a few common hydrocarbon and fluorocarbon fluid refrigerants. This study provides fundamental insight into the effects of the shape of the liquid-vapor interface on the phase-change performance in the capillary-enhanced filmwise condensation mode. [ABSTRACT FROM AUTHOR]

Seed coating with fungicides is a common practice in controlling seed-borne diseases, but conventional methods often result in high toxicity to plants and soil. In this study, a nanoparticle formulation was successfully developed using the metal–organic framework UiO-66 as a carrier of the fungicide ipconazole (IPC), with a tannic acid (TA)-ZnII coating serving as a protective layer. The IPC@UiO-66-TA-ZnII nanoparticles provided a controlled release, triggered and regulated by environmental factors such as pH and temperature. This formulation efficiently controlled the proliferation of Fusarium fujikuroi spores, with high penetration into both rice roots and fungal mycelia. The product exhibited high antifungal activity, achieving control efficacy rates of 84.09% to 93.10%, low biotoxicity, and promoted rice growth. Compared to the IPC flowable suspension formula, IPC@UiO-66-TA-ZnII improved the physicochemical properties and enzymatic activities in soil. Importantly, it showed potential for mitigating damage to beneficial soil bacteria. This study provides a promising approach for managing plant diseases using nanoscale fungicides in seed treatment. Highlights: IPC-loaded UiO-66 with tannic acid-ZnII shells for precision management of rice seedling disease through intelligent, responsive release. A pH- and temperature-sensitive, controlled-release nanoparticle system was developed. Tannic acid-ZnII-modified nanoparticles penetrate into rice roots and fungal mycelium. Nanoparticles provide better control of Fusarium fujikuroi and promote seedling growth. Nanoparticles reduce the pollution of soil environment by conventional seed coatings. [ABSTRACT FROM AUTHOR]

Textile-based SrAl 2 O 4 (SAO): Eu2+, Dy3+ composite material offers functional, aesthetic, and safety benefits, making it a valuable innovation with diverse applications in various industries. The susceptibility of textile-based SAO: Eu2+, Dy3+ composite material is degraded with repeated washing, which can diminish its luminescent properties over time. Our major goal was to create a cloth with durable photoluminescent qualities by incorporating waterborne polyurethane (WPU) as a protective coating that could generate light constantly without a light source. Through a systematic approach involving the synthesis of photoluminescent SAO: Eu2+, Dy3+ particles and their integration into a cloth substrate with waterborne polyurethane, a durable cloth with enhanced durability, protection, and adhesion properties are achieved. Cotton fabric and a rotary screen-printing machine were used to apply a thin, translucent layer of glow-in-the-dark pigment to produce the photoluminescence characteristics of the developed cloth revealing efficient light absorption and emission behavior, with emission spectra centered around absorption wavelength between 560 nm and 880 nm, with a 500 nm emission peak, exhibiting of the presence of Eu2+ and Dy3+ activator ions. In addition, to assess the comfort of the treated cotton fabric, a fabroOmeter test was conducted, that provided insights into its overall comfort level. Furthermore, the cloth demonstrates excellent stability and longevity of photoluminescence under various environmental conditions, making it suitable for applications requiring high visibility, safety signage, decorative elements, and apparel wear. This research underscores the potential of polyurethane-enhanced photoluminescent textiles as versatile and sustainable solutions for diverse practical applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The development of new encapsulating coatings for flexible solar cells (SCs) can help address the complex problem of the short lifespan of these devices, as well as optimize the technological process of their production. In this study, new laminate-type protective composite coatings were prepared using a silicon oxynitride thin-film matrix obtained by curing the pre-ceramic polymer perhydropolysilazane (PHPS) through two low-temperature methods: (i) thermal annealing at 180 °C and (ii) exposure to UV radiation at wavelengths of 185 and 254 nm. Single-walled carbon nanotubes (SWCNTs) were used as fillers via dry transfer, facilitating their horizontal orientation within the matrix. The optical, adhesive, and structural properties of the matrix films and SiOxNy/SWCNT composite coatings, along with their long-term stability, were studied using Fourier transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, HR-SEM, spectral ellipsometry, and a progressive-load scratch test. In this work, the optical constants of PHPS-derived films were systematically studied for the first time. An antireflection effect was observed in the composites revealing their two-component nature associated with (i) the refractive index of the SiOxNy matrix film and (ii) the embedding of a SWCNT filler into the SiOxNy matrix. The curing method of PHPS was shown to significantly affect the resulting properties of the films. In addition to being used as protective multifunctional coatings for SCs, both SiOxNy/SWCNT composites and SiOxNy matrix films also function as broadband optical antireflective coatings. Furthermore, due to the very low friction coefficients observed in the mechanical tests, they show potential as scratch resistant coatings for mechanical applications. [ABSTRACT FROM AUTHOR]

Zirconium nitride (ZrN) coatings were deposited on the stainless steel using multi-arc ion plating under varying nitrogen partial pressures (P N) ranging from 0.5 to 3.5 Pa. The effect of phase composition, microstructure, and surface morphology on the corrosion resistance and conductivity of the ZrN-coated stainless steel in a simulated proton exchange membrane fuel cell (PEMFC) cathode environment was systematically explored. XRD and TEM revealed that the columnar-structured ZrN coating mainly comprised the fcc-ZrN phase. The Zr 3 N 4 phase was discovered near the substrate during coatings prepared at low nitrogen partial pressures. Surface defects were reduced at nitrogen partial pressures exceeding 2.5 Pa. The ZrN coating exhibited enhanced corrosion resistance and conductivity (ZrN-3.5, E corr = 0.307 V, I corr = 2.085 × 10−7 A/cm2, R ct = 1.125 × 105 Ω·cm2) compared to bare stainless steel in the simulated PEMFC cathode environment. The presence of surface defects influenced the corrosion resistance, while differences in conductivity were related to the phase composition and microstructure of the coating. Thus, the findings indicate that ZrN coatings prepared under optimal deposition conditions can have potential applications in PEMFC bipolar plates. [ABSTRACT FROM AUTHOR]

Biomedical coatings were elaborated by pulsed electrodeposition with hydrogen peroxide (H 2 O 2) into electrolytes on Ti 6 Al 4 V substrates, and the effect of H 2 O 2 concentration on the electrolyte and the heat treatment was studied. The experimental procedures employed in this study produce a consistent hydroxyapatite coating. This coating is well-suited for use in bio-implants, as it enhances the integration of the implant with surrounding bone tissue and improves the mechanical performance. The coatings' surface morphology and chemical composition were assessed using scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDXS) for x-ray microanalysis. X-ray diffraction (XRD) was also utilized to identify the phases and composition of the coatings. Nanoindentation and scratch tests were conducted to analyze the nanomechanical properties and adhesion behavior. Potentiodynamic polarization was employed in the Ringer solution to evaluate the corrosion resistance and replicate the conditions of the human body environment. The results of our thorough investigation revealed that employing pulsed electrodeposition with 9 % H 2 O 2 in the electrolyte, combined with subsequent heat treatment, facilitated the creation of coatings comprising two distinct phases: stoichiometric hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP). Our meticulous research underscores the significance of this process in achieving these specific coating compositions. Under these tests listed above, this composite demonstrated favorable mechanical properties (E = 30.45 GPa and H = 72.2 MPa). It also exhibited superior scratch adhesion and a critical load of 23 MPa and 12 N, respectively. Additionally, an improvement in tribological comportment was observed, and the wear volume decreased from 4.15 106 μm3 to 2.44 106 μm3. The HAP coating heat treated with 9 % H 2 O 2 exhibited the highest corrosion resistance, with E corr at −0.189 V/SCE and i corr at −1.11 μA cm−2 [ABSTRACT FROM AUTHOR]

[Display omitted] Stone-built cultural heritage faces threats from natural forces and anthropogenic pollutants, including local climate, acid rain, and outdoor conditions like temperature fluctuations and wind exposure, all of which impact their structural integrity and lead to their degradation. The development of a water-based, environmentally-friendly protective coatings that meet a combination of requirements posed by the diversity of the substrates, different environmental conditions, and structures with complex geometries remains a formidable challenge, given the numerous obstacles faced by current conservation strategies. Here we report the structural, electrical, and mechanical characterization, along with performance testing, of a nanostructured hydrophilic and self-healing hybrid coating based on hydroxyapatite (HAp) nanocrystals and polyelectrolyte multilayers (PEM), formed in-situ on Greek marble through a simple spray layer-by-layer surface functionalization technique. The polyelectrolyte-hydroxyapatite multilayer (PHM) structure resembled the design of naturally forming trabecular bone, attained at a short procedural time. It exhibited chemical affinity, aesthetical compatibility and resistance to weathering while offering reversibility. The proposed method is able to generate micron-sized coatings with controlled properties, such as adhesion and self-healing, leading to less weathered surfaces. Our results show that the PHM is a highly effective protective material that can be applied for stone protection and other similar applications. [ABSTRACT FROM AUTHOR]

The effect of the spatial arrangement in the physical vapor deposition (PVD) chamber on the composition and properties of coatings is considered using the example of the deposition of the (Ti,Al)N coating. The proposed method is one of the ways (along with varying the arc current of the cathodes and the bias voltage, as well as using alloy cathodes) to change the ratio of elements in the coating, and achieves this across a wide range of values. The three samples were located, respectively, opposite the evaporator with a titanium cathode, opposite the evaporator with an aluminum cathode and in an intermediate position between the two evaporators. The coating was deposited without rotating the turntable. The aluminum content in the coatings decreases from 94.2 at.% for the sample located directly opposite the evaporator with an Al cathode to 10.3 at.% for the sample located opposite the evaporator with a Ti cathode. In the coating deposited on the sample located opposite the aluminum cathode, the formation of a nitrided layer with a thickness of about 250 nm was observed in the substrate. The maximum hardness (32.3 ± 1.7 GPa) belongs to a coating on the sample occupying an intermediate position. The coating on the sample located opposite the aluminum cathode has a hardness of 16.7 ± 0.8 GPa. The coating hardness on the sample located opposite the titanium cathode is 28.5 ± 1.1 GPa. The best fracture strength in the scratch test was observed for the coating on the sample occupying an intermediate position. The nature of the coating fracture in the scratch test was studied. A sufficiently high-quality coating can be obtained without rotating the turntable, and the coating composition can be controlled by changing the position of the sample relative to the evaporators. [ABSTRACT FROM AUTHOR]

Featured Application: This research work demonstrates that undoped a-C:H sputtered coatings can effectively inhibit the metallic release from medical-grade 316L stainless steel in acidic artificial saliva without a significant change in the microstructural characteristics. Moreover, the in vitro biocompatibility with macrophages and/or fibroblasts was significantly improved. In opposition, the a-C:H:N system seems to be unfavorable, even for low N content up to 10 at.%. Hydrogenated amorphous carbon (a-C:H) has been considered a promising biocompatible coating to protect metallic alloys against corrosion for medical applications, namely orthodontics. However, there is still no optimal solution for this biomedical field; hence, the investigation remains open. In this work, the effect of a nonmetallic doping element (N) on sputter-deposited a-C:H coatings was studied concerning both salivary corrosion and cytotoxicity behavior. After a 30-day corrosion test in an acidic modified Fusayama-Meyer artificial saliva, metal release from both coated and uncoated 316L stainless steel (SS) substrates was quantified. Tests on the corrosion extracts were then performed by using monocultures of macrophages and fibroblasts, and their coculture; and cell viability was evaluated via the MTT test. Results show an overall inhibition of the SS corrosion, which enhanced the in vitro biocompatibility with a minimal effect on the coatings' microstructure. Among all the coatings tested, the undoped a-C:H coating performed the best, whereas an increase in N doping led to poorer protection against metal dissolution and a subsequent slightly lower biocompatibility. The findings corroborate that selecting the nonmetallic element N for doping C-based coatings is not a good choice for this biomedical field, even at low contents up to 10 at.%. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals (CNCs) have received an abundance of attention because of their distinctive chiral nematic structure and exceptional optical characteristics. However, the use of free‐standing films is constrained by the inherent stiffness and brittleness. In this work, CNC films with robust mechanical properties are prepared by simply coating them with polymeric spherulites. Maleic anhydride‐grafted polypropylene (PP‐g‐MA) is used to coat CNC films. The optical properties of coated films were also analyzed using polarized optical microscope. It is observed that the circular extinction patterns for the coated CNC film were created by the radial symmetry of banded spherulites, which were responsible for the perception of the optical transmission bands of the CNC film. Interfacial anchoring plays a crucial role in enhancing the overall performance and properties of the composite system. The future development of numerous portable functional components needing improved optical, mechanical, and thermal qualities of CNC films is made possible by this protective coating approach. [ABSTRACT FROM AUTHOR]

Crystallization fouling, a process where mineral scales form on surfaces, is of broad importance in nature and technology, negatively impacting water treatment and electricity production. However, a rational methodology for designing materials with intrinsic resistance to scaling and scale adhesion remains elusive. Here, guided by nucleation physics, this work investigates the effect of coating composition and surface structure on the nucleation and growth mechanism of scale on metallic heat transfer surfaces nanoengineered by large‐area techniques. This work observes that on hydrophilic nanostructured copper, despite its significantly enlarged surface area compared to smooth surfaces, scale formation is substantially suppressed leading to sustained, efficient cooling performance. This work reveals the mechanism through thermofluidic modeling coupled with in situ optical characterization and show that surface bubble formation through degassing is responsible for generating local hot spots enhancing supersaturation. This work then demonstrates a scalephobic nanostructured surface which reduces the accumulated surface scale mass 3.5× and maintains an 82% higher heat transfer coefficient compared to superhydrophobic surfaces with corresponding energy conversion savings. This work not only advances the understanding of fouling mechanisms but also holds promise for practical applications in industries reliant on efficient heat transfer processes. [ABSTRACT FROM AUTHOR]

This review examines the state‐of‐the‐art sensors and sensing technologies employed for structural health monitoring (SHM) in aerospace composites, highlighting the shift from conventional nondestructive evaluation techniques to real‐time monitoring systems. The review discusses the challenges associated with composite materials, such as their anisotropic nature and susceptibility to invisible damage, and how these challenges have driven the improvement of SHM techniques. Fiber‐optic sensors, including interferometric, distributed, and grating‐based sensors, are analyzed for their high sensitivity and multiplexing capabilities, making them suitable for distributed sensing applications. Piezoelectric sensors are evaluated for their effectiveness in both active and passive damage detection methods. At the same time, piezoresistive self‐sensing systems are explored for their potential to integrate sensing directly into composite materials. The review also addresses the challenges encountered in implementing SHM systems. It suggests solutions like protective coatings, advanced data processing algorithms, and modular system design to overcome these challenges. In conclusion, this review provides a comprehensive overview of the current SHM technologies for aerospace composites, underscoring the need for sustained research and development to improve sensor technology, expand data processing capabilities, and ensure seamless integration with aircraft systems, thus contributing to the safety and efficiency of aerospace operations. [ABSTRACT FROM AUTHOR]

New anodes consisting of zirconium-doped PbO2 coating, growth on titanium dioxide interlayer, were deposited on titanium substrates using spin coating method and have been tested for the removal of ampicillin, a β-lactam antibiotic, from water. Morphological, structural, and electrochemical properties of the prepared coatings were characterized by scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray diffraction (XRD), and electrochemical impendence spectroscopy (EIS). Results showed that the incorporation of zirconium dopant had a noticeable modification in the morphology of anodes. An increase in the surface roughness and the specific active area were observed with Ti/TiO2/PbO2- 10% Zr electrode compared to other anodes. The electrochemical measurements indicated that the anode doped with 10% Zr showed a more protective coating performance than the undoped and 20% Zr-doped PbO2 electrodes. The experiments on ampicillin degradation revealed that doped lead dioxide anodes have excellent electrocatalytic activity. The major byproduct generated during anodic oxidation treatment has been identified as ampicilloic acid by liquid chromatography-mass spectroscopy (LC–MS) analysis. Results demonstrated that Ti/TiO2/PbO2- 10% Zr anode presents the best removal rate of ampicillin with a minimum intermediate amount, which leads to conclude that 10% is the optimum percentage of zirconium dopant for antibiotic wastewater treatment. [ABSTRACT FROM AUTHOR]

In almost all electrochemical systems for electrochemiluminescence (ECL) analysis, electrodes are connected with an external power source, either directly or via wireless energy transfer circuit. That is inconvenient and makes some applications impossible. Herein, we use galvanized iron with two different metals as both power source and electrodes to achieve a self‐powered ECL and exploit ECL for the imaging of the corrosion of protective coating of widely used metal (e.g. galvanized iron) for the first time. The self‐powered ECL enables the visualization of the deterioration of galvanic coating on iron using a smartphone and the detection of ascorbic acid with a linear range of 0.5–100 μM and a limit of detection of 0.31 μM. The devices based on self‐powered approach do not require external power supply, thus effectively reducing their volume and cost. The self‐powered ECL holds great promise for metal corrosion imaging and analytical applications. [ABSTRACT FROM AUTHOR]

Understanding the damage evolution of thermal barrier coatings (TBCs) is crucial for optimizing TBCs systems and predicting service lifetime. This study investigates the correlation between mechanical properties and the thermal cycle lifetime of TBCs with conventional air plasma sprayed (APS) and micro-agglomerated particles embedded (EMAP) plasma sprayed structures, utilizing the Gd 2 Zr 2 O 7 (GZO) and GSc 0.075 Ce 0.3 Z (GSCZ) material systems. The damage evolution and cracking behavior of TBCs with varying material compositions and coating structures are evaluated using a combination of three-point bending tests and digital image correlation (DIC) techniques. Experimental results demonstrate that the thermal cycling lifetime of conventional APS TBCs correlates positively with the fracture toughness of the ceramic layer. Specifically, the conventional APS GSCZ coating with a fracture toughness of 1.12 MPa/m1/2 and the APS GZO coating with a fracture toughness of 0.97 MPa/m1/2 exhibit lifetimes of 34 cycles and 31 cycles, respectively. Moreover, the EMAP structural design exhibits notable advantages in enhancing the thermal cycle lifetime of TBCs across all material systems. DIC results confirm that strain accumulation during interface cracking of EMAP TBCs is effectively mitigated compared to conventional APS TBCs. The loose and porous characteristics of this structure significantly improve the compliance and interface fracture toughness of the TBC system, thereby alleviating TBC failure dominated by interface cracking. [ABSTRACT FROM AUTHOR]

Identifying the function and composition of the protein corona (i.e., the set of host proteins interacting with nanoparticles) is considered a crucial step in the development of nanoparticles for medical and pharmacological applications. Evidence suggests that host proteins can alter NP stability, biocompatibility, and pharmacokinetics features. Therefore, in this review, we provide an updated conceptual, methodological, and experimental guideline for the study of the NP protein corona. We surveyed recent literature (2009–2024) focusing on in vitro and in vivo studies. We show that several methods, including shot-gun proteomics, protein identification after in-gel digestion, and TMT proteomics, must be carefully applied and integrated to shed light on this complex phenomenon. Hence, we discuss in detail the relative protocols, highlighting the importance of the experimental conditions, ranging from the administration route to basic, but determinant, parameters like the kind of biological host fluids, the incubation times and the NP concentrations. Additionally, we propose a series of protocols that involve studying the protein corona using purified serum or plasma proteins, as well as sera depleted of specific complement proteins, to investigate the role of their deposition on the nanoparticle surface. We also explore how the role of the protein corona in inducing uptake by phagocytic cells can be examined; finally, we discuss several methodological approaches to study the effects of different coatings on the composition of the protein corona. Available data indicated that it is possible to characterize and punctually study the differential adsorption of specific proteins onto the nanoparticle surface. This allows designing NP chemical coatings features to actively guide the protein corona formation, thus improving nanotheranostic development. [ABSTRACT FROM AUTHOR]

2024 aluminum alloy has high strength, processing performance, and good damage tolerance performance, but it is prone to intergranular corrosion and pitting. Therefore, the development of corrosion protective coatings is essential for the aluminum alloy. In this paper, cerium ion (Ce3+) was doped into chitosan‐modified montmorillonite (Ce‐CS‐MMT) by ion exchange method, and the corrosion protective performance of Ce‐CS‐MMT epoxy coating (Ce‐CS‐MMT/EP) was investigated. The electrochemical analysis of aluminum alloy in cerium‐containing solution showed the corrosion inhibition efficiency reached 95.52%. The result indicates the corrosion inhibition effect of cerium‐containing solution was better than pure NaCl solution and MMT solution. The corrosion study of the coating illustrates that the protection rate of Ce‐CS‐MMT/EP reached 95.82%, which was higher than that 91.83% of Ce‐MMT/EP. The result indicates the resistance of charge transfer was greater and the better shielding effect for electrolyte corrosion ions than MMT and Ce‐MMT epoxy coatings, and the corrosion protective performance was excellent. [ABSTRACT FROM AUTHOR]

• Outdoor terracotta weathering simulated under representative environmental conditions. • Four commercial protective coatings evaluated in term of effectiveness and durability. • Fluorinated coating does not limit water penetration in the terracotta substrate. • Silica nano-coating (followed by alkylpolysiloxane emulsion) suitable for terracotta. Historical-artistic heritage, when located outdoor, is heavily targeted by deterioration phenomena such as weathering and air pollution. This is especially true for terracotta artefacts, as the medium porosity which characterizes them makes their damaging easier. Nevertheless, there is limited academic research on conservation strategies with regards to coatings. Consequently, the restoration of the carbonate terracotta sculpture known as "Muro del vento" (Wind Wall) by Domenico Matteucci has become the starting point for an experimental investigation carried out in order to evaluate the effectiveness and durability - for outdoor terracotta artworks - of an array of protective coatings. In this paper, four commercial protective coatings, recommended both for natural and artificial stones, were evaluated: a vinylidene-fluoride-hexafluoropropene copolymer at 3 % in acetone, an aqueous emulsion of alkylpolysiloxane, an aqueous dispersion of functionalized silica nanoparticles, and a nanostructured and functionalized silica gel in hydroalcoholic solution. Coated and uncoated representative calcium-rich terracotta specimens were subjected to two different accelerated ageing procedures: rain runoff test and climatic chamber exposure. Concurrently, a long-term outdoor exposure was set up. The characterization of the specimens and the evaluation of the coating's performances were carried out through color, contact angles, water absorption and mass variation measurements, 3D digital microscopy, scanning electron microscopy, X-Ray diffraction, Raman micro-Spectroscopy and atomic absorption spectroscopy in order to quantify calcium release in rain. Overall, the proposed accelerated ageing procedures proved to be successful for evaluating effectiveness and durability of protective treatments on ceramic materials. Silicon-based coatings, especially nanostructured and functionalized silica gel, followed by alkylpolysiloxane emulsion, have been shown to be the most suitable coatings for outdoor terracotta artefacts, while the fluorinated coating did not provide adequate protection as it was not able to limit water absorption under runoff conditions. [ABSTRACT FROM AUTHOR]

Polydopamine has the capacity to adhere to a large variety of materials and this property offers the possibility to bind nanoparticles to solid surfaces. In this work, magnetite nanoparticles were deposited on gold substrates coated with polydopamine films. The aim of this work was to investigate the effects of the composition and morphology of the PDA layers on the sticking of magnetite nanoparticles. The polydopamine coating of gold surfaces was achieved by the oxidation of alkaline solutions of dopamine with various reaction times. The length of the reaction time to form PDA was expected to influence the composition and surface roughness of the PDA films. Magnetite nanoparticles were deposited on these polydopamine films by immersing the samples in aqueous dispersions of nanoparticles. The morphology at the nanometric scale and the composition of the surfaces before and after the deposition of magnetite nanoparticles were investigated by means of AFM and XPS. We found that the amount of magnetite nanoparticles on the surface did not vary monotonically with the reaction time of PDA formation, but it was at the minimum after 20 min of reaction. This behavior may be attributed to changes in the chemical composition of the coating layer with reaction time. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study of layer gradient thermal protection coatings based on NiCrAlY and YSZ obtained by detonation spraying. Modern gas turbines and high-temperature units operate under extreme temperatures and aggressive environments, which requires effective protection of components from wear, corrosion, and thermal shocks. In this study, the use of layer gradient coatings consisting of alternating layers of NiCrAlY and YSZ was investigated with the aim of solving the problem of thermal stress accumulation due to a smooth change in the composition of the layers. Microstructural and phase analysis showed that alternating layers of NiCrAlY and YSZ formed a dense layer gradient structure with clear interphase boundaries and low porosity. Detonation spraying led to a complete transformation of the monoclinic ZrO2 phase into a tetragonal one, which significantly increased the mechanical strength of the coating and its resistance to thermal shocks. Sample 1D1 demonstrated excellent tribological and corrosion properties in a 3.5% NaCl solution, which can be explained by its higher density and reduced number of pores. Mechanical tests revealed stable values of hardness and wear resistance of the coating, especially for the 1D1 coating. Studies have shown that coatings are resistant to thermal shocks, but thicker layers show a tendency to peel off after thermal cycling. The obtained results indicate high prospects for the use of layer gradient coatings based on NiCrAlY and YSZ for the protection of gas turbine components and other high-temperature installations operating under extreme loads and aggressive environments. [ABSTRACT FROM AUTHOR]

Surface modifications not only improve the corrosion resistance of Co-Cr-Mo dental alloys (Bego Wirobond® C) but also ensure their long-term performance and reliability in dental applications. This paper describes the preparation of single-layer TiO2-ZrO2 sol–gel coatings on the Co-Cr-Mo dental alloy using the method of dip-coating. The TiO2-ZrO2 sol–gel coatings were sintered at 300 and 500 °C. SEM analysis shows that sintering at 300 °C produces a uniform, slightly dense structure without micro-cracks, while sintering at 500 °C results in a denser structure with micro-cracks due to higher stress and shrinkage. EDS confirms that sintering temperature affects the elemental composition of the coating, with higher temperatures causing the volatilization or diffusion of Ti and Zr. Roughness measurements indicate that the Ra value increases with the sintering temperature, meeting dental application requirements. Electrochemical measurements by open-circuit potential, EIS, and cyclic potentiodynamic curves demonstrate that sintering temperature and saliva composition affect corrosion resistance, with NaF and mouthwashes (Listerine Total Care Teeth Protection® and Meridol®) generally increasing charge transfer resistance and double-layer capacitance. The ceramic TiO2-ZrO2 coatings significantly reduce pitting corrosion susceptibility at physiological and acidic pH, with the 500 °C sintered coating showing better protective properties. These findings highlight the potential of TiO2-ZrO2 coatings in enhancing the performance of Co-Cr-Mo dental alloys. [ABSTRACT FROM AUTHOR]

Purpose: Organic coatings are widely used for protecting metal equipment and structures from corrosion. Accurate detection and evaluation of the protective performance and service life of coatings are of great importance. This paper aims to review the research progress on performance evaluation and lifetime prediction of organic coatings. Design/methodology/approach: First, the failure forms and aging testing methods of organic coatings are briefly introduced. Then, the technical status and the progress in the detection and evaluation of coating protective performance and the prediction of service life are mainly reviewed. Findings: There are some key challenges and difficulties in this field, which are described in the end. Originality/value: The progress is summarized from a variety of technical perspectives. Performance evaluation and lifetime prediction include both single-parameter and multi-parameter methods. [ABSTRACT FROM AUTHOR]

Good sealing of the gas path is the key to improving the thrust-to-weight ratio and fuel efficiency of an aeroengine, which requires a small radial gap between the rotor blade tips and the corresponding seals to minimize the loss of compressed gas. Due to the extreme conditions in service (e.g., high temperatures of 1500 °C, high pressures of 40 atm, and high linear velocities of 400 m/s), problems, such as wear, oxidation, and hot corrosion at the blade tip, are becoming more and more pronounced. Blade tip protective coatings are an effective way to improve these problems. In this paper, the composition and classification of blade tip protective coatings are summarized. The design concepts and preparation techniques of different blade tip protective coatings are highlighted. The problems of the corresponding blade tip protective coatings and the advantages or disadvantages of the preparation technology are also pointed out. Then, the evaluation means of blade tip protective coatings are concluded. Finally, the development trend of blade tip protective coatings is prospected. [ABSTRACT FROM AUTHOR]

Superalloys go through cyclic oxidation which refers to the progression of reputed exposure of materials to alternating oxidizing and non-oxidizing environments at high temperatures. The oxidation behavior of cobalt-based superalloy coatings depends on several variables, including the environment, surface roughness, manufacturing conditions, & coating composition. Because of their higher temperatures and protective oxide layer, coatings with a greater cobalt concentration are more oxidation-resistant. The behavior of oxidation is influenced by surface roughness, where rough surfaces offer greater surface area to oxidation while smooth surfaces decrease interaction with the environment. The microstructure and porosity of the coating are further impacted by processing variables used in thermal spraying, including temperature, particles velocity, and spray distance. Adding reactive components to the coating composition, such as silicon and aluminum, and applying post-treatments like nitriding or sealing are two ways to increase oxidation resistance. A greater temperature and particle speed can lead to a denser with less porous covering, improving the oxidation process resistance. The two typically used heat spraying techniques are high-velocity oxy-fuel (HVOF) and plasma spraying. To increase the resistance to oxidation of thermal spray cobalt-based superalloy coating, some strategies have been devised, such as inclusion of reactive materials, such as aluminum and silicon, which is the coating composition. These elements may establish an oxide layer protecting the coating's appearance, preventing further oxidation. [ABSTRACT FROM AUTHOR]

TiB 0.19 N 1.06 , TiB 0.70 N 0.66 , and TiB 1.23 N 0.19 coatings were deposited on cemented carbide via the chemical vapor deposition (CVD) method based on the calculated phase diagrams of the Ti–B–N system. The microstructures, mechanical properties and cutting performances of the Ti(B,N) coatings were systematically studied via X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), nanoindentation, etc. The coating compositions obtained via thermodynamic calculations show the same trend as the experimental values. The XRD and selected area electron diffraction (SAED) results of the coatings reveal that the phase assemblages transform from a dominant cubic structure of TiB 0.19 N 1.06 to a hybrid of cubic and hexagonal structure of TiB 0.70 N 0.66 and finally to a dominant hexagonal structure of TiB 1.23 N 0.19. According to the XPS results, the TiB 0.19 N 1.06 and TiB 0.70 N 0.66 coatings consist of the crystalline phases TiN and TiB 2 as well as amorphous BN and TiB, and the TiB 1.23 N 0.19 coating mainly consists of the crystalline phases TiB 2 and TiN. The hardness values of the TiB 0.19 N 1.06 , TiB 0.70 N 0.66 , and TiB 1.23 N 0.19 coatings are 33.6, 35.1, and 39.1 GPa, respectively. The content of amorphous phase in the Ti(B,N) coatings decreases while the hardness increases as the B content increases and N content decreases. The TiB 0.19 N 1.06 coating exhibits a composite structure of nanocrystallite embedded in amorphous matrix. The TiB 1.23 N 0.19 coated tool prepared in this study demonstrates excellent performance in milling titanium alloy TC18 with a long cutting life up to 56.1 min, an increase of ∼9 % and ∼28 % compared to the TiB 1.98 coated tool and commercial grade deposited with CVD TiB 2 coating, respectively. [ABSTRACT FROM AUTHOR]

Industrial boilers operate in extreme environments and are prone to degradation caused by high temperature oxidation, corrosion, and erosion. Protective coatings provide boiler components with protection to prolong their operation lifetime. Thus, a glass-ceramic coating has been developed using a slurry spray technique on carbon steel AS/NZS 3678 substrates. Microstructure, mechanical characteristics, and high temperature performance of the coating were investigated. The coating composed of chemically inert oxide ceramics dispersed in a glassy silicate binder matrix. The adhesion strength of the coating was 10.79 ± 0.86 MPa. Coating mass loss after abrasion test was 0.013 % of the tested specimen. The coating withstood at least 75 air quenched thermal shock cycles from 800 °C to the room temperature without any visible spallation and cracks. The coating mostly remained undamaged after cyclic oxidation at 800 °C for 10 cycles. However, minor iron oxide formation was observed, specifically, in relatively thin sections of the coating. The oxidation resistance of the boiler steel has been improved with the developed coating. The linear oxidation rate constant of the boiler steel has been statistically reduced from 6.90 × 10−4 mg cm−2 s−1 to 1.95 × 10−4 mg cm−2 s−1 for coated steel (p = 0.007). The developed slurry spray glass-ceramic coating is a potential candidate for boiler environments. [ABSTRACT FROM AUTHOR]

Perovskite-type aluminates hold significant promise for applications as thermal protective coatings (TPCs), but their inferior properties necessitate further optimization. In this study, PrAlO 3+δ (PA) and Sr2+ doped Pr 1-x Sr x AlO 3+δ (PSA, x = 1, 2, 5 mol%) were fabricated using the solid-state reaction method. The effects of Sr2+ substitution on properties were thoroughly investigated. The results demonstrated pronounced effects of Sr2+ substitution. PSA exhibited significant lattice volume expansion and enhanced sintering resistance with increasing doping concentration. Also, doping strategy effectively decreased thermal conductivity of PSA 4.38 W/(m·K) at room temperature to 3.48 W/(m·K) at 900 °C, decreasing by about 15 % in comparison to that of PA (6.21–4.07 W/(m·K)). Moreover, mechanical properties of PSA were improved, presenting the lowest elastic modulus (118.7 GPa) in contrast to that of PA (344.3 GPa). Most importantly, despite the lattice distortion caused by doping leading to limited improvement in infrared emissivity in the range of 8–14 μm, the infrared emissivity of PSA was significantly enhanced in the range of 3–5 μm. A highest average emissivity of 0.875 was achieved with x = 2 mol%, representing a 10 % enhancement compared to that of PA (0.796). Furthermore, the enhancement mechanisms were systematically elucidated. [ABSTRACT FROM AUTHOR]

In this work, a bio-based resin of acrylated epoxidized soybean oil (AESO) mixed with three types of active diluents (Isoborneol methacrylates [IBOMA], tripropylene glycol diacrylate [TPGDA], and Ethoxylated trimethylolpropane triacrylate [ETPTA]) is used to form a protective UV-curable coating film on calcium alginate water-carrying microspheres (CA-WCMs). Calcium alginate microspheres (CAMs) have previously been used to encapsulate only ester soluble or oil-in-water core materials, thus limiting their application. After UV-curing with an increased active diluent dose, the pencil hardness, pendulum hardness, and mechanical strength of the CAMs increased. A photopolymerization kinetics study reveals that the maximum double bond (C=C) conversion rates of AESO-IBOMA, AESO-TPGDA, and AESO-ETPTA are 95, 92, and 86%, respectively, and the maximum conversion rate of C=C bond is 87% in their mixed system. Additionally, the water retention rate of the water-carrying microspheres (WCMs) increased with an increasing number of coating layers, plateauing after the number of layers exceeded four. The water retention is favorable, with more than 75% of the water stored for a duration of 50 days. Overall, the cost-effective and environmentally friendly method has shown encouraging results in the acquisition of water-absorbing CAMs, with the potential to overcome existing implementation constraints. [ABSTRACT FROM AUTHOR]