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Focusing on the 3060 Goal, China builds a large energy base in Inner Mongolia. The steel structure facilities are subjected to long-term impacts from hard particles in the desert environment. Damage to the surface coatings of the steel structures resulted in reduced durability, and safety. The impact test of polyurethane coating was carried out by using an automatic ball impactor, the strain field of PU coating under impact load was collected by combining with Digital Image Correlation, the damage degree of PU coating was investigated by using Laser Scanning Confocal Microscopy, and elastic-plastic properties of PU coating were also studied. The results show that at the same impact height, the indentation depth of the substrate was Steel substrate > PU coating-steel substrate bilayer system, indicating that the PU coating played a better role in protecting the steel substrate. The compressive strain area at the impact contact point of the PU coating-steel substrate bilayer system increased with the increase of impact height, and the surface of the coating appeared to have different degrees of cracks and spalling. The dynamic hardness increases and then decreases with the increase of impact height, and the dynamic hardness value is the largest when the impact height is 30 cm. HIGHLIGHTS: The strain field distribution of polyurethane coatings under impact loading was studied in combination with DIC, and the crack extension of polyurethane coatings was analyzed using LSCM. The elastic-plastic characteristics of polyurethane coatings were investigated The research results provide a basis for the preparation of protective coatings for steel structures in special environments [ABSTRACT FROM AUTHOR]

AbstractThere have been studies published on the composition and coating uses of raw lacquers following enzymatic oxidative polymerization. The change of urushiol’ thermal stability and biological activity following polymerization to create oligomer, however, has received little attention. This work using silica gel column chromatography to separate urushiol and urushiol oligomer from polymerized raw lacquer and assessed its antibacterial, antioxidant, and thermal stability in an effort to decrease the allergenicity of urushiol and increase its application. By using gel chromatography, the urushiol oligomer were discovered to be polymers with 2–5 degrees of polymerization. According to characterization results from techniques like UV, FT-IR, and 1H NMR, urushiol was converted into urushiol oligomer by addition reactions, and C–C coupling. The findings demonstrated that the urushiol oligomer’ IC50 values for scavenging DPPH and ABTS free radicals were 40.8 and 27.4 μg/mL, respectively, and that their minimum inhibitory concentrations against Staphylococcus aureus and Staphylococcus epidermidis were 250 and 125 μg/mL. The urushiol oligomer’s thermogravimetric differential curve peak temperature (461.8 °C) was higher than urushiol’s (239.5 °C), indicating that urushiol undergoes polymerization with enhanced thermal stability. The study’s findings establish a foundation for the use of polymerized urushiol and urushiol oligomer in applications including functional materials and additives. [ABSTRACT FROM AUTHOR]

This study investigates the sustainability and efficacy of coatings for archaeological silver. Building on a survey of current practices in silver conservation and a literature review, a group of Chimú (Peruvian north coast, 1100–1400 CE) silver alloy items in the National Museum of the American Indian collection serves as a case study. Assessing treatment options for 80 Chimú items led to the investigation into the implications of introducing a new coating campaign. Experimentation was carried out with coupons approximating the composition and manufacture of Chimú silver. Four conservation grade materials, Agateen® 27, Acrysol® WS24, Paraloid® B-72, and Regalrez® 1126, were tested for protection efficacy in a humid, sulfur-containing environment. Analysis with X-ray fluorescence spectroscopy (XRF), scanning electron microscopy energy-dispersive X-ray spectroscopy (SEM-EDX), and imaging at several phases throughout the experiment provided data on the interaction of the metal and the coating and the effects of coating and re-coating. Oddy testing and Fourier transform infrared spectroscopy (FTIR) conducted on these prepared coatings helped determine their suitability for long-term use. Results indicate that not coating is more appropriate for preservation than coating with any of the four materials tested. [ABSTRACT FROM AUTHOR]

Due to the high oxidation activities at high temperatures, traditional SiC coating was difficult to act as an antioxidant material for ages. In this case, the multilayered Glass-MoSi2-SiC coating was fabricated on the C/C substrate, combined with hydrothermal electrophoresis deposition and simple embedding process. It was found that the composite obtained at 10 V performed outstanding combinations of oxidation resistance and thermal shock resistance properties. The weight loss of this Glass-MoSi2-SiC-C/C composite was only 0.99% after 212 h oxidation at 1773 K. After thermal shock for 130 times, the mass was just 0.05% lower than that of the initial. These excellent heat-resistant performances were much better than those in similar reports, which was attributed to the suitable coating composition and dense interlayer structure. As oxidized at 1773 K, the in-situ SiO2 phases had a self-healing ability to fill micropores and microcracks to protect the structure. The structure failure was related to SiO2 volatilization. This study emphasized the importance of simple techniques in the thermal-resistance coating fields at multiple length scales. [ABSTRACT FROM AUTHOR]

Understanding the impact of high-temperature thermal cycle on coating composition and its corrosion characteristics is essential for coating development. The present study investigated NiCr/TiO2-coated 316L austenitic stainless steel (316L SS) under thermal shock exposure and their corrosion behaviour in 3.5% NaCl solution. The electrochemical parameters were evaluated using potentiodynamic polarisation and electrochemical impedance spectroscopy techniques to understand the corrosion characteristics. Various techniques, viz. field emission scanning electron microscope, energy-dispersive X-ray spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy, were employed to examine the morphology, elemental composition, crystalline and oxidation characteristics of all the samples. The NiCr/TiO2-coated 316L SS demonstrated thermal resistance up to 9-h oxidation period and five thermal cycles. Afterwards, with gradual weight loss, TiO2 spallation appeared on the coated samples. The as-deposited sample revealed an increased pitting potential of 118.76% and improved corrosion resistance over ten times in magnitude than the bare sample. This improvement in the coated sample is attributed to high charge transfer resistance and chemically stable coating layer between the metal matrix and corrosive solution. In contrast, the delaminated sample revealed over four times greater resistance than the bare sample, which is credited to the limited surface area for possible redox reactions and passive NiCr bond coat layer over the metal matrix. [ABSTRACT FROM AUTHOR]

An experimental study has been conducted to develop unique zinc-rich coatings for the protection of low carbon steel reinforcements. These coatings are applied to low carbon steel substrates and subjected to various temperatures (100 °C, 150 °C, 200 °C, and 250 °C) to assess their mechanical integrity, corrosion resistance, and durability, replicating extreme service environments. The study integrates different nanoparticle concentrations into the zinc matrix (including Zn only, 50% Zn + 50% TiO2, 50% Zn + 30% WC + 20% TiO2, 40% Zn + 40% Ni-Cr Alloy + 20% TiO2, 70% Zn + 30% WC, and 50% Zn + 50% Ni-Cr Alloy) to assess their reinforcement effectiveness and contribution to thermal stability. The performance properties are assessed using adhesion tests, coating ratings, hardness assessments, electrochemical analysis, and field emission scanning electron microscopy (FESEM). The findings reveal that zinc coatings with a composition of 50% Zn, 30% WC, and 20% TiO2 provide excellent adhesion, particularly beneficial for high-temperature applications. Coatings containing Ni-Cr alloy display outstanding thermal stability, a vital characteristic for withstanding high-temperature conditions. At 250 °C, evaluating the compositions for the most favorable potential at the highest current densities is imperative. Microstructural analysis from room temperature to 250 °C shows a significant improvement in the integration and refinement of WC and Ni-Cr within the Zn matrix, resulting in the coatings' optimal performance. [ABSTRACT FROM AUTHOR]

In this study the use of AlTiN/aCN, TiAlN/TiN and three types of CrAlN/CrN coatings deposited on HSS steel was investigated. These protective coatings were prepared using PVD (physical vapor deposition) method. The objective of this study was to compare the microstructure, chemical composition and properties of Cr, Al or Ti based coatings deposited on a substrate made of high-speed steel HSS. The thicknesses of coatings based on titanium were approx. 4 µm, and those based on chromium were less than 1 µm. The morphology and chemical composition were studied using scanning electron microscopy (SEM) and X-ray dispersion spectroscopy (EDX). The X-ray photoelectron spectroscopy (XPS) method was applied. The adhesion was evaluated by scratch test. Nanohardness and durability tests of uncoated and coated knifes were performed. It was found that the knifes made of HSS covered with two-layer TiAlN/aCN coating exhibited the best durability characteristic. Coatings containing chromium were less durable due to their small thickness. The highest nanohardness was found in the AlTiN/TiN coating due to its multi-layer nature. The nanohardness of the other coatings is comparable but more than two times lower compared to the multilayer AlTiN/TiN nanocoating. [ABSTRACT FROM AUTHOR]

AbstractIn this study, two 8-hydroxyquinoline derivatives, HAPAQ and EAPAQ, were first synthesized, and their molecular structures were confirmed by 1H and 13C NMR. The effects of HAPAQ and EAPAQ on corrosion processes were investigated using weight loss, electrochemical, and theoretical methods. Overall, the data unmistakably demonstrate that the inhibition performance (η %) increases with an increase as HAPAQ and EAPAQ concentrations rise, peaking at 96.08% (HAPAQ) and 94.37% (EAPAQ) at the optimal concentration (10−3 M) for PPD technology. The two 8-hydroxyquinoline derivatives exhibit inhibitory behavior, as seen by the polarization curve impedance tests; however, they demonstrate that adsorption promotes protective action on metal surfaces, creating a geometric blocking effect and a protective coating that impedes metal breakdown. HAPAQ and EAPAQ's inhibitory efficacy may be reduced by the rising temperature. Furthermore, it adheres to Langmuir’s single-layer adsorption isotherm, and the physisorption and chemisorption mechanisms are linked to the corresponding value of the adsorption energy (ΔGads). Additionally, the MS scanning electron microscope (SEM) has been studied and discussed. The possibility of complex organization between the inhibitor molecules, 8-hydroxyquinoline derivatives (HAPAQ and HAPAQ), and the Fe2+ ions generated during the oxidation process was established by examining the test solutions using UV–visible spectroscopy. Consequently, it is evident from DFT simulations that the surface recovery is dependent on the local reactivity descriptors. The theoretical outcomes derived from DFT are aligned with the findings of the experimental studies. [ABSTRACT FROM AUTHOR]

In this study, solid-phase microextraction (SPME) fiber adsorbents were coated with the metal-organic framework ZIF-67 and protected by layered double hydroxides (LDH) nanotubes. The findings unequivocally show that the extraction selectivity is dependent on the surface element composition of coatings produced from ZIF-67. The ZIF-67@NiCo-LDHs coating was chosen for the enrichment and detection of polycyclic aromatic hydrocarbons (PAH) in water samples due to its long-term stability and superior extraction selectivity. The calibration curves were dynamically linear and ranged from 0.00 to 100 g L−1 at the optimum circumstances, with correlation values (R2) above 0.996–0.999. LOD values ranged from 0.07 to 0.5 ng L−1. Under ideal circumstances, the test compounds" repeatability for one fiber (n = 3), expressed as relative standard deviation (RSD%), ranged between 7.5 and 9.2%. Additionally, the synthetic fiber displayed 40 cycles of extraction and desorption and perfectly controlled development. [ABSTRACT FROM AUTHOR]

The elemental composition, microstructure and corrosion resistance of three different zinc base alloy coatings (Zn–Ni alloy, Zn–Fe alloy and Zn–Co alloy) electrodeposited with the same complexing agent were studied by using a common zincate bath. The suitable current density is designed through experiments. Under the same current density, Zn–Ni alloy coating, Zn–Fe alloy coating and Zn–Co alloy coating are electrodeposited. The types and contents of microcomponent elements were analyzed by energy dispersive spectroscopy (EDS), the surface structure was analyzed by scanning electron microscopy (SEM), and the corrosion resistance was analyzed by electrochemical techniques (AC impedance, Tafel curve). The results show that the microstructure of Zn–Co and Zn–Fe alloy coatings is similar, the surface of the coatings is flat and the crystal distribution is uniform, but the grain of Zn–Co alloy coatings is obviously larger than that of Zn–Fe alloy coatings. In the electrochemical test part, the AC impedance of Zn–Co alloy coating is much higher than that of Zn–Ni alloy coating and Zn–Fe alloy coating, and the self-corrosion current density is lower than that of Zn–Ni alloy coating and Zn–Fe alloy coating, so it has the best corrosion resistance. [ABSTRACT FROM AUTHOR]

Concrete structures are often subjected to harsh environmental conditions, and problems such as corrosion will greatly limit their service life and safety. Stray current is one of the factors that can be easily ignored but seriously affect concrete structure. Therefore, the study of the influence of stray current on concrete structure is conducive to understanding the performance and corrosion mechanism of concrete structure, providing technical support for protecting concrete structure, and improving its service life and safety. In this experiment, the effect of stray current and chloride ion interaction on the corrosion of reinforced concrete structure was studied, and the protective effect of the coating on reinforced concrete was studied by using Zn-Ni alloy plating solution. Electrochemical workstation, silver nitrate spraying, scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and direct observation were used to simulate and compare the corrosion experiments under different current intensities. By analyzing the influence of 0.05 and 0.10 A stray currents on concrete corrosion, the chloride penetration resistance of concrete structures was evaluated, and blank control experiments were set for different current intensity and different energizing time. The corrosion resistance of the steel bar coated with Zn-Ni alloy is compared with the steel bar without changing the coating under the same corrosion conditions. The results show that the corrosion tendency of concrete structures will be further increased under the action of stray current and chloride ion coupling, and the corrosion reaction will be accelerated. In addition, at the same time, the higher the simulated current, the more serious the corrosion of concrete structure; Under the same simulated current, the longer the electrification time, the worse the resistance of concrete structure to chloride ion erosion. Moreover, the corrosion resistance of the steel bar coated with Zn-Ni alloy is better. In summary, this study concludes that the coupling of stray current and chloride ion causes damage to the corrosion of concrete structures, and the current intensity and energized time are proportional to the corrosion degree, and the modified Zn-Ni alloy coated steel bar has better corrosion resistance [ABSTRACT FROM AUTHOR]

We herein report the fabrication of mixed oxide Cu2O/CuO nanowire electrodes through the anodisation of Cu-mesh. These synthesised electrodes are then coated with a protective carbon layer to enhance hydrogen production via photoelectrochemical (PEC) water splitting. Our study addressed Cu2O/CuO nanowire surface modification via anodisation voltage adjustment and analyzed annealing effects on carbon-coated electrodes under controlled temperatures in a nitrogen environment. Optimisation at 5V anodisation potential yielded enhanced photocurrents, with the Cu2O/CuO mixed phase proving crucial for improved PEC activity. XRD, SEM and TEM analyses were conducted to evaluate the structural and morphological characterisation of the synthesised samples. A thin carbon coated sample annealed at 550 °C enhances the photoelectrochemical efficacy of Cu2O nanowires, obtaining a peak photocurrent density of ∼4 mA cm−2 at 0 V (vs. RHE). In contrast, as prepared pristine optimised Cu2O/CuO nanostructured electrodes deliver a photocurrent density of ∼ 2 mA cm−2 at 0 V (vs. RHE) under AM 1.5G light solar irradiation with an intensity of 100 mWcm-2. The Mott–Schottky analysis exhibits p-type semiconducting nature of carbon coated Cu2O/CuO electrodes. The photocurrent stability test alsoconfirms that carbon coated Cu2O/CuO electrodes are one of the best candidates for improving the photoelectrochemical water splitting reaction. [ABSTRACT FROM AUTHOR]

The motivation behind this research is to enhance concrete using a coating fabricated from waste materials. Polyethylene terephthalate (PET) was added to asphalt (AP) cement of 60/70 penetration grade at different percentages. Scanning electron microscope (SEM) images show that 6% PET is the optimum mix proportion, and then ternary blends were done by mixing the prepared AP/PET with nano silica (nS) at different ratios (0.5, 1, 1.5, 2, and 2.5) wt./wt. The prepared coatings were evaluated by determining drying time, dry film thickness (DFT), adhesion strength, impact resistance, and flexibility. The formulated coatings were applied to concrete substrates, and the performance of coated concrete cubes was examined by determining water absorption, contact angle, and chloride diffusion. The durability of coated concrete was evaluated by measuring the changes in compressive strength after immersion in both sulfuric acid and sodium chloride solutions separately. The study proved the eco-efficient use of PET waste bottles in protective coating preparation, and the experimental results detected that nS has a significant mechanism for improving coating performance as follows; drying time of AP/PET-2 reduced with 61% as compared to AP/PET, the increment of DFT of AP/PET-2 was 25%, and adhesion strength was improved by 90%. On the same time, silica nano particles are mainly contributes for enhancing coated concretes. Where water absorption reduced with 75%, contact angle increased by 55%, and chloride permeability resistance enhanced to 40%. Finally, improvement durability of coated concrete was 25% and 20% after immersion for 28 d in both sulfuric (3%) acid and sodium chloride (5%) solutions, respectively. [ABSTRACT FROM AUTHOR]

A reliable and effective diagnosis of coating structure is important for further maintenance. For the problem of slow detection and identification using terahertz non-destructive testing technology in the industrial inspection, a rapid diagnosis algorithm based on the wavelet packet energy and support vector machine method was developed for quick evaluation of the epoxy protective coating. The process mainly included time domain signal acquisition of various epoxy protective coating samples detected by a terahertz pulse imaging system, wavelet packet energy parameters extraction as the diagnosis feature vectors, classification model establishment based on the support vector machine algorithm and coating status evaluation using a three-class classifier. The influence on classification accuracy by the various feature vectors inputs with the support vector machine classifier was analysed. Satisfying results were achieved when the relative wavelet packet energy was taken as diagnostic features. A strong defective area could be quickly identified and more detail targeted analysis could be implemented as needed. The time spent was significantly reduced compared to the terahertz imaging of the whole area along with the manual judgement. The analysis indicated that the proposed method would be very useful and can be effectively employed for the coating monitoring application. [ABSTRACT FROM AUTHOR]

In recent years, wind energy has gained widespread attention and has been regarded as one of the renewable energy resources for the future. However, surface erosion of wind turbine blades, which are key components of wind turbines, can degrade the aerodynamic properties of blades, thereby, reducing the energy efficiency and service life. It has been estimated that wind turbine blade erosion can reduce annual energy production by 20–25% with severe erosion. In this sense, understanding and mitigating of leading edge erosion of wind turbine blades caused by rain and solid particles are critical to develop efficient technologies for wind turbine blades. To protect the wind turbine blades, various types of polymer-based coatings have been developed. In general, polymer composites offer excellent strength, durability, flexibility, ease of fabrication, and low cost. This comprehensive review is aimed to provide broad information and recent developments about the characteristics of leading edge erosion by rain and solid particles, their mechanisms, testing methods and associated standards, and development of erosion protection coatings for wind turbines. Updated advances in characteristics of polymeric protective coatings, process of coating development, coating materials, coating types, and simulation for the coating development against rain and solid particle erosions have also been addressed in this review. [ABSTRACT FROM AUTHOR]

With increasing demand for scratch-resistant flexible electronics, the development of transparent coatings with good scratch resistance and self-healing properties has emerged as a key research topic. In this study, a high-strength self-healing poly(urethane – urea) (PUU)-based nanocomposite coating was prepared by introducing functionalized nanodiamond (ND) into a PUU matrix via solution blending. The PUU matrix had hard-segment repeating units and was constructed using isophorone diamine and isophorone isocyanate. The ND particles were modified using a silane coupling agent, 3-aminopropyltriethoxysilane, to obtain well-dispersed KH-ND nanoparticles. KH-ND promoted microphase separation in the PU matrix, inducing the formation of dense and homogeneous hard domains that dissipated stress, prevented further crack development, and improved the mechanical properties and scratch resistance of the coating. In addition, the coating exhibited excellent self-healing properties. Fourier-transform infrared spectroscopy, scanning electron microscopy, and atomic force microscopy were used to characterize the self-healing and hardening mechanisms of the coating. The environmentally friendly PUU/KH-ND coating is easy to prepare and has broad application prospects in transparent and anti-scratch coatings for flexible electronics, automobiles, and home appliances. [ABSTRACT FROM AUTHOR]

The current budesonide formulations are inadequate for addressing left-sided colitis, and patients might hesitate to use an enema for a prolonged time. This study focuses on developing a single-layer coating for budesonide pellets targeting the descending colon. Pellets containing budesonide (1.5%w/w), PVP K30 (5%w/w), lactose monohydrate (25%w/w) and Avicel pH 102 (68.5%w/w) were prepared using extrusion spheronization technique. Coating formulations were designed using response surface methodology with pH and time-dependent Eudragits. Dissolution tests were conducted at different pH levels (1.2, 6.5, 6.8, and 7.2). Optimal coating formulation, considering coating level and the Eudragit (S + L) ratio to the total coating weight, was determined. Budesonide pellets were coated with the optimized composition and subjected to continuous dissolution testing simulating the gastrointestinal tract. The coating, with 48% S, 12% L, and 40% RS at a 10% coating level, demonstrated superior budesonide delivery to the descending colon. Coated pellets had a spherical shape with a uniform 30 µm thickness coating, exhibiting pH and time-dependent release. Notably, zero-order release kinetics was observed for the last 9 h in colonic conditions. The study suggests that an optimized single-layer coating, incorporating pH and time-dependent polymers, holds promise for consistently delivering budesonide to the descending colon. [ABSTRACT FROM AUTHOR]

Immediately following the use of aluminium alloys, particularly Duralumin, in the construction of aircraft, protective coatings with anti-corrosion properties were developed. Among the numerous solutions to prevent corrosion, the most widely employed materials were organic primers containing chromates. This paper reports the study of the corrosion inhibitive compounds (chromates) used by aircraft manufacturers during World War II. More specifically, we have identified the nature of the compounds and assessed their current efficiency. Our analyses on samples collected from three different wrecks (French and German) excavated on terrestrial sites reveal that the primer contained either zinc tetroxychromate or lead chromate. Using XANES to study the chromium oxidation states elucidated the different phenomena taking place during the aging of the paint primer. We found that the reduction of Cr(VI) to Cr(III) species occurred either within the primer or at the interface of the primer with the Al alloy. This is believed to be due to alteration of the paint layer and its long exposure to the natural environment. However, even after 80 years, Cr(VI) is still present in the primers of these archaeological parts. Although a little altered, the chromate compound can still provide a source of inhibitor, thus maintaining the protection of the alloys. [ABSTRACT FROM AUTHOR]

In this study, the impact wear behaviour of Al-5Mg, used as a corrosion protective coating was investigated in seawater and air environments. Tests were conducted for up to 105 cycles on the plane surface of Al-5Mg coated AISI 316L samples. Wear at the frequency of 2.5 Hz kept the coating thickness at a reliable level. However, the wear that occurred under the frequency of 5Hz reached the substrate surface. In the experiments conducted in seawater, smoother wear scars were formed compared to those in the air environment tests. The coating particles separated by the wear effect were compressed by the impactor on the wear surface with repetitive impacts, causing delamination. Friction oxidation was formed on wear scars. The hydrodynamic effect of seawater reduced the delamination by removing the separated coating particles from the surface. Thus, in seawater, 70% more wear occurred compared to in the air environment. [ABSTRACT FROM AUTHOR]

One of the best ways to obtain TiN coatings is through the nitriding process by efficient methods such as dense plasma focus (DPF). The gas composition of the nitrogen environment is a crucial factor affecting the properties of the coating. In this study, three different atmospheres of 100%N2, 50%N2–50%O2, and 75%N2–25%Ar were used to investigate their impact on the mechanical and biological properties of TiN coatings on NiTi substrate. The operating condition that yielded the coating with the highest hardness, as well as the lowest contact angle and Ni ion release, was chosen as the optimum condition. According to the XRD results, TiN was recognized as the dominant phase which causes high hardness and prevents Ni ion release. Moreover, surface analyses determined that the sample coated in 50%N2 composition possessed higher hardness and as a result displayed better mechanical properties. Also, the improved microstructural properties lead to an enhanced coating/substrate adhesion strength. On the other hand, the reaction of TiO2 and TiN lead to the formation of TiN0.6O0.4 ternary compound and for this reason, the 50%N2–50%O2 sample exhibited better performance in preventing the release of the toxic nickel ion compared to the other samples. Finally, due to the presence of TiO2 and TiN0.6O0.4 in the sample surface treated at 50%N2–50%O2, better hydrophilicity was observed compared to other samples. Results confirm that the applied surface modification method is effective in increasing the mechanical and biological properties of the NiTi, where it may open numerous possibilities for efficient use in orthopedic applications. [ABSTRACT FROM AUTHOR]

The coating's purpose is to enhance the tribological conditions at the tool-workpiece and chip–tool interfaces. In comparison to commercial coatings, the current work offers a coating for high-speed steel (HSS) equipment that is thinner and less expensive. A single-point AISI T6 high-speed steel tool having a square cross-section was used to prepare the cutting inserts for turning purpose. The best conditions for coating the HSS insert with ceramic oxides using the sol–gel process were determined. These precursor conditions involved: viscosity, PH, dispersion materials, and the ageing period. The deposition conditions were the number of coating cycles, the immersion time, the calcination temperature, and dry temperature that affects the layer thickness, adhesion, surface roughness, and homogeneity for coating layer. Titanium tetra-isopropoxide (TTIP), a catalyst HCl, and a dispersion material (triethanolamine) were employed to prepare the precursor (titanium hydroxide). The PH, the viscosity, and the ageing time, of the produced precursor were 6.46 and 8.74 cP, and 6 h, respectively. After the dip coating of the cutting inserts for 5 sec immersion time and two number of coating cycle in titania precursor, the inserts were dried at 355℃ for 1 hour. Then, to form the alumina coating film, the inserts were dipped in the alumina hydroxide sol, which was made by combining aluminium isopropoxide IPA, deionised water H2O, and nitric acid (HNO3). The produced precursor had a PH of 5.83, viscosity of 8.11 cP, with an ageing time of 12 h. The immersion time and number of coating cycles in the alumina precursor were 25 sec, and two, respectively. The inserts were dried at 355℃ for 1 hour, then calcinated at 500°C for 2 h to achieve the appropriate film thickness for the machining test. The study investigates the thermal and tribological properties of coated with single and multiple layers as well as uncoated cutting inserts. The results indicated that the hardness is 1393.3 HV with a thickness of 6 µm for multilayer. X-ray diffraction-phase analysis confirms the presence of phases originating from the coatings and substrate. EDS analysis of the chemical composition of the studied coatings indicates the presence of titanium and aluminium, as well as oxygen. Atomic force microscopy (AFM) was used to examine the surface morphologies of coated surfaces. Scratch hardness is measured in GPa and differs between monolayers (alumina) and multilayers (titania/alumina). Monolayer alumina has a value of 0.374 GPa, whereas multilayer alumina/titania has a value of 1.010 GPa. Multilayer coated inserts, on the other hand, have a lower wear rate than monolayer coated and uncoated inserts. The thermal expansion coefficient of the titania layer is often relatively near to the thermal expansion coefficient of the bulk HSS (11 × 10−6, 13 × 10−6 1/K) that reduces mismatch between substrate HSS and top coating layer (alumina). [ABSTRACT FROM AUTHOR]

Stainless steel (SS) is a well-known engineering material which is predominantly used in multitudinous applications; however, the disquieting entity is its deteriorative nature triggered by the corrosion in biological, chemical, and high-temperature surroundings. Zirconia is a noteworthy material because of its remarkable mechanical, thermal, and biocompatible properties. To further improve the properties, the high-temperature phases of zirconia are stabilized at room temperature. Zirconia and its stabilized derivates are favored candidates as protective coatings for SS. They offer high resistance, allow them to perform in corrosive, sensitive environments, and augment the longevity, serviceability of SS. Deposition of zirconia/stabilized-zirconia (Z/s-Z) coatings is accomplished using vapor-phase methods, which are capital-intensive; they comprise high vacuum and processing time, confined space, and more energy consumption, resulting in fabrication cost maximization. Alternatively, solution-phase deposition methods are advantageous, effortless, and capable of depositing on large-area substrates, promising to lessen fabrication costs and to enhance yield. Solution-phase methods, namely dip, spray, and spin coatings, have been investigated to produce effective, high-grade Z/s-Z coatings on SS. This review summarizes the utilized precursors, solvents, and process parameters for depositing Z/s-Z coatings on different types and grades of steel through mentioned solution-phase methods, respectively. The review emphasizes the researched potential applications of solution-phase processed Z/s-Z with a particular role as a protective coating on SS-based implants, surgical instruments preserving corrosion resistance, nontoxicity and biocompatibility in the body fluids. The review also highlights the defensive property of solution-phase processed Z/s-Z coatings to the underneath SS against corrosive chemical media (acids like H2SO4, HCl, HNO3; chlorides like NaCl and toxic gases like H2S, coal). The oxidation protection to the beneath SS by the mentioned coatings in aggressive high-temperature surroundings is also focused in the present review. [ABSTRACT FROM AUTHOR]

Nowadays, higher performance is being sought in newly built power plants. The efficiency of power plants is mainly achieved by maximizing the steam parameters. Consequently, ever more expensive high-alloy steels are being used. For this reason, design concepts, in which high efficiency with lower investment costs are becoming increasingly popular. Such an innovation is the double-pipe system with a protective coating, which provides thermal insulation for the primary pipe in which the supercritical steam flows. This pipe is also cooled by an external flow by the steam with lower parameters. The article presents the developed two-dimensional numerical model. The use of the Galerkin method enables the complete transient analysis of a double-pipe system to be carried out, considering temperature-dependent material properties. The numerical model was compared with the computational fluid dynamics model. The temperature gradient in the inner pipe wall with and without coating was determined. In addition, the response of the wall temperature to a change in steam temperature was investigated. As observed, the protective layer can improve boiler performance characteristics when applied to thick-walled boiler components. It can also enable the use of less demanding steel. [ABSTRACT FROM AUTHOR]

Marine biofouling is a global problem affecting various industries, particularly the shipping industry due to long-distance voyages across various ecosystems. Therein fouled hulls cause increased fuel consumption, greenhouse gas emissions, and the spread of invasive aquatic species. To counteract these issues, biofouling management plans are employed using manual cleaning protocols and protective coatings. This review provides a comprehensive overview of adhesion strategies of marine organisms, and currently available mitigation methods. Further, recent developments and open challenges of antifouling (AF) and fouling release (FR) coatings are discussed with regards to the future regulatory environment. Finally, an overview of the environmental and economic impact of fouling is provided to point out why and when the use of biocidal solutions is beneficial in the overall perspective. [ABSTRACT FROM AUTHOR]

The objective of this study is to investigate the durability of metallic coating for firefighter protective clothing when subjected to different washing cycles. Firefighter clothing ensemble consists of three layers, i.e. outer shell, moisture barrier, and thermal liner. The exposed surface of the outer shell was coated with silver particles through the physical vapor deposition process also called Magnetron sputtering. Afterwards, these specimens were exposed to radiant heat transmission machine at 30 kW/m2 and 40 kW/m2, respectively. It was found that specimens coated with silver particles showed improved thermal protective performance as compared to uncoated specimens. Later on, silver-coated specimens undergo five cycles of washing and their thermal protective performance in terms of transmitted heat flux density Qc (kW/m2) and radiant heat transmission index (RHTI 24 and RHTI 12) was measured. It was found that after five washing cycles, there was a negligible decline in thermal protective performance when exposed to 40 kW/m2. Afterwards, bending moment and water vapor resistance properties were measured before and after five washing cycles. It was inferred that there was no considerable difference in bending moment and water vapor resistance after different washing cycles, which confirmed stability of silver coating layers. However, when silver-coated outer shells were evaluated for abrasion resistance, there was a substantial decline in thermal protective performance on exposure to 40 kW/m2 after one hundred to five hundred cycles of abrasion. [ABSTRACT FROM AUTHOR]

The hard nanocomposite coatings comprised of titanium, silicon, boron, and carbon (Ti-Si-B-C) and titanium, silicon, boron, carbon, and nitrogen (Ti-Si-B-C-N) were deposited on SS 304 substrate using magnetron sputtering technique. The tribological properties of these Ti-Si-B-C and Ti-Si-B-C-N coatings were explored with the variation of load (200–600 g) and thickness (3–25 mm) against high strength steel ball using a ball on a disc tribometer. The nanoindentation technique was used to investigate the wear tracks and its consequent effect on the mechanical behaviour of uncoated and coated films. The analyses of the phases, microstructure, states of valence, shift of electron, and elemental compositions of the coatings were carried out by HRTEM, FESEM, AFM, XPS, EDX, and Raman spectroscopy techniques, respectively. The 2D crosssectional profiles and 3D topographies of the wear tracks were explored using a 3D profilometer. All these studies established that the 10 mm thick titanium-based sputtered nanocomposite coatings on SS 304 are efficient wear-resistant materials that showed excellent protection of the substrates from wear up till application of 500 g load. A good correlation between the composition, structure, properties, and processing of materials has been discussed based on the obtained wear behaviour. [ABSTRACT FROM AUTHOR]

Nanocomposites have been demonstrated to have much lower density, higher viscoelasticity and can have tunable physical and chemical properties compared to metal alloys. The main advantage of nanofillers reinforcement in the polymer matrix for underwater application has been highlighted in terms of lower water intake as well as less debonding in ionic medium. The different types of fibre-reinforced polymer nanocomposites have been fabricated in order to understand the role of nanofillers at polymer matrix inside the saline water. The bonding of protective coating with the resin surface was found to be affected in salt water whereas the nanofillers were found to diffuse into the empty space of polymer matrix and provide comprehensive chemical resistance in ionic environment. It has been established that the gel coating of the composite was not stable under the dynamic water flow and pressure. On the other hand, nanofillers has been found to comprehensively plugged the voids in polymer and fibers interfaces which showed much higher stability in marine environment by delaying the ageing of structures for offshore applications. [ABSTRACT FROM AUTHOR]

FeCrNiMoCBSi amorphous coating was prepared on marine steel F22 using plasma spraying technique for marine protection. The tribocorrosion behavior of Fe-based amorphous coating was explored in simulated seawater. The material loss of the coating in tribocorrosion behavior was attributed to the combination of wear and corrosion. To identify the interaction between wear and corrosion, the friction behavior of the coating was studied at different applied potentials using an electrochemical workstation. These results revealed that wear was a major factor in the material loss of the coating under the present tribology condition, whereas corrosion was retarded due to the good anti-corrosion properties of the Fe-based amorphous coating. The interaction between corrosion and wear in seawater was positive, indicating that corrosion promoted wear and corrosion promoted wear. The findings provide new insights into the wear-corrosion synergy effect on Fe-based amorphous coating under load-chemistry coupled conditions, and offer available supports for the design of marine protective coatings. [ABSTRACT FROM AUTHOR]

Fusion-bonded-epoxy (FBE)-coated steel rebars have been used in many concrete structures in anticipation of better corrosion resistance. However, due to premature corrosion observed, FBE-coated rebars are banned in many parts of the world. On the other hand, such rebars with damaged coating are still used widely in some other parts of the world. This paper discusses the thickness, continuity, flexibility, and chemical composition of coating. Also, the performance indicators such as electrical resistance, UV-resistance, moisture resistance, and chloride diffusion coefficient of coating, and the chloride threshold of FBE-coated rebars are discussed. Laboratory tests adopted techniques (EIS, LA-ICP-MS, and EDX) on samples of coating peeled-off from coated rebars and specimens of coated steel rebars embedded in cement mortar, indicate that more comprehensive and stringent specifications are required to promote the use of quality epoxy materials, FBE-coated steel rebars, and construction practices are recommended. [ABSTRACT FROM AUTHOR]

The Tsumeb Mine in Namibia represents one of the best-preserved mining sites in the world and is rapidly gaining cross-disciplinary interest among cultural and engineering scientists. Most of the open pit and the shaft mining equipment are still in place, including the ore processing units and the local power plant. The mining area thus deserves recognition as an industrial world heritage site, especially due to the rarity of such locations on the African continent. The Shaft #1 headgear, built in 1924, represents one of the oldest known riveted steel headgears of the Promnitz design worldwide. In contrast to similar steel structures located in the northern hemisphere, it has been exposed to a different rural semi-arid climate since it is located in the Otavi Mountain Land, characterized by semi-annual change of rainy and dry seasons. Parts of the Shaft #1 headgear have remained largely untouched for more than 70 years. Besides its outstanding heritage value, it thus also represents an interesting object for studying the composition of corrosion layers formed on mild steel surfaces when exposed to continental and industrial mining atmospheres. To find a suitable transparent corrosion prevention coating, various on-site coating samples were evaluated after 11 months of outdoor exposure, including Owatrol Oil®, which is based on natural oil and alkyd resin with strong wicking potential. The substance is frequently applied for the conservation of single components but is not yet widely used on large steel structures in the field of industrial heritage conservation. However, it represented the most stable anti-corrosion coating under the local atmospheric conditions in the on-site tests. Thus, the suitability of Owatrol Oil® as a transparent coating for corrosion protection of riveted mild steel structures in such climates was further investigated as a more recent approach for the conservation of large steel structures. Since the protective coatings are exposed to strong UV radiation in the local climate, the addition of a specific UV stabilizer mixture was also tested. For such laboratory tests, two mild steel samples were taken. The first one originated from a diagonal strut of the 1920s and the second one from a handrail mounted in the early 1960s. Using corresponding high-resolution scanning electron microscopy (HR-SEM) and energy-dispersive X-ray spectroscopy (EDX) it was found that the corrosion layers are predominantly composed of lepidocrocite and goethite. A weathering program simulating the specific environmental conditions at Tsumeb in a UV climate chamber was developed and the corrosion resistance of the mild steel surface was subsequently evaluated by potentiodynamic measurements. Such tests proved to be a fast and reliable procedure for ranking the corrosion resistance of the old mild steels. It was found that the long-term corrosion layers already provide significant protection against further corrosion in the simulated environment. However, the study also showed that this can be further improved by the application of the Owatrol Oil® as a protective coating that also seals crevices. The addition of the UV stabilizers, however, led to a significant deterioration in corrosion protection, even in comparison to that of the uncoated long-term corrosion layers on the surface. Regular overcoating seems more advisable for the long-term preservation of the Shaft #1 headgear than modifying the Owatrol Oil® coating with the tested UV-stabilizing additives. [ABSTRACT FROM AUTHOR]

An applied electrochemical method in the form of a chronocoulometry technique is proposed for measuring Fick's diffusion constant of a thin protective coating layer over the conductive base materials. Using this method, the capacitance is monitored for a capacitor formed using the base material, an electrolyte such as aqueous NaCl, and an insulating coating layer in between. The capacitance increases when the distance between the base material and the electrolyte decreases in the diffusion of the electrolyte through the insulating coating layer. Therefore, the change in the capacitance provides a diffusion rate related to Fick's diffusion constant. Conventional gravimetric methods require a long measurement time to reach saturation, and thin coating layers of minimal weight increment through water diffusion were demonstrated to be inadequate for the methods. However, the new electrochemical method is appropriate for thin coating layers and requires a limited duration after the onset of diffusion. Experimental for 1-mm thick PA6 films provided Fick's diffusion constants of safer side with the new method of 15h by reflecting the heterogeneous properties of the surface, while the conventional gravimetric method in 360h provided smaller or danger-side values. [ABSTRACT FROM AUTHOR]

In this study, polymer-stabilised cholesterol-based liquid crystal (PSCLC) films with broadband reflection were prepared using monolayer gelatin nanofiber films as carriers loaded with photoinitiators. To obtain the maximum inhomogeneous distribution of the pitch, a series of studies were conducted on the concentration, temperature, time and UV intensity of the polymerised monomer. By screening different experimental conditions, the optimal conditions for broadening the reflectance band were obtained, and the reflectance band was widened from 240 to 440 nm. The morphology of the nanofibers was observed by SEM, and the effect of doping of the fibre film on the liquid crystals (LCs) weave was characterised by POM. The reflectance wavelength was measured mainly by a UV-vis spectrophotometer. The prepared cholesteric phase LC films with broadband reflection properties have potential applications in brightening films, intelligent windows, infrared shielding devices, laser protective coatings, etc. [ABSTRACT FROM AUTHOR]

High entropy alloys (HEAs), consisting of five or more elements with nearly equal atomic composition with one another (5–35%), are new-generation alloys that have attracted signifi)cant interest since their advent in 2004 because of their unique structural and mechanical properties and thermodynamic and chemical stability. Some characteristics, including high mechanical strength at elevated temperatures, high ductility and fracture toughness at cryo)genic temperatures and high corrosion, erosion and wear resistance, have been demonstrated for HEAs that outperform traditional alloys and superalloys. Laser-cladding (LC) is an additive manufacturing technique that has good feasibility in designing and processing HEAs for advanced structural components and protective coatings. This overview provides a glimpse of recent advances in LC of HEAs in terms of design fundamentals, metallurgical phase and microstructure, specific properties for advanced coating applications and the effect of ceramic particles reinforcement in LC deposition of HEA coatings. [ABSTRACT FROM AUTHOR]

Our purpose is to investigate the relationship between the microbiota of patients' tongue coating microbiota and the severity of COVID-19, and to identify the severity of COVID-19 patients' condition as early as possible. The participants were categorized into three groups: healthy controls (Con group) consisting of 37 individuals, patients with mild to moderate symptoms (M group) comprising 49 individuals, and patients with severe and critical symptoms (S-C group) consisting of 44 individuals. We collected oral swabs from all participants and performed 16S rRNA gene sequencing to analyze the microbiome. The α and β diversity differences were assessed respectively. Additionally, we employed the Linear Discriminant Analysis Effect Size (LEfSe) analysis to evaluate taxonomic differences among the three groups. Our findings revealed a significantly higher richness of tongue coating microbiota in both the S-C group and M group compared to the Con group. When compared with Con group, decreased Prevotella, Neisseria, Fusobacterium and Alloprevotella, and over-expressed Streptococcus and Rothia in M and S-C group were identified. LEfSe analysis indicated a greater abundance of Pseudomonas, Acinetbacter, Lactobacillus, Corynebacterium, Rothia in S-C group. Our study suggests a potential association between tongue coating microbiome and the severity of COVID-19 patients. [ABSTRACT FROM AUTHOR]

There is a continuous demand for a specific type of Chinese silk fabric, which is one of China's national intangible cultural heritage items called Xiang-Yun-Sha. Xiang-Yun-Sha is silk fabric dyed using the vegetable dyes from a yam and the mud from the Pearl Delta River. The ingenious and sophisticated dyeing process inspires us to explore new dyes for silk. Through learning from the traditional mud dyeing process of Xiang-Yun-Sha, especially the contents of the mud, lignin and iron species are recognized as key factors. Yet little attention has been dedicated to lignin as a dye despite its wide applications. In this study, the feasibility of using lignin to dye silk is investigated using sodium lignosulfonate and alkaline lignin as model systems. Thanks to their advantageous polyphenolic features, such as stacking tendency and ability to form stable complexes with iron ions, lignin-related compounds show excellent performance in serving as dyes by themselves, as well as protective coatings for other dyes; the dyed silk fabric could inherit anti-ultraviolet property from lignin. Considering that iron is inexpensive and that leftover lignin is a vastly underutilized biomass resource, this study offers a promising strategy to exploit the enormous potential of these naturally occurring materials by developing high value-added products. [ABSTRACT FROM AUTHOR]

In fabric manufacturing, sizing, also known as slashing is considered as one of the most important processes that provides protective coating on the surface of yarn resulting in weaving fabric with high efficiency and enhanced quality, even though it does not add any functional value during end-use application and is neither a part of fabric manufacturing process. Additionally, it involves desizing process upon the completion of weaving; hence, sizing is often referred as nonproductive process. This review presents a state-of-the-art conceptualization in sizing process along with efforts involved in size-free weaving, development of eco-friendly sizing agents, and sizing machineries. Also, based on the discussion, promising innovations have been highlighted for future research consideration. [ABSTRACT FROM AUTHOR]

Material degradation of metal alloys usually starts from the surface induced by tribological systems along with extremities including elevated temperatures, irradiations, erosion, corrosion, etc. Surface engineering, e.g. cold-working, carbonization, nitridation, etc., and coating are distinct routes that have been developed to protect the surface of metallic components. Laser cladding is an advanced method to produce metal alloys and build them up layer-by-layer, which has the advantage of being feasible in digitalizing the materials engineering via mixing and/or switching amongst individual feedstocks. It is compatible with many other robots- and CNC (computer numerical control)-based processes, such as machining, peening, rolling, burnishing, etc., for advanced remanufacturing. Recent studies on elemental and microstructural evolutions, as well as their response to external fields, e.g. ultrasonic vibrations or magnetic fields, during the solidification of the melt pools, provide new insights into laser cladding of metal alloys. Here, we present a special review on laser cladding of metal alloys with the focus placed on recent advances in technical variants towards high-quality protective coatings. Existing issues and their potential solutions will be discussed in tandem with material characterizations and performance evaluations. Through discussing the process-structure-performance relationships as well as their evaluations assisted by in-situ data collection and machine learning, we present the readers with a perspective on recent advances and provide an outlook on future developments of laser cladding for protective coatings and additive manufacturing. [ABSTRACT FROM AUTHOR]

For carbon steel (CS) in a corrosive hydraulic acid solution, various quantities of the molecule 3-phenyl-isoxazoline-carvone (PIC) were employed (1M; HCL). The inhibitory effects of the 3-phenyl-isoxazoline-carvone (PIC) were evaluated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), weight loss, surface morphology analysis (SEM), quantum chemical calculations (DFT), and Monte Carlo simulations (MC). According to the findings, the compound, 3-phenyl-isoxazoline-carvone (PIC) is a mixed-type inhibitor that significantly decreased the rate of carbon steel (CS) corrosion by creating a protective coating on the carbon steel surface (CS). According to EIS, PDP, and mass loss studies, the molecule 3-phenyl-isoxazoline-carvone (PIC) is a stronger corrosion inhibitor, with corrosion effectiveness of about 95% at 298 K temperature. Adsorption of the 3-phenyl-isoxazoline-carvone (PIC) molecule on the surface of carbon steel includes both physisorption and chemisorption, according to the Langmuir isotherm model. Aside from experimental methods, theoretical methods such as DFT simulations, molecular dynamics simulations, and the radial distribution method were used to provide detailed knowledge about the mechanism of corrosion inhibition and to reveal factors controlling the efficiency of the investigated inhibitor. [ABSTRACT FROM AUTHOR]

Al2O3, TiO2, and Al2O3-TiO2 coatings were deposited on AISI 304 stainless steel plates by the sol–gel dipping technique, and the effects of the coating composition on microstructure, wear, and corrosion characteristics were examined. Tribological features were determined by ball-on-disc sliding tests against an Al2O3 ball under a 10 N load, while corrosion properties were evaluated by potentiodynamic polarisation tests performed in 3.5% wt. NaCl solution. γ-Al2O3, α-Al2O3, and rutile phases were detected in the hybrid coatings. The highest coating thickness was obtained in single Al2O3 film and decreased with an increasing amount of TiO2 nanoparticles. The single Al2O3 layer had both the highest wear resistance and the lowest corrosion resistance. Although TiO2 addition caused an increase in the wear rate, it improved the corrosion resistance of the coating by filling the voids in the Al2O3 film. The Al2O3-TiO2 hybrid film with a relative ratio of 6:1 as a candidate for the wear- and corrosion-resistant coating decreased wear and corrosion losses of the 304 substrates by 83% and 97%, respectively. [ABSTRACT FROM AUTHOR]

Since long back, organic coatings tailored to corrosion protection of the underneath metallic substrates to ensure reliability and durability of the coated part. Whereas, imperfections in these coatings due to weathering leads to crack which eventually exposes a small area of the metal, thus, leads to localised corrosion. Self-healing coatings are smart coatings with the ability to heal such cracks autonomously to restore the protective function of the coatings. In present investigations, the efficiency of linseed oil-filled UF microcapsules was found to be improved by blending soybean oil to linseed oil in varying ratios. The efficiency of various blended microcapsules (SLO) was compared with linseed oil microcapsules (LO) for corrosion resistance in epoxy coatings. The experimental results revealed successful encapsulation of UF microcapsules of blended Linseed-Soybean oil (UF-SLO) and UF microcapsules of Linseed oil (UF-LO) by in situ polymerization. The synthesized microcapsules were characterized by optical microscope, particle size analyser, Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analyser (TGA) to investigate their surface morphology, size distribution, chemical structure (core and shell materials), and thermal stability of the microcapsules respectively. [ABSTRACT FROM AUTHOR]

In order to improve the corrosion resistance and bonding strength of the micro-arc oxidised (MAO) AZ91D magnesium (Mg) alloy, the hydroxyapatite (HA)-chitosan (CS) and polylactic acid hybrid (PLA) coatings on MAO Mg alloy were fabricated via electrochemical co-deposition and dip-coating method. The influences of different concentrations of PLA on the phase composition, surface morphology, hydrophobic, bonding strength, and corrosion resistance were investigated. The surface morphology and immersion test in simulated body fluid (SBF) showed that the PLA coating could further seal the surface and prevent the HA-CS coating from cracking, thus improving the corrosion resistance of the sample. The sample with 20% PLA had the lowest corrosion current density (1.13 × 10−8 A/cm2) and the highest strength (18.84 N). These results manifest that the MAO/HA-CS/PLA is a protective coating on magnesium alloys for implants application. [ABSTRACT FROM AUTHOR]

Plasma electrolytic oxidation (PEO) coatings on commercial pure titanium (Cp-Ti) and hot-dip aluminised Cp-Ti surfaces were prepared in an alkaline electrolyte. The morphological, structural, wear, and corrosion characteristics of the coatings were studied by using SEM, EDS, XRD, electrochemical polarisation, and dry sliding wear tests. The experimental results showed that the main compositions of the PEO coating on Cp-Ti are TiO2 and Al2TiO5 phases, while the PEO coating on hot-dip aluminised (HDA'ed) Cp-Ti mainly consists of the Al2O3 phase. The single PEO coating exhibited more porosity with small diameter micro-pores compared to the PEO coating on the HDA'ed sample. Electrochemical polarisation tests revealed that the PEO coating on the HDA'ed sample exhibited approximately 4.6 times more polarisation resistance than the single PEO coating and 10 times that of the bare Cp-Ti sample. According to the wear test results, the wear resistance of the bare Cp-Ti was doubled by hot-dip aluminising (HDA) and PEO treatments, while the single PEO treatment resulted in better resistance against dry sliding wear. [ABSTRACT FROM AUTHOR]

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Siloxane-polyurethane hybrid coatings were assessed for biofouling control caused by freshwater mussels. Invasive species such as zebra (Dreissena polymorpha) and quagga (Dreissena bugensis) mussels have rapidly spread through the waterways in the United States causing major concerns in reservoir infrastructure and freshwater lakes. Current coating solutions such as biocidal anti-fouling coatings are not suitable given the released biocides which may accumulate in reservoirs. Biocide free fouling release coatings based on silicone elastomers do not have adequate mechanical durability. The siloxane-polyurethane (SiPU) coatings were evaluated using model organism laboratory assays and real-life performance was evaluated in the freshwater field environment. Two coating compositions displayed excellent performance in field trials for up to 2+ years. The surface analysis experiments of the coatings indicate that the morphology of the coatings is affected by the formulations' solvent choice. These coatings show great promise in mitigating biofouling predominated by freshwater mussels. [ABSTRACT FROM AUTHOR]

In the process of electroless coatings, mild steel was used as a substrate for the Ni-P-ZnO composite coatings. Present study focused on annealing temperature effect on microhardness and resistance to corrosion of the ZnO reinforced Ni-P coatings. Variation in microhardness and corrosion resistance was observed in Ni-P-ZnO thin film at 200, 400 and 600°C annealing temperatures. Coatings phase transformation behaviour, surface structure and morphological studies were evaluated by X-ray diffraction and scanning electron microscopy (SEM). Chemical composition of the coatings is measured by using Energy dispersive spectroscopy (EDS). Results reveal that annealing temperature significantly affects the properties of the coatings. Increase in annealing temperature from 200 to 400°C improves the microhardness and corrosion resistance of the coatings. At 600°C annealing temperature, formation of coarse structure decreases the properties of the coatings. [ABSTRACT FROM AUTHOR]

Transition metal diboride-based thin films are promising candidates to replace state-of-the-art protective and functional coating materials due to their unique properties. Here, we focus on hexagonal WB2-z, showing that the AlB2 structure is stabilized by B vacancies exhibiting its energetic minima at sub-stoichiometric WB1.5. Nanoindentation reveals super-hardness of 0001 oriented α-WB2-z coatings, linearly decreasing by more than 15 GPa with predominant 10 1 ¯ 1 orientation. This anisotropy is attributed to differences in the generalized stacking fault energy of basal and pyramidal slip systems, highlighting the feasibility of tuning mechanical properties by crystallographic orientation relations. First report of an anisotropic elastoplastic behaviour in super-hard PVD AlB2 structured WB2-z. Theoretical and experimental verification of thermodynamically most stable sub-stoichiometric α-WB2-z coatings by structural and mechanical analysis. [ABSTRACT FROM AUTHOR]

In this work, the leave extracts of Calotropis gigantean, Eucalyptus globulus and buds of Syzygium aromaticum were prepared and coated on natural fibers based bamboo gauze fabric for wound dressing applications. The fabrics coated with different compositions of the natural extract were enhanced with rhEGF (REGEN-D™ 60). The morphology of developed samples was studied using SEM to know its pores sizes. Various mechanical properties have been studied. The antibacterial activity was studied using Gram positive and negative types of bacteria. The wound healing efficacy of the coated fabric samples were studied through in vivo method. The type of wound selected for the study was second degree wound. The dorsal surface of the rat's skin was removed and second degree wound was created. Then the developed fabric samples were dressed over the wound surface and the wound healing was studied by wound closure rate in equal interval of days. A specified composition of natural extracts coated on bamboo gauze fabric enhanced with rhEGF (REGEN-D™ 60) exhibits good antibacterial property was confirmed from the formation of zone of inhibition in antibacterial test against Escherichia coli and a Staphylococcus aureus and appropriate wound closure rate on second degree wound through in vivo evaluation. [ABSTRACT FROM AUTHOR]

In the part of work, the leave extracts of aloe vera, piper betel, and neem leaf were prepared and coated on bamboo fiber-based material for wound dressing applications. The fabrics coated with different compositions of the natural extract were enhanced with recombinant human epidermal growth factor (REGEN-D™ 150). The FTIR confirms the presence of alcoholic and phenolic group which were responsible for antibacterial activity. The SEM morphology of the developed dressing material was porous nature and more suitable for the process of curing wound. In antimicrobial tests, the zone of incubation of Escherichia coli and Staphylococcus aureus ranges from 18 to 22 mm. In vivo study using albino rats induced with diabetes reveals that the wound healing rate is increased in the range of 25–54% compared to a negative control group. [ABSTRACT FROM AUTHOR]

In this work, the leave extracts of Aloe vera, piper betel and neem leaf were prepared and coated on bamboo fiber based material for wound dressing applications. The fabrics coated with different compositions of the natural extract were enhanced with rhEGF (REGEN-D™ 150). The FTIR confirms the presence of alcoholic and phenolic group which were responsible for antibacterial activity. The SEM morphology of the developed dressing material was porous nature and more suitable for the process of curing wound. In antimicrobial tests, the zone of incubation of E. coli and S. aureus ranges from 18 mm and 22. In vivo study using albino rats induced with diabetes reveals that the wound healing rate is increased in the range of 25% to 54% compared to a negative-control group. Overall, the natural extracts coated dressing material has considerable potential and well suited for clinical application that was evidenced through antimicrobial and in vivo study results. Therefore, natural extracts coated on bamboo-based dressing materials are claimed to have helpful nature for wound healing and the current study will be one of the platforms for natural extracts coated material-based medical textile applications. [ABSTRACT FROM AUTHOR]

In this study, graphene was incorporated into a micro-arc oxidation coating to improve the wear and corrosion resistance of AZ31 alloy. For this purpose, the different concentration of graphene particles was used as 0 g/l, 0.5, 1, and 2 g/l. The wear tests were performed under loads of 2, 4, and 8 N. The composition and morphology of the coatings were investigated by scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The coating thickness increased with increasing graphene concentration. To evaluate the corrosion performance of the coatings, potentiodynamic polarization, and electrochemical impedance spectroscopy tests were performed after immersed samples for 0.5, 16, and 32 h. The wear test results show that wear rates significantly decreases with increasing graphene concentration. Corrosion tests showed that polarization resistance increased and corrosion current density decreased for the coatings with the graphene addition compared to substrate material. [ABSTRACT FROM AUTHOR]