Coating Materials Research Articles

Nanocomposite Coatings for Anti-Corrosion Properties of Metallic Substrates.

Nanocomposites are high-performance materials with exceptional characteristics that possess properties that their individual constituents, by themselves, cannot provide. They have useful applications in many fields, ranging from membrane processes to fuel cells, biomedical devices, and anti-corrosion protection. Well-tailored nanocomposites are promising materials for anti-corrosion coatings on metals and alloys, exhibiting simple barrier protection or even smart auto-responsive and self-healing functionalities. Nanocomposite coatings can be prepared by using a large variety of matrices and reinforcement materials, often acting in synergy. In this context, recent advances in the preparation and characterization of corrosion-resistant nanocomposite coatings based on metallic, polymeric, and ceramic matrices, as well as the incorporation of various reinforcement materials, are reviewed. The review presents the most important materials used as matrices for nanocomposites (metals, polymers, and ceramics), the most popular fillers (nanoparticles, nanotubes, nanowires, nanorods, nanoplatelets, nanosheets, nanofilms, or nanocapsules), and their combinations. Some of the most important characteristics and applications of nanocomposite coatings, as well as the challenges for future research, are briefly discussed.

Undulating and porous structure tuned surface cracking behavior of Yb2Si2O7 environmental barrier coatings under steam cycling

Ytterbium disilicate (Yb2Si2O7, YbDS) is an excellent top-layer material for environmental barrier coatings (EBCs) to protect ceramic matrix composites (CMCs) from harsh corrosion. However, the EBC surface cracking due to the corrosion transformation from YbDS to ytterbium monosilicate (Yb2SiO5, YbMS) during steam cycling is a bottleneck problem for its application. In this paper, four distinct geometric models of EBC with pre-cracks were developed to determine how the undulating and porous structure tuned EBC surface cracking. It was found that the pre-cracks in the valleys of the EBC surface were more likely to propagate than those at the peaks. Wavelength variation on the EBC surface had a more pronounced effect on crack propagation than amplitude variation. The porous structure not only alleviated EBC surface cracking, but also reduced the promotion of crack propagation caused by increasing wavelength. This indicates that optimizing the microstructure of EBCs will contribute to improving their performance.

Structure and thermal properties of SrCe1-xSnxO3 (x=0.1 … 0.5) as a promising thermal barrier coating

Gas turbines efficiency growth is primarily associated with an increase in the operating temperature of the combustion chamber, which places new stringent requirements on the materials of thermal barrier coatings. Strontium cerate doped with tin SrCe1- xSnxO3 where x = 0.1 … 0.5, was proposed as a promising material. The research has shown that the lightly doped solid solution SrCe1-xSnxO3 has an orthorhombic Pnma structure at x < 0.3, whereas at a high content of Sn4+ the monoclinic structure P21/m becomes more favorable. Thermogravimetric analysis (TGA) in reducing atmosphere (5%H2 in Ar) shows no mass lost as a result of unchangeable charge of Ce4+ and Sn4+. An increase in the distortion of the crystal lattice, due to the large difference in the ionic radii of Ce4+ and Sn4+, leads to a deterioration in the symmetry of the crystal lattice, a reduction of thermal conductivity (from 1.9 to 1.4 W m−1 K−1 at 1000 °C) and at the same time, growth of hardness and porosity. The increase in porosity, along with an increase in the required temperature of solid-state synthesis, indicates an enhancement in the melting point of the obtained materials. For the compounds with an orthorhombic structure, the thermal expansion coefficient increases with a growth in the Sn content, achieving a highest point 12.47·10−6 K−1 at 1100 °C for x = 0.3. The combination of the revealed properties and their comparison with advanced refractories makes the solid solution, primarily SrCe0.5Sn0.5O3, a promising material for application as thermal barrier coatings.

High-temperature wear and oxidation behavior of (CrNbTaMoVW)N high entropy films deposited by reactive magnetron sputtering

Rapid advancements in industrial technology necessitate mechanical parts capable of operating at high temperatures. High entropy alloy films have emerged as promising material for high-temperature resistant coatings, providing improved friction control and wear reduction. In this study, (CrNbTaMoVW)N high-entropy films were fabricated on YG6 cemented carbide substrates using reactive DC magnetron sputtering. The oxidation and tribological performance of the films were investigated across a temperature range from room temperature to 800 °C. Oxidation results revealed that (CrNbTaMoVW)N film maintained its simple Face-Centered Cubic (FCC) structure up to 600 °C for 3 h in the presence of air. At 800 °C, complete oxidation occurred, resulting in the formation of complex metal oxides and metal oxynitrides, and a structural transformation from FCC to these compounds. Following oxidation at 600 °C for 3 h, High-Entropy Alloy (HEA) film exhibited the maximum values of hardness (30.6 GPa) and modulus (301.7 GPa). Tribological results demonstrated an increase in both friction coefficient and wear rate with rising test temperature. However, (CrNbTaMoVW)N film showed a relatively low wear rate ranging from room temperature to 600 °C, approximately 10−15 m3/N•m, thus indicating excellent high-temperature tribological properties. Notably, the wear resistance of (CrNbTaMoVW)N film was significantly compromised at 800 °C due to the formation of loosely bonded metal oxides with reduced hardness, in contrast to the test temperature of 600 °C.

A Modified BRDF Model Based on Cauchy-Lorentz Distribution Theory for Metal and Coating Materials

This paper presents a modified Bidirectional Reflectance Distribution Function (BRDF) model based on the Cauchy–Lorentz distribution that accurately characterizes the reflected energy distribution of typical materials, such as metals and coatings in hemispherical space. The proposed model overcomes the problem of large errors in classical models when detecting angles far away from the specular reflection angle by dividing the reflected light into specular reflection, directional diffuse reflection, and ideal diffuse reflection components. The newly added directional diffuse reflection component is represented by the Cauchy–Lorentz distribution, and its parameters are directly obtained from experimental measurement curves without distribution fitting. Surface morphology and model parameters are determined through measurements, and the comparison between simulation and actual measurement results shows that the modified BRDF model is in excellent agreement with the measured data. The proposed model not only achieves higher accuracy and universality, but it also represents a significant advancement in the field of BRDF modeling research. Its contributions have profound implications for advancing the state of the art in BRDF modeling, as well as having a broader impact on computer graphics and computer vision domains.

Research on Thermal Insulation Characteristics of Thermal Barrier Coating Materials Based on Human-Machine-Environment Engineering

Aiming at the problem that automotive human-machine-environment engineering research the temperature in the vehicle is too high to restrict the working efficiency of personnel and the comprehensive performance of the vehicle. This paper expounds the essence of human-machine-environment engineering research, analyzes the current research status of thermal barrier coating materials, compares and analyzes the thermal insulation performance of thermal barrier coating materials at various stages, and verifies the thermal insulation characteristics of thermal barrier coating materials through experiments, which provides a theoretical reference for the research of human-machine-environment engineering in the automotive field.

Fire Damage Characteristics of Fire-Resistant Coating Materials in Petrochemical Plant Facilities

As industrial facilities, petrochemical plants require prompt investigation, diagnosis, and recovery in the event of fire damage associated with disasters and accidents. Due to the characteristics of petrochemical plants, which are mostly composed of steel structures with fire-resistant coating materials, the coating materials are the first to be damaged. Accordingly, in this study, the fire damage characteristics of fire-resistant coating materials were analyzed experimentally, verifying the possibility of estimating the heating temperatures based on such characteristics. The results show a correlation between the foam expansion ratio and the heating temperature of intumescent fire-resistant coating materials with foam properties. A significant correlation was found between the density and adhesion strength ratio and the heating temperature of spray-applied fire-resistant coatings. The results suggest the possibility of estimating the heating temperatures based solely on the fire damage characteristics of the coating materials, which could provide a platform for simplifying existing methods for investigating and diagnosing fire damage.

Simulation of metal ceramic single layer coatings for solar energy applications

The coating materials, thickness and number of layers directly influence the reflectance and absorptance properties of the thin films. However, while selecting the materials for single and coatings, the substrate’s refractive index; bond layer, functional layer and protective layer have to be carefully chosen to obtain the desired reflectance and absorptance values. Hence, modelling and simulating the thin film coatings is essential before conducting the experiments to get meaningful results. The simulation results of single coatings have been discussed. Generally, glass is one of the widely used substrate materials for solar reflectors, aluminum is the optimal functional material, with a reflection of 93 % of light. Nickel would be a preferable functional layer with a reflection of 64 % and absorptance of 36 %, Si3N4 being the acceptable bond layers and protective layers with a reflection of 68 % some solar thermal receiver tube applications however research effort is being made to find alternate lightweight materials for this application. Polycarbonate has been chosen as an alternate material for the substrate because it is light in weight with a reflection of 93 %, which is durable and not fragile.

Preparation of Active Food Packaging and Coating Material Based on Bacterial Cellulose to Increase Food Safety

The use of bacterial probiotic metabolite-based active-packaging and coatings is an innovative approach that has gained widespread attention worldwide. Additionally, its utilization can lead to improvements in qualities and properties of food products. This study was aimed to develop a food spoilage prevention system using active food packaging and coating material in preventing food spoilage while increasing its shelflife. The materials used were bacterial cellulose (BC) based bioplastics fortified with fermented soymilk extracts (FSME) using Lactobacillus acidophilus as the producer of the antimicrobial and antioxidant agents. Moreover, the applications of FSME containing probiotic bacterial metabolites are discussed to highlight their efficacy in enhancing the quality and shelf life of food products.The antimicrobial test showed that the FSME could inhibit the growth of pathogenic microbial cultures at minimum inhibitory concentration (MIC) of 10% (v/v) as shown by clear zones, around colonies of E. coli (14.33±0.58 mm), S. aureus (18.33±6.03 mm), S. Typhimurium (11.67±1.15 mm), L. monocytogenes (11.33±2.31 mm), and B. cereus (13.33±3.06 mm). Meanwhile the results of IC50 for antioxidant activity test (µg/mL) indicated that the FSME showed radical scavenging activity against DPPH at approximately 75.27±2.552 (2.5%, v/v), 55.00±0.791 (5.0%, v/v), 43.17±1.603 (7.5%, v/v) and 15.05±0.346 (10%, v/v), respectively. The shelflife of strawberries coated with the active food coating using the bioplastic fortified with FSME showed an increase in shelf life of 14 days at 4°C. The overall results indicated that the use of BC based bioplastics fortified with FSME can play an important role in preventing premature spoilage and increasing the shelf life of food products.

Evaluation of the Polymer Modified Tack Coat on Aged Concrete Pavement: An Experimental Study on Adhesion Properties

This study addresses the challenges of overlaying old concrete pavement with asphalt by introducing a new trackless tack coat material containing polymer. The aim is to enhance the durability of asphalt concrete overlay pavement on old cement concrete pavement. It contributes to the development of improved construction techniques for pavement rehabilitation and highlights the need for reliable adhesion performance evaluation based on different spray amounts and surface conditions. Additionally, to evaluate the effect of the adhesion performance based on the spraying amount, a tensile adhesion test was conducted by applying spray amounts of 0.30, 0.45, and 0.60 l/m2 on different surface conditions. The basic and adhesion performances of the polymer-modified tack coat material are evaluated through direct tensile and shear bond strength tests. The test outcomes demonstrated that the newly developed polymer-modified tack coat material had considerably greater adhesion strength compared to the traditional rapid-setting products. Its adhesive strength was 1.68 times higher on concrete and 1.78 times higher on asphalt. The new trackless tack coat material exhibited an adhesion performance of 1.05 MPa in direct tensile strength at 0.45 l/m2, which was 1.21 times higher than the rapid-setting tack coat. Results also confirmed that the new tack coat material exhibits values 1.90 times greater than the conventional rapid-setting tack coat material in shear bond strength, respectively. By simulating the process of separation and re-adhesion of pavement layers caused, the new tack coat material shows a tensile adhesion strength of 63% of the original state, which is advantageous for securing the durability of the pavement. Overall, the newly developed polymer-modified trackless tack coat has been shown to effectively enhance the adhesion performance between pavement layers without process delay, highlighting the potential of the new tack coat material to enhance the durability of asphalt concrete overlay pavement on old cement concrete pavement.

A Review: Combination of Fungicide, Polymer Coating and Packaging Materials on Improve Germination Rate and Improve Uniformity of Seedling Emergence of Different Seeds during Storage

Seed coating is a method of encasing seeds in adhesive materials to improve germination and performance while lowering cost. Seed coating has been widely used in agriculture as an efficient way to reduce biotic and abiotic stressors, hence boosting crop growth, productivity, and health, in order to satisfy the demands of the development of precision agriculture. Plant-beneficial microorganisms include Trichoderma, rhizobium, arbuscular mycorrhizal fungusfungi and plant growth-promoting bacteria. Fungicide seed treatment is easy, affordable, and efficient. Additionally, it is well known that the selection of chemicals for seed treatment also has a favourable impact on seed viability and vigour during germination storage. Seed coating polymers are utilised in conjunction with active components like fungicides and insecticides. A new era of biocontrol techniques has recently begun. By utilising hostile microbes to fight seed-borne illnesses, new technology is being developed. Beneficial fungus like Trichoderma harzianum and Trichoderma viride are among the bioagents most powerful and efficient fungus- and soil-borne pathogen suppressants such as seedling blight, collar rot, stem rot, root rot, dry root rot, and their use may can effectively manage each of these illnesses, and thus encourage crop growth and yield.

Comprehensive Analysis of Different Coating Materials on the POM Substrate.

This study presents a comprehensive analysis of different coating materials on the POM substrate. Specifically, it investigated physical vapour deposition (PVD) coatings of aluminium (Al), chromium (Cr), and chromium nitride (CrN) of three various thicknesses. The deposition of Al was accomplished through a three-step process, particularly plasma activation, metallisation of Al by magnetron sputtering, and plasma polymerisation. The deposition of Cr was attained using the magnetron sputtering technique in a single step. For the deposition of CrN, a two-step process was employed. The first step involved the metallisation of Cr using magnetron sputtering, while the second step involved the vapour deposition of CrN, obtained through the reactive metallisation of Cr and nitrogen using magnetron sputtering. The focus of the research was to conduct comprehensive indentation tests to obtain the surface hardness of the analysed multilayer coatings, SEM analyses to examine surface morphology, and thorough adhesion analyses between the POM substrate and the appropriate PVD coating.

Simulation study of nanomaterials in heat pipe enhanced high power LED heat sink

To facilitate the simulation of heat dissipation of high-power LED lamps, a set of simplified models for tubular heat pipes and carbon nanotube arrays were first established to estimate their thermal conductivity. Then several kinds of radiators were designed. The application of nanomaterials and heat pipes in the heat dissipation of lamps was studied by the finite element method. It is found that the radiator with vertical suspended fins strengthened by a heat pipe and heat dissipation coating has a better heat dissipation effect than other radiators. Finally, the simulation study of thermal interface materials and heat dissipation coatings for lamps and lanterns heat dissipation is carried out. The results show that the thermal interface materials of carbon nanotubes and carbon nano coatings can enhance the heat dissipation performance of lamps.

Photoluminescent Material for Protective and Decorative Coatings of Building Constructions and Elements of Evacuation Systems

Photoluminescent Material for Protective and Decorative Coatings of Building Constructions and Elements of Evacuation Systems

P‐80: Process Optimization of High Hardness Polarizer for Touch Display

In this article, we optimized the preparation process of Hard Coat (HC) materials, studied the influence of UV and postbake parameters on curing rate and film surface warpage, improved the warpage of the film during the curing process, and successfully prepared a high‐hardness HC film that can be applied to touch display. At the same time, by optimizing the pretreatment of the film surface, the adhesion of the Anti‐Fingerprint (AF)material on the HC surface is improved, so that the surface of HC film has no scratches after abrasion test, and the WCA is kept above 110°, which meets requirement the of touch display.

EFFECTS OF ALLOYING ELEMENTS AND SURFACE PROPERTIES ON THE CORROSION BEHAVIOR OF HVOF-DEPOSITED WC COATINGS

The main purpose of this study is to investigate the corrosion behavior of nickel-aluminum buffer and tungsten-carbide-based ceramic-metal composite coated materials on EN 1.4404 quality stainless steels in a sulfuric acid (H2SO4) environment for petrochemical industry applications. For this purpose, tungsten-carbide-based coatings were produced on nickel-aluminum-deposited 1.4404 stainless-steel substrates using the HVOF (High Velocity Oxy-Fuel) technique. In the characterization of coatings, X-ray diffraction (XRD) for phase analysis, optical microscope and scanning electron microscope (SEM) for surface morphology, image analyzer for coating thickness measurements, energy distribution spectroscopy (EDS) for elemental analysis, and roughness device for surface structures, were used. WC-, Co-, Ni-, and NiAl-based phases were observed in the coatings. According to metallographic studies, all the coatings had a similar coating microstructure and made good contact with the substrate. Potentiodynamic polarization measurements and corrosion tests were carried out to determine the corrosion behavior of HVOF plasma-sprayed coatings using a potentiostat/galvanostat. The results showed that the WCCo-NiAl-coated stainless-steel substrate had a higher corrosion resistance to the H2SO4 environment than the NiAl and WCNi-NiAl samples.

Effect of Seed Coating and Packaging Material on Viability and Vigor of Soybean Seed in Room Temperature Storage

Soybean seed procurement was challenging due to the quality degradation during the seed storage period. Seed coating is necessary in order to overcome the leakage of seed metabolites. Seed coating has to be supported by a storage package that can protect the seed from temperature and humidity fluctuations in storage. This study aimed to determine the effect of seed coating using antioxidants and storage packaging to maintain the viability and vigor of soybean seeds. The experiment was carried out factorially with the basic pattern of Completely Randomized Design (CRD) and was repetitively replications by three times. The first factor was seed coating, which consisted of 4 levels such as M1=no coating, M2= 3% of Arabic gum + ascorbic acid, M3= 3% of Arabic gum + tocopherol, and M4= 3% of Arabic gum + mangosteen peel extract. The second factor was that the storage package consisted of 3 levels, which were N1= aluminum foil, N2= polyethylene plastic, and N3= plastic sack. The interaction between the seed coating material and storage package on seed moisture content with the best treatment was seed coating using ascorbic acid and aluminum foil package, seed coating treatment carried out the best effect without implementing the seed coating, and the storage package treatment that presented the best effect was aluminum foil package.

Fabrication and Characterization of Carrageenan/ZnO/Chitosan Composite Films.

In this study, a high-performance carrageenan/ZnO/chitosan composite film (FCA/ZnO/CS) was fabricated by the solution/dispersion casting method and layer-by-layer method. The first layer was nano-ZnO dispersed in carrageenan solution, and the second layer was chitosan dissolved in acetic acid. The morphology, chemical structure, surface wettability, barrier properties, mechanical properties, optical properties, and antibacterial activity of FCA/ZnO/CS were evaluated compared with a carrageenan film (FCA) and carrageenan/ZnO composite film (FCA/ZnO). This study revealed that the Zn element in FCA/ZnO/CS existed in the form of Zn2+ in FCA/ZnO/CS. There existed electrostatic interaction and hydrogen bonding between CA and CS. As a result, the mechanical strength and transparency of FCA/ZnO/CS were enhanced and the water vapor transmittance of FCA/ZnO/CS was decreased compared with that of FCA/ZnO. Furthermore, the addition of ZnO and CS greatly enhanced the antibacterial activity of Escherichia coli and also had a certain inhibitory effect on Staphylococcus aureus. FCA/ZnO/CS is expected to be a potential candidate material for food packaging, wound dressings, and various surface antimicrobial coatings.

Thermo-physical properties, morphology and thermal shock behavior of EB-PVD thermal barrier coating with DLC YbGdZrO/YSZ system

(Yb0.1Gd0.9)2Zr2O7 (YbGdZrO) rare earth modified zirconate ceramics is one of the novel thermal barrier coatings (TBCs) materials which has attracted much attention in recent years and is suitable for higher temperature applications. YbGdZrO ceramic powders gained from solid-phase synthesis show a single defect fluorite structure. After calcined at 1723 K upon 400 h, whose powder does not form any new phases and exhibit outstanding thermal durability. The thermal expansion coefficient of YbGdZrO ceramics with the elevated temperature to 1573 K is attained to 10.76 × 10−6 K−1, which is slightly smaller than that of Gd2Zr2O7 (GZO) material (10.98 ×10−6 K−1) at the same temperature. The arithmetic mean of coefficient of thermal diffusion of YbGdZrO bulks measured at 1273 K is 0.385 mm2/s, that seems to be equivalent to that of GZO ceramics (0.388 mm2/s, 1273 K). The X-ray diffraction feature peaks of electron beam physical vapor deposition (EB-PVD) YbGdZrO ceramic coatings almost resemble to its ingot, except that the crystal face indices of their two strongest peaks are different. The pyramid-like shape can be scrutinized on top tip of columnar grain of the as-deposited YbGdZrO ceramic layer, which is associated to the cubic lattice in the fluorite structure. After 3000 cycles of flame thermal shock, the upper half of the coated sample surface occurs light green. While the closer is the position to edge of the specimen, the more obvious is the color. In addition, many small black spots with disorderly distribution are observed on the coating surface. A large number of irregularly distributed and cross-linked micro-cracks are displayed on the surface of YbGdZrO ceramic top layer as well as the averaged width of these micro-cracks is determined to be ∼8.523 µm. Although the ceramic coating appears to have a small number of layered exfoliation, the chemical composition of the exposed region still contains only elements of Yb, Gd, Zr and O. It does not stretch to either interface of double-ceramic-layer (DCL) YbGdZrO/YSZ or interior of YSZ ceramic coating.

Synthesis and Evaluation of Antimicrobial Biobased Waxes as Coating Materials.

The objective of this study was to synthesize and evaluate the efficacy of antimicrobial waxes to be used as both physical and biological protection to perishable fruits and vegetables. The existing wax materials used in postharvest coating applications do not provide this antimicrobial functionality. One class of such waxes was obtained by covalently linking quaternary ammonium compounds (QACs) featuring alkyl, benzyl, and stearyl ester hydrophobic side groups to the terminal position of a bromo stearyl ester. A second class was obtained by linking these QACs to the pendant hydroxyl group of an aliphatic diamide made of 12-hydroxystearic acid, stearic acid, and ethylene diamine. In total, six distinct structures having three different QAC groups were synthesized. Compounds containing QACs with C8 alkyl groups exhibited potent inhibition toward the growth of both bacteria and fungi. Notably, the complete inhibition of Penicillium italicum and Geotrichum candidum, two fungi detrimental to the postharvest quality of fruits, as well as the complete destruction of viable cells for Gram-positive and Gram-negative bacteria was observed when these organisms were incubated in contact with QAC waxes or dispersed in an aqueous system at a concentration of 1.0 mM. Comparatively, benzalkonium chloride with an alkyl chain length of 10 carbon can completely inhibit Staphylococcus aureus at a concentration of 1.44 mM. The properties of the attached hydrophobic groups appeared to exert a strong influence on antimicrobial activity presumably due to differences in molecular orientation, size, and differences among microbial cellular structures.