Coating Technology Research Articles

Review on hard particle reinforced laser cladding high-entropy alloy coatings

Since their advent in 2004, high-entropy alloys have allured the field of materials science and engineering. Laser cladding technology, with its advantages of a small heat-affected zone and rapid heating and cooling, has become a popular technique for preparing high-entropy alloy coatings. Traditional high-entropy alloys have the problem of strength-plasticity mismatch, which limits the further application of laser cladding high-entropy alloys in industry. As a method to solve these challenges, hard particle reinforced alloy coating technology can effectively control the comprehensive properties of high-entropy alloy coatings. This paper first explores and analyzes the five strengthening mechanisms and four main influencing factors of hard particle reinforced laser cladding alloy coatings. Then, from the perspective of introducing particle types, the research status of ceramic particles, rare earth particles and other types of hard particle reinforced laser cladding high entropy alloy coatings is introduced. Finally, the characteristics of hard particle reinforced laser cladding high-entropy alloy coatings are summarized, and future recommendations for hard particle reinforced alloy coatings technology and its application in laser cladding high-entropy alloys are proposed, which will be helpful for researchers and producers in this field.

Sustainable Fire Protection: Reducing Carbon Footprint with Advanced Coating Technologies

Metallum Fire-Resistant paint, denoted as MFR henceforth, represents a cutting-edge insulating material with dual functionality as a fireproof solution, presenting substantial advantages in the realm of construction applications. This exposition derives its primary insights from the scholarly contributions documented in publications. The focal point of these investigations includes the assessment of fire hazards associated with polyethylene materials in building structures and the enhancement of mortars in high-temperature environments in tunnels. The purpose of this study is to evaluate the effectiveness of a modified cork-based coating (MFR) compared to traditional coatings in terms of corrosion protection, fire resistance, and thermal insulation properties in construction applications. This evaluation focuses on quantifying the efficacy of MFR by examining key properties, such as adhesion, the reduced thickness required for fire protection, thermal conductivity reduction, and corrosion resistance under extreme environmental conditions. MFR is highly effective in fire prevention for buildings and tunnels, withstanding temperatures over 1000 °C while maintaining structural integrity. A unique aspect of MFR is its use of cork shavings, a typically underutilized byproduct from wine-bottle-stopper production. This innovative not only amplifies MFR’s fire-resistant attributes, but also introduces sustainability and judicious resource utilization into its manufacturing processes.

Thermally stable and anti-corrosive polydimethyl siloxane composite coatings based on nanoforms of boron nitride

Coating technology has been emerged as a recognized and cost-effective approach in regard to mitigating issues that are linked to corrosion. We employed in-house synthesized boron nitride nanosheets (BNNS-CVD) and commercially available nanosized boron nitride (BN-nano) as fillers in this study to fabricate composite coatings with enhanced thermal stability and corrosion resistance. These fillers were dispersed in polydimethylsiloxane (PDMS) resin to develop composite coatings. The Fourier-transform infrared spectroscopy (FTIR), UV–visible spectroscopy, field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), and electrochemical impedance spectroscopy (EIS) were employed to characterize the prepared composite coatings. The FTIR analysis revealed a prominent absorption band around 1350 cm−1 that is indication of the distinctive B-N in-plane bending vibrations characteristic of boron nitride (BN). The FESEM images simultaneously confirmed the sheet-like morphology of both BN-nano and BNNS-CVD, which both found to be uniformly dispersed in the PDMS matrix. The EIS revealed that the composite films based on BNNS-CVD exhibited superior corrosion resistance compared to those based on BN-nano when exposed to a 3.5 wt% NaCl solution. Further, TGA profiles indicated that the composite films maintained their structural integrity up to 200 ℃ without degradation. Therefore, thermally stable and corrosion resistant coatings can be valuable for various new technology applications that involve corrosion issues.

(Dielectric Science & Technology Thomas Callinan Award) Rare-Earth Luminescence in Silicon-Based Thin Film Structures

For Si-based materials to be used in solid-state lighting and silicon photonics schemes it is necessary to have precise control of the optical emission from these materials. This can be accomplished using rare earth dopants such as Ce, Tb, and Eu to obtain blue, green, and red emissions, respectively. In this talk, we first will provide a review of our work in this field and then focus on Eu-doped films, which are particularly attractive for silicon photonic applications due to their intense emission in the visible spectral region [1]. We will also discuss the benefits of introducing a novel hybrid radio frequency (RF) magnetron sputtering source in the electron cyclotron resonance (ECR) plasma enhanced chemical vapour deposition (PECVD) reactor chamber [2], using the example of Tb-doped SiON films [3]. This approach contrasts with traditional doping methods which use metal-organic precursors or ion implantation to introduce rare-earth dopant species into the host matrix.[1] F. Azmi et al., “Tunable Emission from Eu:SiOxNy Thin Films Prepared by Integrated Magnetron Sputtering and Plasma Enhanced Chemical Vapor Deposition”, J. Vac. Sci. Technol. A 40, 043402 (2022); DOI: 10.1116/6.0001761[2] J.W. Miller et al., “Integrated ECR-PECVD and Magnetron Sputtering System for Rare-Earth-Doped Si-Based Materials”, Surface and Coatings Technology 336, 99 (2018); DOI: 10.1016/j.surfcoat.2017.08.051[3] Z. Khatami et al., "A comprehensive calibration of integrated magnetron sputtering and plasma enhanced chemical vapor deposition for rare-earth doped thin films", J. Mater. Res. (2023); DOI: 10.1557/s43578-023-01207-2

Research on the Application of Superhard Coating Technology for Cutting Tools in Mechanical Processing

The superhard coating technology for cutting tools has important applications in the field of mechanical processing. This article introduces the development of superhard coating materials for cutting tools, including low-pressure gas-phase synthesis of diamond, cubic boron nitride, and physical vapor deposition (PVD) coating technology. The superhard coating of cutting tools is widely used in turning, milling, tapping, key component machining, high-speed steel drill bits and taps. Research has shown that coatings can reduce cutting forces and improve tool life, but attention should be paid to residual compressive stress. The future development direction includes researching new superhard material cutting tools and developing coating methods that are more wear-resistant and have high temperature hardness.

Optimization design and performance improvement of ther-mal barrier coating (TBC) system

Thermal Barrier Coatings (TBC) technology has become one of the key technologies to improve the performance and prolong the service life of gas turbine and other high temperature equipment. In this study, the selection of materials, coating methods, the influence of environmental factors on the performance of TBC system and the thermal stress analysis and optimization strategy are discussed, improve the overall performance and stability of TBC system. TBC coatings were efficiently prepared by the use of Nikolay bonding layer and stabilized zirconia as top ceramic materials, combined with electron beam Physical vapor deposition (EB-PVD) and plasma spraying (APS) techniques. In addition, the thermal stress model was established by FEA, and the thermal stress distribution of TBC system under extreme operating conditions was analyzed in detail, to reduce thermal stress concentration and improve the thermal barrier effect of the coating. Finally, through the establishment of TBC system life prediction model and in-depth analysis of the failure mechanism, a series of preventive measures and performance improvement strategies are proposed, it provides theoretical basis and practical guidance for coating design of gas turbine and other high temperature equipment.

Construction of a Composite Sn‐DLC Artificial Protective Layer with Hierarchical Interfacial Coupling Based on Gradient Coating Technology Toward Robust Anodes for Zn Metal Batteries

AbstractDeveloping a robust zinc (Zn) anode, free from Zn dendrites and unwanted side reactions, relies on designing a durable and efficient interfacial protection layer. In this study, gradient coating technology is employed to construct a hierarchically structured composite of Sn with diamond‐like carbon (DLC/Sn‐DLC) as an artificial protective layer. The DLC framework endows DLC/Sn‐DLC layer with high stability and adaptability, achieving long‐term stability of the anode–electrolyte interface. The gradual‐composite Sn, with its Sn─O─C interface chemical bonds, facilitates rapid charge transfer and offers ample zincophilic sites at the base, promoting uniform Zn2+ reduction reaction and deposition. Additionally, the DLC/Sn‐DLC composite exhibits a “lotus effect” and favorable hydrophobic properties, preventing water‐reduced side reactions. Leveraging this structural design and the synergistic cooperation of DLC and Sn, the DLC/Sn‐DLC@Zn electrode demonstrates remarkable Zn plating/stripping reversibility, eliminating Zn dendrites and side reactions. Notably, under a high current density of 10 mA cm−2, the DLC/Sn‐DLC@Zn anode‐based symmetrical cell exhibits stable operation for over 1550 h, with a low nucleation overpotential of 101 mV. The DLC/Sn‐DLC@Zn||Mn3O4‐CNTs full battery delivers a high capacity of 109.8 mAh cm−2 after 5800 cycles at 2 A g−1, and the pouch cell shows potential for energy storage applications.

Development of detonation gas spraying technology of coatings in the E.O. Paton electric Welding Institute of the NASU (Overview)

Development of detonation gas spraying technology of coatings in the E.O. Paton electric Welding Institute of the NASU (Overview)

Extending Polymer Opal Structural Color Properties into the Near-Infrared

We report the fabrication and characterisation of near-IR reflecting films and coatings based on shear-assembled crystalline ensembles of polymer composite microspheres, also known as “polymer opals”. Extension of the emulsion polymerisation techniques for synthesis of tractable larger core-interlayer-shell (CIS) particles, of up to half a micron diameter, facilitates the engineering and processing of thin-film synthetic opals, with a tunable photonic stopband spanning an extended spectral range of λ ≈ 700–1600 nm. Samples exhibit strong “scattering cone” interactions, with considerable angular dependence and angle tuning possible, as measured with a goniometric technique. These intense optical resonances in the near-IR, particularly within the important region around λ ~ 800 nm, combined with an appreciable translucency within the visible light spectrum, is indicative of the potential applications in coatings technologies and solar cells.

Overview and Prospects of In-mold Coating and Molding Technology

Overview and Prospects of In-mold Coating and Molding Technology

Review of Underwater Anechoic Coating Technology Under Hydrostatic Pressure

AbstractThe underwater anechoic coating technology, which considers pressure resistance and low-frequency broadband sound absorption, has become a research hotspot in underwater acoustics and has received wide attention to address the increasingly advanced low-frequency sonar detection technology and adapt to the working environment of underwater vehicles in deep submergence. One the one hand, controlling low-frequency sound waves in water is more challenging than in air. On the other hand, in addition to initiating structural deformation, hydrostatic pressure also changes material parameters, both of which have a major effect on the sound absorption performance of the anechoic coating. Therefore, resolving the pressure resistance and acoustic performance of underwater acoustic coatings is difficult. Particularly, a bottleneck problem that must be addressed in this field is the acoustic structure design with low-frequency broadband sound absorption under high hydrostatic pressure. Based on the influence of hydrostatic pressure on underwater anechoic coatings, the research status of underwater acoustic structures under hydrostatic pressure from the aspects of sound absorption mechanisms, analysis methods, and structural designs is reviewed in this paper. Finally, the challenges and research trends encountered by underwater anechoic coating technology under hydrostatic pressure are summarized, providing a reference for the design and research of low-frequency broadband anechoic coating.

Mussel-Inspired Polymer-Based Coating Technology for Antifouling and Antibacterial Properties.

Zwitterionic coatings provide a promising antifouling strategy against biofouling adhesion. Quaternary ammonium cationic polymers can effectively kill bacteria on the surface, owing to their positive charges. This strategy can avoid the release of toxic biocides, which is highly desirable for constructing coatings for biomedical devices. The present work aims to develop a facile method by covalently grafting zwitterionic and cationic copolymers containing aldehydes to the remaining amine groups of self-polymerized dopamine. Reversible addition-fragmentation chain transfer polymerization was used to copolymerize either zwitterionic 2-methacryloyloxyethyl phosphorylcholine monomer (MPC) or cationic 2-(methacryloyloxy)ethyl trimethylammonium monomer (META) with 4-formyl phenyl methacrylate monomer (FPMA), and the formed copolymers poly(MPC-st-FPMA) and poly(META-st-FPMA) are denoted as MPF and MTF, respectively. MPF and MTF copolymers were then covalently grafted onto the amino groups of polydopamine-coated surfaces. PDA/MPF/MTF-coated surfaces exhibited antibacterial and antifouling properties against S. aureus, E. coli, and bovine serum albumin protein. In addition, they showed excellent viability of normal human lung fibroblast cells MRC-5. We expect the facile surface modification strategy discussed here to be applicable to medical device manufacturing.

High-Area-Capacity Cathode by Ultralong Carbon Nanotubes for Secondary Binder-Assisted Dry Coating Technology.

Thick electrodes with high mass loading and increased content of active materials are critical for achieving higher energy density in contemporary lithium-ion batteries (LIBs). Nonetheless, producing thick electrodes through the commonly used slurry coating technology remains a formidable challenge. In this study, we have addressed this challenge by developing a dry electrode technology by using ultralong multiwalled carbon nanotubes (MWCNT) as a conductive additive and secondary binder. The mixing process of electrode compositions and the fibrillation process of the polytetrafluoroethylene (PTFE) binder were optimized. The resulting LiCoO2 (LCO) electrode exhibited a remarkable mass loading of 48 mg cm-2 and an active material content of 95 wt %. Notably, the thick LCO electrode demonstrated a superior mechanical strength and electrochemical performance. After 100 cycles at a current density of 1/3 C, the electrode still exhibited a capacity retention of 91% of its initial capacity. This dry electrode technology provides a practicable and scalable approach to the powder-to-film LIB electrode manufacturing process.

Development and Application of Intelligent Coating Technology: A Review

Coating technology, as a part of surface engineering, has shown remarkable potential in future industrial applications. With the continuous development and improvement of coating technology, coatings have gradually become an indispensable part of industrial manufacturing, possessing various excellent properties and characteristics, such as superhydrophobicity and self-cleaning, enhanced biological antibacterial properties, and improved corrosion resistance. Intelligent coatings are not only rigid barriers between substrates and the environment but also coatings designed to respond to the environment and improve coating life or achieve certain special functions through this response. Biomimetics is a discipline that studies the structure, function, and behavior of living organisms and applies them to engineering design. Combining bionics with intelligent coating materials can not only improve the performance and functionality of intelligent coatings but also create more intelligent coating materials. This paper includes advanced superhydrophobic intelligent coatings, anticorrosion intelligent coatings, biological antibacterial intelligent coatings, and other intelligent coatings with specific functions. We also provide a detailed overview of the preparation methods and technologies of various representative intelligent coatings, as well as their properties and applications, which will offer some valuable references for the development direction of future intelligent coatings.

Enhancing Postharvest Quality and Shelf Life of Strawberries through Advanced Coating Technologies: A Comprehensive Investigation of Chitosan and Glycine Betaine Nanoparticle Treatments.

The application of natural polymer-based coatings presents a viable approach to prolong the longevity of fruits and tissue damage. This study investigates the impact of treatments involving glycine betaine (GB), chitosan (CTS), and chitosan-coated glycine betaine nanoparticles (CTS-GB NPs) on preserving the quality and reducing decay in strawberry fruits. The fruits were subjected to treatments with GB (1 mM), CTS (0.1%), CTS-GB NPs (0.1%), or distilled water at 20 °C for 5 min, followed by storage at 4 °C for 12 days. The results indicate that CTS and CTS-GB NPs treatments resulted in the highest tissue firmness, total anthocyanin content, and ascorbate peroxidase activity, while exhibiting the lowest decay percentage and weight loss, as well as reduced malondialdehyde levels at the end of storage. GB, CTS, and CTS-GB NPs treatments demonstrated elevated catalase activity and antioxidant capacity, coupled with lower electrolyte leakage and hydrogen peroxide levels. These treatments did not significantly differ from each other but were markedly different from the control. The results substantiate that CTS and CTS-GB NPs treatments effectively preserve strawberry quality and extend storage life by bolstering antioxidant capacity and mitigating free radical damage.

The Effect of a Coating Sprayed Using Supersonic Flame Coating Technology on the Mechanical Properties and Interface Structure of a Thick Steel/Aluminum Composite Plate during Hot Rolling

Given the characteristics of a thick steel/aluminum composite plate, such as its large thickness and the significant differences between its components, it is difficult to prepare using direct rolling. Instead, a thick steel/coating/aluminum composite plate may be successfully prepared by combining supersonic flame coating technology with a hot rolling composite process. In this study, the interface shear strength test, SEM, EDS, and other detection methods were applied to investigate the effects of the reduction rate and coating thickness on the interface structure and mechanical properties. The results show that under the condition of single-pass direct rolling, the micro-interface of steel/aluminum is improved with an increase in the reduction rate, but the bonding strength of the interface remains poor. After adding the coating, the thickness of the diffusion layer and the shear strength increase significantly. When the coating thickness is reduced to 0.1 mm, the deformation coordination and shear strength of the composite plate are further enhanced under the combined action of mechanical interlocking and metallurgical bonding. The tensile shear fracture is mainly located at the steel/coating interface. The interfacial shear strength reaches 66 MPa, which exceeds the requirements of the US military standard MIL-J-24445A (SH) for steel/aluminum shear strength. The research results thus support the use of this new method for the simple and efficient production of thick steel/aluminum composite plates.

Special Issue on Corrosion and Coating Technology

Special Issue on Corrosion and Coating Technology

A Review of Nanofiber Coating Technology for Future Food Packaging

This brief review explores the burgeoning field of antimicrobial nanofiber coating technologies, poised to redefine the standards of food packaging for enhanced safety and longevity. With the global imperative for reducing food spoilage and extending shelf life, this paper highlights the revolutionary role of nanofibers infused with antimicrobial agents. These cuttingedge coatings promise not only to actively combat microbial growth but also to maintain the sensory and nutritional quality of food products. By integrating insights from recent studies and technological advancements, the review underscores the necessity for interdisciplinary collaboration among scientists, industry experts, and policymakers. The aim is to accelerate the development, scalability, and regulatory approval of these innovative materials, thereby setting a new benchmark for futureproofing food packaging against microbial contamination.

A Comparative Study between a Thermal Spray CoCrFeMnNi0.8V/WC-Co High Entropy Alloy Composite Coating and Plain CoCrFeMnNi0.8V and WC-Co Thermal Spray Coatings

High entropy alloys (HEAs) have emerged as a frontier in surface engineering, challenging the status quo of traditional alloy systems with their exceptional mechanical properties and corrosion resistance. This study investigates the CoCrFeMnNi0.8V HEA, both as a standalone alloy and in a composite with WC-Co, to evaluate their potential as innovative surface coatings. The CoCrFeMnNi0.8V alloy, enriched with vanadium, demonstrates a unique microstructure with enhanced hardness and wear resistance, while the addition of WC-Co particles contributes to improved toughness and durability. By employing High Velocity Oxy-Fuel (HVOF) thermal spray techniques, coatings are deposited onto steel substrates and subjected to rigorous microstructural characterization, wear, and corrosion resistance testing. The results reveal that the CoCrFeMnNi0.8V coating exhibits impressive corrosion resistance in chloride-rich environments. The composite coating leverages the synergy between the HEA’s inherent corrosion resistance and WC-Co’s wear resistance, striking a balance that suits demanding applications. With optimized processing conditions, the composite WC-Co-reinforced high entropy alloy coating could offer a significant advancement in protective coatings technology, especially for maritime and other corrosive settings. This work not only underscores the versatility of HEAs in surface engineering applications but also opens avenues for the development of new material mixtures.

Extreme High Speed Laser Application: A Revolution in Coating and Repair Technology

Abstract The extreme high-speed laser application (EHLA) process offers efficient deposition of high-performance materials in aerospace manufacturing, providing key advantages compared to conventional laser cladding. As a sustainable alternative to chrome plating, EHLA excels in material integrity, efficiency, and performance, while reducing costs compared to thermal spray and conventional laser cladding. This article discusses how EHLA can help to address many sustainability concerns within the manufacturing sector.