Browse Topic: Coatings, colorants, and finishes
Biomanufacturing uses microorganisms to produce chemicals or materials of interest, much like a brewery uses fermentation by yeast to produce the alcohol in beer. Biomanufacturing relies upon synthetic biology to reprogram yeast or other microorganisms to produce something of greater value, such as fuel, food, or pharmaceuticals. Industrial biomanufacturing has made significant advances and the products it can deliver include reactive coatings and textiles, sensors, optical materials that can bend light, and new therapeutics such as antimicrobials and vaccines. The convergence of synthetic biology, robotics, and artificial intelligence is opening the way to produce materials never before possible in the commercial market. These same technologies create the opportunity for the miniaturization of this technology to fit into ever more compact spaces, bringing forward deployment of these mini-factories closer and closer to the point of need.
P2-type layered oxides are good cathode materials in high-performance sodium-ion batteries since they have desirable two-dimensional ion migration pathways. However, their instability at interfaces and their attenuation as cycles persist also remain a significant challenge. To increase their electrochemical stability, surface coating is also a good plan, but the balance between the coating and ionic conductivity is one of the key challenges. This study constructed an immensely thin layer of alumina (Al2O3) coating, and the influence of the amount of the coating (0.3-1.2 wt percent) on the working of the material was methodically examined. Electrochemical analysis showed that the lowest levels of Al2O3 (0.3 wt) provide the greatest improvement in performance. The optimized sample showed a retention capacity of 96.35 after 100 cycles of operation at 1C, significantly higher compared with samples that had increased coating contents. An analysis of cyclic voltammetry and impedance spectroscopy was subsequently done to corroborate the presence of a 0.3 wt% coating, which infected the electrode-electrolyte interface by inhibiting side reactions but minimally obstructing sodium-ion transport and thus promoting reaction reversibility and improved interfacial kinetics. These results highlight the importance of a less-is-more rule when it comes to surface coating and provide a novel understanding of how long-life sodium-ion battery cathodes can be designed by carefully engineered interfaces.
A team of researchers at the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart developed a biohybrid micro swimmer covered with magnetic material, whose swimming ability is largely unaffected by the coating. The team from the Physical Intelligence Department at MPI-IS published their work in the journal Matter, which covers a wide range of materials science research.
In military and aerospace systems, thin film patterned substrates literally serve as the foundation of some of the most critical electronic assemblies, including radio frequency (RF), microwave, millimeter wave, and high-speed digital circuits. These substrates are typically made by depositing extremely thin layers of conductive and dielectric materials on bases built from materials like alumina, aluminum nitride, quartz, or certain high-performance titanates with various dielectric constants up to a k of 4,000.
Additive manufacturing (AM) processes facilitate the production of components with high geometrical complexity, presenting substantial opportunities for innovation in demanding sectors such as aerospace and biomedical engineering. A significant challenge impeding their broader application is the characteristic surface roughness of as-fabricated parts, which results from the layer-wise construction and the presence of partially melted powder particles. While electrochemical polishing (EP) represents a viable post-processing technique for achieving a smooth surface finish, a comprehensive understanding of how the non-equilibrium microstructures characteristic of AM materials interact with the EP process remains incomplete. This investigation centers on the electrochemical polishing behavior of Ti-6Al-4V alloy fabricated by direct energy deposition (DED), utilizing a sodium chloride-ethylene glycol electrolyte. The findings reveal that the material's distinct engenders anisotropic anodic dissolution. This behavior is attributed to the differential electrochemical potentials among the constituent phases and their crystallographic orientations, which consequently narrows the operational process window for effective, uniform polishing. This preferential dissolution of certain phases results in the formation of a subtle, micro-scale topographical variation that mirrors the orientation of the original columnar grain structure. Notwithstanding this microstructural influence, the EP treatment proved highly successful in refining the surface finish, substantially decreasing the average surface roughness from 0.350 μm to 0.042 μm. Concurrently, the treatment led to a significant enhancement in the alloy's corrosion resistance, attributed to an oxide layer. These findings underscore the critical necessity of accounting for microstructural characteristics when developing optimized electrochemical polishing protocols for additively manufactured components.
The malfunction of the aircraft windshield electric heating system, particularly arc discharge, poses a serious threat to flight safety by causing glass breakage. A systematic study was conducted on the causes and effects of arc faults on windshield structural integrity, employing macroscopic observation, microscopic analysis, and energy dispersive spectroscopy (EDS) following a windshield fracture incident. The results indicate that arc discharge typically occurs at the interface between the heating film busbar and adjacent structures. Localized high temperatures cause the outer glass to fracture, generating radial cracks. The ablation of the busbar silver coating and the carbonization of the PVB interlayer are direct evidence of arc action, whereas the heating wire remains a passive component affected by the high-temperature environment. The fault is primarily attributed to local disbonding at the busbar interface and moisture ingress. Based on the findings, recommendations are proposed for process optimization and inspection method improvement, providing a basis for the safe design and maintenance of windshield structures.
This research demonstrates a facile method for fabricating an anti-icing coating through spray deposition on a metallic substrate. A dual-layer structure was designed to enhance icephobic properties: a primer layer incorporating fluorocarbon resin, butyl acetate, and rod-shaped micrometer-sized metal oxides to establish a secondary roughness morphology, followed by a topcoat composed of butyl acetate and nano-scaled superhydrophobic particles. Evaluation of the coating performance revealed a maximum water contact angle of 171.9°, indicating exceptional hydrophobicity. Furthermore, the coating exhibited notable abrasion resistance and anti-icing capabilities against overlaying ice.
AMS6885/1 gives information about the technical requirements and qualification procedure for unidirectional carbon fiber tape epoxy repair prepreg capable of curing under vacuum for repair of carbon fiber reinforced epoxy structures. The repair system includes an epoxy film adhesive to be applied in a co-bonding process with the prepreg for solid laminate and sandwich bonding.
AMS6885/2 gives specific information about the qualification program for unidirectional carbon fiber tape epoxy repair prepreg capable of curing under vacuum for repair of carbon fiber reinforced epoxy structures. The prepreg system shall include an epoxy film adhesive to be applied in a co-bonding process with the prepreg for solid laminate and sandwich bonding.
Aerospace and defense systems demand materials capable of maintaining performance under extreme environmental and operational stressors, including wide thermal cycling ranges, exposure to hydrocarbon fuels, vacuum conditions, and repeated mechanical strain. Silicone-based materials have become essential in these environments because they can retain elasticity, stability, and functionality where many traditional materials fail. Silicones are widely used as coatings, adhesives, sealants, and elastomers in aircraft and spacecraft applications. Their chemical structure enables resistance to both high and low temperatures, while also providing durability against solvents and fuels such as jet fuel. In contrast, many conventional elastomers degrade under prolonged thermal exposure or become brittle at cryogenic temperatures.
Using an inexpensive electrode coated with DNA, MIT researchers have designed disposable diagnostics that could be adapted to detect a variety of diseases, including cancer or infectious diseases such as influenza and HIV.
Live-line operation is a critical technique for maintaining the reliability and continuity of power supply in modern distribution networks. Insulating mats serve as essential protective equipment during such operations by providing both electrical insulation and mechanical shielding. In practical service conditions, insulating mats are subjected to repeated mechanical contact and friction against conductors, metallic fittings, and ground surfaces, which progressively deteriorates their surface integrity and compromises operational safety. Current performance standards for insulating mats emphasize dielectric and tensile properties, while tribological durability remains unaddressed. In this study, an EVA – PA6 composite film fabricated via the tape casting method was selected as the representative outer insulating layer of insulating mats. Reciprocating friction tests were conducted using an SDR339 abrasion tester to evaluate the effects of normal load and sliding speed on wear behavior. The results indicate that wear mass increased monotonically with friction cycles at a given speed, whereas the incremental wear rate gradually decreased due to contact area evolution. A pronounced transition from mild surface abrasion to severe material removal was observed when the applied load reached 5 N, accompanied by surface scratching and exposure of the internal fibrous layer. These findings demonstrate that the wear resistance of the EVA – PA6 composite film is insufficient for long-term service under realistic frictional conditions. The results provide experimental evidence supporting the necessity of incorporating standardized wear resistance evaluation into performance criteria for insulating mats used in live-line operations.
AMS6885/5 is the Material Specification (MS) which defines the requirements of a unidirectional carbon fiber tape epoxy repair prepreg capable of curing under vacuum for repair of carbon fiber reinforced epoxy structures. It also defines the requirements of an epoxy film adhesive to be applied in a co-bonding process with the prepreg for solid laminate and sandwich bonding.
This Purchasing Specification, AMS6885/4, specifies the batch release and delivery requirements for film adhesive used for repair. This specification is applicable only when the film adhesive is used as part of the repair system defined in AMS6885 and AMS6885/1. This specification also defines the procedure and requirements for storage life extension of materials purchased against this specification. It is only applicable for materials qualified against AMS6885 (refer to PRI-QPL-AMS6885), and shall be carried out within the responsibility of the purchaser and under control of its Quality organisation.
Cold spray deposition is a kinetic-based deposition method that uses an inert gas flow to accelerate particles, where kinetic energy causes plastic deformation upon impact with a substrate, as discussed in Reference 1. Cold spray has been investigated as a method to deposit metal coatings on polymer-based composites, such as aerospace carbon-fiber-reinforced plastics (CFRP's), as discussed in Reference 2. These methods also exhibit low deposition efficiency (15-45%) as shown in Reference 3. In this work, to achieve high deposition efficiency and create an erosion-resistant coating, we use metal-polymer composite powders for cold spray, to make polymer-on-polymer bonding the dominant and effective bonding mechanism; this method lowers impact velocities relative to pure metal deposition to avoid substrate damage. The polymer can also lower the effect of material mismatch, while the nickel can help enhance the erosion performance of the final coating above that of pure polymer. This paper discusses the development of the cold spray deposition process, sample post-processing, erosion testing, and characterization of the samples. The results validate that this method successfully creates a method of depositing a coating with erosion resistance approaching that of bulk titanium without substrate damage on PEEK substrates. Further work is needed to address the issues with depositing on CF-PEEK substrates.
In the design of Rechargeable Energy Storage System (RESS) structures, including battery trays, module side plates, and end plates, there are multiple conflating factors, including: Mechanical requirements necessitating the use of electrically conductive materials (steel and aluminum); proximity between battery module structure and battery cells, necessitating the use of electrical isolation coatings; and, module and pack designs that retain cells via the use of Structural Adhesive Material (SAM). Inherently, with this design approach, organic coatings are placed in a new and perilous position. In a sense, the coating becomes a supplement to an adhesive. As Computer-Aided Engineering (CAE) virtual analysis tools become more sophisticated, there is increasing reliance on these tools to predict the occurrence of structural failures in various load cases. Factors in test method, paint pretreatment, and topcoat affecting adhesion of organic coatings in structural adhesive joints are discussed, including: Adhesive sample preparation; adhesive selection, coating film pretreatment; age of pretreatment bath; acid cleaning; substrate material type (steel vs. aluminum); substrate product form effects within aluminum, and coating thickness. This information is useful for organic coating process development on metallic substrates. It is especially useful for material constructions requiring paint in contact with structural adhesives, as in these joints, paint adhesion is often a limiting factor on the performance of the structural adhesive. The characterization and optimization of this interface is especially important for EV battery modules & packs.
Spectral imaging tools — cameras that capture colors beyond the RGB spectrum visible to our eyes — are vital for gleaning information about an object’s material and structural properties. Marrying them with machine learning has provided a powerful pipeline for identifying features in real-world applications including semiconductor fabrication, pollutant tracking, and crop monitoring.
Five-Axis CNC machines have become essential for creating the complex geometries demanded by industries such as aerospace and defense. These advanced machines offer superior part accessibility and minimize the need for repositioning, enabling shops to eliminate secondary set-ups and post-processing. However, for many machine shops, unlocking the full performance potential of five-axis equipment requires more than sophisticated motion control: it also demands higher spindle speeds. Traditional five-axis machines often top out at spindle speeds between 6,000 and 15,000 RPM. While this is sufficient for heavy roughing operations using large diameter tools, when it comes to finishing intricate features or micro-drilling, small tools require consistent spindle speeds of 40,000 to 90,000 RPM on the toolpath to function effectively. Without that capability, shops risk poor surface finishes, broken tools and unacceptably long cycle times. This is where governed high-speed air-driven spindles offer a transformative upgrade.
Master Bond EP40 is a two-part, room temperature curing epoxy for bonding, sealing, coating, and encapsulating. EP40 bonds well to a variety of substrates, including naval steel, the primary structural metal used in the shipbuilding industry. Master Bond Inc., Hackensack, NJ To reduce its environmental impact and pollution, the shipping industry is investigating methods to construct more lightweight ships. One potential method is using adhesive bonding techniques to replace traditional welding and riveted joints on ships to fabricate lighter ships with smaller carbon footprints. However, adhesives age and deteriorate when exposed to moisture, high temperatures, and ultraviolet light. This makes it necessary to understand how they age in maritime environments to determine whether they can truly replace traditional welding techniques. To this end, researchers at Centro de Investigación en Tecnologías Navales e Industriales (CITENI) and Centro de Investigación TIC (CITIC) developed a new method for studying adhesive aging on naval steel substrates. Master Bond EP40 was selected as the test adhesive for this method due to its strong performance and suitability for marine conditions. By using EP40, the team ensured that the observed adhesive bonding behavior would reflect a high-quality epoxy's potential in ship structures. The goal was to evaluate how EP40 bonds to naval steel and how the bulk epoxy material would behave in seawater to provide insights into the construction of lighter ships using this approach.
Using waste to purify water may sound counterintuitive. But at TU Wien, this is exactly what has now been achieved: a special nanostructure has been developed to filter a widespread class of harmful dyes from water. A crucial component is a material that is considered waste: used cellulose, for example, in the form of cleaning cloths or paper cups. The cellulose is utilized to coat a fine nanofabric to create an efficient filter for polluted water.
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