What is a coating?
A coating is a covering that is applied to the surface of an object. The purpose of applying the coating may be decorative, functional, or both. Coatings are ubiquitous and can be found on walls, furniture, on all sorts of wires and printed circuits, the outside of houses and cars, and much more. In addition, the decorative duties of coatings span quite a broad spectrum.
Decorative coatings are mainly used for their color, texture or other visual property. Functional coatings are applied to change the surface properties of the substrate, such as adhesion, wettability, corrosion resistance, wear resistance and more. In some cases, the coating adds an entirely new property such as a magnetic response or electrical conductivity and forms an essential part of the finished product.
Coatings may be used in various processes, that are roughly divided into: vapor deposition, spraying, chemical and electrochemical techniques, roll-to-roll coating processes and other, less prominent techniques.
What is graphene?
Graphene is a two dimensional layer of carbon atoms, arranged in the form of a honeycomb lattice. It is touted as a “miracle material” because it is endowed with an abundance of astonishing traits - this thin, one atom thick substance is the lightest, strongest, thinnest material known to man, as well as the best heat and electricity conductor ever discovered - and the list does not end there. Graphene is the subject of relentless research and is thought to be able to revolutionize whole industries, as researchers work on many different kinds of graphene-based materials - each one with unique qualities and purpose.
Graphene for coatings
The vast selection of extraordinary properties that graphene possesses can open the door to many interesting types of coatings, paints, inks and more. Graphene's high resistivity can make for durable coatings that do not crack and are resistant to water and oil; its excellent electrical and thermal conductivity can be used to make various conductive paints, and a strong barrier effect can contribute to extraordinary anti-oxidant, scratch-resistant and anti-UVA coatings.
Graphene enables a wide array of functional coatings and paints, for many possible applications. Among these can be high performance adhesives enabled by graphene's high adhesion property, anti-bacterial coatings, solar paints (capable of absorbing solar energy and transmitting it), paints that provide isolation for houses, anti-rust coatings, anti-fog paints and UV ray blockers, non-stick coatings for various domestic applications (like frying pans and countertops) and even a much-hyped possibility (currently under scientific examination) of a coating that turns a regular wall into a screen.
Commercial activity
Graphene-enhanced products are yet to reach widespread commercialization. Nonetheless, given graphene’s impressive array of properties and the vigorous R&D that is taking place, graphene-enhanced coatings should not be too far away.
The Sixth Element Materials, a Chinese company that focuses on R&D, mass production and sales of graphene and related materials, showcased its graphene-zinc anti-corrosion primer used for offshore wind power tower, that can come at a competitive price compared with zinc rich epoxy primer.
Garmor, the University of Central Florida spin-off formed to develop a new graphene oxide flakes production process, has developed graphene oxide-based coatings useful for limiting UV radiation damage to sensors and polymers. Garmor's transparent GO-films are reportedly derived from a commercially-viable and scalable process that can be readily implemented with minimal constraints.
Four layers of GO coating on polycarbonate
The Spain-based Graphenano announced the launch of a graphene-based series of paints and coatings called Graphenstone in 2014. These are said to be very strong and also acts as a protective layer against environmental damage. Graphenstone is made from a graphene powder and limestone powder.
The British Electro Conductive Products released a sprayable transparent conductive coating based on a CNT and graphene platelets (GNP) hybrid material. TBA are targeting the food, electronics, pharmaceuticals and petrochemicals markets.The new ATEX-compliant product is available as a clear, anti-static aerosol, and it should also be available as bulk paint. Its application will safeguard electronic equipment used in explosive environments and bring it up to European standards.
Further reading
The latest graphene coating news:
Applied Graphene Materials' graphene-enhanced anti-corrosion primer used by England’s Environment Agency for flood defense applications
Applied Graphene Materials has announced that England’s Environment Agency (EA) has successfully completed its first application of AGM’s harsh environment anti-corrosion product to one of its flood defense assets on the North East coast of England. The coastal flood defense gates were coated with AGM’s new graphene-enhanced Genable CX-based anti-corrosion primer.
The AGM’s coating system used in this project is a further iteration of AGM’s product offerings for barrier performance and anti-corrosion application. It represents the culmination of 18 months of in-depth testing and evaluation of anti-corrosion performance for both salt-spray and immersion in harsh test regimes.
Tata Steel develops a unique few-layer rGO film material
Tata Steel has developed a new product, a few-layer film of rGO along with its collaborators at CeNS, Bengaluru. The company is now starting to mass-produce the films and offer them to application developers.
Figure 1: (a) Digital image of rGO/Cu foil (5 cm2). Contactact angle (b) and AFM height profile (c) on rGO/Cu
The rGO film is produced (using a modified CVD process) on copper. The film's average thickness is 5-10 nm and offers a corrosion rate of 0.02 mm/year (Tafel) and a water contact angle of ~ 97°.
These unique properties make the film suitable to protect the copper from corrosion, chemical attacks, and thermal oxidations. It also makes copper hydrophobic and can act as an antibacterial surface.
Applied Graphene Materials launches new graphene-enhanced range of coatings, paints and additives
Applied Graphene Materials (AGM) has announced the introduction of two new products based on its GNPs.
The Company has launched a range of industrial anti-corrosion paint incorporating its Genable graphene additives. The two epoxy-based prototype primer systems are said the AGM to represent an easy way for those considering the adoption of graphene to quickly test and evaluate its potential benefits.
Graphene and hBN nano-additives improve eco-friendly lubricant oils
Researchers from the University of Nevada have investigated the introduction of graphene nanoplatelets (GNPs) and hexagonal boron nitride (hBN) to canola oil to improve its tribological properties, as part of an effort to reduce the usage of lubricants based on petroleum as lubricants for reducing abrasion and friction.
Three nanoscale lubricating combinations were created by combining both GNP and hBN settings in varied ratios to get the best beneficial synergy. The team reports that lubrication quality and performance may be increased by using low-weight percentages of nanoparticle (NP) and microparticle additions. One benefit is that it has a reduced coefficient of friction (COF) and wearing.
Sparc Technologies reports successfull testing of graphene-enhanced epoxy coatings
In 2020 Sparc Technologies acquired Graphene Technology Solutions (GTS) and announced plans to become a “significant developer of graphene-based products".
Sparc announced today that after six months of testing, its graphene-based additives was found to offer up to 40% improvement in the anti-corrosive performance of atmospheric epoxy coatings. The company used commercially available epoxy coatings available from leading coatings manufacturers.