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.
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.
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.
The latest graphene coating news:
Micro Powders and Garmor launch GraphShield 730 - graphene-enhanced anticorrosion additive for powder coating applications
Micro Powders, in collaboration with Garmor, recently launched GraphShield 730, a next-generation graphene-based anticorrosion additive for powder coating applications.
GraphShield 730 uses Micro Powders’ wax composite technology to deliver a high loading of Garmor’s unique edge functionalized graphene product, enabling the delivery of an advanced nanomaterial into coating formulations safely and effectively without any changes needed in the customer’s production process. Graphene imbues the final coating with significantly enhanced corrosion resistance on both bare and treated cold rolled steel, with up to 50% reduction in corrosive creep.
Scientists from Chung-Ang University, Korea, led by Prof Hyungbin SonKorea, have observed a unique way in which graphene forms a hybrid layer that prevents copper corrosion.
A challenge with using copper is that its surface oxidizes over time, even under ambient conditions, ultimately leading to its corrosion. Thus, finding a long-term method to protect the exposed surfaces of copper is a valuable goal. One common way of protecting metal surfaces is by coating them with anti-corrosive substances. Graphene is studied extensively as a candidate for anti-corrosive coating, as it serves as a barrier to gas molecules. But, despite these properties, graphene sheets have been said to protect copper from corrosion only over short periods (less than 24 hours). In fact, surprisingly, after this initial period, graphene appears to possibly increase the rate of copper corrosion, which is completely in contrast to its anti-corrosive nature.
Talga Resources has announced the commencement of a new large-scale commercial trial of its Talcoat graphene additive for maritime coatings. At the core of the Talcoat product is Talga’s new patent pending graphene functionalization technology in the form of an on-site dispersible powder that adds graphene to paints and coatings.
Following the former trial, ans supported by the same ship owner, Talga has provided its graphene additive to enhance a primer coating successfully applied over a sizeable area of a second large container ship.
Talga Resources, advanced battery anode materials and graphene additives provider, has announced a commercial-scale trial of a graphene-enhanced coating applied to a 33,000 tonne container ship.
The 700m2 coating of the cargo vessel’s hull is part of advanced testing of Talga’s functionalized graphene (Talphene) additive as a performance booster for existing commercial marine coatings.
Applied Graphene Materials has announced that its graphene primer product is now on sale at Halfords, the UK's leading retailer of motoring, cycling and leisure products and services.
James Briggs (JBL) has also launched its Hycote graphene anti-corrosion primer, developed in collaboration with AGM, for sale on Amazon, and through Tetrosyl Express, the largest supplier of car care, parts and accessories in the UK.