Water repellence; lightning conduction; increased abrasion resistance – all properties which can be imparted to a material through the use of coatings and surface engineering.
Alongside its research and consultancy services focusing on joining and testing, TWI invests considerable resources into developing these versatile technologies for its Members.
Advanced coatings and surface engineering strategies are needed across virtually every sector of industry. A summary of some of the challenges currently being faced with these technologies is provided below.
The complex castings made of difficult-to-weld alloys used in aircraft structures can easily suffer superficial damage, either during their production as a result of casting defects or mismachining, or during service as a result of wear and corrosion.
Through the CORSAIR project, TWI is working with European aerospace companies to develop cold spray techniques to restore damaged areas without adversely affecting the properties of the base material. Although current repairs are ‘dimensional’ (ie not load-bearing), TWI has begun research to develop the next generation of load-bearing repairs through a PhD studentship between Nottingham University and the National Structural Integrity Research Centre.
Alongside surface engineering for repairs, the aerospace sector also needs durable anti-icing and anti-fouling coatings, improved bulk materials for aircraft leading edges, thermally resistant coatings and advanced composite materials for aircraft pipelines. These needs are being addresses by the EIROS project, in which TWI is working with 18 European partners to develop the next generation of anti-icing coating for cryogenic tanks, leading edges and automotive oil pans.
The construction industry is always seeking improved ways to repel moisture, limit the impact of fouling and preserve dimensional stability, appearance and insulation performance. TWI is designing silica-based nano-additives that can provide a water-repellent coating and give building materials improved insulation performance and durability.
This is the focus of the ISOBIO project, in which TWI and partners are developing a vapour-permeable water-repellent treatment for surfaces and natural fibres. This treatment can prevent the decay of insulating panels caused by moisture. A separate project with Edinburgh University is evaluating the impact of a silica-based treatment on insulation material’s fire resistance.
TWI’s efforts in the power sector focus on renewable energies. Here, solar panels and wind turbine blades require durable anti-fouling and anti-icing coatings to maximise operational efficiency. The wind sector also needs fire-retardant composites and advanced bulk materials, developed through nano-enabled resins, for applications such as lightweight blades.
In the solar sector, easy-clean anti-reflective coatings can significantly improve the efficiency of today’s photovoltaic systems. The SOLPLUS project focuses on the development of such a coating, to mitigate the impact of dust and soiling on solar panels and the resultant power efficiency losses. This will reduce maintenance costs and provide a sustainable way of optimising the power efficiency of solar plants that have already been built.
Another focus is on marine energy generation, where the long-term integrity of offshore wind turbine foundations and wave and tidal energy generators is jeopardised by a combination of corrosion and marine bio-fouling.
Existing ways of tackling these problems usually involve a combination of marine paint systems (with or without fast-release biocides or copper, both of which are on borrowed time for environmental reasons), cathodic protection and anodes strapped to the structure. None of these provides a hassle-free, cost-effective, damage tolerant and reliable solution.
In the ACORN project, TWI partnered with organisations in Spain, Sweden and the UK to develop a durable long-life corrosion-resistant antifouling coating system. Follow-on work will refine the coatings and demonstrate their effectiveness in several marine environments.
Oil and gas
Corrosion is the bane of the oil and gas industry, costing an estimated $1.8 trillion every year. Worldwide, five tonnes of steel is degenerated by corrosion every second, and 40 percent of steel produced today is used to replace corroded steel.
Sacrificial corrosion protection coatings based on thermally sprayed aluminium (TSA) are widely used to protect welded offshore structures from seawater corrosion. Several TWI joint industry projects in this area over the past 15 years have greatly advanced the understanding of these coatings.
Further research funded by TWI industrial members is now underway to investigate the damage tolerance of TSA, its interaction with cathodic protection, its performance at higher temperatures, its potential for mitigating corrosion under insulation and the susceptibility to hydrogen embrittlement of TSA-coated and cathodically protected high-strength steels, such as those used for mooring chains.
Corrosion, along with the problem of fouling, is also being addressed through the use of coatings. TWI is developing organic–inorganic hybrid coatings based on sol-gel chemistry and inorganic oxides, to provide an environmentally friendly approach to protection of metals against these factors.
Finally, TWI is a key participant in the WELDAPRIME project, which is developing a zinc-free weldable primer for steel.
Find out more
As the breadth of the above activity makes clear, the potential for coatings and surfacing engineering to improve industry performance is vast. If you would like to discuss a potential application, or believe one of the above developments could improve your business performance, get in touch via our Contact us page.