Turbine blades must keep turning, even under the toughest conditions. Finnester Coatings introduces its vast range of hardy, high-end, all-weather coatings for wind applications.

Finnester Coatings is a flexible, entrepreneur-driven and technology-oriented organisation. Not only does the company design and manufacture tailored coatings for special applications, it also unifies the world of coatings and composites, resulting in composite coatings with unique features. Finnester’s coatings are suitable for various applications, meeting requirements such as high heat resistance, easy cleaning or weathering fastness.

Finnester has an extensive product portfolio across numerous market segments. Its fire-retardant products include gel coats, resins and coatings that are used in train cars and shipbuilding. These products make otherwise combustible composites fire-safe without sacrificing the final product’s appearance.

"All Finnester’s products are solvent-free, non-allergenic and Bisphenol A–free."

Coatings and binders for rehabilitation of sewerage pipes are in demand. All Finnester’s products are solvent-free, non-allergenic and Bisphenol A-free to ensure maximum user-friendliness. They also boast features such as room-temperature curing and accelerated curing with steam.

Polyurea coatings offer high performance at a wide temperature range; they stay elastic below freezing temperatures and are inherently very tough. The downside of traditional polyurea coatings, however, is that their pot life is only a few seconds, so special and expensive equipment is needed. Finnester provides polyurea coatings with an adjustable pot life, meaning only a brush is needed for application. This makes their use much easier, especially in smaller areas.

Hybrid chemistry

In the most demanding applications, the most high-end coatings come into the picture. These coatings are produced by combining inorganic and organic chemistry, and taking the best of them to create hybrid materials. These hybrid coatings will handle outdoor weathering, chemicals and fire. Moreover, they yield hard and non-porous surfaces that are not only easy to clean, but also exhibit anti-graffiti and anti-icing properties. They are used, for instance, in underwater ship hulls as biocide-free anti-fouling coatings.

Finnester’s flagship product, CERASTER CN, is a result of hybrid chemistry. Its ceramic backbone provides unique properties not seen in traditional coatings. It has exceptional adhesion to all substrates (with the exception of polyolefins), strong anti-graffiti and anti-icing properties, and is outstandingly easy to clean. Moreover, it cures in cold conditions, thus widening the application conditions window.

"Laboratory tests indicate that CERASTER CN has outstanding weather resistance."

CERASTER CN has been used to minimise ice adhesion and accumulation in blades on a 1MW wind turbine in Kotka, Finland, and has also been evaluated under laboratory conditions. The on-site testing involved the coating of test areas on turbine blades and subsequent inspections, and the laboratory testing followed international standard procedures as closely as possible. The results showed that the coating performed highly in terms of material properties such as adhesion, film hardness and dirt repulsion. Two winters later, the wind turbine has remained fully operational with no downtime due to ice or snow pick-up on the blades. The field tests are ongoing; the second-generation hybrid coating is being tested in Swedish Lapland next winter.

CERASTER CN: outstanding performance

CERASTER CN can be applied by brush or roller, but to ensure the smoothest possible surface, spraying is recommended. It can be sprayed with a conventional gravity-feed low-pressure gun or with airless high-pressure spraying equipment. No primer is needed; direct application can be made to cleaned and degreased substrate.

CERASTER CN provides exceptional adhesion to gel coat substrates widely used on wind turbine blades. Again, due to its tough ceramic backbone, it has a high harness and non-porous surface that gives outstanding abrasion resistance in order to minimise micro dirt pick-up. In addition to adhesion, the organic part of the coating provides toughness and a high gloss level, both of which promote its use in this application.

Laboratory tests indicate that CERASTER CN has outstanding weather resistance: 1,000 hours in a weathering chamber did not make a UV, temperature or moisture mark on the exposed sample (ISO 4892-2). Abrasion resistance exceeds that of gel coats and polyurethane paints commonly used in wind turbine blades: 1,500 hours of salt spray did not leave a mark on the coated metal plate.

The wind turbine is one of the applications best suited to CERASTER CN.