In Nordic regions, several engineering applications face icing problems yearly. Malfunctioning, inefficient operations and endangering human lives represent some of the consequences of ice accumulation and accretion. Current active anti-icing and de-icing solutions use thermal energy, mechanical vibrations, and chemical fluids to limit the negative effect of ice accretion. However, energy waste, repeated actions, and pollution represent some of the drawbacks of the active methods, which are not sustainable or renewable. Therefore, researchers are working towards developing icephobic coatings that passively repel ice without external energy input.
In her research, Valentina Donadei developed a novel concept of coatings named lubricated icephobic coatings. These coatings are made of two components: a primary polymer with icephobic properties and a minor lubricating additive, further enhancing the coating’s icephobicity. Moreover, she demonstrated the potential of flame spray technology to successfully fabricate icephobic coatings.
With flame spraying, one to several feedstock materials in the form of powder can be fed into a spray gun. The spray gun generates a combustion flame that melts the powder particles. These melted particles are then deposited on a substrate to form a dense coating. As a result, the coating is ready in a one-step process, with no need for solvents or post-treatment, as other coating fabrication methods generally require.
“If we consider the number of plastics available to us, we have innumerable possibilities for fabricating multi-plastic coatings using flame spray technology. The flexibility of this technology makes the research extremely exciting,” explains Valentina Donadei.
The coating’s performance tested at Airbus
Although flame spraying is a simple method to deposit coatings, the presence of the combustion flame in the process is critical for polymers.
“You can easily burn the polymer instead of only melting it. This can degrade the material properties and, consequently, the coating’s performance. It is then essential to control and tune the process parameters to avoid thermal degradation,” she explains.
“Moreover, the employed process parameters will determine the final microstructural features of these coatings. Therefore, it’s important to understand how these features affect the coating’s icephobic behaviour”.
This research was carried out in the context of the LubISS project, a consortium of 11 organisations that included research institutes and industries. The project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant.
Within the consortium, Valentina Donadei collaborated with different partners to develop and test flame-sprayed polymer coatings fabricated at Tampere University. She had the chance to test the coating’s performance at the icing test facilities of Airbus, an industrial partner of the project.
“Seeing the flame-sprayed coatings withstanding severe in-flight icing conditions was exciting and extremely rewarding. The research results are promising, and they show the potential of these icephobic coatings to be used in industrial applications in the future,” she says.
The doctoral dissertation of M.Sc. Valentina Donadei in the field of materials science titled Icephobicity of Flame-Sprayed Polymer Coatings will be publicly examined in the Faculty of Engineering and Natural Sciences of Tampere University on Friday 9 December starting at 12 in the lecture hall K1702 of the Konetalo building (Korkeakoulunkatu 6, Tampere). Professor Ali Dolatabadi from the University of Toronto, Canada, and Associate Professor Carlo Antonini from the University of Milano-Bicocca, Italy, will act as opponents. Professor Emeritus Petri Vuoristo from Tampere University will serve as the custos.
The doctoral dissertation is available online.
Photo: Jonne Renvall