Browsing by Author "Fanicchia, Francesco"

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Microstructural properties and wear resistance of Fe-Cr-Co-Ni-Mo-based high entropy alloy coatings deposited with different coating techniques
    (MDPI, 2022-03-19) Oppong Boakye, Gifty; Geambazu, Laura E.; Ormsdottir, Arna M.; Gunnarsson, Baldur G.; Csaki, Ioana; Fanicchia, Francesco; Kovalov, Danyil; Karlsdottir, Sigrun N.
    Materials can be subjected to severe wear and corrosion due to high temperature, high pressure and mechanical loads when used in components for the production of geothermal power. In an effort to increase the lifetime of these components and thus decrease cost due to maintenance High-Entropy Alloy Coatings (HEACs) were developed with different coating techniques for anti-wear properties. The microstructure, mechanical and tribological properties of CoCrFeNiMox (at% x = 20, 27) HEACs deposited by three different technologies—high-velocity oxygen fuel (HVOF), laser cladding (LC) and electro-spark deposition (ESD)—are presented in this study. The relationship between surface morphology and microstructural properties of the as-deposited coatings and their friction and wear behavior is assessed to evaluate their candidacy as coatings for the geothermal environment. The wear rates were lower for the HVOF coatings compared to LC and ESD-produced coatings. Similarly, a higher hardness (445 ± 51 HV) was observed for the HVOF HEACs. The mixed FCC, BCC structure and the extent of σ + µ nano precipitates are considered responsible for the increased hardness and improved tribological performance of the HEACs. The findings from the study are valuable for the development of wear-resistant HEAC for geothermal energy industry applications where high wear is encountered.
  • Thumbnail Image
    ItemOpen Access
    Research and development on coatings and paints for geothermal environments: a review
    (Wiley, 2023-08-15) Fanicchia, Francesco; Karlsdottir, Sigrún Nanna
    Geothermal power plants are complex systems, where the interplay between different metallic components transforms the enthalpy of hot brine in the form of electricity or usable heated water. The naturally occurring variety in brine chemistry, linked to the presence of specific key species, and its thermo-physical properties, leads to the development of different power plant configurations. Key species and power plant configuration in turn determine the extent of damage experienced by each component in the power plant: erosion, corrosion, and/or scaling, often acting combined. Paints and coatings, compared to changing the component alloy, have represented a preferred solution to mitigate these issues due to advantages in terms of costs and repairability. This is reflected in the large number of publications on research and development in this area within the past ≈50 years, with even an increasing trend in the past 10–20 years, indicating the strong interest to develop this clean and sustainable energy source. Therefore, in this work, the first of its kind after 1980, an in-depth review of all published work on research performed on paints and coatings for geothermal applications, subdivided by the material system, is provided.