The Nanostructure of the Oxide Formed on Fe-10Cr-4Al Exposed in Liquid Pb

An Fe-10Cr-4Al alloy containing reactive elements developed for application in high-temperature liquid lead environments was analyzed after exposure in 600 and 750\ub0C lead with dissolved oxygen for 1,000-2,000 h. Atom probe tomography, transmission electron microscopy, and X-ray scattering were all used to study the protective oxide formed on the surface. Exposure at 750\ub0C resulted in a 2-μm thick oxide, whereas the 600\ub0C exposure resulted in a 100-nm thick oxide. Both oxides were layered, with an Fe-Al spinel on top, and an alumina layer toward the metal. In the 600\ub0C exposed material, there was a Cr-rich oxide layer between the spinel and the alumina. Metallic lead particles were found in the inner and middle parts of the oxide, related to pores. The combination of the experimental techniques, focusing on atom probe tomography, and the interpretations that can be done, are discussed in detail

The methodologies and strategies for the development of novel material systems and coatings for applications in extreme environments - a critical review

The aim of this paper is to present a critical analysis of existing methodologies, approaches and strategies used to develop materials systems and coatings for uses in extreme environments. The extreme or harsh conditions encompass a large variety of in-service forms such as: extreme temperatures, abrasion, corrosion, impact and radiation that can exist in various applications such as those associated with aerospace and aeronautical engineering, land and marine transport, manufacturing machinery, and even microelectronics products. This article describes how working environment and required service performance of a particular part or structure could affect the choice of materials and surfaces to which it is composed. In addition, the paper explains the relevance that abusive working environments have for industry, especially relating to their costs, being followed by an overview of surface deposition approaches that are currently popularly used to improve performance of mechanical devices that need to combat adverse conditions. Finally, a material system and three kinds of protective coatings that could be used in applications in extreme conditions are described. The critical review is an outcome of the strategic review from the EU H2020 SUPERMAT project which deals with materials and manufacture for the products/structural parts used in extreme conditions

New Alumina Forming Martensitic Steels

The work presents a new category of alloys, Alumina Forming Martensitic (AFM) steels, developed for new clean energy power applications such as thermal solar power and Gen IV nuclear power. The aim was to combine the superior corrosion resistance of the alumina scale with the excellent creep properties of the martensitic structure. The alloys were exposed to liquid lead at 550°C for 1824 hours to evaluate their oxidation properties. In addition, the microstructures were analysed in annealed conditions and after the exposure to assess phase stabilities. Using a variety of characterisation techniques, the studies identified Al-rich oxides formed on the surfaces of both specimens after the exposure with no lead penetration. Moreover, martensite, NiAl precipitates, and different carbides were observed in both alloys.QC 20230419</p

New Alumina Forming Martensitic Steels

The work presents a new category of alloys, Alumina Forming Martensitic (AFM) steels, developed for new clean energy power applications such as thermal solar power and Gen IV nuclear power. The aim was to combine the superior corrosion resistance of the alumina scale with the excellent creep properties of the martensitic structure. The alloys were exposed to liquid lead at 550°C for 1824 hours to evaluate their oxidation properties. In addition, the microstructures were analysed in annealed conditions and after the exposure to assess phase stabilities. Using a variety of characterisation techniques, the studies identified Al-rich oxides formed on the surfaces of both specimens after the exposure with no lead penetration. Moreover, martensite, NiAl precipitates, and different carbides were observed in both alloys.QC 20230419</p

Materials for High Temperature Liquid Lead Storage for Concentrated Solar Power (CSP) Air Tower Systems

Today the technical limit for solar towers is represented by the temperature that can be reached with current accumulation and exchange fluids (molten salts are generally adopted and the max temperatures are generally below 600 °C), even if other solutions have been suggested that reach 800 °C. An innovative solution based on liquid lead has been proposed in an ongoing experimental project named Nextower. The Nextower project aims to improve current technologies of the solar sector by transferring experience, originally consolidated in the field of nuclear plants, to accumulate heat at higher temperatures (T = 850–900 °C) through the use of liquid lead heat exchangers. The adoption of molten lead as a heat exchange fluid poses important criticalities of both corrosion and creep resistance, due to the temperatures and structural stresses reached during service. Liquid lead corrosion issues and solutions in addition to creep-resistant material selection are discussed. The experimental activities focused on technical solutions adopted to overcome these problems in terms of the selected materials and technologies. Corrosion laboratory tests have been designed in order to verify if structural 800H steel coated with 6 mm of FeCrAl alloy layers are able to resist the liquid lead attack up to 900 °C and for 1000 h or more. The metallographic results were obtained by mean of scanning electron microscopy with an energy dispersive microprobe confirm that the 800H steel shows no sign of corrosion after the completion of the tests

The methodologies and strategies for the development of novel material systems and coatings for applications in extreme environments − a critical review

The aim of this paper is to present a critical analysis of existing methodologies, approaches and strategies used to develop materials systems and coatings for uses in extreme environments. The extreme or harsh conditions encompass a large variety of in-service forms such as: extreme temperatures, abrasion, corrosion, impact and radiation that can exist in various applications such as those associated with aerospace and aeronautical engineering, land and marine transport, manufacturing machinery, and even microelectronics products. This article describes how working environment and required service performance of a particular part or structure could affect the choice of materials and surfaces to which it is composed. In addition, the paper explains the relevance that abusive working environments have for industry, especially relating to their costs, being followed by an overview of surface deposition approaches that are currently popularly used to improve performance of mechanical devices that need to combat adverse conditions. Finally, a material system and three kinds of protective coatings that could be used in applications in extreme conditions are described. The critical review is an outcome of the strategic review from the EU H2020 SUPERMAT project which deals with materials and manufacture for the products/structural parts used in extreme conditions