The increasing use of fluctuating renewable energy sources requires methods to store energy for a certain time. In concentrated solar power plants (CSP) molten salts are used as a storage and heat transfer medium, which require the use of tailored materials, even the development of new materials and the assessment of life time concepts for the components and its materials in use. Furthermore, molten salts are used in many branches of industry, for example as baths made of molten chloride-salt mixtures for the production of surface alloys or as fluoride salts to clean metal surfaces. In the meantime, molten salt from nitrates and nitrites have become attractive for thermal energy storage (TES) as they comprise high temperature stability, low freezing temperatures and good heat conductivity
In order for high temperature reservoirs and heat exchangers to work reliably and be used economically, comprehensive qualification measures are required for the utilized materials. Complex and time-dependent combinations of mechanical, thermal and chemical demands appear in TES, heat exchanges and pipes that may lead to a critical degradation of the materials.