Corrosion of AISI316 as containment material for latent heat thermal energy storage systems based on carbonates

Considerable effort has been devoted to the characterization of thermal properties of the different types of materials that can be used as thermal energy storage (TES) media, but scarce literature exists concerning the materials to manufacture the tanks that can be used to contain these storage media. One of the main concerns when selecting the most suitable material for these tanks is its resistance to corrosion due to molten salts that constitute the TES system. Dynamic gravimetric analysis is a newly proposed method for the study of corrosion on metals, which optimizes the standard procedure described by ASTM G1–03. The new technique avoids the direct handling of samples, so more accurate values can be obtained. In this work, the resistance to corrosion of AISI 316 stainless steel samples in contact with commercial grade molten salts of the Li2CO3-Na2CO3-K2CO3 system, at 600 °C for different exposure times, has been determined by using this new methodology. The results show that the initial corrosion rate is lower at higher amounts of lithium carbonate present in the molten salts mixture. •A new methodology was tested to determine the corrosion rate (CR) by reducing handling.•The CR on AISI316 in Li2CO3-Na2CO3-K2CO3 mixture pairs is up to 2.07 mm/yr.•The presence of Li2CO3 on eutectic mixtures slows down the CR.•LiFe5O8 formation significantly increases the corrosion level.