Various common steels with a bunch of insulation around it usually, sometimes with a thin coating. The potassium/sodium/calcium nitrate mixes that are used with concentrated solar systems operating in range between 200 C and 600 C. So like, yah you don’t want to touch it, but it’s not gonna do much to steel. It can be somewhat corrosive, but, this is fairly easily mitigated by design.
Molten salt for heat transfer and thermal storage is a pretty mature technology that goes way back before we started using it in concentrated solar systems.
Various common steels with a bunch of insulation around it usually, sometimes with a thin coating. The potassium/sodium/calcium nitrate mixes that are used with concentrated solar systems operating in range between 200 C and 600 C. So like, yah you don’t want to touch it, but it’s not gonna do much to steel. It can be somewhat corrosive, but, this is fairly easily mitigated by design.
Molten salt for heat transfer and thermal storage is a pretty mature technology that goes way back before we started using it in concentrated solar systems.