Screening of Ceramic Filler Materials for a Packed‐Bed Thermal Energy Storage System With Lead as Heat Transfer Fluid

Liquid lead (Pb) is an attractive heat transfer fluid (HTF) for packed-bed thermal energy storage (TES) systems aimed for high temperatures. However, liquid Pb is corrosive and its corrosivity increases with rising temperature. Therefore, compatibility tests of possible filler materials with Pb are mandatory. This study tested the corrosion and thermal alteration of seven ceramic materials (two alumina materials, one alumina zirconia composite material, two zirconia ceramics stabilized with either yttria or ceria, and two zirconium silicates in different compositions) in liquid Pb at 650°C and 750°C in a reducing environment for up to 5000 h. The results showed that the tested zirconium silicates are not suitable due to the high glass content and the ceria stabilized ZrO2 revealed a poor thermal shock resistance. In contrast, the yttria stabilized ZrO2 and the alumina zirconia composite showed a very good compatibility with a negligible reaction with Pb.