A form stable NaCl-Al2O3(50-50 wt-%)composite material for high temperature thermal energy storage was fabricated by cold sintering process,a process recently applied to the densification of ceramics at low temperatur...A form stable NaCl-Al2O3(50-50 wt-%)composite material for high temperature thermal energy storage was fabricated by cold sintering process,a process recently applied to the densification of ceramics at low temperature 300℃ under uniaxial pressure in the presence of small amount o f transient liquid.The fabricated composite achieved as high as 98.65% of the theoretical density.The NaCl-Al2O3 composite also retained the chloride salt without leakage after 30 heating-cooling cycles between 750℃-850℃ together with a holding period o f 24h at 850℃.X-ray diffraction measurements indicated congruent solubility o f the alumina in chloride salt,excellent compatibility o f NaCl with Al2O3,and chemical stability at high temperature.Structural analysis by scanning electron microscope also showed limited grain growth,high density,uniform NaCl distribution and clear faceted composite structure without inter-diffusion.The latent heat storage density o f 252.5J/g was obtained from simultaneous thermal analysis.Fracture strength test showed high sintered strength around 5 GPa after 50 min.The composite was found to have fair mass losses due to volatilization.Overall,cold sintering process has the potential to be an efficient,safe and cost-effective strategy for the fabrication of high temperature thermal energy storage materials.展开更多
文摘A form stable NaCl-Al2O3(50-50 wt-%)composite material for high temperature thermal energy storage was fabricated by cold sintering process,a process recently applied to the densification of ceramics at low temperature 300℃ under uniaxial pressure in the presence of small amount o f transient liquid.The fabricated composite achieved as high as 98.65% of the theoretical density.The NaCl-Al2O3 composite also retained the chloride salt without leakage after 30 heating-cooling cycles between 750℃-850℃ together with a holding period o f 24h at 850℃.X-ray diffraction measurements indicated congruent solubility o f the alumina in chloride salt,excellent compatibility o f NaCl with Al2O3,and chemical stability at high temperature.Structural analysis by scanning electron microscope also showed limited grain growth,high density,uniform NaCl distribution and clear faceted composite structure without inter-diffusion.The latent heat storage density o f 252.5J/g was obtained from simultaneous thermal analysis.Fracture strength test showed high sintered strength around 5 GPa after 50 min.The composite was found to have fair mass losses due to volatilization.Overall,cold sintering process has the potential to be an efficient,safe and cost-effective strategy for the fabrication of high temperature thermal energy storage materials.
