Experimental study reveals enhanced thermal capacity, conductivity, and stability in boride-doped molten salts, suggesting improved reliability for solar power systems.
Key Points
Investigate the impact of hafnium diboride (HfB2) and silicon hexaboride (SiB6) nanoparticles on the microstructure, heat-storage capacity, thermal conductivity, and high-temperature stability of 7NaNO3–53KNO3–40NaNO2 molten salt.
Synthesized nanocomposite salts loaded with 0.5 to 2 wt% of HfB2 or SiB6 nanoparticles.
Characterized structural and thermophysical properties using XRD, FT-IR, FE-SEM/EDX, DSC, TGA, and TPS measurements.
Melting enthalpy increased from 76.2 J/g in the pure salt to 89.4–90.6 J/g with HfB2 and 92.6–95.6 J/g with SiB6, while thermal conductivity rose from 0.951 W/m·K to 1.689 W/m·K (2 wt% HfB2) and 1.529 W/m·K (2 wt% SiB6).
Specific heat capacity peaked at 1.5 wt% HfB2 (55.17% solid, 66.65% liquid increase) and at 1 wt% SiB6 (107.78% solid, 117.79% liquid increase), while thermal degradation onset temperatures climbed from 612 °C to 653 °C and 663 °C, respectively.