Colloidal stability of magnetic nanoparticles in molten salts

Abstract

Molten salts are important heat transfer fluids used in nuclear, solar and other high temperature engineering systems. Dispersing nanoparticles in molten salts can enhance the heat transfer capabilities of the fluid. High temperature and high ionicity of the medium make it difficult to make a colloidally stable dispersion of nanoparticles in molten salts. The aggregation and sedimentation kinetics of different nanoparticles dispersed in molten salts is studied, and trends of settling rates with system parameters like particle size, temperature and concentration are observed. Finally, a hypothesis based on ultra low values of Hamaker coefficient is suggested in order to achieve long term colloidal stability in molten salts medium.