Electrophoretic deposition and electro-codeposition in nanoparticle-containing molten inorganic salts

Molten inorganic salts containing solid nanoparticles with a stable and uniform dispersion have attracted great attention as efficient heat transfer and storage materials1,2 and for catalysis for chemical reactions3-5. Compared with those in aqueous suspensions6,7, electrophoretic deposition and electro-codeposition in molten inorganic salts containing nanoparticles, have not been reported in the literature. Here we report the possibility of electrophoretic deposition of nanoparticles and electro-codeposition of nanoparticles and metal ions in high-temperature molten salts. In molten fluorides and chlorides, a cell voltage of 1.2-1.5 V below the decomposition voltage of the electrolytes, was applied to perform the electrophoretic deposition of nanoparticles (e.g., TiB2 and ZrB2), resulting in compact and adhesive coatings. In molten chlorides containing TiB2 nanoparticles, with the introduction of electroactive specimen MoO3, the electro-codeposition of TiB2 nanoparticles and Mo-containing ions has been achieved to yield a dense and adhesive Mo/TiB2 nanocomposite coating with homogeneous distribution of Mo and TiB2, without the assistance of stirring of molten salts. These findings should present opportunities to synthesize various coatings and films via the proposed processes.