Preparation of di-boride coatings by electrophoretic deposition 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. Electrophoretic deposition in molten inorganic salts containing nanoparticles, have not been reported in the literature, compared with the related wide investigations in aqueous and organic suspensions6,7. Here we report the possibility of electrophoretic deposition of nanoparticles in high-temperature molten salts. In molten fluorides and chlorides, cell voltages of 1.2-1.5 V below the decomposition voltage of the electrolytes, were applied to perform the electrophoretic deposition of nanoparticles (e.g., TiB2 and ZrB2) on different cathode substrates, resulting in compact and adhesive coatings with high hardness. These findings should present opportunities to synthesize additional coatings and films via the proposed process.

Preparation and properties of in-situ grown Cr2O3 diffusion barrier between Ni coating and 316L stainless steel in molten fluorides

A Cr2O3 diffusion barrier was in-situ formed between Ni coating and 316L through electroplating a Ni(NiO) transition layer firstly and then annealing at 900 °C for 8 h in Ar. The obtained Cr2O3 is dense, continuously grown and well-bonded with 316L. The diffusion and corrosion resistance of Ni coating with and without Cr2O3 diffusion barrier were investigated. No visible outer diffusion of elements was found during the heat treatment at 750 °C for 150 h and the Ni coating with a Cr2O3 diffusion barrier can provide a good protection for 316L in molten (Li,Na,K)F.

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.

Inhibition effect of ZrF4 on UO2 precipitation in the LiF–BeF2 molten salt

This study provides an effective solution for controlling and monitoring the nuclear fuel precipitation (UO2) in molten fluorides, which is of great importance for the safe operation and fuel salt design of molten salt reactor (MSR).