Electrophoretic deposition of ZrB2 coatings in molten chloride salts with varying concentrations of ZrB2 nanoparticles

Electrophoretic deposition of ZrB2 nanoparticles in high-temperature molten salts can be used for the preparation of ZrB2 coatings, and its related investigation is still in its early stage. In this paper, a dense and adhesive ZrB2 coating has been produced by electrophoretic deposition in NaCl-KCl-AlCl3 molten salts containing ZrB2 nanoparticles at 983 K, showing good mechanical properties and high-temperature oxidation resistance. Moreover, the effect of ZrB2 nanoparticles concentration (10-100 g/L) on the preparation of ZrB2 coatings by electrophoretic deposition has been explored. The dependence of the consumed charge on the ZrB2 deposition amount under various ZrB2 nanoparticles concentration has been demonstrated. It is assumed that at a low ZrB2 concentration (10-60 g/L), the increase of the deposition amount of ZrB2 corresponds linearly to the increase of the consumed charge; while at a high ZrB2 concentration (70-100 g/L), due to the possible occurrence of agglomeration and sedimentation during the electrophoretic migration, the charge consumed to form a unit weight of ZrB2 deposits is higher than that at a low ZrB2 concentration. It is important to select an optimal ZrB2 concentration to achieve a high deposition efficiency. The study in this paper can provide guidance for the selection of an optimal ZrB2 nanoparticle concentration in the process of preparing ZrB2 coatings by molten salt electrophoretic deposition.