Preparation of TiB<sub>2</sub> Coatings on Graphite via Electrophoretic Deposition in NaCl-KCl-AlF<sub>3</sub> Molten Salts
Qian Kou, Chuntao Ge, Liwen Sun, Wenjuan Qi, Junjie Xu, Jun Zhang, Hongmin Zhu, Saijun Xiao, Heng-Qing Ye
Abstract
The combination of molten salt synthesis of nanoparticles and electrophoretic deposition of them is a novel method for preparing transition metal boride coatings. Herein, TiB 2 nanoparticles were synthesized in NaCl-KCl-AlF 3 molten salts and they were electrophoretically deposited on the graphite substrate to form a TiB 2 coating in the same molten bath. Through the borothermal reduction reaction in this molten system, TiB 2 nanoparticles with a size ranging from 50 to 150 nm were produced. Then, via electrophoretic deposition the prepared TiB 2 coating exhibited excellent corrosion resistance to liquid zinc. In the cell voltage of 1.0–1.4 V, the thickness of TiB 2 coatings first increased, and then decreased with the rise of voltage and reached a peak value of 28 μm at 1.3 V. The coating prepared at 1.2 V exhibited optimal quality. At a cell voltage of 1.2 V, as the EPD duration increased from 1 to 10 min, the amount of TiB 2 deposited on the graphite substrate was linearly related to the total charge consumption, corresponding to 16.6 C for 1 mg of TiB 2 deposition. This study offered fundamental guidance for preparing high-quality coatings through the molten salt synthesis and electrophoretic deposition process.