**Bo Yang 1,2,†, Ruzhen Peng 1,3,†, Dan Zhao 1,†, Ni Yang 1,4,†, Yanqing Hou 1,\* and Gang Xie 1,4,\***


**Abstract:** A TiB<sup>2</sup> wettable cathode coating was deposited on a graphite carbon cathode material via atmospheric plasma spraying (APS). The microstructure and phase composition of the TiB<sup>2</sup> coating were analyzed via scanning electron microscopy (SEM), X-ray diffraction (XRD), and energydispersive X-ray spectroscopy (EDS). The wettability and corrosion resistance of the coating were studied in a molten-aluminum electrolytic system. The results showed that the surface of the TiB<sup>2</sup> coating prepared via plasma spraying was flat and that the main phase of the coating was TiB<sup>2</sup> . The wettability between the TiB<sup>2</sup> coating and liquid aluminum was better than that between graphite cathode carbon block and liquid aluminum. The abilities of the TiB<sup>2</sup> coating and graphite cathode carbon block to resist sodium (Na) penetration and prevent molten salt corrosion were compared through a corrosion test. The TiB<sup>2</sup> coating was found to have better resistance to Na penetration and better refractory cryolite corrosion resistance than graphite cathode carbon block.

**Keywords:** plasma spraying; TiB<sup>2</sup> wettable cathode coating; wettability; corrosion resistance
