Jialie Liu,Junjie Xu,Chuntao Ge,Jie Pang,Weiliang Jin,Geir Martin Haarberg,Saijun Xiao
To enhance the anticorrosion properties of molybdenum metal in liquid zinc, this study successfully fabricated TiB2coatings on molybdenum substrates via the molten salt electrophoretic deposition technique and investigated their corrosion resistance in molten zinc. Initially, TiB2nanoparticles with a size ranging from 50 to 150 nm were synthesized using the borothermal reduction method in a molten NaF-AlF3bath at 1238 K. Subsequently, the electrophoretic deposition experiment was conducted under a cell voltage of 1.2 V (i.e., 0.6 V/cm) for a duration of 1 h in the melt containing TiB2nanoparticles, resulting in a uniform, continuous, and compact TiB2coating (35 μm thick) on the molybdenum substrate. Moreover, the corrosion resistance of the TiB2-coated molybdenum metal to molten zinc was tested through continuous immersion. After 120 h of immersion, the TiB2coating showed no signs of cracking or peeling off, successfully protecting the molybdenum metal substrate from corrosion by molten zinc. The results confirm that the molten salt electrophoretic deposition technique can be used to prepare TiB2coatings with good resistance to molten zinc corrosion on molybdenum metal.
Tao Jiang,Junjie Xu,Chuntao Ge,Jie Pang,Jun Zhang,Geir Martin Haarberg,Saijun Xiao
Molten salt electrophoretic deposition is a novel method for preparing coatings of transition metal borides such as TiB2, which has emerged in recent years. To broaden the applications of transition metal boride coatings prepared by this method, this paper investigates the corrosion resistance of TiB2coatings, produced through molten salt electrophoretic deposition, to liquid zinc. By applying a cell voltage of 1.2 V (corresponding to an electric field of 0.6 V/cm) for 1 h in molten NaF-AlF3, the nanoscale TiB2particles migrated to the cathode and were deposited on the graphite substrate, forming a smooth and dense TiB2coating with a thickness of 43 μm. Subsequently, after subjecting the TiB2-coated graphite to corrosion resistance tested in molten zinc for 120 h of continuous immersion, no cracks were observed on the surface or within the coating. The produced TiB2coating demonstrated excellent corrosion resistance. These research results suggest that the fully dense TiB2coating on the graphite substrate, produced through molten salt electrophoretic deposition, exhibits excellent corrosion resistance to liquid zinc.
Superhard ceramics are suitable materials to improve the surface characteristics of titanium. In this study, TiB 2 nanopowder was coated on titanium substrate using electrophoretic deposition in NaF-AlF 3 -Al 2 O 3 molten salts. The effects of varying deposition voltages and deposition times on TiB 2 coatings were investigated. Additionally, the microstructure of the coating surface was observed by scanning electron microscopy. With an applied cell voltage of 1.2 V and a deposition time of 1.5 h, a dense, defect-free TiB 2 /TiB composite coating (including the outer TiB 2 layer and the inner TiB whiskers layer) approximately 74 μm thick was produced, exhibiting a strong metallurgical bond to the substrate. A densely packed TiB whisker layer forms at the TiB 2 /Ti interface. The work of adhesion, interfacial energy, and electronic structure of the α-Ti(0001)/TiB 2 (0001) interfaces have been calculated using first-principles methods. Simultaneously, the diffusion of B atoms at the TiB 2 /Ti interface was computed to explain the formation process of TiB whisker layers. The work of adhesion calculations indicated that the B-HCP-Ti interfacial model exhibited the highest interfacial bond strength. The electronic structure of the interfacial model was analyzed to show that the Ti-terminated interface model was primarily formed through metallic bonds, while the B-terminated interface model was primarily formed through covalent bonds. Compared to the Ti-terminated interface, the B-terminated interface facilitates the diffusion of boron from TiB 2 into the titanium substrate more effectively.
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