The Effects of Surface Plasma Carburization on the Microstructure and Molten Salt Corrosion Resistance of Ta

In order to enhance the corrosion resistance of tantalum, the double-glow plasma (DGP) metallurgy technique was used to prepare TaC coatings on the tantalum. The morphology, microstructure, and phase constituents of TaC were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Nano-indentation tests were used to evaluate the mechanical properties of the coatings. The specimens were immersed in NaCl-KCl molten salt at 830 °C to evaluate their corrosion resistance. The results showed that the coating prepared by the DGP technique has a thickness of approximately 5 µm, the diffusion layer has a thickness of 2.5 µm, and the nano-indentation hardness is measured to be 17.27 GPa. The high-temperature stable ceramic phase enhances the high-temperature oxidation resistance of pure tantalum (Ta), while the dense corroded surface and oxidation products improve the anti-corrosion property of TaC coatings.