Slippery liquid-infused porous surface with layered double hydroxides for enhanced corrosion and wear resistance of TC4 alloys

The poor wear performance and susceptibility to pitting corrosion of titanium alloys in practical applications have attracted increasing attention. Layered double hydroxides (LDH) coatings, with two-dimensional structure, have shown great potential in protecting metals from corrosion and wear. However, the dense oxide layer on titanium alloys has hindered the development of LDH on these materials. In this study, a ZnAl LDH coating was fabricated on the surface of TC4 alloy via an in situ growth method. Molybdic acid anions were subsequently incorporated into the LDH interlayer through an ion exchange process. Inspired by biomimetic principles, a UV-grafted PDMS-infused slippery surface was prepared based on the nanoporous structure of ZnAl LDH, resulting in a protective surface with excellent hydrophobicity, corrosion resistance, and wear resistance. The anti-corrosion performance of the surface was evaluated using Tafel polarization and electrochemical impedance spectroscopy (EIS). The results demonstrated excellent corrosion protection for the TC4 substrate, as indicated by a low corrosion current density of 2.34 × 10^-7 A/cm². Compared with the bare TC4 alloy, the modified surface exhibited improved improved wear performance, owing to the infused silicone oil and ZnAl LDH nanosheets. This work not only provides valuable insights into the controllable in situ fabrication of LDH coatings but also offers a new strategy for the broader application of TC4 alloys and further research in the field of metal protection.