Tooth enamel-inspired ceramic coating on metal surface for enhanced mechanical properties and corrosion resistance

Stiffness-damping balance, high specific mechanical performance, and corrosion resistance are demanded for metals. Here, we developed an enamel-inspired ceramic (EIC) coating strategy involving hydrothermal growth of a tooth enamel-like ZrO₂ nanorods on Zr foil and amorphous ZrO₂ intergranular phase formation via controlled hydrolysis. The EIC coated Zr foil (Zr-EIC) achieved a high viscoelastic figure of merit (4.6 GPa); as well as excellent specific stiffness and hardness owing to the lightweight of ceramics, surpassing the values of Zr and previously reported Zr-based alloys or Zr-based composites. This was due to the vertically oriented stiff nanorods and unique energy dissipation derived from deformation at the crystalline/amorphous interfaces. It demonstrated exceptional NaCl corrosion resistance. This approach showed universality across Ti, Zn, and Cu substrates, enhancing both mechanical properties and corrosion resistance. By constructing an enamel-like hierarchical structure on the metal surface, the strategy overcomes traditional metal limitations without causing an increase in density.