Effect of Ti Substitution on the Hardness and Electrochemical Property of Laser Clad Zr-Al-Co (ti) Amorphous-Nanocrystalline Coating

Zr60-xAl15Co25Tix (x = 0, 5, 10, and 15 at%) coatings were fabricated on Q235 steel by laser cladding. The influence of Ti substitution on the properties of the coated specimens was evaluated in terms of microstructure, hardness, and corrosion resistance. Results show that the coating exhibited a sound metallurgical bonding to the substrate. The cladding layer composed of amorphous and nanocrystalline phases led to increased hardness and enhanced corrosion resistance compared with the substrate. Microhardness values of the coatings increased with the substitution of Ti for Zr attributing to the higher content of ZrO2 while lower content of amorphous phase. Both the corrosion potential and corrosion current density show that appropriate addition of Ti (5 at%) can further improve the corrosion resistance. The results offer a better understanding of the development and application of Zr-based amorphous coating for corrosive environment.