LAUSR

Abstract Co-P coatings have been widely used as the replacement of hexavalent chromium coatings. In order to improve the properties of Co-P coatings, Co-P-TiO2 nano-composite coatings were prepared using a novel sol-enhanced method. The microstructure, mechanical properties and corrosion resistance of sol-enhanced Co-P-TiO2 nano-composite coatings were systematically investigated. The results show that sol-enhanced Co-P-TiO2 coating with a good dispersion of TiO2 nanoparticles can be obtained by adding an appropriate amount of TiO2 sol to the bath. The microhardness of Co-P-12.5 mL/L TiO2 coating was increased by ∼18% compared to that of Co-P coating. Its wear resistance and corrosion resistance were also significantly improved. The effects of TiO2 sol concentration on the microstructure, mechanical properties and corrosion resistance of Co-P-TiO2 nano-composite coatings were discussed in detail.