Preparation and property of sol-enhanced Ni-B-TiO2 nano-composite coatings

Ni-B-TiO2 nano-composite coatings were fabricated on mild steel by using a novel sol-enhanced method. It was found that highly dispersed Ni-B-TiO2 nano-composite coatings can be directly in-situ electrodeposited by adding a small quantity of TiO2 sol solution and (DMAB) into the basic watts solution. The mechanical property of sol-enhanced Ni-B-TiO2 coatings was significantly improved compared with that of Ni and Ni-B coatings. The microhardness of the sol-enhanced Ni-B-12.5 mL/L TiO2 coating was ∼1061 HV200 compared to ∼677 HV200 of Ni-B coating and ∼350 HV200 of Ni coating. Meanwhile, the wear resistance has also been improved remarkably. The corrosion resistance of sol-enhanced Ni-B-12.5 mL/L TiO2 coating was decreased compared with that of pure Ni coating but significantly better than that of Ni-B coating.