Multifunctional properties of electrodeposited nickel composite coating containing nanosized monoclinic zirconia particles

Nickel-based composite coatings containing ceramic particles as the distributed phase have been widely used in aerospace and automotive industries. In the present work, a Ni-composite coating containing nanosized monoclinic zirconia (ZrO2) powder is prepared by solution combustion (SC) method. The SC method is modified to get phase pure white zirconia powder by using the mixture of fuels approach. Since the synthesized powder contained agglomerated particles, the powder is ball milled and dispersed in a nickel sulphamate bath. The Ni and Ni-ZrO2 coatings are electrodeposited at 0.75 A/dm2 for 6 h. The Ni-ZrO2composite coating exhibits a microhardness of 750 KHN(50 gf) as against 270 KHN(50 gF) observed for plain Ni coating. The Ni-ZrO2 coating exhibits improved corrosion resistance and wear resistance compared to plain nickel coating as confirmed by potentiodynamic polarization and continuous salt spray tests. The as-deposited hydrophobic Ni-ZrO2coating transforms to superhydrophobic upon depositing a thin layer of fluoroalkyl silane on the coating. Thus, the synthesized zirconia particles when incorporated in the Ni matrix impart multifunctional properties to the electrodeposited Ni coating.