Abstract
Various mono- and bi-layered sol-gel films have been prepared and applied as protective coatings for zinc corrosion in 0.5M HCl solution. Smooth and uniform morphology are characteristic for thiol groups containing coatings while, surface deterioration is observed for others. The bi-layer morphology is similar to that of the outer layer. Hybrid mono-layer has higher protection ability than its corresponding bi-layers, except for bi-layers having vinyl groups containing outer layer. The protection abilities of mono- and bi-films are discussed in terms of film structure and functionality.
•Prepared mono- and bi-sol-gel films can be efficiently protect zinc from corrosion in HCl medium.•The protection ability depends on the film structure, functionality, and the interaction between different groups.•Thiol functional group provides the highest protection followed by the epoxy group and finally vinyl group.•Bi-functional mono-layer has higher protection ability than mono-functional one.•In general, mono-layers bifunctional sol-gel films provide better protection than mono-functional bi-layered films.