A comparative study on corrosion inhibitive effect of nitrate and phosphate intercalated Zn-Al- layered double hydroxides (LDHs) nanocontainers incorporated into a hybrid silane layer and their effect on cathodic delamination of epoxy topcoat

•Zn-Al- layered double hydroxides were successfully doped with phosphate ions.•Phosphate loaded nanocontainers showed better inhibition effect than nitrate one and formed passive film on steel surface.•Silane film including Zn-Al-PO43− nanocontainer significantly reduced cathodic delamination of epoxy coating on steel.•The improvement of self-healing ability of the coatings loaded with Zn-Al-PO43− was much higher than Zn-Al-NO3−. This study aims at synthesis and characterization of Zn-Al-PO43− and Zn-Al-NO3− layered double hydroxides (LDHs) through employing FE-SEM, EDS and X-ray photoelectron spectroscopy (XPS) analyses. The smart release ability of the inhibitive spices from LDHs were checked by EIS, polarization and surface analysis tests in 3.5wt.% NaCl solution. A two-layer coating system consisting of silane primer filled with LDHs and epoxy-polyamide top coat were applied on steel and then the active inhibition capability of the coatings was investigated. The addition of Zn-Al-PO43− LDH to the silane coating provides efficient inhibition behavior by releasing PO43− anions through ion exchange process.