Layered epoxy composite coatings with triple function of self-reporting, high barrier and corrosion inhibition

In this work, self-reporting corrosion inhibition coatings with long-term corrosion protection was prepared by different process means. The two-dimensional (2D) materials ZrP-NH 2 and Tannin@SiO 2 (TA@SiO 2 ) microcapsules were introduced into the epoxy resin (EP) coatings, and the Layered EP coatings (TA@SiO 2 layer coatings and ZrP-NH 2 layer coatings) and the Mixed EP coatings were prepared by layered spraying and mix spraying, respectively. In the pre-corrosion stage, the excellent barrier performance of the ZrP-NH 2 layer coating hinders the diffusion of corrosive media. In the later stages of corrosion, the TA@SiO 2 microcapsules in the TA@SiO 2 layer coating releases TA, which forms a TA-Fe 3+ passivation film with the metal substrate and confers the coating with a blue-violet self-reporting function. Furthermore, the synergistic corrosion inhibition mechanism of TA@SiO 2 layer coatings was investigated by DFT theoretical calculations and experiment. Meanwhile, the Layered EP coatings provide the triple functions of excellent physical barrier action, corrosion inhibition and self-reporting under high temperature and high salt conditions.