Abstract:
In this paper, based on the two-layer design, a self-healing superhydrophobic coating self-healing shape memory epoxy resin (SMEP)/polydimethylsiloxane (PDMS)@ZnO@SiO
2 (SMEP/PZS) that could quickly repair physical damages and durably corrosion resistance of stainless steel was prepared. Aiming to solve the slow physical damage repair of epoxy-based superhydrophobic anti-corrosion coatings, and inegrate with the practical application requirements of high efficiency anticorrosion and protection of stainless steel in high humidity and high salt environment for a long time. The double-layer coating was designed by combination of a SMEP and a superhydrophobic material PDMS@ZnO@SiO
2 (PZS). Furthermore, the wettability, corrosion resistance, self-healing and corrosion resistance mechanism of SMEP/PZS coating before and after repairing were discussed in detail. The results show that SMEP/PZS coating has excellent superhydrophobicity and self-cleaning properties, and its superhydrophobicity increases with the increase of perfluorodecyltrimethoxysilane (PFDTMS) content, its optimal water contact angle and rolling angle are 157.6° and 2.6°. Secondly, SMEP/PZS coating has a faster self-healing ability, the best mechanical scratches of SMEP/PZS coating are reduced from 45 μm to 1.0 μm in a shorter time of 20 min at 85℃, and the repair rate reaches 97.8%. In addition, the SMEP/PZS coating shows good corrosion resistance, and after the repaired coating is immersed in 3.5wt% NaCl solution for 14 days, its corrosion resistance is closed to the original coating. When the SMEP/PZS coating is coated on the stainless steel substrate, the pitting corrosion potential
Eb measured in 3.5wt% NaCl solution has increased by nearly 10 times compared with that of the bare stainless steel, and the passive current density
Ip has decreased by 2 orders of magnitude, showing relatively longer corrosion resistance and protection for 304 stainless steel substrate. Finally, the self-healing and anti-corrosion mechanism of SMEP/PZS coating is further discussed.