A multifunctional Sr(HQ)2 filler-reinforced coating for self-healing and physical barrier properties on aluminum alloy

Here, we designed and synthesized strontium (II)-8-hydroxyquinolinate (Sr(HQ)2) by chemical bath deposition and fabricated a Sr(HQ)2-modified fluorocarbon (FC) multifunctional coating (Sr(HQ)2-FC) to enhance the self -healing and physical barrier performances. The obtained Sr(HQ)2 exhibits an obvious plate-like morphology with a smooth surface. The physical barrier performance of Sr(HQ)2-FC is improved by prolonging the diffusion pathway of corrosive media in the coating matrix, and the coating resistance of Sr(HQ)2-FC containing 2 wt% Sr (HQ)2 is 3 times higher than that of the pure FC coating. Furthermore, the introduced Sr(HQ)2 confers an effi-cient self-healing function by active chemical etching-induced redeposition of a stable and dense protective film at the defected region of the coating. The corrosion rate of the aluminum substrate covered by the scratched Sr (HQ)2-FC is one order of magnitude lower than that covered by the pure FC coating. The enhanced physical barrier property and active self-healing function provide the coating with long-term corrosion protection per-formance for aluminum alloys.

Automated summary

We designed and synthesized strontium (II)-8-hydroxyquinolinate (Sr(HQ)2) and used it to modify a fluorocarbon (FC) multifunctional coating (Sr(HQ)2-FC) in order to enhance self-healing and physical barrier performances. The Sr(HQ)2-FC coating showed improved physical barrier performance by prolonging the diffusion pathway of corrosive media and exhibited a 3 times higher coating resistance compared to the pure FC coating. The introduced Sr(HQ)2 also provided efficient self-healing function by redepositing a stable and dense protective film at the defected region of the coating, resulting in a lower corrosion rate compared to the pure FC coating.