The Anticorrosion Research Of Polyaniline Composite Coating And Mn₂O₃Microsphere

Coating is one of the most effectively and widely used ways to protect metal from corrosion. However, the protection action of coating may be weakened due to the inherent porosity, accidentally scratched damage or application under nonideal conditions of coatings. So it is necessary to develop a new strategy to overcome this drawback.This thesis consists of the following three parts:1. ZnO nanorods which grow vertically on the mild steel substrate were deposited by a facile galvanic deposition method. Composite coatings were characterized and tested by SEM, XRD, EIS. We have explored the corrosion resistance and adhesion properties of PANI-ZnO composite coatings. The result shows that the ZnO nanorods play an important role in improving the corrosion resistance of PANI coating and enhance the adhesion significantly between PANI coating and the metal substrate by crosslink effect.2. Porous Mn2O3microsphere was synthesized successfully by a facile method, and then different amount of Mn2O3were incorporated into PANI to prepare PANI/Mn2O3composite coatings. Microspherical particles are inserted or deposited randomly in coatings. The corrosion resistance of samples was studied, and the result shows that additives content of5%Mn2O3particles could improve the corrosion resistance of composite coating the most effectively. PANI-Mn2O3composite coatings can promote mild steel surface to generate passive film by catalytic oxidation, and reduce the corrosion current density effectively.3. A hollow porous Mn2O3microsphere was synthesized by a facile solvothermal method and loaded with8-hydroxyquinoline (8-HQ) to produce an inhibitor delivery system. Hollow Mn2O3spheres with porous shell facilitate the encapsulation and release of corrosion inhibitor due to mechanical and chemical stability. Furthermore, release of8-HQ loaded by Mn2O3microcontainer was studied by EIS. The result shows that the inhibitors continuously release from the microcontainers, inhibiting the corrosion behavior of aluminum effectively. It can be potentially applied in inhibitors encapsulation and further incorporated into coatings to achieve the self-healing function.