Effect of container loading method of corrosion inhibitor combination on corrosion resistance of aluminum alloy coating

Abstract

The composite nanocontainer of corrosion inhibitor (MSN-QB) was prepared by loading octahydroxyquinoline (8-HQ) and benzotriazole (BTA) on mesoporous silica nanoparticles(MSN) simultaneously using vacuum adsorption and layer-by-layer self-assembly technology, and added to the epoxy coating to obtain a new coating (MQB). SEM, TEM, FT-IR, Zeta-potential and TGA were used to study the structure changes of the nanocontainer before and after loading corrosion inhibitors and the stimulus response release behavior of the corrosion inhibitors, and electrochemical test and salt spray test were used to study the improvement of coating protection performance by layer-by-layer self-assembly technique. The results show that the loadings of 8-HQ and BTA in MSN-QB are 6.8%(mass fraction) and 7.1%, respectively. MSN-QB has pH response characteristics. The release of 8-HQ and BTA are both inhibited under neutral conditions, but can be released under alkaline (pH=10) and acidic (pH=4) conditions. The release rate under alkaline conditions is higher. MQB coating has the best corrosion resistance. After immersed in 3.5%NaCl solution 20 d, the MQB coating has the largest|Z|0.01 Hz value(2.0×109 Ω·cm2), more than twice that of MQ+MB coating.

Keywords

• corrosion inhibitor combination
• loading method
• layer-by-layer self-assembly
• aluminum alloy
• corrosion resistance