In the early 1970s, organic corrosion inhibitors began to be widely used and applied in the industry. Its chemical stability is good, it is not easy to be hydrolyzed and degraded, and the effect of corrosion inhibition and scale inhibition is good, and the use dose is small. The organic acid ester inhibitors containing long-chain alkyl groups in some molecules have the ability to coordinate metal ions. Under certain concentrations, they can self-assemble on metal aluminum surfaces into protective films with good corrosion inhibition and hydrophobic properties. However, the adhesion between the film and the aluminum alloy is weak, and it cannot provide long-term protection in harsh environments. Some silane coupling agents (SCA) can significantly improve the interfacial adhesion properties of inorganic phase 2 organic phase. After the aluminum tube is pre-treated by SCA, it is expected that the interface between the metal and the organic coating will have a compact structure and a small free volume. This will significantly improve the corrosion protection performance of the organic coating system. It has become a field of metal surface pretreatment. new technology.
The chemical and chemical engineering of Central South University through aluminum immersed in bis-[3-(triethoxyethoxy)propylene]tetrasulfide (BTESPT) solution, a long-chain alkyl-containing organic acid ester corrosion inhibitor A solution, taken out blowing After drying, it is cured under certain conditions to form a dense hydrophobic composite membrane. The corrosion resistance and microstructure of the composite membrane were investigated and its corrosion resistance mechanism was preliminarily discussed.
Silane bis-[3-(triethoxyethoxy)silylpropyl]tetrasulfide (BTESPT) and long chain alkyl organic acid ester corrosion inhibitor A were used in the test.
Passivation of metallic aluminum was carried out by immersing the specimen in a BTE SPT solution, A solution, and curing at 100° C. for 12 h to prepare a passivation film that resists corrosion. Hydrogen evolution test, alkali leaching weight test, salt spray test and electrochemical test all proved that the corrosion resistance of passivated samples was significantly higher than that of blank samples. The membrane does not contain heavy metals and fluorides and has passed the EU ROHS directive. The surface microscopic morphology of the composite membrane was observed by SEM, and the corrosion resistance mechanism of the composite membrane was preliminary discussed in conjunction with the electrochemical test. The film formation mechanism of the composite film was discussed.
in conclusion
After the 1BTESPT alcohol solution was hydrolyzed for 40 h, the concentration of SiOH in the solution reached a large value. After the composite film was kept at 100°C for 12 hours, it was completely cured.
2 The hydrogen evolution test, alkali leaching weight test, salt spray test and safety test show that the composite film has good corrosion resistance and does not contain harmful substances such as heavy metals, and has industrial application value.
3SEM analysis and electrochemical tests show that the composite membrane is dense and has high substrate coverage. It mainly protects the matrix metal by suppressing the cathodic depolarization reaction during electrochemical corrosion.