Copper Corrosion Inhibitor and Its Corrosion Resistance of Self-assembled Film with Silane Composite

People have discovered a series of organic self-assembled substances that can provide good corrosion resistance to the copper matrix, but individual corrosion inhibitors often only have limited functional groups that react with the copper surface. In response to this issue, this article considers the composite effect of multiple organic film-forming agents to reduce the limitations of using a single corrosion inhibitor to a certain extent, and to modify the surface of copper materials in marine environments to improve the range of use of copper materials under harsh corrosion conditions. Copper and copper alloys often suffer from severe corrosion in marine environments. In order to solve the corrosion of copper and copper alloys in seawater, self-assembled monolayers of methyl-1h-benzotriazole (TTA), cetyltrimethylammonium bromide (CTAB), L-arginine and L-histidine were formed on the copper surface by self-assembly technology. The four inhibitors were mixed with BIS-[γ(Triethoxysilicon) propyl] tetrasulfide (Si-69) to prepare composite self-assembled monolayers. Electrochemical methods were used to study the corrosion resistance of self-assembled monolayers on copper surfaces. The morphology and element distribution of the prepared copper surface self-assembled film were characterized by scanning electron microscopy and X-ray energy spectrum, and the hydrophobicity of the film was characterized through water contact angle testing. The results showed that all the inhibitors and their composite coatings had good corrosion resistance. The order of corrosion resistance (inhibition efficiency) between different inhibitor self-assembled films was CTAB (78.78%) > TTA (61.00%) > histidine (56.03%) > arginine (46.38%). The performance of self-assembled monolayers composed of corrosion inhibitor and Si-69 was better than that of single corrosion inhibitor or silane, and CTAB had the best effect among the four corrosion inhibitors, with the inhibition efficiency of 96.91%, and the rest were TTA (85.38%), histidine (84.91%) and arginine (82.09%) in turn. Compared with the water contact angle of the blank copper sample (76.9°), the contact angle of the CTAB self-assembled film reached 100.7°, while the water contact angle of the CTAB silane composite film layer was 105.6°. The experimental results indicated that four self-assembled films, CTAB, TTA, histidine, and arginine, were prepared on the copper surface in this study. All self-assembled films could effectively improve the corrosion resistance of the material. When four corrosion inhibitors were combined with silane, the corrosion inhibition efficiency was improved. The addition of silane could improve the self-assembled film structure of the inhibitor, enhance the hydrophobicity of the film layer, and improve corrosion resistance. The addition of silane to the four corrosion inhibitors resulted in changes in the polarization curve of the cathode and anode branches, indicating that the silane film simultaneously affected the reaction process of both electrodes. This study mainly focuses on the preparation and performance of composite self-assembled films formed by corrosion inhibitors and silane. It has been proven that the synergistic effect of using corrosion inhibitors and silane to improve the performance of the membrane layer is a feasible approach. Through horizontal comparison between corrosion inhibitors and vertical comparison between corrosion inhibitors and their composite films formed by silane, the influence of film-forming substances on the performance of the film layer on the copper matrix, whether alone or in interaction, is explored, providing a certain reference for future research on copper self-assembly technology. © 2024 Chongqing Wujiu Periodicals Press. All rights reserved.