紫铜表面3-巯丙基三乙氧基硅烷薄膜的制备与耐蚀性能

利用傅里叶变换红外(FTIR)光谱分析了3-巯丙基三乙氧基硅烷分别在酸性和碱性的醇-水溶液中水解后以及在紫铜表面成膜后的结构特征. 利用极化曲线、电化学阻抗谱(EIS)和盐水浸泡实验测试了硅烷膜的耐腐蚀性能. 结果表明: 3-巯丙基三乙氧基硅烷在酸性溶液中能够发生一定程度的水解并生成Si―OH结构, 且当该溶液在自然状态下晾干后, 其水解程度进一步增大. 在碱性溶液中该硅烷只发生少量的水解, 溶液中含有较多SiOCH₂CH₃结构, 且在溶液自然晾干后水解程度也没有明显增大. 由酸性硅烷溶液制得的薄膜中硅烷分子以Si―O―Si 键相互交联的程度比由碱性硅烷溶液制得的薄膜高. 硅烷膜降低了紫铜电极的腐蚀电流密度, 其保护效率分别为90.3%(酸性)和79.2%(碱性). 在3.5% (w) NaCl溶液中浸泡24 h后, 由酸性溶液制得的薄膜表现出更高的阻抗值, 而由碱性溶液制得的薄膜则基本失去了对基底的保护能力.

Preparation of a(3-Mercaptopropyl)triethoxylsilane Film on Copper and Its Corrosion Protective Performance

(3-Mercaptopropyl)triethoxysilane(MPTES) was hydrolyzed in acid or basic ethanol-water solution.Fourier transform infrared(FTIR) spectroscopy was used to characterize the structures of MPTES solutions and MPTES films that formed on copper.The corrosion protective performance of the MPTES films was evaluated by polarization curves and electrochemical impedance spectroscopy(EIS).The results showed that MPTES was hydrolyzed to a certain extent with the formation of Si―OH groups in an acid silane solution and the degree of hydrolysis increased during the aging process of the solution at room temperature.However,a small amount of MPTES was hydrolyzed in the basic silane solution and a large number of SiOCH2CH3 groups were found in it.More Si―O―Si bonds were formed in the film obtained from the acid silane solution compared to the film formed in the basic silane solution.The polarization curves showed that the MPTES films could decrease the corrosion current density of the copper electrodes;the protection efficiencies of the films were 90.3%(for the acid film) and 79.2%(for the basic film).EIS plots indicated that the basic film lost its protective capability after 24 h of immersion in 3.5%(w) NaCl solution while the acid film showed increasing impedance.