月桂基咪唑啉对银的缓蚀性能研究

Performance of lauryl imidazoline in the corrosion inhibition of silver

合成了月桂基咪唑啉(LM),并采用FT-IR对LM进行结构表征。以南京长干寺遗址地宫出土的阿育王塔的银基体模拟样品为试样,通过预膜法、重量法、动电位扫描法、电化学交流阻抗法研究了LM对银试样在Na2S腐蚀介质中的缓蚀性能,并与银质文物上常用的含氮类缓蚀剂苯骈三氮唑(BTA)、含硫类缓蚀剂1-苯基-5-巯基四氮唑(PMTA)在Na2S腐蚀介质中的缓蚀效果进行了比较。结果表明,与裸银试样相比,经质量分数为1%LM预膜处理后的银试样在5mg/L Na2S溶液中的缓蚀率为59.1%;自腐蚀电流密度ic减小了0.111μA/cm2,电化学体系的双电层电容Cd降低了51.39μF/cm2,电化学阻抗Rt增加了73.5 kΩ.cm2;采用重量法、动电位扫描法、交流阻抗法等方法比较了质量分数均为1%的BTA、LM、PMTA对银的缓蚀效果,得出缓蚀率η从大到小顺序排列为:ηPMTA>ηLM>ηBTA。

A lauryl imidazoline （LM） has been synthesized and the structure was characterized by Fourier transform in frared （FT-IR） spectroscopy. The corrosion inhibition ability of LM was studied in Na2S corrosion medium for silver samples which based on composition of the Emperor Asoka Pagoda substrate by pre-filming, gravimetric method, potentiodynamic method and electrochemical impedance spectroscopy. In addition, the corrosion inhibition ability of LM was compared with those of benzotriazole （BTA） and 1-phenyl-5-mereaptotetrazole （PMTA） , which were commonly used corrosion inhibitors in the field of silver heritage conservation. Compared with bare silver sam- pies, the inhibition ratio of prefilmed silver samples by 1% LM was 59.1% in 5 mg/L Na2S corrosion medium; the corrosion current density io decreased by O. 111 μA/cm2and the electrical double-layer capacitance Cd decreased by 51.39 μF/cm2 ; Meanwhile, the electrochemical impedance Rt increased by 73.5 k~. cm2 ; Comparison of the corrosion inhibition effect for LM with those for BTA and PMTA, showed that the inhibition rate ηfor silver decreased in the order ηPMTA〉ηLM〉ηBTA, as confirmed by the results of gravimetrie method, potentiodynamic method and electrochemical impedance spectroscopy.