Nicotinic acid as a nontoxic corrosion inhibitor for hot dipped Zn and Zn-Al alloy coatings on steels in diluted hydrochloric acid
Nicotinic acid as a nontoxic corrosion inhibitor for hot dipped Zn and Zn-Al alloy coatings on steels in diluted hydrochloric acid
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DOI：
10.1016/j.corsci.2007.05.015
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发表时间：
2007-11
影响因子：
8.3
通讯作者：
Hong Ju;Yan Li
中科院分区：
文献类型：
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作者：
Hong Ju;Yan Li
采用量子化学分析、失重试验、电化学测量和扫描电镜（SEM）等方法研究了烟酸对稀盐酸中热浸锌和锌铝合金涂层的缓蚀作用。量子化学计算结果表明，烟酸具有具有多个活性中心的平面结构，Mulliken电荷、最高已占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）的居群主要集中在氧原子和氮原子周围，苯的环也是如此。失重试验和电化学测定结果表明，缓蚀剂的缓蚀率（IE%）随缓蚀剂浓度的增加而增加，最高缓蚀率可达96.7%。从电极表面活性中心的分子吸附阻断电极反应的角度讨论了这些涂层的缓蚀作用。发现烟酸在涂层表面的吸附遵循单分子层Langmuir吸附等温线，烟酸在涂层表面的吸附可能是化学吸附。因此，烟酸可以作为一种良好的无毒缓蚀剂，用于稀盐酸溶液中热浸锌和锌铝合金涂层。
The inhibition effect of nicotinic acid for corrosion of hot dipped Zn and Zn–Al alloy coatings in diluted hydrochloric acid was investigated using quantum chemistry analysis, weight loss test, electrochemical measurement, and scanning electronic microscope (SEM) analysis. Quantum chemistry calculation results showed that nicotinic acid possessed planar structure with a number of active centers, and the populations of the Mulliken charge, the highest occupied molecular orbital (HOMO), and the lowest unoccupied molecular orbital (LUMO) were found mainly focused around oxygen and nitrogen atoms, and the cyclic of the benzene as well. The results of weight loss test and electrochemical measurement indicated that inhibition efficiency (IE%) increased with inhibitor concentration, and the highest inhibition efficiency was up to 96.7%. The corrosion inhibition of these coatings was discussed in terms of blocking the electrode reaction by adsorption of the molecules at the active centers on the electrode surface. It was found that the adsorption of nicotinic acid on coating surface followed Langmuir adsorption isotherm with single molecular layer, and nicotinic acid adsorbed on the coating surface probably by chemisorption. Nicotinic acid, therefore, can act as a good nontoxic corrosion inhibitor for hot dipped Zn and Zn–Al alloy coatings in diluted hydrochloric acid solution.