热镀锌钢材在稀盐酸中的缓蚀和量子化学研究

Corrosion inhibition and quantum chemistry studies of hot dip galvanized steels in diluted HCl solutions

通过量子化学计算、质量损失测试、电化学测试和扫描电镜等研究烟酸、吖啶和小檗碱等杂环化合物对热镀锌钢材在盐酸介质中的缓蚀作用。量子化学计算结果表明,3种化合物均具有多个吸附活性中心,且其前线轨道与镀层表面锌原子的前线轨道能够相互作用,因而使得杂环化合物分子可通过在镀层钢材表面形成吸附膜而阻止热镀锌钢材在盐酸介质中的溶解。质量损失和电化学测试结果表明:3种化合物在盐酸介质中对热镀锌钢材均具有良好的缓蚀作用,最高缓蚀效率可达99%以上;其中小檗碱的缓蚀效果最好,在浓度为1.0×10-4 mol/L时缓蚀效率就已达到80%以上;3种化合物均通过单分子层化学吸附方式吸附在镀层表面,从而起到保护作用,是热镀锌钢材酸洗过程的环境友好型缓蚀剂。

The inhibition effect of nicotinic acid, acridine and berberine on the hot dip galvanized steel in HCl solution was investigated by quantum chemistry calculation, mass loss test, electrochemical measurement, and scanning electron microscopy. Quantum chemistry calculation results show that these heterocyclic compounds have planar structure with a number of active centers, and their frontier orbitals can interact with those of Zn atom on the surface of coatings. Thus they might form an adsorption barrier film on the coating surface to decrease the corrosion rate of zinc. Mass loss test and electrochemical measurement results indicate that these compounds can perform good inhibition for the zinc coating in HCl solution, and the highest inhibition efficiency is up to 99%. Among them, berberine shows the best performance with inhibition efficiency up to 80% when at a relatively low concentration of 1.0×10^-4 mol/L. These compounds can be adsorbed on the coating surface by chemical adsorption with single molecular layer to protect it. Therefore, nicotinic acid, acridine, and berberine are effective and environmental friendly corrosion inhibitors for galvanized steel in HCl solutions.