材料期刊网

目的 对比三氮唑( TA)和苯并三氮唑( BTA)两种缓蚀剂的缓蚀性能,明确两种缓蚀剂在铜表面的吸附类型,并从实验和分子模拟角度解释其吸附机理. 方法 采用动电位极化曲线法测试两种缓蚀剂的缓蚀效率,采用吸附等温拟合方法确定两种缓蚀剂的吸附类型,采用分子模拟中的量子化学计算方法计算两种缓蚀剂在铜表面的吸附能、形变电荷密度和分波态密度等参数,深入揭示其吸附机理. 结果 在不同浓度下,BTA的缓蚀效率均大于TA. 两种缓蚀剂浓度与覆盖度的关系符合Langmuir吸附模型,其吸附自由能介于-35~-37 kJ/mol之间. BTA在铜表面的吸附能绝对值(顶位为4. 41 eV,桥位为4. 36 eV)要大于TA的吸附能绝对值(3. 28 eV),吸附过程发生了明显的电荷转移,电子云处于两个成键原子之间,且N原子s,p轨道与Cu原子d轨道发生重叠. 中性和质子化形式的两种缓蚀剂分子均可在铜表面发生平行吸附. 结论 由于BTA在铜表面的吸附能力强于TA,因此BTA的缓蚀性能优于TA. 两种缓蚀剂在铜表面既能发生化学吸附,又能发生物理吸附. 化学吸附是由于N原子的s,p轨道与Cu原子d轨道相互作用所致,物理吸附是由于中性分子的范德华相互作用和质子化分子的静电相互作用所致.

Objective To compare the inhibition performance of two corrosion inhibitors:1, 2, 4-triazole and benzotriazole, in order to explore their adsorption types on Cu surface and explain the inhibition mechanism from experiment and molecular simula-tion point of view. Methods Potentiodynamic polarization measurement was used to test the corrosion inhibitive efficiency of the two inhibitors. The adsorption isothermal fitting method was used to explore their adsorption types on Cu surface. Adsorption energy, deformation charge density and partial density of states were calculated using quantum chemistry calculation method to explain their inhibition mechanism. Results The results of polarization measurement showed that the inhibition efficiency of benzotriazole was higher than that of triazole at all concentrations. The relationship of concentration and coverage of the two inhibitors accorded with the Langmuir adsorption isotherm, and their adsorption free energy was in range of -35~-37 kJ/mol. The absolute value of ad-sorption energy of benzotriazole (top -4. 41eV, bridge -4. 36 eV) was larger than that of triazole (3. 28 eV). Obvious charge transfer occurred in the adsorption process, and the electron atmosphere distributed between the two bonding atoms. In addition, the s,p orbits of N atoms and the d orbit of Cu atoms overlapped during the adsorption process. Both of the neutral and protonated forms of the two inhibitors could parallelly adsorb onto Cu surface. Conclusion The inhibition performance of benzotriazole was bet-ter than that of triazole, which was due to the higher adsorptivity of benzotriazole compared to that of triazole. Both chemical ad-sorption and physical adsorption existed in the interaction of the inhibitors and the Cu surface, and the chemical adsorption of in-hibitors on Cu surface was attributed to the covalent bond between N and Cu atoms, and the bonding interaction was due to atomic orbits hybridization, while the physical adsorption between the inhibitor and Cu surface consisted of both Van der Waals forces and electrostatic attraction.