碱性溶液中苯甲酸抗坏血酸酯对钢筋的缓蚀行为  

Inhibition Behavior of Ascorbic Benzoate for Steel Rebar in Alkaline Solution

作　　者：冯丽娟[1] 杨怀玉[1] 王福会[1] 

机构地区：[1]中国科学院金属研究所金属腐蚀与防护国家重点实验室,沈阳110016

出　　处：《化学学报》2011年第20期2359-2367,共9页Acta Chimica Sinica

基　　金：国家自然科学基金(No.51071161);国家科技支撑计划(No.2007BAB27B03)资助项目

摘　　要：合成了一种苯甲酸抗坏血酸酯(AB),利用腐蚀电化学和表面分析技术,在含3.5%NaCl的饱和Ca(OH)2溶液中研究了化合物对钢筋的缓蚀性能,结合量化计算和分子动力学模拟对其在铁表面的吸附行为和缓蚀作用机理进行了分析讨论.结果表明,AB的添加可有效降低钢筋的腐蚀电流密度,提高钢筋的耐蚀性能,表明缓蚀剂对Cl-引起的钢筋腐蚀具有良好的抑制作用,为阴极型缓蚀剂.化合物通过吸附和与铁离子形成不溶性络合物,可在钢筋表面形成一层保护膜,进而阻碍介质中Cl-与金属表面的接触,且吸附符合Langmuir等温吸附规律.量化计算和分子模拟结果证明,分子中内酯五元环和苯环既是亲核反应活性中心,也是亲电反应中心,化合物通过与铁原子间的共价键合而以平行于铁表面的方式吸附在金属表面.An ascorbic benzoate（AB） was synthesized and its inhibitive activity towards steel rebar corro-sion in 3.5% NaCl saturated Ca（OH）2 solution was investigated by corrosion electrochemical and surface analysis techniques.Together with the quantum chemical calculations and molecular dynamics simulation（MD）,the adsorption behavior at the Fe surface and the inhibition mechanism of the compound were dis-cussed.The results indicate that the addition of AB can effectively decrease the corrosion current density of steel rebar and enhance its corrosion resistance suggesting that the Cl-induced corrosion of steel rebar is strongly retarded by the inhibitor,which acts as a cathodic type inhibitor.A protective film can be formed on steel rebar surfaces via the adsorption and the formation of insoluble complex with iron ions,hence blocking the Cl-access to the metal surface,and the adsorption on Fe surface obeys to the Langmuir adsorption isotherm.The theoretical calculations and MD show that the moieties of lactone and benzene rings in the molecules are the preferred active sites for the electrophilic attack,also for the nucleophilic attack,and thereby the inhibitor molecules can easily adsorb onto metal surface through the sharing of electrons with iron atoms in the parallel mode to the Fe surface.

关 键 词：钢筋锈蚀 缓蚀剂 缓蚀机理 量化计算 分子动力学模拟 

分 类 号：TG174.42[金属学及工艺—金属表面处理]