硫脲-二乙烯三胺缩聚物对混凝土中钢筋的缓蚀作用

CORROSION INHIBITION BEHAVIOR OF DIETHYLENETRIAMINE/THIOUREA ADDUCT FOR STEEL REINFORCEMENTS IN CONCRETE

用动电位极化曲线及电化学阻抗谱研究了硫脲 二乙烯三胺缩聚物在混凝土孔隙模拟液及混凝土中对钢筋腐蚀的抑制作用。结果表明它是一种混合型缓蚀剂 ,对钢筋的点蚀有较好的抑制作用。在模拟液中添加 1 %的该缓蚀剂就可以使对氯离子的容忍度从 0 0 2mol/L提高到 0 1mol/L。它与NaNO3有较好的协同作用。它既能吸附于钢筋表面 ,又能提高混凝土的密实程度 ,减缓腐蚀介质向混凝土内的渗透。能谱分析的结果表明它能够富集于钢筋 /混凝土界面。

A new polymer DETA TU (isomolar adduct of diethylenetriamine and thiourea) was first introduced into reinforced concrete to inhibit corrosion of the embedded steel reinforcements. Its inhibition behavior and mechanism were studyied with linear polarization, Tafel polarization, EIS method either in simulated pore solution(SPS) or in real concrete. The results showed that DETA TU was a mixing type inhibitor. A 1% dosage was sufficient to hinder the corrosion of steel bar in SPS cntaining 0 1 mol/L NaCl. The salt endurance was increased from 0 02 mol/L to 0 10 mol/L. The results also showed DETA TU and NaNO 2 had a significant synergistic effect for corrosion inhibition of reinforing bar, especially at lower NaNO 2 concentration. The EIS revealed the double beneficial function of DETA TU for reinforced concrete, i.e., densifying the concrete pore structure and adsorbing on the surface of the steel reinforcement. XPS analysis showed the inhibition was concentrated at the steel/concrete interface. The concentration gradient of DETA TU from the steel/concrete interface and bulk concrete was crucial for its inhibition efficiency.