硫脲对块体纳米晶工业纯铁在盐酸溶液中的缓蚀行为

采用电化学阻抗谱(EIS)研究了硫脲对室温下1 mol•L－1盐酸溶液中粗晶和纳米晶工业纯铁的腐蚀行为的影响.从EIS的拟合结果得知,在1 mol•L－1盐酸溶液中,块体纳米晶工业纯铁比粗晶工业纯铁腐蚀倾向小.基于纳米晶和粗晶工业纯铁在添加有硫脲的1 mol•L－1盐酸溶液中阻抗谱随浸泡时间的变化关系,观察到以下现象,当浸泡时间短至5 min时,对应不同浓度(50、100、150、500 mg•L－1)的缓蚀剂添加量,在粗晶工业纯铁的阻抗复平面图上出现一感抗弧,而在纳米晶工业纯铁的阻抗复平面图是一圆心下偏的容抗弧.随着浸泡时间的延长,两种样品的容抗弧半径增大,在150 mg•L－1的浓度时,电荷传递电阻(Rct)出现极值,这表明硫脲是一种吸附型缓蚀剂.抗盐酸腐蚀性能的提高和没有感抗弧的出现, 归因于体纳米化的结果,这与体纳米化的制备技术密切相关.

Corrosion Inhibition of Bulk Nanocrystallized Industrial Pure Iron by Thiourea in HCI

The effect of thiourea(TU) on the corrosion behavior of bulk nanocrystallized and coarse grain industrial pure iron in 1 mol•L－1 HCl at room temperature was investigated, by means of electrochemical impedance spectroscopy(EIS).Bulk nanocrystallized industrial pure iron is less prone to get corrosive than its coarse grain counterpart in blank 1 mol•L－1 HCl at room temperature from the EIS fitting results. On the basis of the variation of impedance behaviors of bulk nanocrystallized and coarse grain industrial pure iron in the inhibitor-containing 1 mol•L－1 HCl solutions with the immersion time, an relationship between immersion time and Nyquist plot was established, for very short immersion time,namely,5 min, an inductive loop appeared at different concentrations in the Nyquist plots of coarse industrial pure iron rod, but it did not appear in those of nanocrystallized industrial pure iron. A critical concentration of thiourea with the largest Rct (charge transfer resistance) in the complex impedance plane appeared for both samples.