硫脲对块体纳米晶工业纯铁在盐酸溶液中的缓蚀行为

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

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-感抗弧,而在纳米晶工业纯铁的阻抗复平面图是-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150mg·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.

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.