在稀硫酸中添加硫脲对块体纳米晶纯铁腐蚀行为的影响

研究了在稀硫酸溶液中添加硫脲(TU)对块体纳米晶工业纯铁(BNII)室温电化学腐蚀行为的影响,并与普通工业纯铁(CPII)的室温电化学腐蚀行为进行了比较.结果表明:将CPII在添加TU的稀硫酸溶液中浸泡5 min,其电化学阻抗(EIS)谱图中出现感抗弧.随着浸泡时间的延长,CPII的EIS谱图表现为一非圆心下偏的半圆;而在相同的条件下,BNII的EIS谱图表现为两个时间常数的容抗弧,表明硫脲对其腐蚀行为有促进作用.动电位极化(PDP)测试结果表明,两种材料的样品均出现阳极脱附现象.

Effect of thiourea on bulk nanocrystallized ingot iron in acidic sulfate solution

Effect of thiourea in acidic sulfate solution on electrochemical corrosion behavior of bulk nanocrystallized ingot iron(BNII) was investigated in 0.1 M H_2SO_4 0.25 M Na_2SO_4 solution at room temperature by electrochemical impedance spectra(EIS) and potentiodynamic polarization method(PDP), compared to that of coarse polycrystalline ingot iron(CPII).The results show that For CPII,an inductive loop appears in the Nyquist plots after 5 minutes'immersion.With the increase of immersion time,the Nyquist plot of CPII is not a perfect semicircle;the Nyquist plots of BNII contain two capacitive loops with two time constants.The inhibition of thiourea to BNII is very limited.However,thiourea promoted the dissolution of BNII.The polarization curves for both samples show the presence of a desorption potential. When the potential is higher than the desorption potential,the anodic dissolution current increases very abruptly.