长春花提取物对Q235碳钢在酸性溶液中的缓蚀作用  

Corrosion Inhibition of Catharanthus Roseus Extract on Q235 Carbon Steel in Acidic Solution

作　　者：李永娟[1] 黄进强 年芳[1] LI Yong-juan;HUANG Jin-qiang;NIAN Fang(College of Science,Gansu Agricultural University,Lanzhou 730070,China)

机构地区：[1]甘肃农业大学理学院,兰州730070

出　　处：《表面技术》2023年第11期300-308,共9页Surface Technology

基　　金：甘肃省高等学校创新能力提升项目(2019A-055) 。

摘　　要：目的 开发一种绿色缓蚀剂,并研究它对碳钢在酸性溶液中的缓蚀作用及机理。方法 用体积分数为70%的乙醇水溶液回流获得长春花提取物(CR-E),通过失重实验、电化学综合实验、火焰原子吸收分光光度法(FAAS)、傅里叶变换红外光谱(FTIR)和扫描电子显微镜(SEM)等分析CR-E对Q235碳钢在0.5 mol/L H_(2)SO_(4)溶液中的缓蚀性能和机理。结果 CR-E对Q235碳钢在H_(2)SO_(4)溶液中的腐蚀具有良好的缓蚀效果,缓蚀效率随着CR-E浓度的增加而增大,在CR-E的质量浓度为1000mg/L时,缓蚀效率达到89.84%。添加CR-E后可迅速抑制腐蚀,并持续发挥缓蚀作用,在浸泡48 h后Q235碳钢的缓蚀效率仍可达89.99%;电化学综合实验结果表明,CR-E是一种有效的混合抑制型缓蚀剂,腐蚀反应的电荷转移电阻随着CR-E浓度的增加而增大,腐蚀电流密度则随之减小;通过FAAS证实阳极铁的溶解被抑制,通过FTIR证实CR-E分子可以有效吸附在Q235碳钢表面,通过SEM证实Q235碳钢表面受到了CR-E的有效防护。缓蚀机理是CR-E缓蚀剂分子在Q235碳钢表面的吸附减缓了铁在腐蚀溶液中的溶解,腐蚀过程受到显著抑制,该吸附以物理吸附为主,且遵循Langmuir吸附等温模式。结论 在0.5 mol/L H_(2)SO_(4)溶液中,CR-E对Q235碳钢的缓蚀作用显著,可作为一种候选绿色缓蚀剂在工业领域推广应用。The work aims to develop a new green corrosion inhibitor and find its corrosion inhibition effect on Q235 carbon steel in acidic solution.Catharanthus roseus extract(CR-E)was obtained by reflux extraction with 70%ethanol aqueous solution.The corrosion inhibition performance and mechanism of CR-E on Q235 carbon steel in 0.5 mol/L H_(2)SO_(4) solution were assessed by classical weight loss experiment,electrochemical comprehensive experiment,flame atomic absorption spectrometry(FAAS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM). The weight loss experiment showed that CR-E had a good corrosion inhibition effect on Q235 carbon steel in 0.5 mol/L H_(2)SO_(4) solution. The corrosion inhibition efficiency increased with CR-E concentration to attain 89.84% at 1 000 mg/L at 298 K. After CR-E was added, it could quickly retard corrosion and continue to exert a corrosion inhibition effect. The corrosion rate of Q235 carbon steel containing CR-E was 21.56% of that in the blank one after 3 h exposure and 8.57% after 24 h exposure. The corrosion inhibition efficiency could still reach 89.99% after soaking for 48 h in 0.5 mol/L H_(2)SO_(4) solution. Adsorption of CR-E on the surface of Q235 carbon steel followed Langmuir adsorption isotherm and was spontaneous. The strong physisorption and weak chemisorption were involved according to the standard Gibbs adsorption free energy (0adsΔG= -25.81 kJ/mol). According to the findings of the polarization curves, the CR-E performed as an effective mixed-type inhibitor. The parallel cathodic branch revealed that the mechanism of the hydrogen evolution was not affected by the addition of CR-E in H_(2)SO_(4) solution. The inhibition efficiency calculated by the corrosion current density and polarization resistance increased and went up to 95.54% and 94.22% at 500 mg/L CR-E concentration respectively. A single capacitive loop and only one time constant were observed from electrochemical impedance spectroscopy (EIS), which indicated that the mechanis

关 键 词：缓蚀剂 碳钢 长春花 吸附 硫酸 电化学 SEM 

分 类 号：TG174.42[金属学及工艺—金属表面处理]