三氯乙酸介质中阴离子表面活性剂对钢的缓蚀性

Corrosion Inhibition of Anionic Surfactant on Steel in Trichloroacetic Acid Medium

为了筛选三氯乙酸(Cl_(3)CCOOH)溶液中成本低廉且环境友好的缓蚀剂,用失重法和动电位极化曲线法研究了阴离子表面活性剂十二烷基硫酸钠(SDS)在三氯乙酸溶液中对冷轧钢表面的缓蚀性能,同时采用扫描电子显微镜(SEM)、原子力显微镜(AFM)和接触角测量仪系统表征了钢表面的腐蚀微观形貌及亲水性变化。结果表明:SDS对冷轧钢在0.10 mol/L Cl_(3)CCOOH中具有良好的缓蚀作用,缓蚀率随SDS浓度增加而增大,20℃时SDS用量仅为50 mg/L时缓蚀率可高达90.5%。SDS在钢表面的吸附符合Temkin吸附等温式,标准吸附Gibbs自由能为-27.3 kJ/mol。腐蚀电位在添加SDS后发生负移,对腐蚀阴极反应发生显著抑制作用,但对阳极反应基本无抑制作用。SEM和AFM分析表明冷轧钢表面在含有SDS的Cl_(3)CCOOH中腐蚀程度和表面粗糙度急剧下降,且接触角测试表明缓蚀钢表面的接触角增大。

In order to screen low-cost and environmentally friendly corrosion inhibitors in trichloroacetic acid(Cl_(3)CCOOH)solution,the corrosion inhibition performance of anionic surfactant of sodium dodecyl sulfate(SDS)on cold rolled steel in trichloroacetic acid(Cl_(3)CCOOH)solution was studied by weight loss and potentiodynamic polarization curves.The corrosive micro-topography and the change of hydrophilic/hydrophobic properties of steel surface were studied systematically by scanning electronic microscope(SEM),atomic force microscope(AFM)and contact angle instrument.Results showed that SDS could effectively retard the corrosion of cold rolled steel in 0.10 mol/L Cl_(3)CCOOH solution,and the inhibition efficiency increased with the increase of SDS concentration.The maximum inhibition efficiency was up to 90.5%at 20℃with just adding 50 mg/L SDS.Moreover,the adsorption of SDS on steel surface obeyed Temkin adsorption isotherm,and the standard adsorption Gibbs free energy was-27.3 kJ/mol.The presence of SDS shifted corrosion potential to negative position.The cathodic reactions were efficiently retarded,and yet there was no obvious inhibition effect on anodic reactions.In the presence of SDS,the result of SEM and AFM clearly showed the corrosive degree and surface roughness of steel in Cl_(3)CCOOH solution significantly were reduced,and contact angel measurements indicated the hydrophobic angle increased.