Investigation, on the Accelerated Dissolution of Metal Induced by AFM Tip Scratching and Suppressed by Inhibitors

应用原子力显微镜(AFM)探针刮伤技术研究缓蚀剂对探针诱导铜镍合金加速溶解作用的影响.实验表明,在1.5 mol/L NaC l和0.01 mol/L HC l溶液中,使用AFM探针在750 nN的力负载条件下以接触模式对铜镍合金表面持续扫描,会加速样品的溶解,并在探针刮擦区域形成蚀坑.将有机缓蚀剂十二胺及无机缓蚀剂铬酸钠添加到腐蚀介质中后,由于在合金表面形成了吸附膜和钝化膜,从而抑制探针刮擦引起的铜镍合金的加速溶解.The accelerated dissolution behavior of Cu-Ni alloy induced by AFM tip scratching and the inhibition effect of corrosion inhibitors were investigated. The results showedthat, with a tip loading of 750nN ,continuous scan for 30 min in a contact mode on 4×4 μm~(2) of copper-nickel alloy in 1.5mol/L NaCl and 0.01mol/L HCl could enhance the dissolution of the sample and produced pits on the scratched area. Adding inorganic inhibitors, sodium chromateand organic inhibitor dodecylamine, to the solution suppressed the dissolution of copper-nickel alloyinduced by tip scratching, respectively, by improving the surface passivationperformance of metal surface and forming adsorption films on copper-nickel alloy.作者联系地址：华中科技大学化学系,华中科技大学化学系 湖北武汉430074 ,湖北武汉430074Author's Address: Chemistry Department, Huazhong University of Science and Technology, Wuhan 430074,Chin

Study on Adsorption Behavior of Inhibitors on N80 Steel

应用极化曲线和交流阻抗技术研究了 4种缓蚀剂在N80钢基体和碳酸亚铁膜上的吸脱附行为 .实验表明 ,对同一种缓蚀剂 ,其在N80钢光洁表面和在腐蚀产物膜上的吸附力强度不同 ,而酸性缓蚀剂和小分子缓蚀剂在N80钢光洁金属表面和碳酸亚铁膜上各表现出不同的缓蚀行为The de_adsorption behavior of four inhibitors on N80 steel with and without carbonate film was investigated by polarization and electrochemical impedance spectroscopy (EIS) techniques. It was found that,for different inhibitors,de_adsorption behavior and adsorbability between with and without carbonate film are different.Furthermore,acidic inhibitor and small size molecule inhibitor shows different inhibition behavior.作者联系地址：华中科技大学化学系,华中科技大学化学系,华中科技大学化学系 湖北武汉430074 ,湖北武汉430074 ,湖北武汉430074Author's Address: Chemistry Department,Huazhong University of Science and Technology,Hubei 430074,Chin

Investigation of Electrochemical Noise in the Crevice Corrosion of Q235 Carbon Cteel

应用电化学噪声和电化学阻抗技术研究Q235碳钢在NaHCO3+NaCl溶液中的缝隙腐蚀行为.结果显示,缝隙腐蚀过程可以被清楚地划分为3个阶段:孕育期、快速转换期和稳定发展期.电化学噪声的特征和噪声电阻在各阶段有着显著的变化.缝隙外、内表面积比(r)对缝隙腐蚀的孕育和发展有着十分重要的影响:r越大,孕育期越长.但是,在缝隙腐蚀稳定发展期,r较小时,缝隙外电极表面处于活性溶解状态,缝隙内外电位差很小,缝隙内腐蚀速率较小;倘如r很大时,则缝隙外电极表面处于钝态,缝隙内外电位差大,最终将导致严重的缝隙腐蚀.The crevice corrosion behavior of Q235 carbon steels in a NaHCO3+NaCl solution was investigated by electrochemical noise(EN) and electrochemical impedance spectroscopy(EIS).Three stages of crevice corrosion including the induction,the rapid transform and the stable development could be clearly distinguished.The characteristics of the electrochemical noise and the noise resistance Rn showed remarkable differences at each stage.The electrode area ratio(r) of outside to inside the crevice had a significant influence in the development of crevice corrosion.The time of the induction stage increased with increasing r.However,under the stable development stage of the crevice corrosion,the surface outside the crevice was at an active dissolution state when r was small,while the potential difference between outside and inside the crevice and the corrosion rate inside the crevice were small.When r was big,the surface outside the crevice was at a passive state and the potential difference between outside and inside the crevice was large,which causes serious crevice corrosion.作者联系地址：华中科技大学化学与化工学院材料化学与服役失效湖北省重点实验室;Author's Address: School of Chemistry and Chemical Engineering,Huazhong University of Science and Technology,Hubei Key Laboratory of Materials Chemistry and Service Failure,Wuhan 430074,Chin

Electrochemistry Characteristic of Carbon Steel under Biofilm and Sulfide Film

应用丝束电极技术比较了SRB生物膜以及硫化物膜对Q2 35碳钢腐蚀过程的影响机制 ,采用电位、电流扫描技术测试了生物膜和FeS膜下的碳钢腐蚀不均匀性特征 ,发现由于膜的导电性致使表面电位扫描已不能作为膜下局部腐蚀的判据 .动电位扫描表明无氧近中性溶液中 ,硫化物膜对碳钢具有一定保护作用 .电化学阻抗谱显示 ,硫化物膜电容增加缓慢 ,其极化电阻Rp 随时间呈先增后降的趋势 .与硫化物膜相比 ,生物膜表现出极大的电容 (10 4 ～ 10 5μF/cm2 ) ,且膜电容随时间呈S型增加 ,而极化电阻Rp 则呈指数下降 ,由此可知生物膜加速了腐蚀Wire Beam Electrode (WBE) made of Q235 carbon steel was applied to study the heterogeneous corrosion beneath biofilm formed by Sulfate Reducing Bacteria (SRB) in culture and sulfide film in solution with 1% NaCl and 300 mg/L S 2- . The potential,galvanic density mapping,as well as polarization curve and Electrochemical Impedance Spectrum (EIS) were measured to predict the localized corrosion under biofilm and sulfide film.As a result,the mapping showed the potential fluctuation on the WBE surface decreased over time due to the conductivity of the biofilm and sulfide film.Therefore,the potential mapping could not be a criterion of localized corrosion under biofilm.Instead,the current mapping could give a good prediction to the MIC.The sulfide film could inhibit corrosion of carbon steel.However,the biofilm accelerate the corrosion.Polarization resistance R p increased over time in the Na 2S solution if lack of O 2.In addition,the biofilm capacity moved up to a very large level (～10 5 μF/cm 2)in shape of Sigmoid with its polarization resistance decreasing exponentially when SRB grew.作者联系地址：华中科技大学化学系!湖北武汉430074,华中科技大学化学系!湖北武汉430074,华中科技大学化学系!湖北武汉430074,华中科技大学化学系!湖北武汉430074Author's Address: Dept. of Chem.,Huazhong Univ. of Science and Technology,Wuhan 430074,Chin