深海静水压力环境下低合金高强度钢腐蚀行为研究

通过自行设计的深海环境模拟装置,采用静态挂片失重、动电位极化曲线及电化学阻抗谱（EIS）等方法系统研究了深海静水压力环境下低合金高强度钢（HSLA钢）在3.5% NaCl溶液中的腐蚀行为,并与常压下的结果对比,探讨了静水压力下HSLA钢在深海环境中的腐蚀行为. 结果显示,静水压力并没有改变HSLA钢在3.5% NaCl溶液中的腐蚀历程,不甚影响其阴极过程,而主要提高了其阳极腐蚀速率,这可能与高静水压下Cl-活性的增加有关.     

3.5% NaCl饱和Ca(OH)2溶液中醇胺缩聚物对碳钢腐蚀的抑制

利用动电位极化, 电化学阻抗谱(EIS)和表面形貌观察方法, 并结合量子化学计算, 在3.5% NaCl饱和Ca(OH)₂ 溶液中研究探讨了山梨醇与二乙烯三胺缩聚物(SDC)对碳钢腐蚀的抑制行为. 结果表明: SDC的加入可有效降低碳钢的腐蚀电流密度, 提高碳钢的点蚀电位, 表明阻绣剂对Cl^-诱导的局部腐蚀具有良好的抑制作用, 为混合型阻锈剂; 且在所研究浓度范围内, 随添加浓度增加, 缓蚀效率提高. 化合物对碳钢腐蚀的抑制主要源自阻锈剂分子在碳钢表面的静电吸附, 且吸附遵循Langmuir等温吸附规律.     

咪唑啉酰胺在电偶电极表面的吸附行为

采用原子力显微镜技术研究了有机阳离子缓蚀剂(咪唑啉酰胺)在电偶电极表面的吸附行为, 并探讨了其腐蚀抑制机理. 结果表明, 金属表面的过剩电荷较大地影响缓蚀剂分子的吸附行为. 在1%的NaCl溶液中, 碳钢电极表面带有过剩的负电荷；不锈钢电极表面带有过剩的正电荷；碳钢电极和不锈钢电极耦合后, 其表面分别带有过剩的正电荷和负电荷. 在耦合前阳离子缓蚀剂分子仅吸附在碳钢表面, 耦合后缓蚀剂分子在偶对的阴极(不锈钢)和阳极(碳钢)表面均有吸附, 但缓蚀剂分子在碳钢表面的吸附强度和覆盖度较之耦合前降低, 缓蚀剂的腐蚀抑制能力减弱.     

电场作用下金属锌在薄液膜下的腐蚀电化学研究

采用薄液膜实验装置,测量了外加直流电场作用下锌在薄液膜体系中的腐蚀电位、阴极极化电流以及阴极极化曲线等. 研究了外加直流电场对锌在薄液膜下腐蚀行为的影响. 结果表明,外电场的作用可以使锌电极的腐蚀电位负移,也可以使锌电极在阴极极化条件下的阴极电流增加. 分析结果表明,外电场与薄液膜体系中锌电极电化学过程中的相关因素发生了协同作用,改变了锌电极的阴极过程.     

Q235碳钢缝隙腐蚀的电化学噪声研究

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.     

锌铋合金电极在溶胶电解液中的电化学行为

锌电极的自腐蚀速率, 持续放电下的阳极溶解速率和电极钝化的难易程度是碱性电池性能的重要电化学参数. 本文应用线性极化、恒流放电等电化学实验方法研究了电解液中添加Carbopol树脂以及电极中添加Bi对锌电极电化学行为的影响. 并应用金相显微镜和环境扫描电子显微镜(ESEM)对锌电极和锌铋合金电极浸蚀及放电后的形貌进行了表征. 结果表明: 电解液中添加适量的Carbopol树脂可明显提高电极的极化电阻, 显著降低电极的自腐蚀速率; 阳极的溶解电位出现不同程度的正移, 阳极过电位显著增大且大电流密度放电时较明显促进电极钝化. 锌电极中添加一定量的Bi对改善电极表面氧化物膜的沉积形貌和电极表面固液界面的传质条件, 减小电极的自腐蚀速率, 抑制电极自腐蚀等方面具有显著作用.     

水性环氧铝粉涂层/碳钢体系的腐蚀电化学行为

应用电化学阻抗谱(EIS)和扫描振动电极技术(SVET)研究了碳钢基体上含人造缺陷的水性环氧铝粉涂层浸泡在3.5%NaCl溶液中的腐蚀电化学行为.结果表明,浸泡初期,涂层缺陷处为阳极活性区,涂层阻抗随时间延长逐渐降低,活性区逐渐扩展;之后,由于腐蚀产物的自修复作用使整个涂层/金属界面电化学反应活性降低,导致涂层阻抗快速增加.浸泡后期,由于腐蚀介质渗入到涂层/基体界面,出现了更多的阳极活性区,涂层产生破坏剥离.     

碳钢在生物膜和硫化物膜下的电化学腐蚀行为

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     

锌-铟合金电极在浓KOH溶液中的电化学行为

应用动电位扫描,恒流放电等电化学方法研究含铟锌电极的电化学行为.用SEM和EDS观察放电后的Zn-In合金电极表面形貌,初步探讨了不同In含量的锌-铟合金电极在浓KOH溶液中电化学行为及其影响因素.结果表明,与纯锌电极相比,Zn-In合金的电极致钝电流增大,达到钝化的时间缩短,从而明显地提高了该电极的电化学活性.     

饱和NaCl溶液浸泡下混凝土试块中有机阻锈剂对钢筋腐蚀行为的影响

利用电化学阻抗谱(EIS)、半电池腐蚀电位(Ecorr)和宏观电池腐蚀电流密度(Icorr)测量技术,在饱和NaCl溶液浸泡的硬化混凝土试块中,研究了4种醇胺基阻锈剂对钢筋电极腐蚀电化学行为的影响和长期阻锈性能.在浸泡初始的100d内,与空白样相比,添加阻锈剂后钢筋电极腐蚀电位升高,阻抗膜值增大,腐蚀电流密度值降低,表明电极表面处于钝态,阻锈剂表现出良好的阻锈性能.随浸泡时间延长,电极腐蚀电位和阻抗膜值下降,腐蚀电流密度增大.浸泡后期,除添加醇胺基CI-4样外,电极电位和腐蚀电流密度与空白样相比无明显差别,表明电极由钝态转变为活性腐蚀状态.但添加CI-4样品,钢筋电极始终保持在钝化状态,阻锈性能最好.基于阻锈剂与Cl-间的竞争吸附,分析探讨了可能的阻锈机理.     

Surface analysis and corrosion resistance of new nickel base thin film alloys

Electroless Zn–Ni–P thin films were deposited on low carbon steel from an alkaline non‐cyanide aqueous electrolyte. The newly developed ternary alloys structure and microstructure investigations were carried out via X‐ray diffraction and SEM. Chemical composition of the coatings was investigated via energy dispersive spectroscopy. Polarization tests were used to study the corrosion properties of the coatings in a 3.5 wt.% NaCl solution. The results confirmed the high corrosion resistance of Zn–Ni–P alloy plated steel sheet. The surface analysis of the thin film samples before and after corrosion was performed by XPS. The incorporation of Zn in Ni–P thin film is proven for all initial samples to be as a mixture of zinc and zinc oxide, while nickel exists in +2 and +3 oxidized states. A passive film of a mixture of oxide and hydroxide of zinc and nickel forms on the surface and prevents the Zn–Ni–P thin films from corrosion. Copyright © 2014 John Wiley & Sons, Ltd.     

Smart Coating Based on Urea-Formaldehyde Microcapsules Loaded with Benzotriazole for Corrosion Protection of Mild Steel in 3.5 % NaCl

Urea-formaldehyde (UF) microcapsules loaded with linseed oil (LO) and benzotriazole (BTA) as core materials have been synthesized by in situ emulsion polymerization. The capsules were characterized by FTIR spectroscopy and particle size analysis. Surface morphology of the microcapsules was analyzed using scanning electron microscopy (SEM). The microcapsules were incorporated into epoxy resin and coated on a mild steel substrate to form a corrosion resistant organic coating. The self-healing property of coatings loaded with different weight % of microcapsules containing LO + BTA was tested by immersion of the UF coated mild steel specimens in 3.5 wt % NaCl solution. It was analyzed through visual inspection, weight loss measurements, and SEM of the scribed region of coating. It was observed that the addition of microcapsules enhances the corrosion resistance of the scratched samples.

     

The electrochemical synthesis of poly(o-phenylenediamine) on stainless steel and its corrosion protection ability in 3.5 % NaCl solution

In this study, electrochemical synthesis of poly(o-phenylenediamine) (PoPDA) on 316L stainless steel and its corrosion inhibition effect were studied. Electropolymerization of o-phenylenediamine (oPDA) was carried out by a potentiodynamic method using 0.5 M H₂SO₄ solution containing 0.05 M oPDA monomer. The corrosion protection ability of the PoPDA in 3.5 % NaCl was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy, and change of open circuit potential with immersion time (E_OCP ? t). The results showed that PoPDA acted as a protective layer on stainless steel against corrosion in 3.5 % NaCl solution.     

A3钢在缓蚀颜料提取液中的EIS研究

应用EIS研究了A3钢在不同 pH值的磷酸锌或三聚磷酸铝 3.5 %NaCl提取液中的腐蚀行为 .结果显示 ,相同条件下 ,A3钢的电阻值随溶液 pH值增加而增加 ,电容值则相反 .在磷酸锌3.5 %NaCl提取液中 ,因磷酸锌的溶解度太小 ,没有足够的量对金属基底A3钢进行有效的保护 .在 pH值为 6的三聚磷酸铝 3.5 %NaCl提取液中 ,A3钢表现出较明显的缓蚀现象 ,可能是因为三聚磷酸根离子与腐蚀产物Fe2 + 、Fe3+ 络合并在钢表面形成了一层致密的保护膜 ,从而有效地阻止了腐蚀介质的进一步入侵 .防蚀颜料的溶解度大小是决定它的缓蚀性能优劣的重要因素之一     

碳钢缝隙内溶液化学和阳极极化行为研究

为研究缝隙腐蚀的溶液化学和缝中金属阳极极化行为,设计一种楔形缝隙模拟装置。以碳钢为研究对象,分别测试了在３．５％（ｗｔ）ＮａＣｌ溶液中缝内各位置的电极电位,Ｃｌ＾－浓度,ｐＨ值以及缝外阳极极化时电流密度的变化。     

钼酸盐封闭后处理的热镀锌钢板硅烷膜的耐蚀性

为进一步增强硅烷膜的耐蚀性, 将硅烷化热镀锌钢板用钼酸盐溶液进行封闭后处理, 并采用扫描电子显微镜(SEM)、中性盐雾(NSS)实验、盐水全浸实验和电化学技术研究了所得复合膜层的表面形貌和耐蚀性能. 结果表明: 经钼酸盐溶液封闭处理后, 硅烷膜的孔隙被填充, 在锌层表面形成了由硅烷膜和钼酸盐转化膜构成的连续完整致密的复合膜; 复合膜的耐蚀性能明显提高, 且与钼酸盐溶液的封闭时间有关, 封闭60 s时所形成的复合膜的耐蚀性最佳. 在5%(w, 质量分数)NaCl溶液中的电化学测量结果表明: 硅烷化热镀锌钢板经钼酸盐溶液封闭处理后, 同时抑制了腐蚀过程中的阳极和阴极反应, 但主要是抑制阴极反应, 导致腐蚀电流密度明显减小, 发挥了单一硅烷膜和单一钼酸盐转化膜腐蚀防护的协同效应, 腐蚀防护效率高达99.1%; 随浸泡时间延长, 试样低频扩散阻抗先增大后减小, 表明膜层具有一定的“自愈”能力, 其耐蚀性优于常规铬酸盐钝化膜.     

镍铝介金属镀膜之抗坑蚀行为

采用3种原子百分比Ni52Al48,Ni60Al40及Ni70Al30成分的靶材以阴极电弧放电离子被覆技术制备不同组成的Ni＿Al薄膜于AISI1045中碳钢基材表面上,并观察镀膜微结构与成分随靶材成分的变化,评估应用Ni＿Al于抗坑蚀功能方面的可行性.研究结果显示:使用上述3种靶材所获致的镀膜组成依次为Ni62Al38,Ni63Al37及Ni69Al31,镀膜镍含量随靶材镍含量增加而增加.3种镀膜的相组成均以Ni3Al为主,从富镍Ni70Al30靶材所得的镀膜尚含有部分镍相.镀膜具有极强的附着性并反映在镀膜的抗坑蚀性上.在纯水中,所有的Ni＿Al镀膜试片均能提高中碳钢基材的抗坑蚀性,约达10倍.在3.5wt%盐水与3.5wt%盐酸中亦分别有两倍以上的效果.而在这3种测试环境中,3种镀膜试片的坑蚀损失差别均不明显,无法判断镀膜组成对抗坑蚀性的影响.从动电位极化曲线可以看出,镀膜试片均能大幅提高基材在盐酸与盐水溶液中的抗蚀性,然而因坑蚀破坏而形成的孔洞会由于孔蚀而导致腐蚀加剧,造成镀膜试片在腐蚀溶液中之抗坑蚀效果低于电化学量测时所预期的保护效果.     

Structural and electrochemical characterization of sputter-deposited nitrided NiCr alloys

Nickel-based coatings are potential candidates for the protection of electrochemical dissolution of steel surfaces. Such coatings, elaborated by magnetron sputtering in a nitrogen atmosphere, offer good corrosion protection, good adherence as well as stability for metallic structures. NiCr alloys with almost constant composition have been deposited with different nitrogen contents on stainless steel and carbon steel surfaces. The coating uniformity, homogeneity, composition and crystallinity have been studied by scanning electron microscopy, energy-dispersive X-ray spectrometry, atomic force microscopy and X-ray diffraction techniques. The corrosion degradation behavior of all the samples was tested in NaCl and NaCl and CO₂ mixture exposures using electrochemical impedance spectroscopy measurements. Nitrided NiCr alloys on a stainless steel substrate resulted with better adhesion than carbon steel, by delaying the corrosion mechanism when exposed to NaCl and CO₂ solution. A comparison of the corrosion resistive behavior of the substrates (stainless steel, carbon steel) and the coatings is made by using the electrical capacitance concept from a double-layer model for the coating–metal interface.     

EIS study on the corrosion performance of a Cr(III)-based conversion coating on zinc galvanized steel for the automotive industry

The corrosion performance of a new industrial Cr(III)-based conversion coating on zinc galvanized FeP04 steel for the automotive industry was studied. For comparison, the zinc galvanized steel submitted to a Cr(VI)-based passivation treatment was also examined. The corrosion behavior was assessed by means of potentiodynamic polarization and electrochemical impedance spectroscopy measurements in aerated 0.1 M NaCl solution. The behavior of untreated zinc galvanized FeP04 steel in aerated 0.1 M NaCl solution was also studied. The results obtained indicate that with the same thickness, the coating generated in the Cr(III) treatment bath exhibits better corrosion properties compared to the coating formed in the Cr(VI) treatment bath. The difference in the corrosion protection given by the two conversion coating types can be ascribed to the difference in the chromium content and coating composition.