纳米纤维聚苯胺膜在不锈钢电极表面的生长过程

研究了脉冲电流法(PGM)聚合苯胺时, 纳米纤维聚苯胺(PANI)膜在不锈钢(SS)电极表面的生长过程. 用计时电位法和扫描电子显微镜(SEM)表征了聚苯胺生长过程的电化学特征和微观形貌; 并通过循环伏安(CV)法研究了苯胺的聚合速率. 结果表明, 聚苯胺的生长经历了两个阶段, 首先是在裸不锈钢电极表面上形成颗粒状聚苯胺, 此时聚合电位约为1.10 V, 经历了30 s后, 电极表面被一层颗粒状聚苯胺膜所覆盖; 在此基础上, 聚苯胺以纳米纤维状结构继续生长, 当颗粒状聚苯胺被纳米纤维状聚苯胺膜完全覆盖时, 聚合电位降至0.75 V左右并保持稳定.     

Characterization of stainless steel electrode modified by a thin film of polyaniline containing pt particles and its electrocatalytic activity for methanol oxidation

The catalytic behavior of stainless steel (SS) electrode modified by a thin film of polyaniline (PANI) containing platinum particles was studied for electrooxidation of methanol and compared with a platinated Pt/PANI electrode in acidic aqueous solution. Cyclic voltammetry (CV), chronoamperometry, CO stripping techniques were used to investigate electrochemical properties and electrocatalytic activity of SS/PANI/Pt and Pt/PANI/Pt electrodes. The morphology and particle size of Pt catalysts were characterized by Transmission Electron Microscopy (TEM) measurement. The effects of various parameters such as thickness of polymer film, medium temperature and stability of the modified electrodes on methanol oxidation were also investigated. The results indicated that the modified SS electrode exhibited a considerably high electrocatalytic activity on the methanol oxidation as well as the modified Pt electrode.     

改性316L不锈钢表面聚苯胺的制备及电化学性能

采用原位氧化技术调整316L不锈钢(SS316L)基体元素Cr和Ni在界面的浓度和分布, 形成了Ni和Cr富集改性界面. 应用计时电位技术, 通过Cr和Ni改性层催化草酸溶液中的苯胺单体在其表面吸附并聚合, 在SS316L表面沉积了附着力良好的聚苯胺(PANI)膜. 与SS316L相比, 表面富Ni-Cr的SS316L在涂覆PANI膜后, 在80 ℃ 0.5 mol/L H₂SO₄+5 mg/L F^-溶液中阳极和阴极的腐蚀电位分别提高470和500 mV, 维钝电流均下降2~3个数量级; 在模拟质子交换膜燃料电池运行环境中, 经36000 s恒电位极化, 其阳极和阴极的腐蚀电流分别下降约1和2个数量级, 腐蚀速度分别约为6~9 和< 5 μA/cm²; 在1.4 MPa压力下, 聚苯胺膜层与Toray 060碳纸间接触电阻下降约250 mΩ·cm². SS316L表面形成富Ni-Cr改性层并涂覆聚苯胺膜后, 其耐蚀性和导电性均明显优于原始SS316L, 这主要取决于富Ni-Cr改性层的结构、 组成和聚苯胺膜的厚度.     

基底材料对脉冲电流法制备的聚苯胺膜性能的影响

本文采用脉冲电流法(PGM)在不同的基底材料表面沉积PANI, 通过平均电位\|时间曲线及扫描电子显微镜(SEM)等方法研究了基底材料对PGM法制备PANI的影响; 并采用循环伏安(CV)和电化学阻抗谱(EIS)研究了不同电极材料表面PANI的电化学性能.     

Corrosion and tribocorrosion behaviour of super‐thick diamond‐like carbon films deposited on stainless steel in NaCl solution

Super‐thick diamond‐like carbon (DLC) film is a potential protective coating in corrosive environments. In the present work, three kinds of DLC films whose thickness and modulation periods are 4 µm and 3, 21 µm and 17 and 21 µm and 7, respectively, were fabricated on stainless steel. The effect of different thickness and modulation periods on corrosion and tribocorrosion behaviour of the DLC‐coating stainless steel was investigated in 3.5 wt% NaCl aqueous solution by a ball‐on‐flat tribometer equipped with a three‐electrode electrochemical cell. The DLC‐coating stainless steel served as a working electrode, and its OCP and potentiodynamic polarization were monitored before and during rubbing. The wear–corrosion mechanism of the DLC films was investigated by SEM. The results showed that the increasing thickness can prolong significantly lifetime of DLC films in NaCl aqueous solution. In particular, the modulation period has a significant impact on the tribocorrosion resistance of the DLC super‐thick films. The study suggested that the increasing thickness of compressive stress layer could suppress film damage by reducing crack propagation rate. Thus, the super‐thick DLC film with thickness of 21 µm and 7 periods presented the best tribocorrosion resistance among all studied films. Copyright © 2016 John Wiley & Sons, Ltd.     

抗菌处理含铜铁素体不锈钢的耐微生物腐蚀性能

采用电化学测试技术及微生物学方法, 研究了抗菌处理含铜铁素体不锈钢在含有培养基的异养菌溶液中的耐蚀性能. 结果表明, 不锈钢的腐蚀电位随异养菌的新陈代谢呈现规律性变化, 抗菌处理使不锈钢在菌液中钝化膜的稳定性得到改善, 点蚀敏感性降低; 抗菌不锈钢表面弥散分布的ε-Cu析出相的杀菌作用, 降低了异养菌的活性, 减缓了异养菌对抗菌不锈钢的腐蚀, 提高了抗菌不锈钢耐微生物腐蚀性能.     

Characterization of the Passive Film and Corrosion of Martensitic AM355 Stainless Steel

Electrochemistry methods were used to investigate the influence of pH on the passive film and corrosion behavior of ultrahigh strength AM355 stainless steel in chloride-containing media. Analysis of the Pourbaix diagram indicates that AM355 stainless steel exhibits higher corrosion resistance in natural and near-natural environments than that in acidic and alkaline conditions. Electrochemistry measurements and composition analysis of the passive film show that pitting potential increased due to the enhanced repassivation capacity of AM355 stainless steel with increasing pH. The mixed MnS/oxide inclusions are the main pitting sensitive locations under all conditions. Morphological observations and energy-dispersive spectroscopy showed that the influence of the gap between the martensitic laths is significant with increasing pH. The inclusions, element concentrations, and microstructures weaken the resistance of ultrahigh-strength martensitic AM355 stainless steel against corrosion.     

磁场对316L不锈钢微生物腐蚀行为的影响

采用循环极化、微生物分析法、扫描电镜及表面能谱分析等方法,研究了磁场对316L不锈钢在含硫酸盐还原菌(SRB)的土壤模拟溶液中的腐蚀行为。结果表明,磁场可以抑制SRB的生长;未外加磁场时316L不锈钢表面膜层以局部堆积为主,加有磁场时,局部堆积明显减小,膜层均匀致密的排列于基体表面;无论有或没有外加磁场,316L不锈钢表面均发生钝化膜破裂型点蚀,未外加磁场时的点蚀电位低于加有磁场时的。在相同的浸泡时间,未外加磁场时循环极化滞后环面积明显比加有磁场时的大,说明磁场可以有效抑制316L不锈钢点蚀的形成与发展,降低316L不锈钢的点蚀诱发能力。     

Effect of thermal annealing of poly(3-octylthiophene) films covered stainless steel on corrosion properties

The effect of thermal annealing of poly(3-octylthiophene) (P3OT) coatings on the corrosion inhibition of stainless steel in an NaCl solution was investigated. P3OT was synthesized by direct oxidation of the 3-octylthiophene monomer with ferric chloride (FeCl₃) as oxidant. P3OT films were deposited by drop-casting technique onto 304 stainless steel electrode (304SS). 304SS coated with P3OT films were thermally annealed during 30 h at different temperatures (55°C, 80°C, and 100°C). The corrosion resistance of stainless steel coated with P3OT in 0.5 M NaCl aqueous solution at room temperature was investigated by using potentiodynamic polarization curves, linear polarization resistance, and electrochemical impedance spectroscopy. The results indicated that the thermal treatment at 80°C and 100°C of P3OT films improved the corrosion resistance of the stainless steel in NaCl solution; the speed of corrosion diminished in an order of magnitude with regard to the 304SS. In order to study the temperature effect in the morphology of the coatings before and after the corrosive environment and correlate it with corrosion protection, atomic force microscopy and scanning electron microscopy were used. Morphological study showed that when the films are heated, the grain size increased and a denser surface was obtained, which benefited the barrier properties of the film.     

羧甲基壳聚糖掺杂聚苯胺的制备及其在盐酸溶液中对碳钢的缓蚀性能研究

选用结构中同时带有羟基、羧基和氨基的羧甲基壳聚糖为掺杂酸,通过改变掺杂酸与苯胺单体的比例实现了产物从纳米纤维(直径为100nm)到空心微米小球(直径为200nm)的转变.傅立叶红外(FTIR)和紫外可见光谱(UV)表征结果表明,纳米纤维和空心微米小球均为掺杂态聚苯胺.另外,采用电化学交流阻抗技术和动电位极化方法研究了所得聚苯胺在0.5mol/L盐酸溶液中对碳钢的缓蚀作用.结果表明,聚苯胺的加入量为40mg/L时,其对碳钢的缓蚀效率高达91.6%～92.3%.     

A study on the electrochemical polymerization, characterization, and corrosion protection of o-toluidine on steel

Poly(o-toluidine) (POT) coatings were electrochemically synthesized on 304 stainless steel using cyclic voltammetric method. These coatings were characterized by Fourier transform infrared spectroscopy, UV–vis absorption spectroscopy, and cyclic voltammetry. The corrosion performance of POT coating in aqueous 3 wt% sodium chloride was assessed by the electrochemical techniques such as open circuit potential measurements, potentiodynamic polarization technique, cyclic potentiodynamic polarization measurements, and electrochemical impedance spectroscopy. The results reveal that POT coating on 304 stainless steel prevents general and localized corrosion, and reduces the exchange current density almost by a factor of 45 than bare 304 stainless steel.     

Synthesis of waterborne nanopolyanilne latexes and application of nanopolyaniline particles in epoxy paint formulation for smart corrosion resistivity of carbon steel

Polyaniline (PANI) latexes were synthesized by emulsion polymerization using dodecyl benzene sulfonic acid (DBSA) and sodium dodecyl sulfate (SDS) as a surfactant. Synthesized PANI–DBSA and PANI–SDS latexes were characterized by IR and UV‐visible spectroscopies, and surface morphology was analyzed by transmission electron microscopy. The PANI–DBSA were found to be nanograin shaped whereas PANI–SDS were as nanofibers. In the second stage rheological properties of waterborne PANI latexes were characterized by viscosity measurement and their dispersion stability in water. The surface morphology of the coating was examined by scanning electron microscope (SEM). The anti‐corrosion performance of uncoated carbon steel, PANI–DBSA and PANI–SDS coated carbon steel was evaluated by tafel slope analysis and immersion test studies of 0.5, 1, and 1.5% PANI/Epoxy coatings were done in 5% NaCl aqueous solution. The results indicated that the nanoPANI in epoxy coating might work as an adhesion promoter and corrosion inhibitor. The waterborne latexes, thus, were found to be highly suitable and avoid the use of organic solvents or strong acids under environmentally benign conditions. Copyright © 2010 John Wiley & Sons, Ltd.     

A zirconia-polyester glycol coating on differently pretreated AISI 316L stainless steel: corrosion behavior in chloride solution

The effect of zirconia and zirconia-polyester glycol hybrid coatings on the corrosion resistance of mechanically polished or anodized AISI 316 stainless steel (316L), was studied by potentiodynamic polarization and electrochemical impedance spectroscopy in 0.1 M NaCl and scanning electron microscope and atomic force microscopy examinations. The deposition of zirconia coatings was achieved by the sol–gel technique by immersing the samples in either the inorganic polymer or the organic–inorganic polymer mixture. From potentiodynamic and impedance measurements, the grade of protection is reduced with the exposure time to the electrolyte, which is mainly associated with lost of film adhesion and, consequently, detachment from the metal substrate. However, the uncoated anodized sample revealed an unexpected corrosion behavior; the anodic film formed during anodizing readily increased the corrosion resistance of the 316L stainless steel in 0.1 M NaCl, revealing a considerable reduction in the corrosion current density and an increase in the pitting potential.     

双相不锈钢的选择性腐蚀研究(英文)

双相不锈钢中的铁素体(α相)和奥氏体(γ相)具有不同的晶体结构和化学成分,使之在水溶液环境中表现不同的耐蚀特征.本文应用空间分辨电化学技术测量2205双相不锈钢中铁素体和奥氏体的电位差异,并用电镜技术分析了α相和γ相的选择性腐蚀形态.结果表明,在0.01mol/LNaCl溶液中,铁素体的腐蚀电位比奥氏体高,而在2mol/LH2SO4+xmol/LHCl溶液中,双相不锈钢在活化＿钝化电位区出现两个明显的阳极电流峰.铁素体相的选择性腐蚀发生在较负的阳极峰电位,而奥氏体则在较正的阳极电位峰发生选择性腐蚀.     

Study on the Corrosion Resistance of 304L Stainless Steel

304L is an austenitic stainless steel with very low carbon content, and is served as the application to the oxidizing media, however, its corrosion resistance is not satisfactory in reducing media. For example, the pitting corrosion occurred on 304L stainless steel tube, which had been mounted for one year, somewhere at the power station in die seashore of China. For this reason we have studied the corrosion behavior of 304L in some media and invented a novel surface treatment technique of stainless steel for extremely improving the corrosion resistance of 304L. The characteristics of the modified passive film on the steel were examined in this paper, and the corrosion resistance of treated 304L stainless steel was tested in our laboratory and the testing ground. The results are satisfactory.     

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.     

XPS depth profile study of porous zirconia films deposited on stainless steel by spray pyrolysis: the problem of substrate corrosion

Zirconia (ZrO₂) films of tissue‐like structure and narrow pore size distribution have been deposited by spray pyrolysis using aqueous zirconyl chloride octahydrate (ZrOCl₂·8H₂O) precursor solutions. Stainless‐steel sheets, protected or unprotected by a ZnO barrier layer, have been used as the substrate material held at 473 K. The ZnO barrier layers have been deposited on the stainless steel held at 523 K by spray pyrolysis using a zinc acetate precursor. Their property of corrosion protection to stainless steel has been proved by electrochemical polarization measurements in 0.5 M NaCl solution. A complementary study of XPS (depth profiling, mapping) and x‐ray diffraction has shown that the unprotected steel substrates were corroded during ZrO₂ film post‐annealing in air at T ≥ 773 K, whereas steel substrates protected with a compact barrier layer of crystalline ZnO before ZrO₂ film deposition did not show surface corrosion even after annealing up to 997 K. Copyright © 2004 John Wiley & Sons, Ltd.     

The effect of the polyaniline morphology on the performance of polyaniline supercapacitors

The polyaniline (PANI) prepared by the pulse galvanostatic method (PGM) or the galvanostatic method on a stainless steel substrate from an aqueous solution of 0.5 mol/l H₂SO₄ with 0.2 mol/l aniline has been studied as an electroactive material in supercapacitors. The electrochemical performance of the PANI supercapacitor is characterized by cyclic voltammetry, a galvanostatic charge–discharge test and electrochemical impedance spectroscopy in NaClO₄ and HClO₄ mixed electrolyte. The results show that PANI films with different morphology and hence different capacitance are synthesized by controlling the synthesis methods and conditions. Owing to the double-layer capacitance and pseudocapacitance increase with increasing real surface area of PANI, the capacitive performances of PANI were enhanced with increasing real surface area of PANI. The highest capacitance is obtained for the PANI film with nanofibrous morphology. From charge–discharge studies of a nanofibrous PANI capacitor, a specific capacitance of 609 F/g and a specific energy density of 26.8 Wh/kg have been obtained at a discharge current density of 1.5 mA/cm². The PANI capacitor also shows little degradation of capacitance after 1,000 cycles. The effects of discharge current density and deposited charge of PANI on capacitance are investigated. The results indicate that the nanofibrous PANI prepared by the PGM is promising for supercapacitors.     

不锈钢点腐蚀发生的早期过程 Ⅰ. 扫描微参比电极法研究

本文应用扫描微参比电极联机测量系统对18-8型不锈钢在含Cl~-介质中点腐蚀发生的早期过程进行研究。结果表明, 在点腐蚀发生的早期阶段, 可用特征电位E_r表征表面钝化膜的局部破坏和微点腐蚀的发生, E_r电位与传统的E_P电位不同, E_r电位通常比E_p, 电位更负100—400 mV, E_r电位值与钝化膜的表面状态直接有关, 且随介质Cl~-浓度的增加和pH的降低而负移。在E_r电位附近, 微点腐蚀开始发生, 但一般不能稳定发展, 电位越接近于E_p, 则已发生的微点腐蚀越容易扩展为宏观点腐蚀, 由此, 作者提出“不稳定微点腐蚀”的新概念, 并对不锈钢点腐蚀发生的早期过程机理加以讨论。     

Controlled growth of polyaniline fractals on HOPG through potentiodynamic electropolymerization

Polyaniline (PANI) in fractal dimension has been electrodeposited reproducibly on highly oriented pyrolytic graphite (HOPG) from 0.2 M aniline in 1 M aqueous HCl solution by potentiodynamic sweeping in the range of -0.2 to 0.76 V vs Ag/AgCl at room temperature. Fractal growth of PANI dendrimers is affected by diffusion limited polymerization (DLP) at a sweep rate of 15 mV s(-1) for 43 min. This type of PANI dendrimer is prepared for the first time on such large area HOPG substrate by electrochemical technique using rather simple cell setup. The fractal dimension has been determined by chronoamperometry (CA) and box counting technique and is found to vary from 1.4 to 1.9 with the duration of electropolymerization. The sweep rate, terminal oxidation potential, and the diverse surface anisotropy of the HOPG surface are found to be crucial factors in controlling the growth of such PANI fractals.