苯并三氮唑和8-羟基喹啉对铜缓蚀作用的研究

通过采用失重法、电化学极化曲线和电化学阻抗谱研究了3％NaCl溶液中苯并三氮唑（BTA）和8－羟基喹啉（HQ）的缓蚀协同作用。BTA和HQ复配使用后增强了对铜的阳极极化过程的抑制作用，提高了电极的膜电阻，降低了电极的膜电容。通过PPP－SCF量子化学方法优化分析了BTA和HQ的分子结构及其缓蚀协同效应。     

pH and iodide ion effect on corrosion inhibition of histidine self-assembled monolayer on copper

Self-assembled monolayer (SAM) of histidine (His) was prepared on copper surface at various pH values. The effect of KI additives on corrosion protection efficiency of His SAM was also studied. The protection abilities of these films against copper corrosion in 0.5 M HCl aqueous solution were investigated using electrochemical impedance spectroscopy and polarization techniques. The results show that the film formed on the electrode is more stable at pH = 10 than that at other pH values. When the iodide ions were added into the His self-assembly solution (pH = 10), protection efficiency was further improved. The inhibition mechanism has been discussed by quantum chemical calculations.     

含H2S的NaCl溶液中溶解氧对PH13-8Mo钢腐蚀性能的影响

为研究新型马氏体沉淀硬化不锈钢PH13-8Mo在含饱和H_2S的NaCl溶液中的腐蚀行为,利用极化曲线、电化学阻抗谱等电化学测试和浸泡实验相结合的方法,通过扫描电子显微镜(SEM)和X射线光电子能谱分析技术(XPS),观察了该高强钢在含H_2S的除氧和不除氧的NaCl溶液中的腐蚀形貌,并对其腐蚀产物的成分进行了分析.结果表明:在除氧的NaCl溶液中,阳极极化曲线的形状发生了明显的变化,电化学阻抗谱的容抗弧的幅值也较未除氧的溶液中变小;在除氧的NaCl溶液中浸泡7 d后,由于H_2S水解后的S~(2-)或HS~-离子侵入到钝化膜的内部,并与钝化膜或金属基体发生反应,使得试样表面发生全面腐蚀,腐蚀产物主要为Fe、Cr、Ni、Mo的氧化物和硫化物;而在未除氧的NaCl溶液中浸泡后,试样表面仅发生局部腐蚀.     

Electrosysnthesis of poly(aniline-co-m-amino benzoic acid) for corrosion protection of steel

Conducting polymer (poly(aniline-co-m-amino benzoic acid)) has been deposited on steel surface by cyclic voltammetric technique. The copolymer film was characterized by FTIR, XPS and SEM techniques. The corrosion protection performance of copolymer film on steel was found out by impedance and tafel polarization methods in 1N HCl. The copolymer film was found to be highly corrosion resistant.     

铜表面硅烷-稀土掺杂膜的制备及缓蚀性能

运用分子自组装技术在铜片表面组装γ-巯丙基三甲氧基硅烷(MPTS)与稀土的掺杂膜。用原子力显微镜(AFM)观察了铜表面成膜过程,用金相显微镜观察铜片在0.5mol/L盐酸溶液中腐蚀72h后的表面形貌,运用电化学测量法对其防腐蚀性能进行评价。结果表明,硅烷-稀土掺杂膜对铜的缓蚀效率较单一的硅烷膜有明显提高,稀土浓度及组装时间对掺杂膜抗腐蚀性能有一定影响。经过极化曲线和交流阻抗的测定,确定硅烷-稀土掺杂膜的最佳组装条件为:LaCl3质量浓度为10g/L,组装30min,缓蚀率达93%。     

Electrochemical impedance spectroscopy investigation on indium tin oxide films under cathodic polarization in NaOH solution

The electrochemical corrosion behaviors of indium tin oxide (ITO) films under the cathodic polarization in 0.1 M NaOH solution were investigated by electrochemical impedance spectroscopy. The as-received and the cathodically polarized ITO films were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction for morphological, compositional and structural studies. The results showed that ITO films underwent a corrosion process during the cathodic polarization and the main component of the corrosion products was body-centered cubic indium. The electrochemical impedance parameters were related to the effect of the cathodic polarization on the ITO specimens. The capacitance of ITO specimens increased, while the charge transfer resistance and the inductance decreased with the increase of the polarization time. The proposed mechanism indicated that the corrosion products (metallic indium) were firstly formed during the cathodic polarization and then absorbed on the surface of the ITO film. As the surface was gradually covered by indium particles, the corrosion process was suppressed.     

Photosensitive self-assembled membrane of cysteine against copper corrosion

Complex self-assembled membrane (SAM) was prepared by modifying the adsorption of cysteine with fluorescent reagent sodium 1-naphthylamine diacetate (NADA) on copper surface. The SAM has a fluorescence emission at 430 nm. Its protective effects against copper corrosion were investigated by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) in 0.5 M NaCl solution. It suppresses cathodic current densities and shifts the corrosion potential toward more positive values. The variation of the fluorescence intensity is correlated to that of the impedance resistance. The fluorescence detection provides a potential monitoring method for the protection of the SAM on copper surface.     

铜表面修饰硅烷膜在碱性溶液中的耐蚀性能研究

为了提高铜的耐蚀性,用自组装技术在铜表面上制备了3-巯基丙基三甲氧基硅烷(MPTS)自组装膜. 利用红外光谱和扫描电子显微镜研究了该膜的结构,运用极化曲线和交流阻抗图谱等电化学方法考察了 MPTS膜在0.5 mol/L NaOH溶液中对铜电极的缓蚀性能.结果表明,MPTS在铜表面可能以化学吸附方式强烈吸附到铜表面, 同时在表面以Si-O-Si键自我交联形成了线性低聚物, MPTS浓度越高, 其膜更致密.与裸铜电极相比,经MPTS修饰后的铜的腐蚀电位正移200 mV, 腐蚀电流降低一个数量级,其缓蚀效率为86.5%.     

不同添加剂对镀锌层钼酸盐钝化膜腐蚀电化学性能的影响

利用塔菲尔(Tafel)极化曲线和电化学交流阻抗谱,研究了不同添加剂单乙醇胺、硝酸铈、植酸和羟己叉基二膦酸对镀锌层钼酸盐钝化膜腐蚀电化学性能的影响,并与加速腐蚀试验结果进行了对比.结果表明,添加剂的加入明显改变了钝化膜层的自腐蚀电位,使钼酸盐钝化膜的耐腐蚀性明显增强,且钝化膜的阻抗谱呈明显单一的容抗弧,腐蚀过程受电化学控制.     

Electrochemical impedance spectroscopy characterization of passive film formed on implant Ti–6Al–7Nb alloy in Hank's solution

The influence of potential on electrochemical behavior of Ti-6Al-7Nb alloy under simulated physiological conditions was investigated by electrochemical impedance spectroscopy (EIS). The experimental results were compared with those obtained by potentiodynamic polarization curves. All measurements were carried out in Hank's aerated solution at 25 degrees C, at pH 7.8 and at different potentials (corrosion potential, 0 mV(SCE), 1000 mV(SCE), and 2000 mV(SCE)). The EIS spectra exhibited a two-step or a two-time constant system, suggesting the formation of a two-layer oxide film on the metal surface. The high corrosion resistance, displayed by this alloy in electrochemical polarization tests, is due to the dense inner layer, while its osseointegration ability can be ascribed to the presence of the outer porous layer.     

Investigation of electrochemical behavior of nitrogen implanted Ti–15Mo–3Nb–3Al alloy in Hank’s solution

Titanium alloy Ti–15–3–3 (Beta-21S) was implanted with nitrogen ions by plasma immersion ion implantation at 700, 750 and 800 °C. Micro Raman and XPS results confirm the formation of nitrides after implantation. Corrosion current density (i_corr) of the treated samples in simulated body fluid (Hank’s solution) is higher than that of the substrate. Treated samples also exhibit lower charge transfer resistance and higher double layer capacitance as compared to that of substrate in electrochemical impedance spectroscopic studies. However, no corrosion related effects are observed after 28 days of immersion in SBF. EDS results show the presence of oxygen after corrosion studies. XPS spectra from the implanted samples show the presence of nitride and oxynitride on the surface and formation of oxide due to corrosion process.     

Effect of menthol coated craft paper on corrosion of copper in HCl environment

Natural menthol was coated on craft paper by impregnation and studied as volatile corrosion inhibitor for copper in hydrochloric acid environment. The effect of menthol on copper corrosion was studied by gravimetric and electrochemical methods such as potentiodynamic polarization and electrochemical impedance measurements. The results indicate that menthol adsorbs on the metal surface, which protects copper against further corrosion. The adsorption behaviour of menthol on copper surface was found to obey Temkin’s adsorption isotherm.     

3种吡啶甲酰腙席夫碱自组装分子膜对铜的缓蚀作用

用3种自制油溶性吡啶甲酰腙席夫碱在铜表面制备自组装单分子膜(SAMS),研究了该膜在3.5%NaCl中对铜的缓蚀作用。通过极化曲线法和交流阻抗法的研究,发现在3.5%NaCl溶液中,3种吡啶甲酰腙席夫碱对铜均有良好的缓蚀效果,其中L2B的缓蚀效果最好,L4B次之,后为L3B,常温下,缓蚀率分别为91.75%,90.68%和88.27%。同时缓蚀效果受温度影响不大。交流阻抗法测试结果表明,3种酰腙化合物在自组装膜和缓蚀过程中未发生分解,同时分析表明它们都是以抑制阴极为主的混合型缓蚀剂。最后通过密度泛函理论对其缓蚀机理进行了初步探讨。     

The effects of acetate ions (CH3COO) on electrochemical behavior of copper in chloride solutions

The corrosion behavior of copper has been investigated in presence of acetate ions, at various temperatures in highly corrosive chloride solution. For this aim, potentiodynamic and EIS (electrochemical impedance spectroscopy) measurements were used. Corrosion rates have been determined by extrapolating the polarization curves. The role of temperature, ionic species and the effect of oxide film formation have been interpreted in aspect of anodic and cathodic processes rate. Thermodynamical properties ΔG (free enthalpy), ΔH (enthalpy), ΔS (entropy) and E_a (activation energy) values have been evaluated with help of current–potential measurement results. The experimental results showed that acetate ions have decreased the corrosion rate of copper in chloride containing solutions of pH 8.5. It was also shown that the acetate ions could provide protection behavior at elevated temperatures. The changes in thermodynamic properties showed that acetate ions formed stable and protective complex which physically adsorbed on the surface. The ΔG value decreased and E_a values increased in presence of acetate ions.     

Formation and electrochemical behavior of Al and O plasma-implanted biodegradable Mg-Y-RE alloy

Mg-Y-RE alloy is potentially useful in biodegradable implants but the fast degradation rate in the physiological environment restrains actual applications. In order to enhance the corrosion resistance, aluminum and oxygen ion implantation is employed to modify the surface of the Mg-Y-RE alloy. X-ray photoelectron spectroscopy (XPS) is conducted to obtain elemental depth profiles and determine chemical state changes. Electrochemical impedance spectroscopy and potentiodynamic polarization are employed to investigate the electrochemical behavior in simulated body fluids (SBF). After polarization, the corroded surface is further studied by scanning electron microscopy (SEM). The results indicate Al and O ion implantation produces an Al₂O₃-containing protection layer which improves the corrosion resistance of Mg-Y-RE alloy. After the surface treatment, localized corrosion becomes the dominant corrosion mechanism instead of general corrosion.     

Enhancement of corrosion protection efficiency of iron by poly(aniline-co-amino-naphthol-sulphonic acid) nanowires coating in highly acidic medium

Nanowires of copolymers film based on aniline and 1-amino-2-naphthol-4-sulphonic acid were electrochemically synthesized on the iron electrode by cyclic voltammetry using oxalic acid as a supporting electrolyte. Protective properties of copolymer film on the iron surface in 1.0 M HCl solution was investigated by chronoamperometry, potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The results showed that the copolymer film showed the significant shifting in the corrosion potential and greater charge transfer resistance. Moreover, the copolymer showed the larger degree of surface coverage onto the iron surface, reflecting the higher protection for corrosion of the iron in acidic medium. In addition, the film constitutes a physical as well as a chemical barrier layer due to the presence of -OH and -NH groups in ANSA unit, which provides passivity protection in polymer coatings. The mechanism of corrosion protection of iron by these copolymers was investigated by surface morphology and EIS techniques. In addition, by using scanning electron microscopy, the effect of morphology of copolymer on corrosion protection of metal was investigated.     

Improving the corrosion resistance of Mg–4.0Zn–0.2Ca alloy by micro-arc oxidation

In this paper, corrosion resistance of the Mg–4.0Zn–0.2Ca alloy was modified by micro-arc oxidation (MAO) process. The microstructure and phase constituents of MAO layer were characterized by SEM, XRD and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of MAO treated Mg–4.0Zn–0.2Ca alloy in the simulated body fluid were characterized by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The microstructure results indicated that a kind of ceramic film was composed by MgO and MgF₂ was formed on the surface of Mg–4.0Zn–0.2Ca alloy after MAO treatment. The electrochemical test reveals that the corrosion resistance of MAO treated samples increase 1 order of magnitude. The mechanical intensity test showed that the MAO treated samples has suitable mechanical properties.     

In vitro corrosion behaviour of Ti–Nb–Sn shape memory alloys in Ringer’s physiological solution

The nearly equiatomic Ni–Ti alloy (Nitinol) has been widely employed in the medical and dental fields owing to its shape memory or superelastic properties. The main concern about the use of this alloy derives form the fact that it contains a large amount of nickel (55% by mass), which is suspected responsible for allergic, toxic and carcinogenic reactions. In this work, the in vitro corrosion behavior of two Ti–Nb–Sn shape memory alloys, Ti–16Nb–5Sn and Ti–18Nb–4Sn (mass%) has been investigated and compared with that of Nitinol. The in vitro corrosion resistance was assessed in naturally aerated Ringer’s physiological solution at 37°C by corrosion potential and electrochemical impedance spectroscopy (EIS) measurements as a function of exposure time, and potentiodynamic polarization curves. Corrosion potential values indicated that both Ni–Ti and Ti–Nb–Sn alloys undergo spontaneous passivation due to spontaneously formed oxide film passivating the metallic surface, in the aggressive environment. It also indicated that the tendency for the formation of a spontaneous oxide is greater for the Ti–18Nb–5Sn alloy. Significantly low anodic current density values were obtained from the polarization curves, indicating a typical passive behaviour for all investigated alloys, but Nitinol exhibited breakdown of passivity at potentials above approximately 450 mV(SCE), suggesting lower corrosion protection characteristics of its oxide film compared to the Ti–Nb–Sn alloys. EIS studies showed high impedance values for all samples, increasing with exposure time, indicating an improvement in corrosion resistance of the spontaneous oxide film. The obtained EIS spectra were analyzed using an equivalent electrical circuit representing a duplex structure oxide film, composed by an outer and porous layer (low resistance), and an inner barrier layer (high resistance) mainly responsible for the alloys corrosion resistance. The resistance of passive film present on the metals’ surface increases with exposure time displaying the highest values to Ti–18Nb–4Sn alloy. All these electrochemical results suggest that Ti–Nb–Sn alloys are promising materials for biomedical applications.     

Chemical treatment of zinc surface and its corrosion inhibition studies

The surface treatment of zinc and its corrosion inhibition was studied using a product (BTSC) formed in the reaction between benzaldehyde and thiosemicarbozide. The corrosion behaviour of chemically treated zinc surface was investigated in aqueous chloride-sulphate medium using galvanostatic polarization technique. Zinc samples treated in BTSC solution exhibited good corrosion resistance. The measured electrochemical data indicated a basic modification of the cathode reaction during corrosion of treated zinc. The corrosion protection may be explained on the basis of adsorption and formation of BTSC film on zinc surface. The film was binding strongly to the metal surface through nitrogen and sulphur atoms of the product. The formation of film on the zinc surface was established by surface analysis techniques such as scanning electron microscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FTIR).     

Ni2＋掺杂聚苯胺膜的制备及其抗腐蚀性能

聚苯胺是最常用的一种导电聚合物,它作为腐蚀抑制剂覆盖在金属表面并形成一层很薄的保护膜,可以降低金属的腐蚀速度。采用循环伏安法在不锈钢表面电化学合成掺杂态（NiH）聚苯胺膜。利用极化曲线法和交流阻抗法研究了掺杂态聚苯胺膜的耐腐蚀性能及其影响因素。结果表明：在3．5％NaCl溶液中,不锈钢表面覆盖掺杂态聚苯胺膜的腐蚀电位比...