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1.
3.5% NaCl饱和Ca(OH)2溶液中醇胺缩聚物对碳钢腐蚀的抑制 总被引:1,自引:0,他引:1
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. 相似文献
2.
LD-2复合缓蚀剂对海水介质混凝土中钢筋阻锈作用研究 总被引:6,自引:0,他引:6
利用电化学检测技术和海水浸泡试验等方法 ,观测和研究了经筛选研制的LD_2复合缓蚀剂对海水介质中钢筋腐蚀电化学行为的影响 ,考察和评价了复合缓蚀剂对钢筋的阻锈作用 .结果表明 ,LD_2复合缓蚀剂主要起阳极型缓蚀剂作用 .在海水中加入 2 5 g·L- 1复合缓蚀剂后 ,钢筋的腐蚀电位提高约 0 .2 2 0V ,腐蚀电流降低至未加缓蚀剂的 1% ,缓蚀效率达 99% .钢筋混凝土试样在海水中浸泡 2年 ,表明混凝土中加入占水泥重量 1.0 %~ 2 .5 %LD_2复合缓蚀剂时 ,能有效阻止混凝土中钢筋的腐蚀 相似文献
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采用恒电流法电化学除氯处理受氯离子污染的钢筋混凝土试样,并用pH/Cl-复合探针原位检测电化学除氯过程钢筋混凝土不同位置孔隙液的氯离子含量与pH值分布,同时用线性极化曲线和交流阻抗谱图等电化学技术考察钢筋的腐蚀性能,探讨电化学除氯过程的混凝土微环境和钢筋腐蚀速率. 研究结果表明:在电化学除氯过程,混凝土孔隙液的氯离子浓度逐降,而pH值在初期略有升高,随之其pH值略降;电化学除氯施加的阴极电流,使钢筋处于阴极极化状态而得到保护;除氯停止(即退极化)后钢筋的腐蚀电位明显正移,腐蚀电流降低,极化电阻升高,表明电化学除氯能改善钢筋的腐蚀环境,降低钢筋的腐蚀速率. 相似文献
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应用腐蚀电位(Ecorr)、极化电阻(Rp)和砂浆保护层电阻率(ρc)研究了苯并三唑(BTA)对钢筋电极腐蚀电化学行为的影响. 通过电化学阻抗谱(EIS)、循环极化(CP)和循环伏安(CV)结果对比了BTA与NaNO2 (SN)对钢筋电极在未处理、预锈蚀和内掺氯盐3种状态下3.5% (w)氯盐浸泡360 d后的阻锈效率. 利用环境扫描电镜(ESEM)与能谱分析(EDS)解释了BTA对水泥基材料中钢筋的阻锈机理. 结果表明: 3种状态下BTA均能明显降低砂浆中钢筋的均匀腐蚀速率, 且其阻锈效率高于SN. 在未处理与预锈状态下, BTA抑制点蚀的能力稍弱于SN; 但在内掺氯盐的状态下, BTA表现出了较大的点蚀阻力. BTA除了能在钢筋表面形成复杂的保护膜, 从而有效抑制氯盐的破钝化作用. ESEM/EDS结果表明BTA还能与砂浆基体形成较多富钙C-S-H凝胶, 可能优化了钢筋/砂浆界面区的孔结构, 形成更致密的微观结构, 显著延缓了氯盐向钢筋表面的传输进程, 较好地保护了钢筋. 适量的BTA对砂浆360 d的基本力学性能无明显影响. 相似文献
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锌铋合金电极在溶胶电解液中的电化学行为 总被引:1,自引:0,他引:1
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. 相似文献
10.
采用恒电流法在316 L不锈钢电极表面合成聚吡咯(PPy), 通过开路电位、 生物显微镜(BM)、 Tafel极化曲线及电化学交流阻抗(EIS)研究了聚吡咯防止微生物附着及防腐蚀特性. 研究表明, 沉积聚吡咯的316 L不锈钢电极浸泡在天然海水中(0~20 d), 开路电位基本保持不变, 表明电化学合成的聚吡咯膜有良好的防止微生物附着能力, 并通过生物显微镜进行了验证, 且在浸泡的过程中其腐蚀电流密度维持在10-7 mA/cm2, 表现出良好的防腐蚀特性; 浸泡50 d后, 其防腐蚀效率仍高达97.45%. 因此, 电化学合成的聚吡咯具有优异的防止微生物附着和防腐蚀特性. 相似文献
11.
Mercedes Sánchez Hitham Mahmoud Maria Cruz Alonso 《Journal of Solid State Electrochemistry》2012,16(3):1193-1202
The passivation of two high strength duplex stainless steels (HSSS) was investigated in alkaline solutions simulating the
pore solution of concrete by the growth of natural and induced passive films. Induced passive films were generated both by
cyclic voltammetry and by chronoamperometry. Natural passive films were spontaneously grown by the immersion of the steel
in the alkaline electrolyte. These passive layers were characterised by electrochemical impedance spectroscopy, corrosion
current density (i
corr) and corrosion potential (E
corr) monitoring. The effect of significant parameters, such as the pH in the HSSS/alkaline solution interface, the composition
of the duplex stainless steels and the ageing of the passive layer, on the electrochemical performance of both induced and
spontaneously grown passive films has been analysed. The increase of alkalinity highly influences the electrochemical performance
of the passive film by promoting the formation of a passive layer with a less resistant electrochemical response. The electrochemical
behaviour of the passive layer is also affected by the alloying elements like Mo or Ni. Both natural and induced passive films
show similar electrochemical trend with respect to significant parameters such as the pH and the composition of the steel.
The ageing of the spontaneously grown passive layer promotes a higher resistive electrochemical response which might be related
to the enrichment of the passive layer in non-conducting (or semi-conducting) oxides. 相似文献
12.
This investigation potentiodynamically evaluates the corrosion behavior of a high strength titanium alloy, VT-9, in 4 M sulfuric acid solution containing different concentrations (10, 20, 30 ppm) of the organic inhibitor, 2-phenyl-4-[(E)-1-(4-sulfanylanilino)methylidene]-1,3-oxazole-5(4H)-one (L-SH), at different temperatures (293, 303 and 313 ± 1 K). The open circuit potential values noted before and after each experiment varied appreciably with time. These values, in the presence of L-SH, were negative before polarization, but after completion of the experiment turned positive and remained stable over a long period of time. The cathodic current density values increased with increasing cathodic potential (more negative). The corrosion potential (Ecorr) increased remarkably with the addition of L-SH. The corrosion current densities (Icorr), critical current density (Icr), and passive current density (Ip) all decreased when L-SH was used. However, only the decrease in the Icorr with increasing amounts of inhibitor was significant compared to that of Icr and Ip. L-SH expanded the range of the passive potential. SEM micrographs and open circuit potential measurements revealed the formation of a uniform and protective film on the alloy surface in the presence of L-SH, which acted as an efficient inhibitor. 相似文献
13.
R. Rosliza H.B. Senin W.B. Wan Nik 《Colloids and surfaces. A, Physicochemical and engineering aspects》2008,312(2-3):185-189
The corrosion inhibition of aluminum and its alloys is the subject of tremendous technological importance due to the increased industrial applications of these materials. This study reports the results of potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) on the corrosion inhibition of AA6061 aluminum alloys in seawater using sodium benzoate as an inhibitor. The electrochemical measurements for aluminum alloys in seawater after varied immersion period showed that the presence of sodium benzoate significantly decreases the corrosion currents densities (icorr), corrosion rates and double layer capacitance (Cdl), as simultaneously increase the values of polarization resistance (Rp). Charge transfer process and development of thin film on the specimen have been proven by morphology study using SEM. 相似文献
14.
Corrosion resistances of passive films on low‐Cr steel and carbon steel in simulated concrete pore solution
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Ming Liu Xuequn Cheng Gucheng Zhao Xiaogang Li Yue Pan 《Surface and interface analysis : SIA》2016,48(9):981-989
The passive ranges of carbon steel rebar and 3Cr steel rebar in saturated Ca(OH)2‐simulated concrete pore solution with pH 12.6 were determined by means of cyclic voltammetry and potentiodynamic polarization curves. Chronopotentiometry was used to obtain steady‐state conditions for the formation of passive films on rebar samples at different anodic potentials. Electrochemical impedance spectroscopy, Mott–Schottky and X‐ray photoelectron spectrometer curves were employed to compare the formed passive films at different potentials. Additionally, cyclic polarization curves were used to compare the corrosion resistances of formed passive films on the two rebars in saturated Ca(OH)2‐simulated concrete pore solution with different concentration of Cl?. The results show that the passive ranges of the two rebars are all between ?0.15 and +0.6 V, and more stable passive films can be formed on both rebars at the anodic potential of +0.3 V. In the absence of Cl?, the stability and corrosion resistance of the passive film formed on the 3Cr rebar are better than those of CS rebar. The passive film of 3Cr steel has the relatively better pitting corrosion resistance than carbon steel in saturated Ca(OH)2‐simulated concrete pore solution that contains different concentration of Cl?. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
15.
Weiming Liu Yingqiao Zhang Hanqian Zhang Zhaoxia Qu Jinfu Li 《Journal of Solid State Electrochemistry》2009,13(11):1645-1652
Electrochemical methods were used to study the characteristics of corrosion process for the high-strength low-alloy steel
and carbon steel used as a huge oil storage tank in NaHSO3 solution. The polarization curve results show that both steel samples take place in active solution, and the high-strength
low-alloy (HSLA) steel has higher i
corr value than carbon steel, which is due to the small grain size that provides high density of active sites for preferential
attack. The electrochemical impedance spectroscopy (EIS) results make known that the corrosion process presents two stages.
In the first 136 h, one-time constant in EIS diagrams can be shown. Both steels have similar corrosion resistance due to the
combination effects of the grain size and microstructure. After 240 h of immersion, a complete passive film forms on the specimen
surface, and two-time constants can be shown in EIS diagram. The HSLA steel exhibited improved corrosion resistance when compared
with the carbon steel, which is due to the effect of the shape Fe3C in microstructure and the deposition of FeSO4 on the electrode surface. The scanning electrode microscopy analyses show that both steels take place in homogenous corrosion,
and the carbon steel shows higher surface roughness and many Fe3C residues. XRD results show that both steels have similar phase constitutes of corrosion products. 相似文献
16.
A systematic study on the corrosion and passivation behavior of AZ91D alloy in relation to the influence of concentration,
temperature, pH, and immersion time was made in aqueous sulfate solution using electrochemical techniques including open-circuit
potential, potentiodynamic polarization and impedance spectroscopy. It was found that the corrosion and pitting potentials
(E
corr and E
pit) of the alloy drift to more active values with increasing either concentration (0.01–1.0 M) or temperature (278–338 K) of
the test solution, suggesting that sulfate solution enhances the alloy dissolution, particularly at higher temperatures. On
the other hand, values of the total film resistance (R
T) indicate that neutral solution (pH 7.0) supports the formation of a better protective layer on AZ91D surface than alkaline
(pH 12.5) or acidic (pH 1.0) medium. The growth of a protective film on the alloy surface at short immersion times (up to
∼50 h) is evinced by a rapid positive evolution of E
corr and fast decrease in the corrosion rate (i
corr). However, for a long-term exposure (up to 500 h) E
corr drifts negatively and i
corr increases due to breakdown of the protective film, which causes a decrease in the alloy stability. Fitting the impedance
data to equivalent circuit models suitable to each behavior assisted to explore the mechanism for the attack of the sample
surface at various testing times. The results obtained from the three studied electrochemical techniques are in good agreement. 相似文献
17.
Mechanical polishing,surface roughness,near‐surface deformation,and electrochemical corrosion of Alloy 690TT
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The effects of mechanical grinding/polishing, surface roughness, and near‐surface deformation on the electrochemical corrosion behavior of thermally treated (TT) Alloy 690 were studied in a sodium chloride solution. The X‐ray photoelectron spectroscopy and transmission electron microscopy analyses revealed that mechanical grinding/polishing can change the ratio of the elements at the surface of the as‐received Alloy 690TT specimen by removing its Cr‐rich outer layer and causing deformation at the near‐surface microstructure, something which has a direct impact on the rate of the oxygen reduction reaction (ORR), the pitting potential (Epit), and the corrosion potential (Ecorr) of Alloy 690TT. It was observed that the ratio of Cr in the surface is a significant factor that controls the rate of the ORR and the corrosion parameters such as Ecorr. Higher amounts of Cr at the surface accelerate the ORR. The near‐surface deformation shifts the Epit values towards less positive potentials. It was also found that due to the different near‐surface chemical composition of the as‐received Alloy 690TT specimen compared with the ground and the polished specimens, the surface roughness parameters do not have a regular correlation with the rate of the ORR and the values of the Ecorr and the Epit. Only the passive current density increases when the surface roughness is increased. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
18.
《Journal of Saudi Chemical Society》2023,27(4):101681
The corrosion inhibition of orthodontic wire made of SS 18/8 alloy in artificial saliva, with and without the presence of tablet esomeprazole − 40 mg has been investigated by electrochemical analysis. Polarisation study indicates that in the presence of the mentioned tablet, polarisation resistance (Rp) value increases and corrosion current (Icorr) decreases. That is, the corrosion resistance of SS 18/8 alloy in artificial saliva increases. AC impedance spectroscopy reveals that charge transfer resistance value (Rct) value increases and double layer capacitance value (Cdl) decreases. The open circuit potential (OCP) values for the inhibited system are more negative than that of the uninhibited blank system. The vibration peaks obtained from the FTIR spectra indicates the presence of functional group in esomeprazole pill and these characteristic peaks are slightly shifted in the analyzed scratched film from the surface of the orthodontic wire after immersion. AFM micrograph image of the polished specimen sample immersed in artificial saliva (AS) with esomeprazole tablet solution shows lesser degree of surface deterioration than those for SS 18/8 specimen immersed only in artificial saliva. From the present work, it is reported that people clipped with orthodontic wire made of SS 18/8 alloy need not worry about orthodontic corrosion for taking esomeprazole tablet for the treatment of gastro esophageal reflux disease and other medicinal purpose. 相似文献
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Potentiodynamic sweep and electrochemical impedance spectroscopy measurements were applied to investigate the effects of both temperature and acetic acid (HAc) on the anodic and cathodic reactions in CO2 corrosion of P110 steel in 3.5% NaCl solution. The temperatures were controlled at 30 and 60 °C. The concentrations of HAc were controlled at 0, 1000, 3000 and 5000 ppm. In this work, the corrosion parameters of polarization curves, such as corrosion potential (Ecorr), corrosion current density (icorr), and anodic and cathodic branch slopes (ba and bc), are presented and discussed in detail. In addition, the equivalent circuit models and ZsimpWin software were utilized to discuss the Nyquist plots. The plots showed that the Ecorr values shifted in the positive direction as the HAc concentration increased. The icorr values increased with the increase in HAc concentration, indicating that HAc could accelerate the corrosion. The impedance spectra measured at 30 and 60 °C have different time constants and characterization. The coverage fraction θ and the thickness L of corrosion film are two most important controlled variables that influence and control the CO2 corrosion mechanisms. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
20.
Soheila Faraji Afidah Abdul Rahim Norita Mohamed Coswald Stephen Sipaut Bothi Raja 《Arabian Journal of Chemistry》2013,6(4):379-388
The Cu–P and Cu–P–SiC composite coatings on carbon steel substrates were deposited via electroless plating. The anti-corrosion properties of Cu–P and Cu–P–SiC coatings were studied in 3.5% NaCl solution. The anti-corrosion properties of Cu–P and Cu–P–SiC coatings were investigated in 3.5% NaCl solution by the weight loss, potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) techniques. It has been found that the shift in the corrosion potential (Ecorr) towards the noble direction, decrease in the corrosion current density (Icorr), increase in the charge transfer resistance (Rct) and decrease in the double layer capacitance (Cdl) values indicated an improvement in corrosion resistance with the incorporation of SiC particles in the Cu–P matrix. The effects of varying the SiC concentration on the corrosion resistance of carbon steel were investigated and it was found that the best anti-corrosion property of Cu–P–SiC is at 5 g L?1 SiC in the bath formulation. 相似文献