共查询到17条相似文献,搜索用时 183 毫秒
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扫描电化学微探针的发展及其在局部腐蚀研究中的应用 总被引:1,自引:0,他引:1
简要概述当前国内外具有空间分辨能力的扫描微探针技术及其在腐蚀研究中的应用,包括扫描微电极技术(SMET)、扫描电化学显微镜(SECM)、原子力显微镜(AFM)、扫描Kelvin探针技术(SKP)等,其中SMET、SECM、SKP及局部交流阻抗技术可直接测定腐蚀电极表面或界面电化学不均一性的分布图像,而原子力显微镜技术则是通过分子间作用力从纳米尺寸测量腐蚀过程表面形貌的变化.文中侧重介绍作者近年先后建立的具有微米空间分辨度的电化学微探针技术,并利用各种扫描探针技术研究金属/溶液界面电化学不均一性及其局部腐蚀过程.研究表明,空间分辨电化学方法的发展及应用,加深了人们对金属表面和金属/溶液界面电化学不均一性,特别是金属局部腐蚀发生、发展及过程机理的认识. 相似文献
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扫描复合微pH电极原位测量局部腐蚀体系pH分布图象 总被引:4,自引:1,他引:4
金属点腐蚀是一种典型的局部腐蚀,点腐蚀过程不仅与金属相组分,夹杂及表面状态等有关,而且与许多环境因素密切相关,其中在金属/溶液界面Cl^-浓度和pH的分布及影响金属点腐蚀发生,发展过程最为重要的微化学环境因素。 相似文献
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Al合金表面Ce转化膜成膜机理研究 总被引:1,自引:0,他引:1
Ce转化膜作为一种Cr转化膜的理想替代品而日益受到人们的重视,但其成膜机理还不很清楚.本文应用自行研制的扫描微参比电极技术(SMRE),原位测量经CeCl3溶液处理的2024-T3 Al合金表面微区电位分布,并结合X光电子能谱(XPS)和交流阻抗谱(EIS),对Ce转化膜的成膜机理进行探讨.结果表明,在CeCl3溶液中,Ce转化膜的形成过程是 Ce3+和Cl-相互竞争的动态过程.当由Cl-的不均匀吸附引起的局部腐蚀使pH升高时, Ce(OH)3就会首先在局部位置发生沉积.阴极反应过程产生的H2O2可将Ce(OH)3部分氧化成CeO2. 相似文献
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Al合金铈盐转化膜缓蚀机理研究 总被引:3,自引:0,他引:3
Ce盐作为一种环境友好的Al合金缓蚀剂日益受到重视 ,但缓蚀机理还不很清楚 .本文应用自行研制的扫描微参比电极技术 (SMRE) ,原位测量经CeCl3处理和未处理过的 2 0 2 4 T3Al合金表面微区电位分布 ,并用扫描电子显微镜 (SEM )和X 射线能量散射谱 (EDS)表征样品形貌特征 ,结合其它电化学技术 ,对Ce盐缓蚀机理作了深入探讨 .结果表明 ,经Ce盐处理的Al合金表面可形成一层不均匀分布的转化膜 ,抑制了O2 和电子传输 ,表现为一种优良的阴极缓蚀特性 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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腐蚀介质中混凝土/钢筋界面电极电位分布的立体分析 总被引:5,自引:0,他引:5
由于混凝土的隔离和高绝缘性 ,常规的电化学技术、微探针扫描技术均难于获得在腐蚀介质的浸泡下混凝土 /钢筋界面 ,特别是不同深处的混凝土 /钢筋界面的电位分布 .本文提出用阵列电极法并结合电子技术和微机控制技术 ,获得同一水平面上混凝土 /钢筋界面以及不同深处的混凝土 /钢筋界面的电位分布立体信息图 .结果表明 :在NaCl介质中经过一段时间的浸泡 ,混凝土中的钢筋腐蚀可发生并发展 ;而在Na2 SO4 介质中经过一段时间的浸泡 ,虽钢筋腐蚀一般不发生 ,但混凝土可能破坏 .不同深处混凝土 /钢筋界面腐蚀优先发生在混凝土覆盖较浅的部位 . 相似文献
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Cl-对API P105钢在含CO2溶液中的电化学腐蚀行为的影响 总被引:12,自引:0,他引:12
用电化学阻抗谱(EIS)及极化测量,研究了在含CO2的溶液中Cl^-1对APIP105钢的电化学腐蚀行为的影响。结果表明,Cl^-促进了钢铁的阳极溶解,其电化学反应级数为0.7.Cl^-不参与钢铁的阴极反应,在含Cl^-的饱和CO2溶液中,阴极反应主要为H2CO3的去极化反应。 相似文献
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Yasakau KA Zheludkevich ML Lamaka SV Ferreira MG 《The journal of physical chemistry. B》2006,110(11):5515-5528
The mechanism of corrosion protection of the widely used 2024-T3 aluminum alloy by cerium and lanthanum inhibitors in chloride media is described in detail in the present work. The corrosion process was investigated by means of scanning Kelvin probe force microscopy (SKPFM), in situ atomic force microscopy, and scanning electron microscopy coupled with energy dispersive spectroscopy. Employment of the high-resolution and in situ techniques results in a deep understanding of the details of the physical chemistry and mechanisms of the corrosion processes. The applicability of the SKPFM for mechanistic analysis of the effect of different corrosion inhibitors is demonstrated for the first time. The inhibitors under study show sufficient hindering of the localized corrosion processes especially in the case of pitting formation located around the intermetallic S-phase particles. The main role of Ce(3+) and La(3+) in the corrosion protection is formation of hydroxide deposits on S-phase inclusions buffering the local increase of pH, which is responsible for the acceleration of the intermetallics dealloying. The formed hydroxide precipitates can also act as a diffusion barrier hindering the corrosion processes in active zones. Cerium nitrate exhibits higher inhibition efficiency in comparison with lanthanum nitrate. The higher effect in the case of cerium is obtained due to lower solubility of the respective hydroxide. A detailed mechanism of the corrosion process and its inhibition is proposed based on thermodynamic analysis. 相似文献
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F. Mansfeld 《Russian Journal of Electrochemistry》2000,36(10):1063-1071
The rare earth metal salt (REMS) compounds which are non-toxic and inexpensive have been used successfully for the corrosion
protection of commercial aluminum alloys as well as of mild steel. The resistance to localized corrosion of aluminum alloys
such as Al 2024, Al 6061 and Al 7075 has been greatly improved by immersion in hot cerium salt solutions. Cerium oxides/hydroxides
were formed at sites where intermetallic compounds containing copper were located and eliminated the formation of local cathodes.
REMS solutions were also used for sealing of anodized layer on Al alloys replacing toxic chromates. In addition to increased
corrosion resistance excellent paint adhesion was observed. Cerium nitrate and yttrium sulfate solutions produced the most
satisfactory results. Cerium salts were also applied successfully as inhibitors and as pretreatment for the corrosion protection
of carbon steel in hot NH3/water solutions used in absorption heat pumps. Factorial design experiments have been used to determine the optimum concentrations
of CeCl3 and H2O2 as well as the treatment time used in the cerating process for mild steel. The corrosion protection provided by the cerated
layer was further improved by cathodic polarization in cerium chloride. A dual corrosion protection strategy employing cerating
and addition of a REMS to the working solution is expected to provide long-lasting corrosion protection of mild steel.
Dedicated to the ninetieth anniversary of Ya.M. Kolotyrkin’s birth.
This article was submitted by the author in English. 相似文献
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A. Samide I. Bibicu M. S. Rogalski M. Preda 《Journal of Radioanalytical and Nuclear Chemistry》2004,261(3):593-596
The effect of the NO3? anion on the corrosion of carbon steel in a solution of 0.1M NH4Cl (pH 5.5) was studied by galvanostatic polarization and Mössbauer spectrometry. The anion has an inhibiting effect by decreasing the expansion rate of generalized corrosion of carbon steel in a solution of 0.1M NH4Cl. Mössbauer spectroscopy shows that a superficial compound is formed on the electrode surface as a result of corrosion, presenting no magnetic ordering. Its parameters show the initial stage of corrosion. We assume that at this stage the main corrosion product is a mixture of ferrihydrite Fe(III) and FeOOH (α and/or γ). 相似文献