几种稀土盐封闭的铝阳极氧化试样的腐蚀行为

为提高铝硫酸阳极氧化膜的抗污染和防腐蚀性能，分别采用环境友好的铈盐、钇盐和镧盐溶液对阳极氧化膜进行了封闭处理。采用动电位极化法比较了不同稀土盐封闭的铝阳极氧化试样在弱酸性NaCl腐蚀介质中的电化学行为，采用扫描电子显微镜（SEM）和能量色散谱（EDS）对封闭试样腐蚀前后的表面形貌、组成进行了表征。结果表明：在腐蚀介质的侵蚀及强电化学极化条件下，铈盐和镧盐封闭的阳极氧化膜对铝基体具有较好的保护作用，而钇盐封闭膜的保护作用则较差。这种差别的主要原因是不同稀土盐封闭过程中封闭产物的析出倾向及速率不同。     

金属氢化物电极表面处理方法及其表面氧化膜研究：Ⅰ.富镍表面处理及氧化？

发展了两种贮氢合金表面处理新方法。光电子能谱和循环伏安实验表明，经过处理后得到了富镍表面层，可提高电极的反应性能、采用光电化学方法对不同处理的电极表面由动电位氧化形成的氧化膜进行了表征，分别观察到与表面膜吸附氢氧化和氧化还原反应有关的阳极光电流和阴极光电流，同时依照电极在循环过程中的光电流变化区分了两种处理方法的得到的表面层抗氧化性能之差异     

铝阳极氧化膜成长的现场椭圆法研究

用椭圆法（ｅｌｉｐｓｏｍｅｔｒｙ）对３％酒石酸溶液中（ｐＨ＝５．５）铝阳极氧化膜的成长过程进行了现场（ｉｎｓｉｔｕ）研究。控制不同阳极极化电压测量得出的椭圆仪数据（Δ和Ψ），经曲线拟合最优化分析，结果表明：Ａｌ电极表面生成的Ａｌ２Ｏ３膜是一种较均匀、致密的单层膜，其厚度与阳极氧化电压呈线性增长关系，斜率约为１．３５ｎｍ／Ｖ     

金属氢化物电极表面处理方法及其表面氧化膜研究 Ⅰ.富镍表面处理及氧化膜的光电化学方法研究

发展了两种贮氢合金表面处理新方法．光电子能谱和循环伏安实验表明,经过处理后得到了富镍表面层,可提高电极的反应性能．采用光电化学方法对不同处理的电极表面由动电位氧化形成的氧化膜进行了表征,分别观察到与表面膜吸附氢氧化和氧化还原反应有关的阳极光电流和阴极光电流,同时依照电极在循环过程中的光电流变化区分了两种处理方法所得到的表面层抗氧化性能之差异．通过粉末单电极初期充放电实验,证实了电极经方法１处理以后其放电性能得到提高．     

丁二酸在Ti/TiO2膜电极上的电化学合成

在包含原料马来酸的硫酸溶液中, 通过原位阳极氧化法制备了Ti/TiO2膜电极, 然后采用极性转换技术在原溶液中电化学合成丁二酸. 采用XPS, XRD和SEM分析了膜电极上的元素组成、价态分布和氧化膜的晶相结构及表面形貌. 结果表明, 阳极氧化膜层内只含有Ti和O两种元素, 且Ti均为Ti4+; TiO2氧化膜是金红石相, 表观呈现带孔的条纹形貌. 通过循环伏安、恒电位阶跃和恒电流电解技术研究了Ti/TiO2原位氧化膜电极的电化学性质, 结果表明, 该膜电极对马来酸电还原合成丁二酸具有较好的电催化活性. 以钛基氧化钌电极(DSA)为阳极, Ti/TiO2原位氧化膜电极为阴极进行恒电流电解了实验. 结果表明, 丁二酸的还原产率为95.94%, 电流效率为95.57%, 产物纯度为99.28%, 熔点为185~187 ℃.     

钛表面二氧化钛膜中氧空位点缺陷传输性能的电化学研究

"钛/TiO2氧化膜/溶液"界面电极体系的电化学性能主要决定于钛表面的TiO2氧化物膜.本文利用多种电化学技术,结合半导体物理的Mott-Schottky分析和Einstein方程,研究了金属钛在1.0mol·L-1HClO4溶液中表面半导体TiO2氧化膜的生长及氧化膜中氧空位点缺陷在外加电场作用下的传输性能,并根据离子性电荷传输与电子性电荷传输对电场变化响应时间之不同特点,确定氧化膜中点缺陷扩散系数.结果表明,电极电位或阳极析氧反应对稳态电流(iss)、氧化膜的阳极化常数(α)、膜中电场强度()、以及膜中氧空位点缺陷的扩散系数(D0)等重要物理化学参数,均有显著影响,并依据氧化膜中的结构变化进行分析.     

聚吡咯膜的电氧化形成和伏安特性

本文对铂电极上聚吡咯膜电氧化形成进行了探讨。获得了均匀、有透明感并显现电钯特性的聚吡咯膜。新生成的聚吡咯膜在一些电解液中表现电氧化-还原活性。但长期往复极化后会逐渐退化到高阻的惰性状态。应用聚吡咯膜保护烧结n-CdS光阳极的尝试未取得满意的效果。     

铂微电极位点上氧化铝纳米孔的制备

金属微电极表面的纳米级处理可以大大提高电极的性能。本文基于微加工及电化学技术在铂微电极位点上制备了一致性良好的氧化铝纳米结构。通过对基片铂层表面等离子体处理,使铝膜与铂层之间粘附力明显增强。利用二次阳极氧化法,在铂微电极位点上制备出纳米孔。结果表明,30V是该条件下比较理想的氧化电压。同时,通过对氧化过程中电流的监测,发现当铝膜完全氧化后电流大幅上升,可将此现象作为终止阳极氧化的标志。这种微电极位点处的氧化铝模板可进一步用于不同材料纳米微电极的制备。     

硼砂-对苯二甲酸电解液中AZ91D镁合金的阳极氧化处理

研究了硼砂-对苯二甲酸环保型电解液中AZ91D镁合金的阳极氧化.考察了对苯二甲酸对镁合金阳极氧化过程及其氧化膜性能的影响,并利用扫描电镜(SEM)、X射线衍射(XRD)、能量散射谱(EDS)、动电化极化和电化学交流阻抗谱(EIS)等进行了分析表征.结果表明,对苯二甲酸的浓度对阳极氧化成膜过程、氧化膜的表面形貌、厚度、相结构和耐腐蚀性能都有重要影响.在硼酸盐电解液中加入适量的对苯二甲酸后,氧化电流密度降低,过度放电现象受到了明显的抑制,所制得的阳极氧化膜的质量也有了显著改善.氧化膜表面变得光滑、致密,膜厚度略有降低.氧化膜与镁合金基底的结合更紧密,而且其耐腐蚀性能也得到了明显增强.该研究对于镁合金阳极氧化处理工艺的环保化及阳极氧化膜质量的提高都具有积极意义.     

镁钙合金表面贻贝类吸附蛋白膜的NaIO4氧化处理及抗腐蚀性能

利用极化曲线及电化学阻抗谱,并结合扫描电镜、原子力显微镜、电子探针显微镜及红外光谱技术研究氧化处理对镁钙合金表面贻贝类吸附蛋白膜层抗蚀性能的影响. 结果表明,在NaIO₄氧化作用下,镁钙合金表面的贻贝吸附蛋白（Mefp-1）膜层由孔状结构转变为网状结构,且趋于均匀致密;未氧化处理的蛋白膜层对镁钙合金的保护作用随时间逐渐增加,而氧化处理的蛋白膜层使镁钙合金的点蚀电位正移,3 d时其腐蚀保护性能达到最佳,浸泡时间延长,膜层的防护性能略有下降.     

阳极氧化AZ91D镁合金在氯化钠稀溶液中的腐蚀行为

利用盐雾实验、极化曲线扫描、电化学阻抗谱和电化学噪声技术等电化学研究方法结合扫描电镜表面观测技术对AZ91D镁合金氧化膜在1%(w)氯化钠溶液中的耐蚀性能进行了评价. 结果表明, 氧化前后的镁合金腐蚀行为发生明显改变, 如未封孔的阳极氧化膜耐中性5%氯化钠盐雾试验时间超过200 h; 氧化后的镁合金自腐蚀电位明显正移, 点蚀诱导期延长; 阳极氧化膜的高频阻抗约为裸露镁合金的数千倍, 这些变化证明阳极氧化处理使镁合金获取了十分优异的耐蚀性能. 首次利用分形维数Df的变化规律初步描述氧化后AZ91D镁合金的腐蚀过程. 可以发现随着浸泡时间的延长, Df呈现出初期快速增长, 随后出现波动, 最后稍有降低的变化过程. 这种现象对应于氧化后AZ91D 镁合金在1%氯化钠溶液中腐蚀的三个阶段.     

Film characteristics of anodic oxidized AZ91D magnesium alloy by applied power

This study examined the film characteristics of an anodized AZ91D magnesium alloy by varying the direct current and pulse frequency conditions. In order to evaluate the effect of the pulse frequency on film formation, anodic oxidation was carried out by applying direct current and pulse current at a current density of 300 mA/cm². Compared with the sample groups treated with the direct current, a large number of small arcs were generated continuously on the film treated with the pulse current and the film formation rate was found to increase. Homogeneous and compact pores were formed with increasing frequency, and the rate of formation was increased rapidly to the arrival voltage. The film thickness increased and the surface roughness decreased with increasing anodic oxidation time at a fixed frequency of 125 Hz. However, treatment for more than 3 min led to decomposition of the oxidized film onto the previously formed film, which caused an increase in the number of cracks and pores within the film. The most uniform and smallest pores were acquired when the surface was anodized for 3 min at a current density and frequency of 300 mA/cm² and 125 Hz, respectively. X‐ray diffraction revealed the formation of MgO and Mg₂SiO₄ peaks, with a relative decrease in peak intensity for the MgO and Mg substrate. The Vickers hardness value was higher on the treated groups than on the untreated group, and the potentiodynamic polarization test revealed satisfactory corrosion resistance through a decrease in corrosion density and a large improvement in the corrosion potential. Copyright © 2009 John Wiley & Sons, Ltd.     

AZ31镁合金表面聚吡咯的化学氧化合成及其耐蚀性能

以对甲苯磺酸钠为掺杂剂, 三氯化铁为氧化剂, 用化学氧化聚合法在AZ31 镁合金表面制备聚吡咯(PPy)膜. 采用傅里叶变换红外(FTIR)光谱分析了镁合金表面聚吡咯膜结构, 通过电化学极化曲线、电化学阻抗谱(EIS)研究了其耐蚀性能, 通过扫描电子显微镜(SEM)、X射线能量散射谱(EDS)分析了表面形貌和成分. 和镁合金裸样相比, 聚吡咯膜对镁合金腐蚀有一定的抑制作用. 硅烷预处理改善了镁合金/聚吡咯体系的耐腐蚀性能, 使腐蚀电位较镁合金裸样正移了110 mV, 电流密度减小了约2个数量级.     

Corrosion behavior of Mg,AZ31, and AZ91 alloys in dilute NaCl solutions

Corrosion behavior of extruded Mg, extruded AZ31 alloy, and cast AZ91 alloy was investigated by electrochemical measurements in dilute NaCl solutions. Corrosion products and passivation films were analyzed by X-ray diffraction and X-ray photoelectron spectroscopy. All specimens exhibit the corrosion and passivation zones in dilute NaCl solutions. The aluminum content and alloy microstructure influence the corrosion and passivation processes. AZ91 alloy shows the broadest passivation zone followed by AZ31 alloy and Mg. AZ91 alloy reveals a highest corrosion resistance, and preferential attack is located at the primary Mg phase. Its relatively fine β-phase (Mg₁₇Al₁₂) network and Al₂O₃/Al(OH)₃ compounds produced on the passivation film are the main factors which limit the corrosion progress as compared with AZ31 alloy and Mg. The thick passivation product on AZ31 alloy is the key factor which restricts the corrosion attack in dilute solutions.     

XPS study of the effect of aluminium on the atmospheric corrosion of the AZ31 magnesium alloy

The surface characteristics and corrosion behaviour of the AZ31 magnesium alloy exposed to a high relative humidity (RH) atmosphere were investigated. During the first 15 days of humidity test at 98% RH and 50 °C, a significant increase of magnesium carbonate and a decrease of magnesium oxide were detected on the surface film by XPS; after this stage, increased exposure times did not produce substantial changes on the relative amounts of these compounds. The surface film of commercially pure magnesium, also examined for comparison purposes, revealed more magnesium carbonate and less magnesium oxide compared with the AZ31 alloy. Unlike the AZ31 alloy, the surface of pure Mg disclosed almost complete substitution of MgO by magnesium carbonate after 30 days of exposure time. Mass gain values of tested specimens and scanning electron microscope characterisation of corroded surfaces indicated lower corrosion susceptibility of the AZ31 alloy compared with the commercially pure Mg, suggesting superior chemical stability of the oxide/hydroxide film formed over the magnesium–aluminium alloy surface. XPS and energy dispersive X‐ray (EDX) analyses did not revealed any substantial enrichment of aluminium in the corrosion products film on the AZ31 alloy after 30 days of testing. Copyright © 2008 John Wiley & Sons, Ltd.     

Ellipsometric analysis of corrosion behavior of 3C magnesium alloy surface touched by simulated sweat

As an optimum shell material, AZ80 magnesium alloys are widely applied in the 3C (computers, communications and consumer electronics) industries. The case of 3C products corroded by a sweaty hand has been simulated and the corrosion characters have been investigated by ellipsometric technology. Thickness variation of corrosive medium film on a Mg alloy surface was monitored. Surface structure of a corrosion layer was described with a three‐layer optical model (substrate—EMA—Cauchy) and thickness of each layer for different soaking time was obtained by fitting experimental data with the model. The corrosion product films with a refractive index of 1.45–1.62, loose corrosion product layer, can only provide limited protection to the substrate when a Mg alloy surface is corroded by sweat again. Copyright © 2010 John Wiley & Sons, Ltd.     

Mg0.9Ti0.1Ni0.85Co0.15合金的石墨粉及镍粉球磨表面包覆性能

选用非晶态的Mg0.9Ti0.1Ni0.85Co0.15合金粉末与石墨粉及镍粉进行球磨表面包覆。SEM分析结果表明,己包覆石墨和镍粉的合金表面上吸附着一层小的颗粒,形成薄层将原来的合金表面包覆起来。使用XPS分析了合金表面元素。结果表明,包覆石墨粉后,合金表面碳元素的质量分数和原子分数均增加,Mg的质量分数从22.74%减小至22.23%,原子分数从36.43%减小到32.94%,从而减小了Mg在碱液中的腐蚀几率,提高合金的抗腐蚀性能;包覆镍粉后,合金表面Ni的质量分数由59.89%增加到60.04%,原子分数由40.63%增加到41.02%,形成合金表面富Ni的保护层,提高了合金的抗腐蚀性能。充放电循环测试表明,循环30周后,包覆石墨粉的合金电极容量保持率为32.05%,包覆镍粉的合金电极容量保持率为41.26%,而未包覆的电极容量保持率仅为17.88%。合金电极极化曲线测试结果表明,石墨或镍粉的包覆提高了Mg0.9Ti0.1Ni0.85Co0.15合金电极的循环稳定性和在KOH碱液中的抗腐蚀性能。     

Stearate as a green corrosion inhibitor of magnesium alloy ZE41 in sulfate medium

The efficiency of stearate as a corrosion inhibitor for magnesium alloy ZE41 has been studied in sodium sulfate medium, employing electrochemical techniques like potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results of polarization study imply that stearate functions as a mixed-type corrosion inhibitor with a predominant anodic control. The adsorption of stearate on alloy surface is found to obey the Langmuir adsorption isotherm. The proposed inhibition mechanism involved adsorption of stearate onto metal surface, followed by precipitation of magnesium stearate within the microdefects of Mg(OH)₂ surface film which enhanced the barrier effect of an otherwise porous partially protective film.     

铈、锂盐对铝阳极氧化膜的协同封闭作用

研究了铈、锂盐在铝阳极氧化膜封闭处理中的协同作用.场发射扫描电镜和X射线衍射谱对铈、锂盐协同封闭前后铝阳极氧化膜形貌和结构的研究结果表明，封闭后膜表面的孔洞消失，封闭产物分布均匀，封闭后膜仍然以非晶态形式存在.根据X射线光电子能谱的结果，封闭后的膜主要由含结晶水的Al2O3及铈、锂的混合氢氧化物组成，同时膜中还含有及封闭溶液组分中的一些阴离子.电化学阻抗谱的研究结果表明铈、锂盐协同封闭能够显著提高膜的耐蚀性能.在实验结果基础上，初步认为铈、锂盐封闭是通过生成结构紧密的封闭产物填充、覆盖膜孔，从而显著提高铝阳极氧化膜的耐蚀性能.