醋酸介质中溶解氧对不锈钢和磷脱氧铜腐蚀行为影响

应用极化曲线法和溶解氧测量技术研究不锈钢_2 0 6和磷脱氧铜在醋酸介质中的腐蚀行为以及过程的控制特征 .分析在含氧及采用抗坏血酸去除部分溶解氧的醋酸介质中 ,醋酸浓度、氯度、温度对上述两种金属腐蚀行为的影响因素 ,为石油化工中的醋酸设备的正确选材及有效防腐提供理论和实验依据     

有机化合物的新型极谱催化波 ——KIO3存在下醋酸甲羟孕酮的极谱催化波研究

在水和DMF两种介质中,研究了醋酸甲羟孕酮（MPA）的极谱行为和极谱催化波机理.结果表明,在0.2 mol/L HAc-NaAc(pH=}5.0)缓冲水溶液中,MPA的C=C双键首先经单电子单质子还原产生质子化的中间体自由基HMPA     

芳基对硝基苯乙快基汞的合成

采用芳基醋酸汞或芳基氢氧化汞与对硝基苯乙炔在碱性介质中反应，合成了１２种新的取代苯基对硝基苯乙炔基汞化合物。紫外可见光谱实验表明此化合成反应为可逆反应。通过元素分析及ＩＲ，ＭＳ，＾１ＨＮＭＲ和ＵＶ光谱对化合物结构进行了鉴定。     

罗丹明6G-锰（Ⅱ）-过氧化氢体系荧光法测定常见油性种子的抗氧化活性

碱性介质中罗丹明6G能产生特征荧光，其最大激发波长和发射波长分别为350nm和550nm；Mn^2 -H2O2体系在碱性介质中产生的羟自由基可以迅速氧化罗丹明6G使其荧光猝灭，而油性种子的浸提物可以清除羟自由基，从而使溶液的荧光猝灭程度降低，据此建立了测定油性种子抗氧化性的新方法。实验观察到：抗氧化剂维生素C和硫脲等在低浓度范围内对羟自由基的清除率与用量呈上升关系，而在大浓度下反而下降。讨论了样品的水、醋酸、乙醇溶剂浸提物对羟自由基的清除效率。用水、醋酸作提取剂，分别测试了7种常见油性种子的抗氧化活性。     

杂多酸在活性炭上的固载化Ⅲ．活性炭在酸性介质中对钨硅杂多酸（SiW_（12））的吸附

在氢离子浓度均为３ｍｏｌ／Ｌ的硫酸，盐酸，磷酸，醋酸水溶液中和冰醋酸中研究了具有Ｋｅｇｇｉｎ结构的硅钨杂多酸（ＳｉＷ＿（１２））在不同来源活性炭上的吸附作用。各活性炭对ＳｉＷ＿（１２）吸附等温线的形式是不相同的，吸附剂载体的微孔结构以及杂多酸的溶剂化起着重要的作用。并且在无机酸介质中，杂多酸的吸附量比在水溶液中成规律性地增加，且与酸强度成正比关系。在有机酸介质中，吸附作用比较复杂。根据所得结果，提出了在酸性介质中杂多酸在活性炭表面的吸附模型。     

杂多酸在活性炭上的固载化：III.活性炭在酸性介质中对钨硅杂多酸（SiW12…

在氢离子浓度均为３ｍｏｌ／Ｌ的硫酸，盐酸，磷酸，醋酸水溶液中和冰醋酸中研究了具有Ｋｅｇｇｉｎ结构的硅钨杂多酸（ＳｉＷ１２）在不同来源活性炭上的吸附作用，各活性炭对ＳｉＷ１２吸附等温线的形式是不相同的，吸附剂载体的微孔结构以及杂多酸的溶剂化起着重要的，工且在无机酸介质中，杂多酸的吸附量比在水溶液中成规律地增加，且与酸强度正比关系，在有机酸介质中，吸附作用比较复杂，根据所得结果，提出了在酸性中杂多酸在     

化学计量学-动力学分光光度法同时测定两种糖皮质类激素

在碱性介质中,高锰酸钾能将糖皮质类激素(醋酸泼尼松和地塞米松)氧化,而本身被还原成绿色的锰酸钾,基于这一反应,本文提出了同时测定醋酸泼尼松和地塞米松的化学计量学-动力学分光光度法.研究发现反应体系在610 nm处有一个吸收峰,实验以该波长为检测波长,优化实验条件.在该条件下,检测醋酸泼尼松和地塞米松的线性范围分别为0....     

阻抑动力学荧光光度法测定苯胺

在醋酸介质中，痕量苯胺对溴酸钾和过氧化氢氧化罗丹明6G使其荧光猝灭的反应有抑制作用，据此建立了阻抑动力学荧光法灵敏测定痕量苯胺的新方法。方法检出限为0．50μg/L，测定范围为8．40－58．7μg/L。方法用于环境废水中苯胺的测定，结果令人满意。     

模拟萃合物二(二甲基甲酰胺)氯化醋酸铀铣UO2(OAc)Cl(DMF)2的结构测定

本文通过对一系列UO2(OAc)Cl.L2类型的化合物进行了化学合成和分子结构的研究,进一步证明协萃化合物是真子的氯化醋酸铀酰而不是氯化铀酰与醋酸铀酰的混合物, 并阐明醋酸根离子与氯离子交换的机理。二(二甲基甲酰胺)氯化醋酸铀酰分子结构的测定显示出在OAc^-和Cl的混合介质中所产生的协同萃取效应。     

聚缩醛药物载体的合成表征及其降解动力学的NMR研究

在对甲苯磺酸催化下, 将聚乙二醇2000(PEG2000)和氨基保护的丝胺醇与三甘醇二乙烯基醚三元共聚, 再脱去丝胺醇的氨基保护基团, 合成了4种氨基含量不同的聚缩醛PA1, PA2, PA3和PA4, 用1H NMR表征了其结构. 同时, 利用1H NMR监测了聚缩醛PA3在pH值为7.4, 6.5和5.7的磷酸缓冲液及pH值为4.7, 4.1和3.8的醋酸缓冲液中的降解行为. 结果表明, PA3在酸性缓冲液介质中的降解反应符合一级反应动力学方程, 且随着介质pH值的减小降解速率常数增大, 降解半衰期减小.     

氯化钠溶液中铜丝尺寸效应对腐蚀行为的影响

为了研究半径变化对铜丝腐蚀行为的影响, 通过极化曲线和交流阻抗测试方法研究了半径为0.04-0.82 mm的铜丝在自然通气的0.5 mol·L-1 NaCl(pH=7.4)溶液中的腐蚀行为. 结果表明, 当铜丝半径小于氧的扩散层厚度(0.56 mm)时, 随着半径减少, 非线性扩散的存在加速了电化学反应的传质过程, 其影响由慢到快迅速增大, 使得受扩散过程控制的阴、阳极反应速率增大, 铜丝的腐蚀电流密度显著增加. 对铂丝、不锈钢丝的氧阴极还原反应过程研究也得到了类似的反应特征. 上述现象表明铜丝腐蚀行为的尺寸效应具有一定的普遍性.     

An Electrochemical Study on the Corrosion Inhibition of Stainless Steel by Polyaniline Film

Polyaniline(PANI)film was electrosynthesized on 304 stainless steel by cyclic voltammetry using aqueous oxalic acid as supporting electrolyte.The potential sweep rates were changed to achieve the PANI film with different thickness and structures.Protective properties of the PANI film for corrosion of stainless steel in 3% NaC1 aqueous solution were investigated by monitoring potentiodynamic polarization curves and electrochemical impedance spectroscopy(EIS).The results showed that the PANI film which was formed with lower sweep rate led to more positive shift of corrosion potential and greater charge transfer resistance,reflecting higher inhibition for corrosion of the stainless steel.     

电感耦合等离子体原子发射光谱同时测定不锈钢食用器皿铬、镍、镉溶出量

用4%醋酸溶液浸泡取自不锈钢食用器皿钢片样品,在室温条件下浸泡24h,将浸泡液按6:1浓缩.通过优化试验确定实验条件,用电感耦合等离子体发射光谱仪准确测定浸泡液中Cr、Ni、Cd的浓度.实验过程操作简单,多种元素同时测定节约试验时间.精密度试验和回收率试验说明该方法检测结果准确可靠.     

Numerical Simulation for Crevice Corrosion of 304 Stainless Steel in Sodium Chloride Solution

The authors presented a mechanistic model describing the chemical reactions within a corroded thin, nar-row crevice. In the mathematical model, a two-dimensional steady-state was used to predict the crevice pH profile by taking into account dissolved oxygen and hydrogen ions within the crevice. It consists of six parallel electrochemical reactions: multi anodic reactions(Fe, Cr, Ni dissolution reactions) and three cathodic reactions(the oxygen reduction, the hydrogen reaction and water dissociation). Current density distribution and oxygen concentration distribution were determined to be corresponding to the evolution of potential distribution within the crevice. The contribution of each metal reaction to the overall corrosion process was in proportion to the mole fraction, and the simulation pro-vided a good agreement with published experimental results for the crevice corrosion of stainless steel in sodium chloride solution.     

Corrosion inhibition of 302 stainless steel with schiff base compounds

The effects of 2,2′-[bis-N(4-cholorobenzaldimin)]-1,1′-dithio (BCBD) and bis-(2-aminophenyl) disulphide (BAPD) on the corrosion behavior of 302 stainless steel in 0.5 M sulfuric acid solution as corrosive medium were investigated using weight loss and potentiostatic polarization techniques. Some corrosion parameters such as anodic and cathodic Tafel slopes, corrosion potential, corrosion current density, surface coverage degrees and inhibition efficiencies were calculated. The polarization measurements indicated that the inhibitors were of mixed type which inhibited corrosion by parallel adsorption on the surface of stainless steel due to the presence of more than one active centre in the inhibitor molecule. The adsorption followed Langmuir adsorption isotherm. The activation energy and thermodynamic parameters were calculated at different temperatures. Results showed that BCBD had a higher inhibition efficiency compared with BAPD.     

18／8型不锈钢在受力形变条件下腐蚀电化学行为的研究

应用电化学稳态技术、电化交流阻、抗微区电化学技术及扫描电等方法，研究１８／８型不锈钢在Ｎａ２Ｓ２Ｏ３稀溶液中，受外力形变条件下，的腐蚀电化学行为，结果表明，力学因素可使表面腐蚀电化学活性增加，表面微裂纹的发生、消失和再钝化的动态过程，同时受电位和拉应力的影响；点腐蚀可优先发生在应力集中位置，点蚀的发展可能诱导不锈钢的应力腐蚀开裂。     

Effect of Dissolved Oxygen on the Corrosion Rate of Stainless Steel in a Sodium Chloride Solution

Russian Journal of Electrochemistry - The corrosion currents of 17-4РН stainless steel in an NaCl solution at various contents of dissolved oxygen are obtained by the method of Tafel...     

Stressed Corrosion of an Austenitic Stainless Steel Studied by Scanning Kelvin Probe Force Microscopy

Under the ambient temperature (25°C) and pressure (one Standard Atmospheric Pressure) conditions, surface Volta potential of an austenitic stainless steel was measured using the Scanning Kelvin Probe Force Microscopy (SKPFM) to study its stressed-related corrosion behavior in a 0.5 M chloride solution. In an oxygen and water regulated environment (using a glovebox), the steel shows a map of Volta potentials with high contrasts among the different grains and grain boundaries, which was then linked to the actual corrosion potential (w.r.t. a saturated calomel electrode) based on a rigorous calibration procedure. Corrosion behavior of the steel under tensile stress was then compared to that of the same sample under no tensile stress in light of the measured Volta potential, which was found to be sensitive to the level of applied tensile stress, although the tested stainless steel in general is known for its high corrosion-resident capability. According to this study, surface Volta potential measured by SKPFM can be used as a high-accuracy indicator for localized corrosion of steels.     

Impact of sensitization on dissolution process of AISI 304 stainless steel during intergranular corrosion evaluated using DEIS technique

The paper presents the results of instantaneous impedance changes measurements vs. reactivation potential performed by means of dynamic electrochemical impedance spectroscopy (DEIS) technique for AISI 304 stainless steel (SS) dissolution process during intergranular corrosion (IG) in 0.5 M H₂SO₄ + 0.01 M KSCN solution. With the use of DEIS method, it was possible to estimate dynamic changes of the examined system’s impedance in conditions of proceeding IG process. Furthermore, the paper proposes an alternative way of evaluating AISI 304 stainless steel dissolution rate during intergranular corrosion based on approximation to theory of iron dissolution in sulfuric acid medium. Simultaneously, based on the DEIS measurements, information about the degree of sensitization of the examined material were obtained. Performed research revealed the advantages of the DEIS technique over the classical double-loop electrochemical potentiokinetic reactivation tests when investigating intergranular corrosion process.