磷脱氧铜和不锈钢在醋酸介质中腐蚀行为的电化学研究

应用交流阻抗和极化曲线法研究磷脱氧铜和ＳＷ－２０６不锈钢在醋酸介质中腐蚀行为及过程的控制特征，比较介质温度，浓度及溶解氧对这两种金属在醋酸中腐行为的影响，分析其原因所在，为石油化工中的醋酸设备的正确选材及有效防腐提供实验依据。     

稀土-四苯基卟啉络合物在丙酮介质中的伏安行为

研究了15种稀土离子与四苯基卟啉(H_2TPP)在丙酮介质中直接形成络合物后的电还原行为和溶解氧对它们的影响。轻重稀土卟啉络合物的伏安行为并不一样,但中心离子均能从三价还原到两价,还原后与溶解氧的还原产物超氧基O_2~-形成稀土卟啉过氧化物,在相当负的电位下,络合加合物不解体。     

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.     

钴(Ⅱ,Ⅲ)与meso-四(4-苯基磺基)卟啉(TPPS)络合物的伏安行为研究

木文报道了钴(Ⅱ,Ⅲ)与meso-四(4-苯基磺基)卟啉(TPPS)络合物的形成条件和电还原行为.结果表明在醋酸缓冲溶液(pH3.5)中,Co²⁺-TPPS还原同时产生催化氢波.在氨性缓冲溶液(pH9.0)中,Co²⁺-TPPS产生络合吸附波,讨论了其伏安行为,认为络合物中Co²⁺和TPPS是一步同时还原.溶解氧可以把Co²⁺-TPPS氧化为Co³⁺-TPPS,对比Mn³⁺-TPPS讨论了络合物的形成和溶解氧的作用,认为氧对卟啉络合物中心离子价态变化和电子转移起着重要作用.     

碘-淀粉光度法测定水中溶解氧含量

根据碘与淀粉反应生成蓝色络合物以及此络合物在574 nm波长处有吸收峰,提出了水样中溶解氧的光度测定法.为固定样品中的溶解氧,于碱性介质中加入硫酸锰与之形成三氧化二锰沉淀物.测定时加入硫酸使与沉淀物反应而释出所固定的氧,并立即与同时由溶液中已加入的碘化钾与硫酸反应而释出碘而使溶液中呈现蓝色.用光度法在574 nm波长处测得其吸光度.从由碘酸钾标准溶液作为溶解氧标准所制作的标准曲线上查得试样中溶解氧的含量,对显色的条件作了系统试验并选定了优化的反应条件,溶解氧的质量浓度在0.027～0.80 mg·L-1之间符合比耳定律.取3种不同来源的水样按此方法测定其溶解氧含量,所得结果与碘量法及溶解氧测定仪所测得的结果相符.     

血红蛋白过氧化物模拟酶胶束催化显色体系

在胶束Tween80介质中，研究了以血红蛋白（hemoglobin,Hb)作为过氧化物模拟酶、隐性亮绿（recessive brilliant green,RGB)为氢供体底物、溶解氧为受氢体的酶催化反应特性。在pH5.64(NH4)2HPO4-KH2PO4缓冲溶液中，利用模拟酶对溶解氧作为受氢体催化RBG氧化生成亮绿（brilliant green,BG)而拟定了测定Hb含量的新方法。讨论了胶束介质对酶体系催化反应的影响及酶催化反应的可能机理。     

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     

用双波长分光光度法测定稀土和钪在其混合物中的含量

氨基C酸偶氮氯膦曾用于稀土胶溶络合物体系[1]。该显色剂在醋酸介质中与各稀土元素及钪形成稳定的络合物。这两种络合物的吸收光谱有明显的差异,利用这些差异,我们应用双波长分光光度法直接分别测定了稀土和钪在其混合物中的含量。方法简便、快速。     

IO_3~--I~--吖啶红-聚乙烯醇体系分光光度法测定环境水样中溶解氧

1 引言 溶解氧(Dissolved oxygen,DO)是指溶解于水中的分子态氧,是环保、油田井下注水、工业锅炉用水、生物养殖用水和科研用水的重要检测指标之一.目前,测定溶解氧常用的方法有碘量法(即Winkler法)、氧电极法、水相化学发光法和分光光度法等.本方法依据碘量法中可以析出与溶解氧相当的I_2,利用I_3~-与吖啶红(AR)在H_2SO_4-聚乙烯醇(PVA)介质中反应生成离子缔合物,采用光度法测定水体中溶解氧,本方法以基准物KIO_3为溶解氧标准溶液,灵敏度高,克服了原有碘量法中Na_2S2O_3为溶解氧标准溶液不稳定的不足.由于试剂便宜易得,无污染,适用于大批试样的测定.     

重金属铊在环境介质中的分布及其迁移行为

铊是剧毒重金属元素,它在自然界中是典型的稀有分散金属。环境介质中铊的自然本底值较低,但随着铊矿床的开发和铊资源的广泛应用,岩矿石中的铊在自然力或人为作用下向环境介质中迁移。综述了铊在岩（矿）石、土壤、水体、动植物和人体中的分布,以及在上述环境介质及大气中的迁移行为。研究表明,人类活动是导致环境介质中铊含量增加的主要原因。铊在环境介质中的迁移是反复循环的复杂过程,通过风化、溶解、淋滤、吸收、沉降、固结等方式在环境介质中循环往复,从而危害环境生态和人体健康。铊污染应引起人们的普遍重视。     

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.     

碳钢在N-甲基二乙醇胺介质中的电化学阻抗谱研究

应用电化学阻抗谱(EIS)研究碳钢在N-甲基二乙醇胺(MDEA)介质中的腐蚀行为.实验表明,未经预阴极活化处理的碳钢表面存在氧化膜,溶解氧促使它腐蚀速率增大,经活化处理去除氧化膜后则相反.在不含热稳定性盐(HSS)的MDEA溶液中,碳钢的腐蚀性随MDEA浓度的增加呈先上升后下降趋势;而在HSS高含量的溶液中,其腐蚀性则随MDEA浓度的增加而单调下降.在含有HSS模拟溶液中,碳钢的阳极极化EIS随极化电位由低到高分别出现感抗、负阻抗以及Warburg阻抗响应等特征,对应于孔蚀、活化状态向钝化状态过渡以及进入钝化的趋势,腐蚀反应的阴极过程表现为电化学反应和扩散传质混合控制,阳极过程为电化学反应控制.     

Electrochemical behavior of stainless steel in aerated NaCl solutions by electrochemical impedance and rotating disk electrode methods

Electrochemical behavior of stainless steel in 0.5 M NaCl solutions is studied. It is shown that, for this steel, under a considerable cathodic polarization of electrode, the oxygen electroreduction proceeds via a four-electron mechanism. The corrosion current is estimated. From the impedance spectra, elements of an equivalent circuit that describes the electrode behavior under the ac conditions are calculated. A mechanism of the steel passivation in the electrolyte is proposed.     

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...     

铜在3%NaCl溶液中腐蚀行为的光电化学研究

Cu以其优异的导电性、导热性和易加工性广泛用于工农业生产中．自然Cu的腐蚀和防腐成为人们很关注的问题．人们已经注意到，Cl-对Cu的腐蚀有影响，并进行过一些研究．但目前使用光电化学方法研究这一问题的文章尚不多见，特别是利用测量开路光电压及其瞬态波形这一现场的、无损的、灵敏的监测方法研究户对Cu电极腐蚀全过程的文章尚未见到．本文正是利用如上方法及XPS，AES方法，研究了Cl-对Cu电极腐蚀的全过程，取得了一些有意义的结果．1实验方法Cu电极用99．99％（质量分数）的Cu制成，面积约为39mm2；电极底部由Cu导线焊接引出，…     

Effect of cyclic oxidation on electrochemical corrosion of type 409 stainless steel in the simulated muffler condensates

The electrochemical corrosion behavior of 409 stainless steel after cyclic oxidation below 400 °C was investigated in the simulated muffler condensates by using surface analysis and electrochemical measurement techniques. In the cyclic processes of condensate-dipping and oxidation, specimens may form defective oxide films and weak Cr depletion underlying the oxide films. Sulfate from the condensate-dipping will give rise to sulfidation during the cyclic oxidation, being detrimental to both the oxidation and corrosion properties of stainless steel. The oxidation above 300 °C deteriorates the corrosion resistance, even leading to active corrosion in the acidic condensate solutions. Comparatively, specimens oxidized cyclically without condensate-dipping show much higher condensate corrosion resistance. It is suggested that the acidic condensate corrosion is accelerated by the synergetic effect of oxidation and condensation in the mufflers, and then may result in perforation through the defects such as cracks and nodules in oxide films on the stainless steel surface.     

Electrochemical Behavior and Nonlinear Mott-Schottky Characterization of a Stainless Steel Passive Film

The electrochemical behavior of 304-stainless steel in solutions with different pH values and chloride concentrations was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and a nonlinear Mott-Schottky analysis method. The results showed that the corrosion behavior of 304-stainless steel was affected by various factors, such as pH, chloride ion concentration, and dissolved oxygen. The pit initiation and propagation stage were observed in EIS plots through the addition of sodium chloride. In addition, the effect of pH on the passive film dominated one of the film growth kinetic reactions. The effect of chloride ion concentration was caused by the generation of more cation vacancies, leading the passive film more susceptible to pitting, which was also demonstrated by X-ray Photoelectron Spectroscopy. The results are consistent with the point defect model.     

铜电极表面硅烷膜的自组装及其性能研究

应用自组装技术在铜电极表面上制备3巯基丙基三甲氧基硅烷自组装膜.红外光谱研究该自组装膜结构,电化学方法考察3-巯基丙基三甲氧基硅烷膜在5%NaCl溶液中对铜电极的缓蚀性能.结果表明,于不同浓度的3-巯基丙基三甲氧基硅烷乙醇溶液中自组装的硅烷膜表现出较好的抗腐蚀性.     

Application of Polytyramine Nanoparticles to the Corrosion Protection of Copper

Electrochemical polymerization of tyramine was achieved on copper electrode surface from tyramine in 0.3 M oxalic acid (pH=1.2) solution by using cyclic voltammetry technique. The formation of polytyramine nanoparicles (PTN) were characterized by cyclic voltammetry (CV), fourier transform infrared‐attenuated total reflectance (FTIR‐ATR) spectroscopy and scanning electron microscopy (SEM). The corrosion behavior of PTN coated copper was investigated by means of the change of open circuit potential with exposure time (E_ocp t), electrochemical impedance spectroscopy (EIS) and anodic polarization curves in 3.5 % NaCl solutions at room temperature. The obtained results showed the shift of corrosion potential toward positive values for electropolymerized copper and a significant decrease in corrosion current and corrosion rate in comparison with bare copper, so that the PTNs coating could be used as an important protection against corrosion of copper.