新型杂环化合物碳钢酸洗缓蚀剂的合成、评价及机理研究

缓蚀剂在金属防护工程中占有重要的地位，在国民经济建设中发挥着越来越重要的作用。从目前热力设备防腐及其他工业领域防腐情况来看，酸洗时使用缓蚀剂是一种行之有效、经济效益显著的防腐手段。虽然目前缓蚀剂从分子设计、合成路线与工艺，复配增效，应用性能等方面都取得了较大的发展，但是其理论进展仍远滞后于实践，对于不少缓蚀剂的缓蚀机理尚存争议，因此运用各种手段方法研究缓蚀剂的作用机理，发展和完善缓蚀剂理论，成为目前缓蚀剂研究领域的热门课题。本论文筛选或合成了三种类型十二种新型杂环化合物作为缓蚀剂，通过失重实验，电化学实验，量子化学计算及扫描电镜实验多种手段和方法测试了所选化合物在1mol/LHCl溶液中对碳钢的缓蚀性能，分析了它们对碳钢的缓蚀机理，从理论上探讨了缓蚀剂分子与金属表面的作用方式，总结归纳了分子结构与缓蚀效果之间的关系。 本论文中涉及的三类新型杂环化合物为：嘌呤类化合物，席夫碱-三唑类化合物和硫脲-三唑类化合物，针对不同类化合物的不同特点采用了不同的处理方法，研究的主要成果如下： 失重、电化学及扫描电镜实验结果表明，嘌呤类化合物对碳钢有较好的缓蚀效果和较高的缓蚀效率。针对嘌呤分子是平面型小分子的特点，结合实验现象及量子化学计算结果，推断了其吸附特点。在国内外缓蚀剂研究领域首次建立并使用了108个铁原子的碳钢表面模型，在此基础上，根据嘌呤类分子的吸附特点作了吸附曲线，证明嘌呤类分子的吸附机理为平面接近碳钢的物理吸附，嘌呤分子与碳钢表面的相互作用源于π-π超共轭作用。吸附曲线模型的创立和使用使得对缓蚀剂机理的研究不再仅仅局限于对缓蚀剂分子本身结构特点的分析与推测，而是可以在整个腐蚀体系的基础上对缓蚀剂分子在金属表面的作用机理进行研究，更重要的是，提供了一种在一定范围内从理论上筛选缓蚀剂的初步模型。 实验结果表明席夫碱-三唑类化合物对碳钢有很好的缓蚀效果以及很高的缓蚀效率，其中CMTT化合物，在10-3mol/L时对碳钢的缓蚀效率可达97%。针对席夫碱-三唑类化合物分子活性中心多，分子柔性刚性相结合的特点，量子化学计算中采用了富奎指数判断分子中起作用的活性吸附中心，推断了席夫碱-三唑类化合物的吸附为化学吸附。其机理为：通过巯基硫原子提供电子与碳钢表面铁原子成键，而碳钢表面多余的负电荷反馈至席夫碱的碳氮双键形成反馈键。新型席夫碱-三唑类化合物作为缓蚀剂的研究不但提供了新型高效无毒的酸洗缓蚀剂，而且碳氮双键与杂环的结合在提高了化合物缓蚀效率的前提下，还针对杂环化合物水溶性差的缺点提供了一种提高水溶性的解决方法，为更多新型化合物用于缓蚀剂领域提供了可行之道。 硫脲-三唑类化合物同样对碳钢有很好的缓蚀效果以及很高的缓蚀效率，尤其是TBU化合物，在10-3mol/L时对碳钢的缓蚀效率高达98%。针对硫脲-三唑类化合物分子缓蚀过程中硫原子的突出贡献，量子化学计算中将硫原子连接在碳钢表面上，然后对整个体系进行了结构优化，从理论上证明了该类化合物的吸附机理为：通过巯基硫原子提供电子与碳钢表面铁原子形成配位键，而硫脲-三唑类化合物分子中以苯环为主的共轭体系则以π-π超共轭作用覆盖在碳钢表面，是以化学作用为主物理-化学作用共存的吸附方式。而且在研究该类化合物的吸附机理中，发现了分子中小基团的立体位阻因素对化合物的缓蚀性能造成很大影响，目前关于此类的报道非常罕见。 值得一提的是，在各类缓蚀剂交流阻抗谱的测试与处理过程中，发现缓蚀剂分子的吸附过程对阻抗谱图有很大影响，本论文中采用了两种等效电路图相结合的方法对阻抗谱图进行了处理，体现了吸附过程的影响，得到更好的拟和结果。 新型杂环化合物作为缓蚀剂的研究，不但提供了多种具有潜在应用前景的高效低毒的新型酸洗缓蚀剂，对目前缓蚀剂领域存在的部分问题提出了解决方案，更重要的是，将新的模型和方法运用于对缓蚀剂机理的研究分析中，为缓蚀剂的筛选提供了一种新的理论模型，为新型缓蚀剂分子的设计合成提供了一定的科学依据，对缓蚀剂理论的发展与完善起到了一定的促进作用。

聚三氟氯乙烯氟碳涂料在紫铜表面的耐蚀阻垢性能

面临世界上严重的淡水资源紧缺，海水淡化和海水利用技术是可行的解决方案之一。铜及其合金因其良好的机械性能、可成型性、导热性以及在海洋环境中优良的耐腐蚀性能成为海水冷凝器的首选材料，但由于海水成分的多样性和复杂性，对铜及其合金还是造成了一定的腐蚀和结垢问题，因而制约着海水利用技术的发展和应用。 氟碳涂料是一种新型的高科技功能性涂料，其聚合物分子间的作用力低，决定着它具有非常低的表面自由能。因此，氟碳涂料具有不可润湿性、防沾污性和自润滑性。而它本身所特有的螺旋结构则决定了它具有一般涂料所难以比拟的优异的物理性能，在防腐蚀领域特别是复杂苛刻的海洋环境中有着广阔的应用前景。 本文选择了性能优异的聚三氟氯乙烯这种氟碳涂料，涂覆在紫铜上，研究了其阻垢能力和耐海水腐蚀性能。实验首先是通过配制超硬度的实验用水，测试了不同温度下，试样上所结水垢的量，然后通过SEM-EDX做了样品表面成分分析，结果表明涂料在样品表面附着均匀、致密，与基底金属结合紧密，可以有效地防止水垢的生成，并且还防止了金属铜的腐蚀问题。为进一步研究涂层的耐蚀性能，做了中性盐雾试验和电化学实验。在经过3000h的盐雾试验后，样品表面几乎没有变化，腐蚀增重率很小，金属腐蚀可以忽略不计；在为期90d的交流阻抗实验过程中，刚开始时阻抗弧不稳定，到第十天达到最大，然后慢慢减小，但始终为单弧容抗，只有一个时间常数。而且，在90d以后，极化电阻值仍然在10000Ω以上，因此，在实验期间，腐蚀介质不能到达涂层/基底金属界面，基底金属受到了良好的保护。

硫酸盐还原菌和极化电位对海洋结构用钢在海泥中应力腐蚀开裂敏感性的影响

海洋设施长期处于恶劣的腐蚀环境中，如不加以防护，一旦发生应力腐蚀开裂（SCC），损失就会极为惨重。海底泥土区环境十分重要，因为管线和平台桩腿等都埋在海底泥中。海底泥中硫酸盐还原菌（SRB）十分活跃，而且为了防止腐蚀，海泥中的设施无一例外地采取了阴极保护，相当于设施处在长期稳定的充氢状态。因此非常有必要研究海泥中的活性SRB和极化电位对海洋结构用钢在海泥中的氢渗透行为和SCC敏感性造成的影响，弄清SCC发生和发展的过程以便采取相应的措施减缓或防止SCC。 本文通过慢应变速率拉伸实验（SSRT）、电化学阻抗谱（EIS）技术、动电位扫描极化曲线测定实验和氢渗透实验等研究了海泥中SRB和极化电位对16Mn钢和管线钢X56（API X56）的SCC敏感性造成的影响。 从渤海海泥中富集得到SRB菌种，并做出了SRB在海泥中的生长曲线；在荧光显微镜下观察SRB为弧状，可以归为脱硫弧菌属，为革兰氏阴性菌；海泥中活性SRB数量与硫电位等主要腐蚀环境因子具有一定的对应关系。 SSRT结果表明，施加阴极极化电位可以使试样断裂脆性特征明显，SCC敏感性增大；海泥中活性SRB浓度越高，断裂脆性特征越明显，SCC敏感性越大。在含SRB海泥中或阴极极化电位条件下，两种钢都容易发生SCC，氢脆（HIC）起主要作用。 随着浸泡天数的增加，试样在灭菌海泥中的Rp一直增大；在含SRB海泥中Rp先增大，又变小，并呈现出显著的Warburg阻抗特征；在灭菌海泥中，两种试样在阳极电位范围内无SCC敏感区，而在阴极电位范围内有明显的SCC敏感区；在含SRB海泥中，在阳极电位范围和阴极电位范围内均有SCC敏感区；SRB代谢产物既有阳极去极化作用，又有阴极去极化作用，能使腐蚀电流密度增加。 活性SRB的存在能够促进试样在海泥中的氢渗透；在实海工程应用中，两种钢在含SRB海泥中的氢渗透电流密度大约是在不含SRB海泥中的3~4倍。阴极极化电位能够促进试样在灭菌海泥中的氢渗透。在含SRB海泥中对试样施加阴极极化电位，氢渗透电流密度大于不加阴极极化电位时的氢渗透电流密度，也大于在不含SRB的海泥中的氢渗透电流密度。

硫酸盐还原菌对海洋用钢腐蚀行为的影响及其控制

本文研究了海水和海泥环境中硫酸盐还原菌（SRB）对海洋用钢腐蚀行为的影响及控制，探讨了SRB影响下的腐蚀机制，腐蚀产物的形成及转化过程，并研究了含有SRB的海泥环境中阴极保护对钢腐蚀的影响。 从我国青岛胶州湾海底泥中富集培养出SRB，进行分子生物学分析确定了研究菌种为肠状菌属，并以荧光显微镜和透射电镜（TEM）观察了SRB的形貌特征。 以失重法、电偶腐蚀、交流阻抗（EIS）、电子探针（EPMA）、TEM等手段研究了海洋用钢在含有活性SRB的海泥和海水环境中，从最初的细菌附着到代谢产物导致腐蚀产物从氧化物到硫化物的转化，腐蚀产物的形貌及成分确定，对腐蚀由抑制到加速的过程。此外从钢基体与腐蚀产物界面角度对SRB点蚀的形成和扩展，以及单晶氧化铁立方体在SRB菌液中的生物矿化进行了探讨。 对埋在含有SRB海泥中的低碳钢的阴极保护的可靠性进行评价，重点研究活性细菌存在下不同阴极保护电位下的交流阻抗行为，并结合失重法测试不同电位下的腐蚀速度、MPN法细菌计数以得出保护电位、腐蚀速度以及细菌活性之间的关系。为达到有效的保护，-950mV (CSE)甚至更低的保护电位是需要的。较高保护电位下，细菌的生长活性与稳定性低于低电位。

铜管不锈钢管腐蚀性能及铁牺牲阳极保护研究

铜管一直是电厂凝汽器的主要应用管材，但由于其抗冲刷和抵御污染物腐蚀的能力差，特别不耐氨蚀，美国和欧洲大量使用不锈钢管替代铜管作为冷凝管，然而不锈钢管在我国的运用仅处于初步阶段。 常使用锌、铝阳极对铜管进行牺牲阳极保护，然而存在着电位差过大、阳极溶解过快的问题。铁基牺牲阳极与铜电位差适当、来源广泛、价格便宜，在一些工程上有所应用，但是目前针对铁基牺牲阳极的理论研究报道很少。 本文选用紫铜管、304不锈钢管作为实验用管材，首先运用实验室全浸实验、极化曲线和电化学阻抗研究了二者在海水和淡水中的腐蚀性能以及CO2、溶解氧对其腐蚀的影响。结果表明：CO2会加速二者的腐蚀，溶解氧却对它们的腐蚀影响不同，促进铜管的腐蚀却抑制不锈钢管的腐蚀；随浸泡时间的延长，紫铜管由于表面产物膜的生成耐蚀性提高，304不锈钢管的耐蚀性却降低；淡水中，304不锈钢管和紫铜管都具有很好的耐蚀性能。随后，运用失重法和极化曲线对比研究了紫铜管、304不锈钢管的氨蚀性能，运用SEM分析和电化学阻抗研究了紫铜在不同浓度氨溶液中的腐蚀机理。发现，304不锈钢管的耐氨蚀能力远远好于铜管；溶解氧是影响氨蚀的关键因素，其对二者氨蚀的影响也不同；紫铜管在低氨浓度和高氨浓度溶液中腐蚀机理和产物不同，低氨浓度时形成保护性的产物膜（CuO 和Cu(OH)2），高氨浓度时由活化溶解控制，生成可溶的[Cu (NH3)4]2+。 选用工业纯铁、35钢为牺牲阳极材料。恒电流实验结果表明它们具有良好的牺牲阳极性能；通过极化曲线和自腐蚀电位测试分析，认为将二者用于铜管牺牲阳极保护是可行的；实验室阴极保护效果测试表明，工业纯铁和35钢对紫铜管具有良好的保护效果，保护度达90%以上。

硫酸盐还原菌对海洋腐蚀行为的影响

本文通过使用多参数水质分析仪、循环伏安法、电化学阻抗法等测试手段研究了硫酸盐还原菌生长过程中硫酸盐还原菌数量、环境参数和碳钢腐蚀行为三者之间的关系；建立了一种有效的快速检测硫酸盐还原菌数量的方法并研究了其检测的机制；研究了硫酸盐还原菌对阴极氧还原反应的影响。 研究发现，硫酸盐还原菌生长过程对介质化学状态影响主要为在硫酸盐还原菌的新陈代谢过程作用下，硫离子浓度在增殖期快速增加，并在衰亡期和残余期保持不变，体系的还原性也与硫离子浓度同步变化。该介质中碳钢腐蚀行为与活性硫酸盐还原菌并无直接关系，主要取决于体系氧化还原性能。即在硫酸盐还原菌增殖期增强了阳极过程与腐蚀速度，并在硫酸盐还原菌衰亡期和残余期保持不变。 采用测定银电极的电极电位的方法可以检测体系中硫酸盐还原菌的数量，检测范围为50~10000ml-1，检测时间为2~3分钟。硫酸盐还原菌的吸附及其代谢生成硫离子的过程是导致银电极电位负移的原因。 在氧气饱和的3.5% NaCl溶液中，玻碳电极的阴极氧还原反应包括氧气一电子还原为超氧离子、氧气二电子还原为过氧化氢以及过氧化氢二电子还原为水分子三个步骤。硫酸盐还原菌催化了第一步和第二步反应中间产物超氧离子和过氧化氢的分解，从而使得阴极氧还原反应电流加大。

Hydrogen ion reduction in the process of iron rusting

Since the acceptance of the electrochemical rusting mechanism, oxygen reduction has been considered the main cathodic process, while H+ reduction has been overlooked for the past four decades because oxygen can be readily renewed due to the thin layer Of Solution film formed during atmospheric corrosion. This study shows that measurable hydrogen call be detected at the surface opposite to the corroding side of the specimen during wet-dry cycles, and a clear correlation exists between the quantities of hydrogen permeated through iron sheet and weight loss. Results Suggest the intrinsic importance of H+ reduction that merits further investigation. (c) 2004 Elsevier Ltd. All rights reserved.

Berberine as a natural source inhibitor for mild steel in 1 M H2SO4

Berberine was abstracted from coptis chinensis and its inhibition efficiency on corrosion of mild steel in 1 M H2SO4 was investigated through weight loss experiment, electrochemical techniques and scanning electronic microscope (SEM) with energy disperse spectrometer (EDS). The weight loss results showed that berbefine is an excellent corrosion inhibitor for mild steel immersed in 1M H2SO4. Potentiodynamic curves suggested that berbefine suppressed both cathodic and anodic processes for its concentrations higher than 1.0 x 10(-4) M and mainly cathodic reaction was suppressed for lower concentrations. The Nyquist diagrams of impedance for mild steel in 1 M H2SO4 containing berbefine with different concentrations showed one capacitive loop, and the polarization resistance increased with the inhibitor concentration rising. A good fit to Flory-Huggins isotherm was obtained between surface coverage degree and inhibitor concentration. The surface morphology and EDS analysis for mild steel specimens in sulfuric acid in the absence and presence of the inhibitor also proved the results obtained by the weight loss and electrochemical experiments. The correlation of inhibition effect and molecular structure of berberine was then discussed by quantum chemistry study. (c) 2005 Elsevier B.V. All rights reserved.

Characteristics of anodic coatings oxidized to different voltage on AZ91D Mg alloy by micro-arc oxidization technique

With increasing applied voltage, three types of anodic coatings, passive film, micro-spark ceramic coating and spark ceramic coating were made by micro-arc oxidization (MAO) technique on AZ91D magnesium alloy in alkali-silicate solution. The structure, composition characteristics and the electrochemical properties of coatings were also studied with SEM, XRD and EIS (electrochemical impedance spectroscopy) technique, respectively. It is found that the electrochemical properties are closely related to the structure and composition characteristics of the anodic coatings. At the same time, the characteristics of the three types of anodic coatings differ significantly, among them, the micro-spark ceramic coating, prepared in the voltage range of 170similar to220V exhibits compact, homogeneous structure and highest corrosion-resistance.

Relationship between the ennoblement of passive metals and microbe adsorption kinetics in seawater

The relationship between microbial colonization of two kinds of passive metals and ennobling of their corrosion potentials (E-corr) were studied. Two types of passive metal coupons were exposed to natural seawater for about ten days. Under laboratory conditions, all corrosion potentials of the samples ennobled for about 200 mV. Epifluorescence microscopy showed that bacteria adsorption was the main process during about the first day immersion and bacteria reproduced in the following days. The bacteria number increased on the metal surface according to an exponential law and the kinetics of bacteria adsorption at the metal surface during this period was proposed. The ennoblement of E-corr was similar to the increasing bacteria number: E-corr increased quickly during the bacteria adsorption process and increased slowly after biofilms had formed.

The synergy between deformation and anodic dissolution of an austenitic stainless steel in acidic chloride solution

In corrosion medium, metals can deform under tensile stress and form a new active surface with the anodic dissolution of the metals being accelerated. At the same time, the anodic dissolution may accelerate the deformation of the metals. The synergy can lead to crack nucleation and development and shorten the service life of the component. Austenitic stainless steel in acidic chloride solution was in active dissolution condition when stress corrosion cracking (SCC) occurred. It is reasonable to assume that the anodic dissolution play an important role, so it's necessary to study the synergy between anodic dissolution and deformation of austenitic stainless steels. The synergy between deformation and anodic dissolution of AISI 321 austenitic stainless steel in an acidic chloride solution was studied in this paper. The corrosion rate of the steel increased remarkably due to the deformation-accelerated anodic and cathodic processes. The creep rate was increased while the yield strength was reduced by anodic dissolution. The analysis by thermal activation theory of deformation showed a linear relationship between the logarithm of creep rate and the logarithm of anodic cur-rent. Besides, the reciprocal of yield strength was also linearly dependent on the logarithm of anodic current. The theoretical deductions were in good agreement with experimental results.

Grey interrelation analysis to assess the influence of elements on the galvanic efficiency of Al sacrificial anode

Grey interrelation analysis method was used to study the correlation of Al-anode elements and its galvanic efficiency at 20 degreesC, 40 degreesC and 60 degreesC. Twenty-eight kinds of Al-anodes were made for experiments by the method given by Chinese National Standard GB4948-85 [1] and the correlation degree of elements added in the anodes were calculated. The results showed that the order of elements affecting galvanic efficiency at different temperature is basically the same, and the correlation degree can reflect the variation of Al-anode galvanic efficiency when changing temperature. It is suggested that the elements being added in Al-anode are Zn, In, Ga, Mg.

Analysis of corrosive environmental factors of seabed sediment

The corrosivity of seabed sediment at spots at different distances from seashore was studied based on in situ investigations in the northern sea area of the Yellow River mouth. The results show that there is close relation between distance from seashore and corrosivity of seabed sediment.

Study on growth factors of intermetallic layer within hot-dipped 25% Al-Zn alloy coating on steel

25%Al-Zn alloy coating performs better than hot dip galvanized coating and 55%Al-Zn-Si coating with regard to general seawater corrosion protection. This study deals with the interfacial intermetallic layer's growth, which affects considerably the corrosion resistance and mechanical properties of 25%Al-Zn alloy coatings, by means of three-factor quadratic regressive orthogonal experiments, The regression equation shows that the intermetallic layer thickness decreases rapidly with increasing content of Si added to the Zn-Al alloy bath, increases with rise in bath temperature and prolonging dip time. The most effective factor that determined the thickness of intermetallic layer was the amount of Si added to Zn-Al alloy bath, while the effect of bath temperature and dip time on the thickness of intermetallic layer were not very obvious.

Pure mechanical wear loss measurement in corrosive wear

The method for the measurement of the pure mechanical wear loss for 321 stainless steel, 1045 steel and pure iron in the study of the synergy between corrosion and wear was studied, The methods studied included the measurement in distilled water, by cathodic protection and by adding inhibitor KI, and all were compared with the wear loss in air. The experiment showed that the pure mechanical wear losses and friction coefficients obtained by the three methods were close to each other and can be used to calculate the various wear components in the study of the interaction of corrosion and wear, but the measurements in distilled water for pure iron and 1045 steel are not recommended due to their corrosion.