研究了材料表面电荷对硫酸盐还原菌 (SRB) 初始附着行为的影响。分别将6-胺基-1-己烷硫醇，6-巯基-1-己醇和6-巯基己酸修饰在Au电极表面，形成不同荷电状态的自组装膜 (SAMs)。用电化学阻抗 (EIS) 和扫描电子显微镜 (SEM) 监测SRB在3种SAMs表面的附着。结果表明，荷正电的SAMs表面有利于SRB的初期附着，而荷负电的SAMs表面则会抑制SRB初期附着并使其可逆附着过程的时间延长。另外，3种表面的电荷转移电阻变化率 (?Rct%)可在一定程度上反映SRB的初期附着情况。
Sulphate-reducing Bacteria (SRB) is the most popular corrosive microorganisms in marine environment and their initial adhesion on materials is an important stage of microbiological induced corrosion (MIC). Three kinds of thiol molecules, 6-Amino-1-hexanethiol, 6-Mercapto-1-hexanol and 6-Mercaptohexanoic acid, were applied onto the Au surface, forming three kinds of self-assembled monolayer films (SAMs), which were positively charged, electrically neutral and negatively charged at pH 7.4 respectively. Then the influence of surface charge of SAMs on SRB adhesion was investigated by measurement with electrochemical impedance spectroscopy (EIS) and observation with scanning electron microscopy (SEM). On the positively charged surface the initial adhesion of SRB was promoted, while on the negatively charged surface the process was inhibited and the reversible adhesion time was prolonged. Moreover, the change rate of charge-transfer resistance (?Rct%) may be adopted as an index of the tendency of SRB adhesion to a certain extent.
The influence of post-sealing treatment on corrosion behavior of anodized 2195 Al-Li alloys was studied by potentiodynamic polarization, Electrochemical Impedance Spectroscopy (EIS), salt spray test and immersion test in solution of phosphoric acid/chromic acid. The anodic films were post-treated with boiling water, potassium dichromate, nickel sulfate and cerium nitrate, respectively. The results show that the post-sealing can greatly enhance the corrosion resistance of the anodized 2195 Al-Li alloy. The corrosion resistance of the anodic oxide film after post-treatment with cerium nitrate is far better than that with boiling water, but slightly inferior to those with potassium dichromate and nickel sulfate. Finally long term spray test results reveal that the anodized 2195 Al-Li alloy after sealing treatment with potassium dichromate exhibits the highest corrosion resistance among the four post-sealing treatments.
采用铂片微排电极研究了硫酸盐还原菌 (SRB)生物膜在有无磁场环境下的电化学行为。结果表明：无磁场下铂片电极表面覆盖一层很厚的生物膜，通过显微镜观察厚度为141.4 μm，生物膜电阻较大，生物膜脱吸附过程进行时间较长，生成的腐蚀性产物较多。磁场存在下SRB细菌不容易在铂片电极表面吸附，进而形成的生物膜较薄 (厚度为67.06 μm)，生物膜在很短时间内达到了脱吸附平衡状态，从而生物膜内腐蚀性物质较少，对基体的腐蚀作用较弱。电荷传质电阻Rct表明，磁场的引入极大地阻碍了电极表面电荷的运动，从而影响了电化学过程的顺利进行。
The electrochemical behavior of sulfate-reducing bacteria (SRB) biofilm was investigated by means of micro electrode of platinum in the absence and presence of a static magnetic field (SMF) respectively. The results showed that a 141.4 μm thick biofilm with high resistance (Rf) was form on the surface of Pt metal in the absence of SMF, and the process of adsorption and desorption of the biofilm took a long time resulting in corrosion products on the Pt foil surface. In the presence of SMF, it was hard to adsorb on the surface Pt foil for SRB and the biofilm was thinner (the thickness was 67.06 μm). The?adsorption and desorption of the later biofilm proceeded rapidly and reached an equilibrium state after short time indicating that little amount of corrosion products was generated in the biofilm, which means that the corrosion rate of the metal beneath the biofilm is lower. The value of charge transfer resistance (Rct) suggested that the applied SMF might greatly suppress the movement of surface charge, thus affect electrochemical process.
通过分析不同粗糙度下的316L不锈钢在0.01 mol/L NaCl溶液中小孔腐蚀早期的电流波动，研究了粗糙度与不锈钢亚稳态孔蚀电位Em和稳定孔蚀电位Eb之间的关系，以及粗糙度 (Ra) 对亚稳态小孔生长机制的影响。结果表明，Em和Eb均随Ra的对数的增大而线性下降；Ra增大，亚稳孔的平均形核率和平均寿命增大，生长速率变化不大，但是同样的生长速率下粗糙表面的亚稳孔具有更强的可持续生长能力，加之高的形核频率导致强的腐蚀累积效应促进了亚稳态小孔向稳定孔的转变。
The influence of the surface roughness (Ra) on the metastable pitting potential (Em) and the stable pitting potential (Eb) as well as on the growth mechanism of metastable pittings was studied by analyzing the current fluctuations at the early stages of pitting corrosion for 316L stainless steel with three level of surface roughness. The results show that as lgRa increases both Em and Eb values decrease linearly. With the increase in surface roughness, the average nucleation rate and lifetime of metastable pits decrease while its growth rate shows little change. But by the same growth rate the metastable pits on the steel with larger surface roughness has bigger sustained growth ability, which in combination with the accumulated corrosion damage resulted from high nucleation rate may be beneficial to the transformation of metastable pits into stable pits.
采用硅藻土模拟土壤实验室加速腐蚀法研究了接地网材料Q235钢在10%~50%含水率条件下埋置15 d的腐蚀行为。结果表明，土壤含水率对Q235钢腐蚀行为影响显著，随含水率的增加，腐蚀速率呈现先快后慢的趋势；低含水率 (10%) 时，Q235钢发生全面腐蚀；随含水率升高，腐蚀形态由全面腐蚀转化为不均匀腐蚀，当含水率为30%时，腐蚀速率达到最大。对腐蚀锈层进行XRD分析，腐蚀产物主要是α-FeOOH、γ-FeOOH、Fe3O4和Fe2O3，与实际土壤腐蚀产物一致，针状的α-FeOOH所占比例较大。
The corrosion behavior of a grounding material Q235 steel was investigated in an artificial acid soil made of diatomite. Steel coupons were buried for 15 d in the artificial soil with different water contents in a range 10% to 50%. The results indicated that the water content had a great effect on corrosion behavior of Q235 steel. The corrosion rate of the steel increased initially and then reduced with the increasing water content. General corrosion occurred for the steel in the soil with 10% water. With the increasing water content in the soil the corrosion of the steel changed to local corrosion. The steel exhibited the highest corrosion rate in a soil with 30% water. XRD analysis of the corrosion rust layer showed that the corrosion products were mainly composed of α-FeOOH, γ-FeOOH, Fe3O4 and Fe2O3，which were consistent well with those detected for the steel buried in actual fields.
通过高温高压鲜酸 (10%HCl+1.5%HF+3%HAc+5.1%TG201缓蚀剂)、残酸、地层水CO2腐蚀实验及电化学分析，研究TP140钢在苛刻工况条件下的耐蚀性。结果表明：TP140钢在鲜酸、残酸和地层水CO2腐蚀实验条件下，其均匀腐蚀速率分别为3.7490，0.4361和0.5524 mm/a。残酸实验后，试样表面存在不完整Cu膜。未去除Cu膜的TP140钢试样的自腐蚀电位 (-658 mV) 高于去除Cu膜的TP140钢试样的 (-692 mV)，腐蚀驱动力小，但其自腐蚀电流密度 (3.1141×10-5 A/cm2) 明显高于去除Cu膜的 (1.0926×10-5 A/cm2)。相比于TP140钢基体 (Fe)，Cu为正电性金属，膜的覆盖不致密形成典型的大阴极-小阳极结构，导致严重的局部腐蚀。TP140钢在鲜酸、残酸和地层水CO2腐蚀实验条件下，试样表面最大点蚀深度可达150 μm。
The corrosion behavior of TP140 steel was investigated based on the corrosion tests in such severe conditions as the live acid solution (15%HCl+1.5%HF+3%HAc+5.1% inhibitor), spent acid and formation water containing CO2 corrosion with high pressure and high temperature. Also the electrochemical analysis was used to evaluate the corrosion resistance of TP140 in these environments. The results show that the uniform corrosion rate of TP140 in live acid solution, spent acid and formation water containing CO2 environment is 3.7490, 0.4361 and 0.5524 mm/a respectively. After spent acid corrosion, an incomplete Cu film is formed on the surface of the sample. The corrosion potential (-658 mV) of TP140 sample without removing the Cu film is higher than that (-692 mV) of the sample with removed Cu film, which results in the corrosion driving force of the former is weaker than that of the latter. However, the self corrosion current density (3.1141×10-5 A/cm2) of the sample without removing the Cu film is significantly higher than that (1.0926×10-5 A/cm2) of the specimen with removed Cu film. Compared with the TP140 matrix of Fe, Cu is electropositive metal. So a typical large cathode-small anode structure because of incomplete Cu film is formed, which leads to serious local corrosion. The maximum depth of the corrosion pittings in these tests is up to 150 μm.
采用pH值为2.5，3.5和4.0的草酸溶液，对红黏土水泥土复合体试样进行了长期浸泡 (200 d)，通过观测浸泡过程中，试样外观和耗酸量随时间的变化，分析了草酸对红黏土水泥土复合体的腐蚀和作用机理。结果表明：草酸对红黏土水泥土复合体的侵蚀为一个分解和重结晶过程，复合体中水泥水化产物和Fe2O3被分解，重结晶生成难溶的草酸钙 (CaC2O4) 和草酸亚铁 (FeC2O4)，最终使红黏土水泥土复合体中的骨架连接物由水泥水化产物转换为草酸钙和草酸亚铁。
Long-term immersion (200 d) test of red clay-cemented soil composite was carried out in oxalic acid aqueous solutions with pH value of 2.5, 3.5 and 4.0. Through monitoring the changes of acid consumption and the variation of appearance of the test composite with time to reveal the corrosion behavior and the relevant mechanism of red clay-cemented soil composite in the oxalic acid. Results shows that the corrosion of the composite in the oxalic acid is a process related closely with sub-processes of decomposition and recrystallization, i.e. the hydration products of cement and Fe2O3 in the red clay-cemented soil composite are decomposed and then recrystallized into indissolvable CaC2O4 and FeC2O4, and finally the skeleton like connectors of the red clay-cemented soil were transformed into other products such as calcium oxalate and ferrous oxalate.
The influence of CO2 concentration on corrosion behavior of X80 pipeline steel in a simulated soil solution of Ku'erle area was investigated by potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS) and weight loss, and then the corroded surface morphology was observed using scanning electron microscopy (SEM). It was found that the corrosion rate of X80 steel increased with increasing the volume proportion of CO2 to N2 in the aerated gaseous flow in the simulated solution. It follows that the pH value of the solution could be decreased from 9.1 to 4.7 by inducing CO2; therewith the control step of cathodic process of steel corrosion was transferred from the oxygen reduction to hydrogen reduction, which then resulted in the increase of cathodic reaction rate. On the other hand, defects in the corrosion product film also increased due to the presence of CO2, thus exhibited lower protectiveness to X80 steel. The above two factors all promote the corrosion of X80 steel in the simulated solution.
研究了烟酸体系镀银高择优取向镀层制备工艺条件与沉积速率和电流效率的关系。通过XRD测试镀层结晶的择优取向、结晶度、晶粒尺寸，称量法测试电流效率和沉积速率，随着AgNO3浓度的提高晶粒尺寸不断增大，在 (111) 晶面择优取向先减小后增大，电流效率和沉积速率不断增大。随着导电盐K2CO3浓度的提高，晶粒尺寸不断增大，但是当K2CO3浓度达到95 g/L时，晶粒尺寸增大趋势减小，在 (111) 晶面的择优取向先减小后增大；电流效率和沉积速率先增大，在K2CO3浓度达到95 g/L时开始减小。
Effect of processing parameters on the deposition rate and current efficiency as well as on the texture was studied of silver coating on stainless steel 316L prepared by electroplating in a cyanide-free bath. The crystallization degree and the grain size were determined by using XRD. The results show that the current efficiency, deposition rate and grain size all increase with the increasing silver nitrate concentration in the bath. On the other hand, the grain size also increases with the increasing potassium carbonate concentration, however until the potassium carbonate concentration is up to 95 g/L, the grain size starts to decrease again. The current efficiency and deposition rate show the same variation tendency as the grain size. In the contrast, the tendency of preferential orientation of crystal plane (111) increases firstly and then decreases with the increasing potash concentration.
采用静态挂片和极化曲线测试技术研究了铜铁试剂对Q235碳钢在3.5%NaCl溶液中的缓蚀作用。结果表明，碳钢在3.5%NaCl溶液中腐蚀严重，主要为活性溶解，并且伴有明显的点腐蚀。铜铁试剂的加入促进了碳钢的阳极钝化，当铜铁试剂的含量为12.8 mmol/L时缓蚀效率达到90%以上，当铜铁试剂浓度增大为19.2和25.6 mmol/L时，缓蚀效率不变。铜铁试剂主要通过在Q235碳钢的表面吸附实现对Q235碳钢的缓蚀。
The corrosion inhibition of Q235 carbon steel in 3.5%NaCl solution by cupferron was investigated by means of static immersion test and electrochemical experiments. The results indicated that Q235 steel suffered from serious corrosion with a characteristic of active corrosion, and obvious pits were observed after immersion. Cupferron promoted the passivation of Q235 steel in 3.5%NaCl solution, and the inhibition efficiency was approximately 90% when the concentration of cupferron was up to 12.8 mmol/L. The inhibition efficiency almost maintained constant when the concentration of cupferron increased up to 19.2 and 25.6 mmol/L. The inhibition effect of cupferron was mainly resulted from the adsorption on the steel surface.
The intergranular corrosion susceptibility of HR3C steel aged at 600 ℃ was investigated by electrochemical double-loop potentiodynamic reactivation (EPR), scanning electron microscopy with energy dispersive spectroscopy. Experimental results show that intergranular corrosion occur due to the precipitation of M23C6 along grain boundaries, and the amount of precipitates play an important role. With the change of aging time, the morphology of M23C6 precipitates formed along grain boudaries and the precipitating rate of M23C6 varied accordingly. At the initial stage precipition of M23C6 along grain boundaries occured rapidly, which leads to the increase of intergranular corrosion susceptibility. With the increase of aging time, the amount of M23C6 precipitates increased steadily, resulting in a steady increase of intergranular corrosion susceptibility. It is found that the variation of intergranular corrosion susceptibility can be correlated with the amount of M23C6 precipitates.
The corrosion thickness loss of a Ni-containing weathering steel and a common low-alloy steel Q420 was comparatively studied, by means of a dry-wet cyclic immersion test, which aims to simulate the atmospheric environment at coastal area. SEM and Raman spectroscopy were used to characterize the morphology, microstructure and phase composition of the formed rust scales. The results show that Ni has an important impact on the structure of weathering steel rust scale; the rust scale on weathering steel exhibits layered structure with an inner layer consisted mainly of α-FeOOH, which seems to be stacked with small clusters resulting in a compact layer with good continuity and protectiveness. Besides the formed rust scale is strongly adhesive to the steel substrate so that to ensure the integrity of the rust scale during exposure in coastal environment with high salt content. In the contrast, the rust oxide scale on Q420 steel is so loose and porous with large sized grains of γ-Fe2O3 and Fe3O4 hence its corrosion resistance is very poor. Furthermore, a relatively flat interface may not be favorable to the adhesion between the rust layer and Q420 steel substrate.
在介绍硫化物应力破裂 (SSC) 和氢致开裂 (HIC) 的研究方法的基础上，阐述了湿H2S环境中介质因素，材料因素，管道因素对输气管道内腐蚀的影响。建议进一步开展H2S和CO2共存条件下的腐蚀研究和流场作用下的H2S腐蚀研究并制定硫化物应力腐蚀开裂 (SSCC) 实验标准。为合理的管道运行参数选择，管道选材及腐蚀寿命预测提供参考。
热镀锌是输变电钢构件普遍使用的大气防腐方法，其防腐效果主要取决于大气环境条件。调查结果显示，输变电钢构件热镀锌的首次防腐维护时间主要集中在20 a之内，以后的防腐维护间隔周期为3~11 a，平均5.5 a；在工业及沿海，首次维护的周期一般低于10 a。频繁的周期维护大幅度增加了运行成本。分析认为，在高湿多雨和硫污染严重地区，输变电钢构件不宜采用单一热镀锌作为初建防腐方法。为实现全寿命周期成本的最优化，应在工程设计之初对工程环境腐蚀性进行评价，优化选择新型防腐技术替代单一热镀锌，以延长维护周期，直至实现全周期免防腐维护。