直流匀强电场作用下镍钛合金的高温变形行为

在600℃和较低应变速率下进行NiTi合金的拉伸实验,研究了拉伸过程中外加电场(E=1 kV/cm)对其高温变形行为的影响。采用金相显微镜和扫描电镜对材料的微观组织进行分析。结果表明:外加电场可有效降低NiTi合金的屈服强度和塑性变形的流动应力,提高断裂延伸率;同时外加电场有效地抑制了NiTi合金在塑性变形过程中空洞的形成。在600℃,2.6×10-2s-1下,不加电场进行拉伸,得到应力—应变曲线的周期性波浪曲线,而在同样条件下施加电场时,动态再结晶与应变硬化同时发生,形成稳态的流动曲线。研究认为,施加电场促进了NiTi合金高温塑性变形时的位错运动。     

电场提高激光-TIG复合焊熔深的机制

通过对比电场对单激光和单TIG焊接电弧在镁合金板材上堆焊熔深的影响,分析了外加电场对激光-TIG复合焊熔深的影响机制.同时通过研究在不同激光功率、不同TIG电流强度下电场的作用效果,对该机制进行了验证.结果表明,外加电场对激光-TIG复合焊熔深的作用是通过对激光小孔内等离子中带电粒子运动的控制来实现的.外加电场使小孔内电子向小孔底部运动时,可以增加焊接熔深;激光功率越大,外加电场增加熔深效果越明显;增大TIG焊接电流,削弱外加电场对熔深的增加作用.     

钙离子对碳钢微生物腐蚀的影响

利用原子力显微镜、电子探针和电化学测试等技术，研究了Ca^2 离子对碳钢表面生物膜的形成、微生物腐蚀程度以及杀菌剂杀菌效果的影响．结果表明：Ca^2 离子促进了硫酸盐还原菌(SRB)的生长，增加了生物膜的致密性，降低了碳钢微生物腐蚀的敏感性．但同时也增加了SRB对杀菌剂的敏感性，给防治SRB带来更大困难。     

外加电场对合金凝固组织的影响

综述了外加电场对合金凝固组织影响的研究现状,分析总结了外加电场对合金凝固过程和凝固组织的影响机理。在此基础上,讨论了目前外加电场影响合金凝固研究中存在的问题,初步探讨了这一方法的研究方向和应用前景。     

应力促进PZT铁电陶瓷的电致滞后断裂

用单边缺口拉伸试样研究了外加应力强度因子对PZT-5铁电陶瓷电致瞬时断裂以及在硅油中电致滞后断裂的影响。结果表明，在硅油中发生瞬时断裂的临界电场强度EF随外加应力强度因子KI的升高而线性下降，外加正、负恒电场在硅油中能发生滞后断裂，外加KI则促进电致滞后断裂，电致滞后断裂的门槛电场EDF随KI升高而线性下降，且和电场符号无关，外加应力促进恒电场下的滞后断裂表明，应力、电场和环境对铁电陶瓷的断裂存在耦合作用。     

极化电位对X70钢在含SRB海洋环境中电化学行为的影响

采用光密度法研究了极化电位对硫酸盐还原菌(SRB)生长周期的影响,并结合电化学阻抗谱研究了不同极化电位对X70钢在含SRB的模拟海水中电化学行为的影响。结果表明,无外加电位时,SRB生长周期分为对数生长期和衰亡期两个阶段,在第7 d时SRB数量达到最大值。在外加阳极电场的刺激下,SRB繁殖被抑制,且在进入对数生长期后迅速死亡。在外加阴极电场的作用下,SRB的有丝分裂周期缩短,细胞分裂速度提高,从而促进SRB的繁殖;然而阴极电场同样也加速了SRB的死亡。在SRB的生长期,X70钢在海洋环境中最佳阴极保护电位为-0.85 V(SCE)。当SRB进入死亡期后,由于SRB代谢出的大量H_2S的存在,阴极极化促进了析氢腐蚀。     

生物膜在B30合金微生物腐蚀中的作用

采用电化学阻抗谱、扫描电镜和X射线能谱分析等技术研究了硫酸盐还原菌（SRB）作用下B30合金表面生物膜的结构及其对合金微生物腐蚀的影响.结果表明，在接种了SRB的培养基中，金属表面很快形成一层含有铜的硫化物的生物膜；该生物膜疏松多孔，没有保护作用;生物膜下的氧化膜被破坏，阳极过程加快，有Cu的选择性溶解和Ni的富集现象.     

外加直流电场条件下熔渣电场分布的数值模拟

为探究外加直流电场条件下熔渣电场的分布规律,运用COMSOL数值模拟软件建立了模拟熔渣外加电场模型,研究了外加电压、电极直径、电极插入深度、熔渣介电常数等参数对熔渣电场分布和系统电场能量的影响。结果表明:模拟结果符合电场线的分布规律,表明用该模型模拟外加直流电场条件下熔渣的电场线分布是可行的;随着外加电压、电极直径和电极插入深度的增加,系统的电场能量和电场强度均增大。而随着熔渣介电常数的增加,系统电场强度降低,电场能量增加。     

磁场作用下的微生物腐蚀研究进展

磁体周围存在磁场,磁体间的相互作用就是以磁场作为媒介的,磁场力包括洛伦兹力和安培力.概述了磁场对微生物和金属腐蚀过程的影响,包括对单一细菌和混菌体系、电化学控制和浓差极化控制的电化学过程的影响.归纳了磁场作用于微生物金属腐蚀的防控方法,包括微生物竞争手段、缓蚀杀菌剂的应用以及存在的不足等问题.在此基础上,重点综述了近年来磁场条件下金属微生物腐蚀的研究进展,分析了磁场对于微生物生长特性和生物膜形成的影响,分别以不同微生物存在的体系、电化学过程控制的类型等方面展开详细讨论.针对磁场存在的环境,总结了微生物对金属的腐蚀机理,包括生物膜理论、离子干涉理论、自由基理论等.最后结合磁场对金属腐蚀过程的相关机理,展望了后续磁场对微生物腐蚀防控的研究方向.     

电场诱导Fe-Ti-C系燃烧合成：电流对合成产物的影响

采用Gleeble-1500D热模拟试验机，利用电场诱导Fe—Ti—C体系发生燃烧合成反应，并研究了外加电流对合成产物的影响。对产物进行了X射线衍射（XRD）和扫描电镜（SEM）等分析。结果表明：产物中均存在TiC相，而少量的Fe2Ti相仅存在于特定的阶段：随着外加电流的增加，颗粒的平均尺寸也发生不同程度的减小。外加电场能够促进反应物粒子的固相扩散和形核长大，并最终影响合成产物的物相组成和颗粒尺寸。     

铜离子杀菌剂灭活SRB的研究

通过静态的SRB培养实验,考察铜离子最低杀菌浓度与水样初始菌量的关系;铜离子最低杀菌浓度与作用时间的关系;铜离子和其它三种杀菌剂在单项或不同组合情况下对水样中SRB杀灭效果。实验结果表明,最低杀菌浓度随初始菌量的增大而增大;杀菌剂与水样的接触时间90min最佳;与其它杀菌剂相比,铜离子对SRB的灭活效果更好,当铜离子和其它杀菌剂共同作用时,协同作用效果不明显。     

SRB生物膜与碳钢腐蚀的关系

利用间歇式方法培养硫酸盐还原菌（ＳＲＢ）并制备ＳＲＢ生物膜,研究表明,随着细菌的生长,细菌代产物改变了介质的ＰＨ,生物膜百度增加,膜中含菌量升高。在３％ＮａＣｌ水溶液中,覆盖有不同生长期生物膜的碳钢试片的腐蚀速度有明显的差异;电子能谱对生物膜表面分析结果表明,不同生长期生物膜腐蚀产物的Ｆｅ／Ｓ比各不相同。为了验证生物膜中主要腐蚀因素,利用化学方法在试片表面沉积ＦｅＳ膜,利用细菌滤膜隔离ＳＲＢ,在度     

硫酸盐还原菌杀菌剂应用现状及研究进展

综述了硫酸盐还原菌常用杀菌剂应用现状及研究进展,针对目前存在的关键问题,如对环境生态的破坏性、对抗药菌的防治、对生物膜内微生物的抑制等,提出研究开发符合现场实际需要的新型杀菌剂,必须以微生物生长代谢机理及相应杀菌剂杀菌机理的研究为指导,弄清杀菌剂的作用机理、结构与性能之间的关系等。同时,对于微生物腐蚀的防治,还应从环境保护的角度考虑,寻找基于微生物自身特点的防治方法,以及开发环境毒性低的高效杀菌剂。     

BZ25-1油田生产水处理系统SRB控制初探

为满足BZ25-1油田注水水源中硫酸盐还原菌(SRB)的指标要求,进行了现场SRB分布及生长规律统计和化学药剂筛选,并研究硫化氢浓度、硫离子浓度、总铁离子浓度、硫酸根离子浓度对杀菌剂作用效果的影响,设计了杀菌剂注入方案.建议对该区块的SRB控制进行生物竞争抑制技术试验.     

Electrochemical analysis of the microbiologically influenced corrosion of steels by sulfate-reducing bacteria

The differences between the general corrosion and microbiologically influenced corrosion (MIC) of steels were investigated in terms of its electrochemical behavior and surface phenomena. The corrosion potential of steels in the absence of SRB (sulfate-reducing bacteria) shifted to a negative value with the immersion time. However, the potential of the presence of SRB shifted to a positive value after 30 days' incubation, indicating the growth of SRB biofilms on the test metal specimens and the formation of corrosion products. In addition, the color of a medium inoculated with SRB changed from gray to black. The change in color appeared to be caused by the formation of pyrites (FeS) as a corrosion product, while no significant change in color was observed in a medium without SRB inoculation. Moreover, corrosion rates of various steels tested for MIC were higher compared to those of steels in the absence of SRB. In particular, the corrosion current density of TMCP steels in the presence of SRB was larger than that of other steels. Pitting corrosion was also observed at the surface of all steels in the SRB-inoculated medium. The pitting corrosion likely occurred due to SRB that was associated with the increasing corrosion rates through increasing cathodic reactions, which caused a reduction of sulfate to sulfide as well as the formation of an oxygen concentration cell.     

Effects of SRB on cathodic protection of Q235 steel in soils

The effects of sulfate reducing bacteria (SRB) on cathodic protection (CP) of the Q235 steel in the soils have been studied by bacterial analyses, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and energy‐dispersive X‐ray analysis (EDX). The results showed that the pH value of the soil around the steel gradually increased, the number of SRB and the corrosion rate of the steel decreased, and the CP efficiency increased with the increasing of applied cathodic potential. At the cathodic polarization potential of ?1050 mV, SRB still survived in the soils. At the same potential, the CP efficiency in the soil without SRB was higher than that with SRB, and the corrosion rate of the steel in the soil with SRB was much higher than that without SRB. The cathodic current density applied for the steel in the soil with SRB was bigger than that without SRB at the same cathodic potential.     

含硫酸盐还原菌土壤中阴极保护对Q235钢腐蚀的影响

利用交流阻抗测试技术、扫描电镜及表面能谱、微生物分析等方法，研究了阴极保护对土壤中Q235钢硫酸盐还原菌腐蚀的影响.30天的实验结果表明，在相同的阴极极化电位下，有菌土壤中Q235钢所需要的阴极极化电流密度均大于灭菌土壤，有菌土壤中Q235钢的平均腐蚀速率均大于灭菌土壤.随着阴极极化电位负移的增大，有菌及灭菌土壤中Q235钢试件周围土壤逐渐呈碱性，有菌土壤中Q235钢试件周围土壤中硫酸盐还原菌数量逐渐减少，当阴极极化电位为-1050 mV时，Q235钢试件周围土壤中硫酸盐还原菌仍能够存活.     

Study on biological control of microbiologically induced corrosion of carbon steel

A strain of Thiobacillus Denitrificans (TD) isolated from the soil was selected to reduce the corrosion caused by Sulfate Reducing Bacteria (SRB). The optimal pH was determined as 7.0 for the growth of TD. The growth environment of TD was found to be similar to that of SRB. Thus they can be cultured together. When they were grown together, it was observed that TD reduced the corrosion caused by SRB, being attributed to that TD might consume corrosive sulfides produced by SRB and restrict the SRB biofilms from accumulation. Scanning probe microscopy observations ex‐situ demonstrated that the topography of mixture biofilm formed in the mixed culture of TD and SRB was more compact than that for SRB along. Therefore, the process of charge transfer is baffled, leading to a decrease of the corrosion caused by SRB.     

The hydrogen permeation investigation of API X56 steel in sea mud

It was found that the corrosion rate of steel in the sea mud with sulfate‐reducing bacteria (SRB) could be as high as 10 times of that in the sea mud without SRB. And the hydrogen permeation reaction would occur when metals were corroded. So it is necessary to investigate the effect of living SRB on hydrogen permeation in the sea mud. Cathodic potential was often added to metals in order to protect them. But hydrogen permeation could be affected by the cathodic potential. So it is also necessary to study the effect of cathodic potential on hydrogen permeation. In this paper, the hydrogen permeation actions of API X56 steel in the sea mud with and without SRB at corrosion and cathodic potential were studied with an improved Devanathan‐Stachurski's electrolytic cell. Experimental results showed that during the growth of SRB, the current density curve of hydrogen permeation was accordant with the growth curve of SRB. But the hydrogen permeation current density of API X56 steel hardly changed in the sterilized sea mud. Compared with the hydrogen permeation current density of API X56 steel in the sterilized sea mud, the hydrogen permeation of API X56 steel in the sea mud could be accelerated by living SRB. Experimental results also showed that the hydrogen permeation current density increased rapidly when the cathodic potential was added to the three‐electrode system of the cathodic cell, and then the hydrogen permeation current density could obtain a stable value slowly. So the cathodic potential added to the cathodic cell could accelerate hydrogen permeation.