共查询到17条相似文献,搜索用时 140 毫秒
1.
2.
3.
对比了电偶对材料的自腐蚀电位和各自的极化曲线,以及同一阴阳极面积比下,偶接后的混合电位和电流密度,研究了09MnNiDR和不锈钢(316L、304冷轧板、304热轧板、201)电偶对在3.5%的Na Cl溶液中的电偶腐蚀特性。结果表明,09MnNiDR处于活化状态,4种不锈钢则比较稳定;不锈钢的自腐蚀电位高于09MnNiDR,偶接后不锈钢作为阴极被保护,而09MnNiDR作为阳极腐蚀加剧。电偶腐蚀效应的大小为:09MnNiDR/316L09MnNiDR/20109MnNiDR/304热轧板09MnNiDR/304冷轧板。 相似文献
4.
1电偶腐蚀的影响因素(1)面积效应(阴极和阳极之间的面积比)是电偶腐蚀的一个重要因素,对腐蚀速度有着重大的影响,随着阴极对阳极面积比的增大,阳极金属的腐蚀增大。(2)氯化钠浓度低于1%时,腐蚀速度随其增高而增大;等于1%时,腐蚀速度达到最大值;高于1... 相似文献
5.
6.
7.
研究土壤中Cl-质量分数对金属材料的腐蚀影响,选出在不同环境下与石墨基柔性接地装置搭配使用的金属材料接地引下线的最优材料种类.进行土壤埋片试验和电化学试验,研究镀锌钢、304不锈钢、铜金属材料在不同Cl-离子质量分数的土壤中以及在与石墨基柔性接地带偶接后的腐蚀行为.在腐蚀发生后利用金相显微镜观察金属材料腐蚀前后的形貌.结果表明:随着土壤介质中Cl-质量分数的增加,土壤介质的导电性逐渐增大,金属材料的腐蚀速度逐渐加快,石墨材料与金属材料偶接后,高电位的石墨材料对镀锌钢金属材料的腐蚀影响较为显著,而对304不锈钢的腐蚀影响较小.因此,在石墨基柔性接地装置中不宜选用镀锌钢材料用作接地引下线,可选用304不锈钢或不锈钢与石墨材料复合接地引下线. 相似文献
8.
根据川东北元坝气田油套环空中存在腐蚀介质的现状,模拟开展了各种因素对钢片腐蚀行为的研究,并探讨了相关腐蚀机理。实验结果表明:Cl-会导致钢材表面保护膜致密性降低,钢片腐蚀速率随[Cl-]上升而增加;硫酸盐还原菌等细菌存在一个最佳活性温度,形成局部电池腐蚀钢片;当温度为160℃时溶解氧对钢片腐蚀速率达到0.734 mm/a;环空材质之间电偶腐蚀受电极面积比影响,但总体上腐蚀速率较低;CO2/H2S对钢片存在腐蚀敏感区域为60~80℃,钢片腐蚀速率随酸性气体压力增大而增加。 相似文献
9.
10.
11.
《Desalination》1987
Galvanic currents and potentials have been measured for bimetallic couples involving carbon steel, three grades of stainless steel, 90 Cu/10 Ni and titanium when exposed to seawater in the laboratory at temperatures of 18C and 60C and varying oxygen content. The galvanic currents flowing between couples consisting of two of the corrosion-resistant materials were very small. The galvanic corrosion rate of carbon steel, when connected to one of the other materials, was dependent upon the cathodic-polarisation characteristics of the noble-material surface with indications that, at a given area ratio, the galvanic corrosion of carbon steel was greater when coupled to the 90 Cu/10 Ni alloy than when connected to stainless steel or titanium. The usual effects of increasing the anode/cathode area ratio were observed and data were obtained to demonstrate quantitatively the significant beneficial effect of coating the cathode in a bimetallic couple. Intermediate air exposures were not found to promote any large, long-term, effects on galvanic corrosion. There was evidence that galvanic corrosion rates were very small when the dissolved oxygen content was controlled at low levels and some interesting aspects of galvanic corrosion at the higher temperature were noted. 相似文献
12.
The changes in the anode and cathode potentials in the horizontal plane of a phosphoric acid fuel cell (PAFC) under starving conditions for either air or fuel were studied using a single cell furnished with twenty-four reference electrodes which were located around the anode or the cathode. When air starvation occurred, both the anode and cathode potentials became nearly 0 V against RHE, and hydrogen generation began to occur on the cathode side. Fuel starvation occurred when fuel utilization became more than 95%, and the cathode potential in the fuel outlet area shifted significantly toward the positive and, simultaneously, CO and CO2 were detected in the air exhaust gas, indicating the occurrence of carbon corrosion of the cathode components. By further increasing the fuel utilization, the cell voltage changed to negative and the anode potential in the fuel outlet area became the highest. At that time, significant amounts of CO and CO2 were detected in the fuel exhaust gas, indicating the occurrence of carbon corrosion of the anode components. Immediately after the termination of fuel starvation, the cathode potential in the fuel outlet area shifted quickly and remarkably toward the positive, and exceeded 1 V against RHE in a few seconds. 相似文献
13.
A new occluded corrosion cavity (OCC) simulation cell was designed to study the underscale corrosion behavior of carbon steel
(N80) in 0.2 mol L−1 NaCl solution. The chemical components of the solution in the OCC were measured and the electrochemical behavior of the occluded
anode and the bulk cathode were studied by electrochemical impedance spectroscopy (EIS). The newly designed OCC cell can easily
simulate the auto-catalyzing acidification process and may be used to study the mechanism of underscale corrosion. The corrosion
scale exacerbates the underscale corrosion and the area ratio of the bulk cathode to the occluded anode (R = Sc/Sa) determines the development of simulated localized corrosion in the OCC cell. When R was within a certain range, the corrosion rate in the OCC could be kept at a persistently high level. The pH of the solution
in the OCC decreased and the chloride ions (Cl−) concentrated as the local corrosion developed. The anodic process on the occluded anode was controlled by irreversible charge
transfer and the cathodic process on the bulk cathode was controlled mainly by oxygen diffusion. 相似文献
14.
15.
全有机系高效环保缓蚀剂的研制及电化学研究 总被引:1,自引:0,他引:1
以双咪唑啉季铵盐、D-异抗坏血酸钠、新洁尔灭、丙酮肟、EDTA二钠盐为主要缓蚀成分,通过正交挂片实验复配出一种高效、环保、全有机系盐酸复配酸洗缓蚀剂,缓蚀效率大于96%,静态腐蚀速度小于0.6g/(m2·h)。利用失重法、Tafel极化曲线和电化学交流阻抗法对复配缓蚀剂的缓蚀性能进行了研究。结果表明:复配缓蚀剂在盐酸酸洗工艺的温度范围内,具有良好的缓蚀效果,缓蚀率一直大于96%;Fe3+浓度对缓蚀效率影响较大,在酸洗过程中Fe3+浓度应控制在300mg/L以下;复配缓蚀剂抑制了阴极和阳极过程,以阴极控制为主,为电荷传递控制型缓蚀剂。 相似文献
16.
In this work, corrosion and localized corrosion behavior of X65 pipeline steel were studied in a simulated, CO2-saturated oilfield formation water by various electrochemical measurement techniques, including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization curves, galvanic current and localized EIS (LEIS). The morphology and composition of the formed corrosion scale were characterized by scanning electron microscopy and energy-dispersive X-ray analysis. A conceptual model was developed to illustrate the occurrence of localized corrosion of the steel under scale. Both galvanic current and LEIS measurements showed that a galvanic effect existed between the bare steel and the scale-covered region. The scale-covered region served as cathode and the bare steel site as the anode. The big cathode vs. small anode geometry accelerated the local corrosion reaction. At an elevated temperature, a compact, crystalline scale was formed on the steel surface, enhancing the galvanic effect. Moreover, the stability of the scale was increased with time, and localized corrosion of the steel under scale experienced mechanistic changes with time. 相似文献
17.
对镍白铜合金废料进行直接低电流密度电解回收,考察了电解液温度、电流密度、明胶浓度对阴极铜纯度和表面质量的影响. 结果表明,一定范围内电解液温度升高阴极过电势降低,铜离子扩散速度加快,阴极表面铜离子缺乏程度缓和,阴极铜结晶细化;在Cu2+浓度45 g/L、H2SO4浓度180 g/L、电流密度100 A/m2的条件下,48 h内电流密度小于极限电流密度的0.1倍,电解区域处于塔费尔控制区,阴极铜产品平整光滑;控制明胶浓度40 mg/L、电解液温度60℃和电流密度100 A/m2时,镍白铜废料直接电解所得阴极铜纯度达99.98%,表面平整韧性良好,阳极残极率为17%~19%,铜回收率达98.6%. 相似文献