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1.
本文用电化学动电位再活化法(EPR法)研究了奥氏体不锈钢在H_2SO_4+Na_2S_4O_6溶液中钝化区回扫电位、扫描速度、溶液温度、溶液浓度等因素对测试灵敏度的影响,确定了AISI304、316系列奥氏体不锈钢在此溶液中的最佳实验条件。并进行了不同敏化状态的奥氏体不锈钢在此溶液中的EPR测试。研究结果表明:采用Na_2S_4O_6作为活化剂的EPR法同样是一种快速、定量、非破坏性的评价奥氏体不锈钢晶间腐蚀敏感性的方法。但在实际应用时,对于304系列不锈钢选用H_2SO_4+KSCN溶液比较灵敏,而对于 相似文献
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In order to replace the hazardous chromate‐based surface treatment, a new cerium chemical conversion coating was developed on 316L stainless steel through a mixed solution of hydrated cerium nitrate, citric acid, and hydrogen peroxide. The chemical composition was characterized by energy‐dispersive spectroscopy, X‐ray photoelectron spectroscopy and atomic force microscope. The dense conversion coating is composed of CeO2 with a small amount of Ce2O3 and has small grain size lower than 50 nm. Its thickness is about 47.4 nm as determined by spectroscopic ellipsometry analysis. Potentiodynamic polarization was used to study the corrosion behavior of the coatings in the concentrated artificial seawater at 72 °C. In comparison with the conventional nitric acid‐chromate passivated specimens, the cerium conversion coatings show much higher pitting potentials. It is suggested that the cerium conversion treatment is more effective than the nitric acid‐chromate passivation to improve the pitting resistance of 316L stainless steel used in the hot seawater environments. 相似文献
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电化学动电位再活化法评定不锈钢晶间腐蚀敏感性的研究 总被引：4，自引：1，他引：4
本文用电化学动电位再活化法(EPR法)研究了奥氏体不锈钢在H_2SO_4+Na_2S_4O_6溶液中钝化区回扫电位、扫描速度、溶液温度、溶液浓度等因素对测试灵敏度的影响,确定了AISI304、316系列奥氏体不锈钢在此溶液中的最佳实验条件。并进行了不同敏化状态的奥氏体不锈钢在此溶液中的EPR测试。研究结果表明:采用Na_2S_4O_6作为活化剂的EPR法同样是一种快速、定量、非破坏性的评价奥氏体不锈钢晶间腐蚀敏感性的方法。但在实际应用时,对于304系列不锈钢选用H_2SO_4+KSCN溶液比较灵敏,而对于316系列不锈钢则选用H_2SO_4+Na_2S_4O_6溶液更为灵敏。 相似文献
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采用表面机械研磨(Surface Mechanical Attrition Treatment,SMAT)在304不锈钢表面制备出纳米晶层(平均晶粒尺寸20nm)。采用腐蚀失重试验和极化曲线测试等方法比较了粗晶(Coarse-grained,CG)和纳米晶(Nano-crystallized,NC)304不锈钢在室温及80℃条件下5%(质量分数)硫酸溶液中的耐蚀性,采用透射电镜(TEM)观察表面纳米化后的微观结构,并利用扫描电镜(SEM)分析了腐蚀行为和微观结构的关系。失重试验结果表明,在两种温度条件下的稀硫酸溶液中,纳米晶结构的304不锈钢耐腐蚀性能明显变差,腐蚀特征以沿晶破坏为主,局部显示出均匀腐蚀形态。电化学测试结果表明,纳米化后的304不锈钢具有更低的自腐蚀电位和更高的自腐蚀电流密度。 相似文献
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利用动电位极化曲线、电化学阻抗谱和恒电位极化电流响应曲线对一种高氮不锈钢在含不同浓度Cl~-的0.5mol/L NaOH溶液中的腐蚀行为进行了研究。结果表明:高氮不锈钢在含Cl~-的0.5mol/L NaOH中具有良好的耐蚀性,极化曲线表现出阳极钝化特征,Cl~-浓度对点蚀电位无显著影响,钝化电流密度随Cl~-浓度的增加而增大;当Cl~-浓度增加到1.00mol/L时,高氮不锈钢表面生成的钝化膜呈n型半导体,仍具有良好的保护性,钝化膜的载流子密度随着Cl~-浓度的增加而增大。 相似文献
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Improvement of the corrosion resistance capability of a workpiece being processed by the electropolishing (EP) is one of the most importance process characteristics. In this paper, the effects of the EP process parameters on the corrosion resistance performance of the SS 316L stainless steel were studied based on the uniform and localized intergranular corrosion (IGC) analyses. The IGC is the prominent characteristics of localized corrosion in stainless steel.
The workpiece (anode) material was the SS 316L stainless steel. The cathode material under study was platinum. The electrolyte was composed of sulfuric acid, phosphoric acid, glycerin and DI water. The test specimens were all polished before experiments in order to reduce the effect of the bailby layer. Variables of the EP process parameters gap between the electrodes and the process time.
The specimens were analyzed, first, by the surface roughness measurement. Secondly, they were observed under the optical microscope for surface marks and defects. It was followed by the linear polarization analysis for the uniform corrosion performance. The electrochemical potentiokinetic repassivation (EPR) test was employed to study the localized, IGC. Finally, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) analyses were conducted to analyze the metallurgical composition and the thickness of the passive film. The results showed that the EP process greatly improved the corrosion resistance of the SS 316L stainless steel. 相似文献
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L. Sjögren G. Camitz J. Peultier S. Jacques V. Baudu F. Barrau B. Chareyre A. Bergquist A. Pourbaix P. Carpentiers 《工业材料与腐蚀》2011,62(4):299-309
To be able to give safe recommendations concerning the choice of suitable stainless steel grades for pipelines to be buried in various soil environments, a large research programme, including field exposures of test specimens buried in soil in Sweden and in France, has been performed. Resistance against external corrosion of austenitic, super austenitic, lean duplex, duplex and super duplex steel grades in soil has been investigated by laboratory tests and field exposures. The grades included have been screened according to their critical pitting‐corrosion temperature and according to their time‐to‐re‐passivation after the passive layer has been destroyed locally by scratching. The field exposures programme, being the core of the investigation, uses large specimens: 2 m pipes and plates, of different grades. The exposure has been performed to reveal effects of aeration cells, deposits or confined areas, welds and burial depth. Additionally, investigations of the tendency of stainless steel to corrode under the influence of alternating current (AC) have been performed, both in the laboratory and in the field. Recommendations for use of stainless steels under different soil conditions are given based on experimental results and on operating experiences of existing stainless steel pipelines in soil. 相似文献
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将445铁素体不锈钢的主要化学成分、力学性能、成型性能和焊接性能等基本性能与304奥氏体不锈钢进行对比,结果表明,445不锈钢具有较好的机加工性能。采用盐雾试验及10%的NaCl溶液加速腐蚀试验等方法,对比445水箱、304水箱及两者混合搭配的内胆水箱的太阳能热水器的耐腐蚀性能。结果表明,445不锈钢耐腐蚀性稍逊于304不锈钢,在80～120℃时,445与304不锈钢均发生蒸汽腐蚀、水线腐蚀,且445不锈钢出现较为严重的点蚀现象。 相似文献
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采用慢应变速率拉伸的应力腐蚀试验法,结合应力应变试验、显微组织观察、力学性能测试和断口形貌分析,研究了不同时效处理后17-4PH马氏体不锈钢在N2、通入饱和H2S的NACE A溶液和3%CO2+3%H2S+N2+H2O三种介质中的抗应力腐蚀性能。结果表明,通入饱和H2S的NACE A溶液对17-4PH不锈钢的应力腐蚀最为严重,试样断口呈现脆性断裂特征。时效工艺对材料的应力腐蚀敏感性有明显影响,600℃+605℃双级时效处理后17-4PH不锈钢的抗应力腐蚀性能优于600℃时效处理。 相似文献
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Galvanic corrosion behavior of TA2/316L composite plate was investigated in the solution of 3.5 wt% NaCl by galvanic potential monitoring, scanning localized electrochemical impedance spectroscopy (LEIS) and scanning vibrating micro‐electrode (SVME) techniques. The results demonstrated that the pitting corrosion resistance of 316L for the galvanic combination sample is lower, and the coupled current density is higher than for the single 316L sample. It indicates that the galvanic action works on the corrosion behavior of the TA2 titanium alloy/316L stainless steel galvanic combination in sodium chloride solution. The galvanic effect width was determined as 1500 µm. 相似文献
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18-8奥氏体不锈钢的晶间腐蚀 总被引：5，自引：0，他引：5
介绍了奥氏体不锈钢晶间腐蚀的机理，讨论了C、C、N等元素以及加热时间、温度、冷却速度和焊接等工艺条件对晶间腐蚀的影响，并提出了相应的预防措施． 相似文献
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C. Sun H.X. Li S.Q. Zhang State Key Laboratory for Corrosion Protection Institute of Corrosion Protection of Metals The Chinese Academy of Sciences Shenyang China 《金属学报(英文版)》1999,12(5):929-931
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结合现场试验、施工实践,分析了奥氏体不锈钢（牌号为304）管件（如三通、弯头等连接件）的性能、焊接缺陷与产生原因,提出了防止与消除管件-管子焊接中易产生的能引发晶间腐蚀等缺陷、优化施工质量的工艺措施等. 相似文献
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采用电化学测试法、点腐蚀试验法、盐雾腐蚀试验法和慢应变速率测试法,分别对比研究了核级316NG控氮奥氏体不锈钢和321奥氏体不锈钢的局部腐蚀行为,并利用扫描电子显微镜、光学显微镜等分别观察腐蚀后不锈钢的表面形貌。结果表明:316NG和321不锈钢晶间腐蚀再活化率分别为3.83%和4.47%,点腐蚀速率分别为10.74g/(m2·h)和45.97g/(m2·h),盐雾腐蚀速率分别为2.14×10-2 g/(m2·h)和12.32×10-2 g/(m2·h),应力腐蚀开裂敏感指数分别为0.078和0.10;316NG不锈钢中N和Mo元素提高了其耐局部腐蚀性能,因此其耐局部腐蚀性能均优于核电站结构材料321不锈钢的。 相似文献
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Smooth polypyrrole (PPy) films were successfully electrosynthesized on a stainless steel (SS, 1Cr18Ni9) surface by a self‐catalytic two‐step process. SS substrate dissolution during PPy electrosynthesis was effectively depressed. The redox properties and corrosion behavior of PPy film coated SS electrodes were investigated by cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization. The reduction of PPy was found to include two reaction processes: an anion dedoping process and a cation insertion process. The PPy film was found to lose its electroactivity when polarized at high potentials due to peroxidation. EIS of SS/PPy mainly corresponds to PPy film response and charge transfer resistance decreases as film thickness increases, indicating that SS corrosion can be inhibited effectively by the PPy film. 相似文献
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Muntasir Hashim Farnoosh Farhad David Smyth‐Boyle Robert Akid Xiang Zhang Philip J. Withers 《工业材料与腐蚀》2019,70(11):2009-2019
The environmental performance of 316L grade stainless steel, in the form of tensile specimens containing a single corrosion pit with various aspect ratios, under cyclic loading in aerated chloride solutions is investigated in this study. Results from environmental tests were compared and contrasted with those obtained using finite element analysis (FEA). Fractography of the failed specimens obtained from experiments revealed that fatigue crack initiation took place at the base of the shallow pit. The crack initiation shifted towards the shoulder and the mouth of the pit for pits of increasing depth. This process is well predicted by FEA, as the strain contour maps show that strain is the highest around the centric strip of the pit. However, for shallow pits, local strain is uniformly distributed around that strip but begins to concentrate more towards the shoulder and the mouth region for increasingly deep pits. 相似文献