Corrosion behavior of high-strength spring steel for high-speed railway

The corrosion resistance and evolution of corrosion products in medium-carbon high-strength spring steels were investigated in a neutral salt spray(5 wt% Na Cl solution). A formation model of γ-Fe OOH and a transformation model describing the conversion of γ-Fe OOH to α-Fe OOH were constructed. The results indicated that, at the initial corrosion stage, the corrosion resistance was gradually improved with the addition of Cr; however, with the addition of alloying element V, the corrosion resistance decreased. These results were attributed mainly to the initial corrosion stage being closely related to the matrix microstructure parameters such as grain-boundary character and dislocation density. After the rust layer was formed at a later corrosion stage, the corrosion resistance was reinforced with the addition of Cr and V because Cr strongly influenced the composition, structure, and morphology of the corrosion products. The results presented herein show that Cr was conducive to the transformation of γ-Fe OOH into α-Fe OOH. Moreover, V and Cr exhibited obvious synergy and were enriched in the inner layer of the corrosion products.

Effect of trace boron on corrosion resistance of rust layer of high-strength low-alloy steel in 3.5 wt.% NaCl solution

The influence mechanism of trace boron on the corrosion resistance of high-strength low-alloy(HSLA)steel in a simulated marine environment was studied by combining first-principles calculation with experiment.The effect of boron on the corrosion properties and corrosion morphology of the rust layer formed on the surface of HSLA steel was studied by means of corrosion weightlessness method,polarization curve,scanning electron microscopy(SEM)and X-ray diffraction(XRD)technique.The mass loss measurements and polarization curves revealed that the corrosion resistance of HSLA steel is improved by adding trace boron.XRD and SEM results show that the rust layer is produced byα-FeOOH(the main protective phase),Fe_(3)O_(4) andγ-FeOOH,and boron contributes to stability ofα-FeOOH.Based on the first-principles calculation,the solid solution of B atom in the corrosion product is beneficial to the fixation of Cl atom and to the reduction of the corrosion of Cl atom to the steel matrix.

材料腐蚀与防护实验教学案例设计

针对材料类学生教学需求,以科研项目为牵引,设计了稀土合金化增强耐候钢表面锈层保护性能的实验教学案例。该实验案例以海洋大气环境下耐候钢耐蚀性能亟待提高这一实际工程问题为切入点,通过现场大气曝露腐蚀实验、实验室模拟加速腐蚀实验来评价耐候钢的耐腐蚀能力。通过扫描电镜、X射线衍射分析等物理方法和极化曲线等电化学方法,研究分析了稀土耐候钢在近海大气环境下表面锈层的形貌、物相组成、合金元素分布及其电化学腐蚀行为。利用综合实验结果分析了特定腐蚀环境下稀土耐候钢的耐蚀性能和耐蚀机理。该实验教学案例以“问题提出-材料制备-腐蚀行为分析-耐蚀性能评价”为主线,综合性强,涉及材料合金成分设计、电化学腐蚀机理、表征技术、电化学分析等众多知识点,在一定程度上实现了专业知识的系统化和一体化,对学生创新意识和研究能力的培养具有很好的推动作用。

稀土Ce对低碳微合金钢耐腐蚀性能的影响

为了提高低碳微合金钢在海洋环境中的耐腐蚀性能,采用金相显微镜、SEM、EBSD、电化学分析等测试手段研究了不同稀土Ce含量的试验钢在3.5%NaCl溶液模拟的海洋环境中的腐蚀行为。结果表明:试验钢的显微组织主要由铁素体和珠光体组成,稀土Ce可以细化晶粒,减小夹杂物的尺寸,将试验钢中Al_(2)O_(3)、MnS、Al_(2)O_(3)+MnS夹杂物改性为MnS+CeAlO_(3)、Ce_(2)O_(3)夹杂物,并且改性后的夹杂物应力明显降低,减小了微孔洞、裂纹萌生的概率。另外,稀土Ce的加入可以降低试验钢的腐蚀电流密度,提高腐蚀电压,使得腐蚀产物中γ-FeOOH的含量减少,同时α-FeOOH和Fe_(3)O_(4)含量增多,可降低反应活性,提高锈层对基体的保护作用。因此,相对于未添加稀土Ce的低碳微合金钢,添加稀土Ce的低碳微合金钢表现出更好的耐海水腐蚀性能。

一种Mo系耐候钢表面锈层稳定剂的性能

制备了一种Mo系耐候钢表面锈层稳定剂,并通过实验室周期浸润腐蚀试验、宏观和微观腐蚀形貌观察、锈层成分分析和电化学测试等方法,研究了该锈层稳定剂对耐候钢锈层结构、成分和耐蚀性的影响。结果表明:锈层稳定剂可避免锈液流挂现象的产生,降低耐候钢的腐蚀速率,促使Mo元素在内锈层与基体结合处发生聚集,促进了α-Fe OOH的生成,还生成了稳定的氧化物MoO_(3)和不溶性的Fe Mo_(O4),增大了锈层电阻,提高了耐候钢的耐蚀性。

Corrosion Resistance on High Strength Bainitic Steel and 09CuPCrNi After Wet-Dry Cyclic Conditions

The accelerated wet-dry cyclic corrosion tests have been carried out of a high strength bainitic steel and 09CuPCrNi. The results indicated that the corrosion resistance of 09CuPCrNi was better than that of the bainitic steel based on the mass loss measurements. The morphology and composition of the rusting products have been investigated in order to realize the mechanism of rust formation on the two steels. The rust scale on both steels was composed of a dense inner layer and a loose outer layer. The inner layer grew thicker and denser as the test proceeding. Both of inner and outer layers were mainly composed of magnetite （Fe3O4） and maghemite （γ-Fe2O3） with a small amount of lepidocrocite （γ-FeOOH） and akaganeite （β-FeOOH）. The rust phase of γ-Fe2O3 was detected in a higher amount of the inner layer, resulting in a much denser inner layer. The inner rust layer of 09CuPCrNi being denser and thicker than that of the high strength bainitic steel was attributed to the alloying elements such as copper, chromium and phosphorus enriched in it. The protective inner rust layer plays an important role in the corrosion resistance of the steel.

稀土元素对耐蚀钢腐蚀性能影响的研究综述

随着工业的不断发展,世界各国对钢材质量的要求也越来越高,如何提高钢材的耐蚀性,已成为目前的研究重点。耐蚀钢因其具有较强的抗腐蚀性能,广泛应用于土木建筑、汽车制造、造船等领域,为进一步提高耐蚀钢的耐腐蚀性能,通常在钢中添加稀土元素。文中综述了稀土元素对耐蚀钢的净化作用、对钢内夹杂物的影响、对钢材腐蚀性能及锈层影响的研究进展,为促进稀土元素在钢中的应用提供理论依据。稀土元素对耐蚀钢耐蚀性影响的具体机理和稀土元素在材料工程中的可持续发展是当前研究的重点。

Effect of La on the Corrosion Behavior and Mechanism of 3Ni Weathering Steel in a Simulated Marine Atmospheric Environment

The corrosion behavior and mechanism of 3Ni weathering steel in a simulated oceanic atmospheric environment are investigated in order to comprehend the impacts of La,as determined through electrochemical analysis and rust layer characterization.The results of this study demonstrate that the addition of La enhances the corrosion resistance of 3Ni weathering steel in the marine atmospheric environment,thereby reducing the corrosion rate and improving the protection of the rust layer.The influence of La on corrosion resistance can be attributed to two primary factors.Firstly,La functions as a grain refiner,minimizing the potential difference of the micro-regions on the substrate surface,thereby significantly reducing the corrosion of bare steel in the marine environment.Secondly,La inhibits the process of Fe_(3)O_(4) oxidation back toγ-FeOOH during corrosion at the local site,thus decreasing the formation ofγ-FeOOH and enhancing the charge transfer resistance.This research work may serve as a reference for expanding the application of rare earth elements in the field of weathering steel.

耐候钢新型表面锈层稳定剂处理及其耐3.5%NaCl溶液周浸腐蚀性能

目的解决耐候钢裸露使用初期锈液流挂与飞散的问题。方法制备了新型耐候钢表面锈层稳定剂,通过周期浸润循环腐蚀试验、锈层微观分析和电化学测试等方法研究了在模拟海洋大气环境下,锈层稳定剂对耐候钢锈层结构及耐腐蚀性能的影响。结果表面锈层稳定化处理后,耐候钢表面生成的锈层区分为致密且连续的内锈层和外锈层。室内加速腐蚀168 h后,耐候钢的失重腐蚀速率由未处理的5.71 g/(m^2×h)降低到表面处理后的3.31 g/(m^2×h),失重腐蚀速率降低了约42%。耐候钢的锈层电阻由未处理的96?·cm^2提高到表面处理后的167.7?·cm^2,锈层电阻提高了约75%。表面处理后的耐候钢锈层中,Cr元素以α-(Fe_(1-x)Cr_x)OOH的形式存在于基体与锈层的界面处,Cr元素在内锈层与基体结合处发生聚集。结论新型锈层稳定剂可以明显改善耐候钢锈层结构,细化锈层晶粒,阻碍Cl^-的渗透,有助于耐候钢表面快速生成致密、连续且稳定的保护性锈层。

新型耐海水腐蚀低合金钢10CrCuSiV锈层分析研究报告

新型耐海水腐蚀低合金钢10CrCusiV，在大连海域全浸区挂片试验7a后的腐蚀率为0．23mm／a．通过金相、岩相、X射线衍射及扫描电镜、电子能谱等分析，都证明了10CrCuSiV钢的锈层致密，附着牢固，粘附性系数小；内锈层以Fe3O4为主，有良好保护性；而合金元素在蚀坑内的富集有效地抑制了局部腐蚀作用．

含Cu耐候钢中稀土对耐蚀性的影响研究

利用周期浸润加速腐蚀试验方法对10PCuRE和10PCu耐候钢进行了腐蚀试验。通过X射线衍射分析、电子探针和扫描电镜等手段对两种钢的表面锈层性能进行了研究,得到了10PCuRE钢致密锈层的种类、形成过程以及保护机理。通过对加稀土与未加稀土的耐候钢表面锈层的对比研究,可知10PCuRE钢的表面锈层比10PCu耐候钢的锈层要均匀致密,保护性能更好。稀土耐候钢的锈层分为两层,包括外锈层和均匀致密的内锈层,内锈层的组成相中超过80%为保护性的α-FeOOH。稀土促进了合金元素Cu在内锈层的富集,有利于保护性内锈层的生成,因而提高了钢基体的耐蚀性能。

热镀锌板线状缺陷分析方法探讨

以热镀锌板为测试材料,采用表面直接观察、截面观察和表面脱镀层观察等方法对其线状缺陷进行研究,并通过SEM、EDS分析对其线状缺陷形貌和组成进行表征。结果表明,采用这些方法可判定热镀锌板线状缺陷产生的原因,从而为使其产品表面缺陷得到有效控制提供依据。

Cr,Ni对钢在海水飞溅区的锈层及耐蚀性的影响

为了解Cr，Ni对钢在海水飞溅区的耐蚀性、锈层物相组成和性质的影响，采用x射线衍射（XRD）和扫描电子显微镜（SEM）技术研究了合Cr钢和含Ni钢在飞溅区锈层的物相组成和微观形貌，获得了含Cr钢和含Ni钢在海水飞溅区的腐蚀速率；讨论了cr，Ni对钢在飞溅区的锈层及耐蚀性的影响。结果表明：添加1％～2％Cr对飞溅区钢锈层的物相组成及其含量无明显影响，但提高了内锈层的致密度，使钢在飞溅区的耐蚀性略有提高。添加2％～3％Ni使钢锈层中α-eOOH的含量明显增加，使锈层的非晶化程度提高，致密度提高，从而使钢在飞溅区的耐蚀性显著提高。

模拟工业环境下耐候钢水性锈层稳定剂耐蚀性的研究

用以丙烯酸树脂、铁氧化物颜料、促进剂、分散剂等制成的水性锈层稳定剂处理耐候钢表面(涂覆试样),然后将裸耐候钢和涂覆试样浸入用于模拟工业环境的0.01 mol/L亚硫酸氢钠水溶液进行周期性腐蚀试验。72 h后通过扫描电镜、能谱仪和X射线衍射仪表征了它们的形貌、成分和物相,用失重速率、极化曲线和电化学阻抗谱评价了它们的耐蚀性。结果表明,腐蚀试验后,裸耐候钢表面产生了疏松锈层,生成了α–FeOOH,基体中的Cr元素有向表面富集的倾向。而涂覆试样未生成锈层,物相未发生明显变化,耐蚀性显著增强。

稀土对耐候钢耐蚀性能的影响研究

通过X射线衍射分析、电子探针和扫描电镜等手段对10PCuRE和10PCu耐候钢的表面锈层性能进行了研究,得到了10PCuRE钢致密锈层的种类、形成过程以及保护机理。通过对加稀土与未加稀土的耐候钢锈层的对比研究,可知稀土耐候钢的锈层分为两层,包括外锈层和均匀致密的内锈层,内锈层的组成相中超过80%为保护性的α-FeOOH。稀土促进了合金元素Cu在内锈层的富集,有利于保护性内锈层的生成,提高了钢基体的耐蚀性能。

Cu对耐候桥梁钢耐腐蚀性能的影响

采用干湿周浸实验模拟海洋大气环境研究含Cu耐候桥梁钢腐蚀过程中耐腐蚀性能的变化,并利用XRD,SEM等方法研究了两种不同Cu含量耐候桥梁钢的锈层变化.结果表明:Cu能够有效地降低钢的平均腐蚀深度和腐蚀速率,利于提高钢的耐蚀性能.锈层组成随腐蚀时间而变化,腐蚀初期锈层主要由Fe3O4和γ-FeOOH组成,腐蚀中期锈层开始生成Ni(0.6～1)Fe(2.4～2)O4尖晶石类复合氧化物和α-FeOOH两种晶相;腐蚀后期组成基本保持不变,主要由Ni(0.6～1)Fe(2.4～2)O4、α-FeOOH、γ-FeOOH和少量Fe3O4组成.

高强度耐候H型钢和普通C-Mn低合金H型钢耐大气腐蚀性能比较

通过周浸加速腐蚀试验,对比了高强度耐候H型钢与普通C-Mn低合金H型钢的耐蚀性能,采用扫描电镜(SEM)、X射线衍射(XRD)及电化学阻抗谱(EIS)等方法研究了两种钢腐蚀产物的形貌、组成以及电化学性质的差异。结果表明,在模拟工业大气环境下,高强耐候H型钢的耐蚀性显著优于普通C-Mn钢,腐蚀产物性质的差别是导致两种钢腐蚀率差异的主要原因。普通C-Mn钢腐蚀后表面粗糙,锈层疏松且存在大量贯穿性裂纹;耐候H型钢锈层连续致密,且腐蚀产物主要由保护性较好的α-FeOOH和非晶态锈组成,能有效减缓电化学腐蚀反应的进行。

超低碳贝氏体钢(ULCB)和耐候钢09CuPCrNi的耐蚀性

通过周期性浸润腐蚀试验测定了ULCB钢(%:0.05C、1.61Mn、0.51Cu、0.17Cr、0.26Ni)和耐候钢09CuPCrNi(%:0.09C、0.35Mn、0.09P、0.31Cu、0.45Cr、0.31Ni)14 mm板的耐腐蚀性能,并用偏光显微镜,X-射线衍射仪和能谱仪等研究了耐蚀机理。结果表明,ULCB钢的耐腐蚀性能优于09CuPCrNi钢;发现两种钢均存在由α- FeOOH,β-FeOOH和Fe_3O_4组成致密的内锈层、由α-,γ-FeOOH和Fe_3O_4组成的疏松外锈层;Cu和Cr合金元素在锈层和锈层-钢基体界面均存在富集现象。

耐候钢锈层稳定化处理的研究

以WSD-N耐候钢为基板,采用周期轮浸试验方法,对研制的锈层稳定化表面处理剂进行了试验.结果表明,在锈层稳定化处理剂中,促进剂起主要作用,其含量在0～ 216 g范围内越高越好;Fe3O4和Fe2O3起次要作用.经锈层稳定化表面处理的试样,基体发生的腐蚀可看成是耐候钢致密锈层下的稳定腐蚀,与裸样相比腐蚀率可降低50％.

不同显微组织钢板耐蚀性研究

采用周浸加速腐蚀试验对Q235B、Q345B低合金钢以及X70管线钢的耐蚀性能进行对比研究,并采用OP、SEM等分析方法对表面以及剖面锈层形貌进行分析。结果表明:不同显微组织钢的耐蚀性能存在显著差异,随着珠光体含量的增加,低合金钢的耐蚀性能逐渐降低。X70管线钢由于其显微组织主要为针状铁素体+粒状贝氏体,组织均匀,相间电位差较小,其耐蚀性能明显优于铁素体+珠光体型的低合金钢。