基于岸基与远洋移动平台的7B04铝合金腐蚀行为比较研究

目的 研究动态海洋大气环境与静态海洋大气环境对7B04铝合金腐蚀行为的影响.方法 采用7B04铝合金,分别在远洋船舶移动平台和万宁站海洋平台开展1年户外大气暴露试验,利用腐蚀形貌、腐蚀失重、力学性能表征7B04铝合金在海洋大气环境中的腐蚀规律和行为.结果 经过1年的户外大气暴露试验,在动态和静态两种海洋大气环境作用下,7B04铝合金的腐蚀类型均为点蚀,且远洋船舶移动平台7B04铝合金的腐蚀程度更严重.在远洋船舶移动平台开展动态自然环境试验的7B04铝合金腐蚀速率为67.4μm/a,在万宁站海洋平台开展静态自然环境试验的7B04铝合金腐蚀速率为16.6403μm/a,远洋船舶移动平台7B04铝合金的腐蚀速率约为万宁站海洋平台的4倍.远洋船舶移动平台试验7B04铝合金的拉伸强度、规定塑性延伸强度和断后伸长率保留率分别为91％、87.5％和54.3％.结论 7B04铝合金在远洋船舶移动平台和万宁站海洋平台的腐蚀类型均为点蚀,远洋船舶移动平台的动态海洋大气腐蚀性强于静态海洋大气,且对7B04铝合金力学性能的降低主要体现在断后伸长率方面,可显著加速7B04铝合金的腐蚀.     

环境对高强度铝合金应力腐蚀行为的影响

利用C型环试样、单轴加载的拉伸试样和预制裂纹的试样研究了高强度铝合金在大气环境下的应力腐蚀性能，并与实验室加速试验结果进行对比。施加应力后的试样分别暴露于北京、团岛、万宁3个不同的大气试验站，同时在实验室进行了C型环试样在3．5％NaCl溶液中周期浸润腐蚀试验、单轴拉伸试样在3％NaCl＋0．5％H2O2溶液中的拉伸应力腐蚀试验和预制裂纹的试样在3．5％NaCl溶液中腐蚀试验。结果表明，高强度铝合金在不同环境中产生应力腐蚀的敏感性不同，在海洋性环境下应力腐蚀性较高；在海洋性环境下2A12铝合金的应力腐蚀的敏感性比7A04铝合金高，在暴露期间未开裂的2A12铝合金C环试样发生严重剥落腐蚀，未开裂的7A04铝合金C环试样则遭受严重点腐蚀；3．5％NaCl溶液中周期浸润腐蚀试验和3％NaCl＋0．5％H20：溶液中的拉伸应力腐蚀试验作为高强铝合金SCC敏感性判定方法，模拟海洋大气腐蚀过程，与户外的试验结果具有较好的相关性。     

2024-T3铝合金在模拟海洋大气环境中的腐蚀行为

通过循环盐雾腐蚀实验,模拟2024-T3铝合金在海洋大气环境中的腐蚀过程。采用腐蚀质量损失测试、扫描电镜(SEM)、X射线能谱(EDS)和电化学技术分别对腐蚀117、242、362、487和598 h的2024-T3铝合金试样进行测试分析,得到腐蚀动力学、腐蚀产物和点蚀坑的形貌、腐蚀产物的成分以及表面锈层的电化学特性,研究锈层对2024-T3铝合金大气腐蚀的影响。动力学分析表明,腐蚀过程中2024-T3铝合金的表面形成了具有较好保护性的锈层;电化学测试结果表明,锈层的保护性呈现随腐蚀时间的延长先增强后减弱然后再略增强的变化过程。     

LY12铝合金在海洋大气环境下加速腐蚀试验和外场暴露试验的相关性

通过对模拟海洋大气加速腐蚀试验和外场暴露试验中的LY12铝合金初期腐蚀形貌、电位和交流阻抗等的测量和分析,研究铝合金在海洋大气环境下的初期腐蚀行为,并考察加速腐蚀试验结果和外场暴露试验结果的相关性。结果表明:铝合金初期腐蚀表面属于吸附型阻抗类型,电位有轻微上升,腐蚀伴随着表面氧化层的开裂。外场暴露腐蚀表面自然氧化层明显龟裂,加速腐蚀表面氧化层开裂不明显。模拟海洋大气加速腐蚀试验和外场暴露试验在腐蚀形貌、电位、交流阻抗等方面具有较好的相关性。     

海军黄铜HSn62-1的长期大气腐蚀行为

通过在3种典型大气环境中进行为期20年的现场暴露试验,研究海军黄铜HSn62-1的腐蚀质量损失和力学性能损失,采用扫描电子显微镜和XRD观察和分析腐蚀外貌、横截面和腐蚀产物。结果表明:HSn62-1的长期大气腐蚀质量损失随暴露时间的关系遵循C=KT n,腐蚀质量损失在工业酸雨大气环境中最大,在海洋大气环境中最小;腐蚀速率在工业酸雨和海洋大气环境中随时间逐渐降低,而在半乡村大气中逐渐升高;暴露20年后,HSn62-1的力学性能损失在工业酸雨大气环境中最大,在半乡村环境中最小;HSn62-1在3种典型大气环境中均发生脱锌腐蚀,腐蚀产物主要为Cu2O和ZnO。     

纯锌在我国热带海洋大气环境耐蚀寿命预测模型

采用周浸加速腐蚀试验模拟纯锌在热带海洋大气环境的腐蚀行为,通过对比腐蚀形貌、腐蚀产物、腐蚀动力学等定性和定量地评价周浸试验与户外大气暴露腐蚀试验的相关性。结果表明:周浸腐蚀试验后,纯锌的腐蚀形貌、腐蚀产物组成及腐蚀动力学均与实际海洋大气环境暴露结果具有较好的相关性;通过灰色关联分析法分析发现采用2%Na Cl溶液模拟万宁大气、5%Na Cl溶液模拟西沙大气兼具模拟性和加速性;采用周浸加速腐蚀试验方法建立纯锌在万宁、西沙两种海洋大气环境下服役的耐蚀寿命预测模型,分别为Twn=95.23t 1.01、Txs=841.60t 0.16。     

纯铝1060在中国南沙群岛严酷海洋大气中的腐蚀以及点蚀行为

通过质量损失测量、扫描电子显微术、能谱分析、X射线光电子能谱和电化学阻抗谱等技术研究纯铝1060在南沙群岛海洋大气环境中暴露34个月后的腐蚀行为以及点蚀行为.结果表明,在纯铝表面发生严重的点蚀,并且暴露13个月后的平均腐蚀速率达到1.28 g/(m2·a).X射线光电子能谱的测试结果表明主要的腐蚀产物为Al2O3、Al...     

2A11铝合金/碳钢偶接件在强化自然环境条件下的腐蚀特性

采用户外周期喷淋试验,研究了2A11铝合金与Q235钢组成的偶接件在强化自然环境条件下的腐蚀行为与规律.结果表明:2A11铝合金的偶接部位发生严重腐蚀,腐蚀严重部位主要在距接触边缘5～10mm的范围内;铝合金的腐蚀质量损失随暴露时间的延长而不断增大;电偶腐蚀和缝隙腐蚀并存是铝合金偶接部位腐蚀严重的主要原因,大气环境中沉...     

0359铝合金海洋性大气腐蚀行为

利用盐雾腐蚀试验研究时间对0359铝合金在海洋大气环境中腐蚀行为的影响,通过失重分析考查了0359铝合金的腐蚀动力学特征,分析了腐蚀产物的微观形貌及元素变化情况.结果表明:腐蚀失重与时间的关系呈幂函数规律,腐蚀48h后,腐蚀速率随时间延长逐渐变小,且趋于平缓;腐蚀形貌以点蚀为主,腐蚀产物主要由Al、O、Si三种元素组成;腐蚀48h后的腐蚀失重数据高于LC4铝合金在万宁地区户外暴露10年的数据,且未发生穿透性腐蚀,在海洋性环境中可满足10年以上的使用寿命.     

海洋大气湿度对LY12铝合金初期腐蚀的影响

根据表面带Cl^-的LY12铝合金在模拟海洋大气环境中的腐蚀形貌、增重、最大点蚀深度以及腐蚀体系的自腐蚀电位、交流阻抗等变化,分析相对湿度对其初期腐蚀行为的影响.结果表明,表面含1mg/dm^2Cl^-的LY12铝合金在大气环境的相对湿度＜70%时,几乎不发生腐蚀;在相对湿度＞70%时,发生明显点蚀;在相对湿度＞90%时,腐蚀较严重.腐蚀增重随相对湿度增大而增大,不同相对湿度条件下的腐蚀增重-时间曲线较好地符合Boltz-man模型.相对湿度为90%左右,倾向于出现最深的蚀坑.LY12铝合金腐蚀形貌的变化几乎不会引起其厚水膜高Cl^-自腐蚀体系的电位改变.其厚水膜高Cl^-自腐蚀体系的Nyquist图是实部收缩的单一容抗弧.     

Atmospheric corrosion behaviour of 30CrMnSiA high-strength steel in rural,industrial and marine atmosphere environments

The atmospheric corrosion behaviour of 30CrMnSiA high-strength steel exposed in rural, industrial and marine atmosphere environments in China for 60 months was investigated in virtue of the weight loss, X-ray diffractometer (XRD), scanning electron microscope (SEM) and grey relational analysis. The results showed that 30CrMnSiA high-strength steel exhibited the highest corrosion susceptibility and the lowest corrosion susceptibility in marine atmosphere environment and rural atmosphere environment, respectively. Lepidocrocite and goethite were found as the major constituents of the rust layer in three types of atmosphere environments, and akaganeite was also detected in marine atmosphere environment. The rust layer exhibited the tendency of flaking away from the substrate and becoming dense in marine atmosphere environment and rural atmosphere environment, respectively. Grey relational analysis demonstrated that, among a variety of environmental factors, the airborne sea-salt was the primary factor influencing the atmospheric corrosion of 30CrMnSiA high-strength steel.     

7B04铝合金及其螺接件的微观腐蚀机制及耐久性研究

目的 以飞机结构用7B04高强铝合金及其螺接件为实验对象,通过室内加速腐蚀试验模拟试样在南海海洋大气环境中的环境损伤,并深入分析其微观腐蚀机制与疲劳性能的内在联系。方法 通过数码相机、3D共聚焦显微镜、扫描电子显微镜等手段,研究模拟南海海洋大气环境下7B04铝合金及其螺接件的宏观/微观腐蚀特征,并借助疲劳测试分析经不同腐蚀周期后铝合金试样及螺接件的疲劳寿命。结果 铝合金及其螺接件经室内加速腐蚀试验后发生的腐蚀行为出现了明显差异,7B04铝合金试样表面发生的腐蚀行为以点蚀为主,而螺接件的腐蚀行为更加复杂。其中,远离螺接区域的暴露区的腐蚀情况与铝合金试样一致,在螺接区域发生了明显的缝隙腐蚀。此外,铝合金试样及螺接件随腐蚀周期变化的劣化规律也有所不同,腐蚀使得试样的疲劳性能均不同程度地下降。7B04铝合金疲劳寿命的递减趋势相对平缓,而螺接件在腐蚀进行到第2周期时其疲劳寿命就已降至原始寿命的一半,在腐蚀进行到第4周期时,螺接件的力学性能基本丧失。结论 经腐蚀后,铝合金试样出现了点蚀,且随着时间的延长出现了均匀腐蚀的趋势,疲劳寿命的递减趋势相对平缓。尽管螺接件的过渡区发生了严重腐蚀,但缝隙区诱发的局部腐蚀导致螺接件的受力面积减小,这是造成其疲劳寿命急剧衰减的首要因素。     

LC4铝合金在格尔木盐湖大气环境中的腐蚀行为

通过在我国西北格尔木典型大气环境进行大气暴露实验,测定LC4铝合金在该地区的腐蚀率;利用扫描电镜(SEM)、能量色散X射线谱(EDX)、电子探针(EPMA)、红外光谱(FTIR)和X射线衍射仪(XRD)观察分析LC4铝合金腐蚀表面形貌、元素分布和腐蚀产物结构。结果表明:LC4铝合金的腐蚀以点蚀为主要特征,比其在非盐湖大气环境中的腐蚀严重,朝地面的腐蚀比朝天面严重,腐蚀产物层中含有大量的氧和铝,较多的氯和硫;主要腐蚀产物为Al2O3,Al2O3.2SiO2.2H2O和Al2Cl6.6H2O;含氯和硫的盐参与铝合金的大气腐蚀过程,并起到促进腐蚀的作用。     

Atmospheric corrosion of carbon steels in tropical and subtropical climates in Southern China

Q235 and Q345 carbon steels were exposed for up to 24 months at three test sites of tropical and subtropical climate. The atmospheric corrosion kinetics of Q235 and Q345 was studied by weight-loss measurement. The results show that the ranking of the atmospheric corrosivity from weak to strong of the three test sites is Xishuangbanna, Guangzhou, and Wanning. The kinetics of the atmospheric corrosion process presents two stages with an accelerated second stage in marine environments of high chloride ion content and high relative humidity, whereas no second stage appears in the kinetics curves in rural and industrial urban environments. The corrosion acceleration stage in the marine environment of the Wanning site is attributed mainly to the high chloride ion concentration and loose rust layer structure.     

Kinetics of atmospheric corrosion of mild steel, zinc, galvanized iron and aluminium at 10 exposure stations in India

As a part of updating Corrosion Map of India project, atmospheric corrosion behaviour of commercially available engineering materials such as mild steel, galvanized iron, zinc and aluminium metals was studied in marine, industrial, urban, and rural environments by weight loss method at 10 exposure stations in India over a period of 5 years. The results of these studies demonstrated that galvanized iron, zinc and aluminium metals were several times more durable than mild steel. Compared to galvanized iron and zinc, aluminium provided superior protection in industrial and marine environment except at Mormugao Port Trust (MPT). It also offered much better resistance to corrosion in rural environments. At certain places, galvanized iron proved to be more durable than aluminium. The results obeyed well with the empirical kinetics equation of the form C = Ktⁿ, where K and C are the corrosion losses in μm after 1 and ‘t’ years of the exposure, respectively, and ‘n’ is a constant. Based on ‘n’ values, the corrosion mechanisms of these metals are predicted. The corrosion products formed on the metal samples in Chennai marine atmosphere were identified by X-ray diffraction analysis.     

不锈钢的大气腐蚀研究—12年暴露试验总结

总结了５种不锈钢在我国７个试验点的１２年大气腐蚀试验结果,材料中包括了最常用的不锈钢,环境中包括了亚热带,温带,工业性,海洋性,干燥环境及湿热环境等各种典型环境。不锈钢在大气中是耐蚀的。当含Ｃｒ量达到１８％以上时耐蚀性很好,钼能明显提高不锈钢的耐蚀性,超低碳也能提高其耐蚀性。     

The atmospheric corrosion kinetics of low carbon steel in a tropical marine environment

The atmospheric corrosion kinetics of low carbon steel exposed for up to 36 months in marine and industrial sites was studied by weight loss measurements. The results show that the mechanism and kinetics of the atmospheric corrosion process presents transition behaviour in marine environments with high chloride ion content and high relative humidity, whereas no transition appears in industrial environment. The average corrosion velocity in marine site reaches a maximum during the period of transition and then fluctuates in a certain range; however, the instantaneous corrosion velocity follows different exponential functions before and after the period of transition.     

海洋大气环境下镁合金腐蚀行为研究进展

本文综合研究了海洋大气环境下镁合金腐蚀行为的研究进展,比较分析了各种因素对腐蚀行为的影响,对当前研究进展进行总结并对未来研究方向进行展望。在海洋大气环境下,表面薄电解质溶液膜的包覆是镁合金发生电化学腐蚀的主要原因,且多发生局部腐蚀。相比于内陆大气环境,海洋大气中含有较多无机盐气溶胶颗粒,导致点蚀成为主要的局部腐蚀形式。相对湿度的升高会导致薄电解质膜厚度增加,进而加速整体腐蚀速率。随气温上升,镁合金的大气腐蚀速率线性增加,而空气中的CO₂可以抑制NaCl对镁合金的侵蚀。该领域未来需更多关注具体使役环境下合金的腐蚀机理,以及各种环境因素对腐蚀行为的协同作用机制,以指导海洋用镁合金材料的设计和制备。     

Studies of long-term weathering of aluminium in the atmosphere

Much information is available on the short- and mid-term atmospheric corrosion of aluminium, in the form of corrosion data (mass loss and pit penetration) as a function of atmosphere type, corrosion mechanisms, environmental variables, surface orientation, etc. However, information on the atmospheric corrosion of aluminium over longer tune periods (10-20 years) is scarce, despite its great usefulness. Furthermore, few studies have focused on the morphology of corrosion product layers. This paper reports corrosion data and morphology of corrosion products formed on aluminium panels after long-term exposure (13-16 years) in various types of atmospheres in Spain: rural, urban, industrial and marine.     

Atmospheric corrosion of field-exposed magnesium alloy AZ91D

The magnesium alloy AZ91D was exposed in three different types of atmospheric environment, viz. urban, rural and marine exposure sites. Corrosion rates, corrosion products formed, and the influence of the microstructure on the corrosion behaviour of the alloy were investigated. The corrosion rate of AZ91D exposed in the marine environment was 4.2 μm/year, and in the rural and urban environments 2.2 and 1.8 μm/year, respectively. The main corrosion product found was magnesium carbonate hydromagnesite (Mg₅(CO₃)₄(OH)₂·4H₂O), which was formed at all three exposure sites. The corrosion attack started in the -phase in larger grains at the boundary between the -phase and the eutectic -/β-phase. Microgalvanic elements were formed with the eutectic -/β-Mg phase as cathodic site and the -Mg grains as anodes. The Al–Mn particles played a minor roll in the initiation process, even though these particles are the most noble in the microstructure and thus the driving force for a corrosion attack around these particles could be expected to be high. A close resemblance was observed between the corrosion mechanisms operating under the field-exposure conditions described here and the mechanisms operating under the previously reported laboratory conditions.