Ni-Cu-P镀层和316L不锈钢在热盐酸溶液中的耐蚀性及机制

采用质量损失法研究了温度和浓度对化学镀Ni-Cu-P镀层和316L不锈钢在盐酸溶液中的腐蚀行为.结果表明,在高温盐酸溶液中,Ni-Cu-P镀层的耐蚀性优于316L不锈钢,盐酸浓度对316L不锈钢腐蚀速率的影响大于Ni-Cu-P镀层,盐酸浓度由5％升高到20％,316L不锈钢和Ni-Cu-P镀层的腐蚀速率分别增大了2.7倍和0.6倍;在盐酸溶液中,Ni-Cu-P镀层发生均匀腐蚀,316L不锈钢发生选择性腐蚀,且温度和浓度越高,选择性腐蚀越严重.     

进气管座表面镀镉层腐蚀原因分析

通过光学显微镜、扫描电子显微镜、能谱分析等手段,分析了进气管座镀镉层表面的白色斑迹,并对生产过程中所用到的F-35防锈油、7804抗化学润滑脂、铁锚352胶3种有机物进行了模拟试验,确定了进气管座表面出现白色斑迹的原因。镀镉试片加速腐蚀试验和有机气氛腐蚀试验结果表明：铁锚352胶及其有机气氛会对镀镉层表面造成腐蚀,进气管座表面白色斑迹为铁锚352胶污染,镉镀层被轻微腐蚀,并未穿透,并进一步提出了涂胶固化后减少有机气氛的工艺改进措施。     

铀表面Ti/Al复合镀层在腐蚀气体中的腐蚀行为

研究了铀表面磁控溅射离子镀Ti/Al复合镀层在200～500℃温度范围,分别在o.05 MPa的O2、H2O和HCl气体中的腐蚀失效形式.采用俄歇电子能谱(AES)分析了腐蚀后腐蚀介质元素在复合镀层中的深度分布,并采用有限元分析方法计算了在腐蚀加热和冷却过程中复合镀层的应力变化.结果表明:O2、H2O、HCl引起铀表面Ti/Al复合镀层的反应腐蚀温度依次降低,界面分离是Ti/Al复合镀层抗气体加热腐蚀的主要失效形式,Al/U和Ti/Al界面分别成为Ti/Al复合镀层在含O气氛和HCl气体中加热腐蚀的薄弱环节;镀层从界面剥离主要是腐蚀气体从镀层缺陷渗透到界面,降低界面的结合力,从而产生应力引起的.     

铀表面离子镀铝层在含HCl气氛中的腐蚀行为

研究了在室温－100℃范围内，含2％HCl的氩气氛中温度对铀表面离子镀铝层腐蚀行为的影响。结果表明，随温度升高，铝镀层抗HCl腐蚀能力下降；与金属铝相比，铝镀层钝化能力增强，抗HCl腐蚀能力优于金属铝和铀，主要表现为氧化腐蚀和氯化腐蚀；同时，与金属铝相似，HCl气体加剧了残余气氛对铝镀层的氧化腐蚀。     

电沉积金属Ni涂层的高温腐蚀性能

通过调控电沉积过程中的阴极电流密度制备具有不同晶粒尺寸和择优取向的Ni镀层.采用透射电镜(TEM)、扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)对高温腐蚀前、后不同Ni镀层进行检测分析,对比研究不同Ni镀层经过960 ℃的78.07%Na3AlF6-9.5%AlF3-5%CaF2(质量分数)熔盐气氛腐蚀后的结构、成分和形貌.结果表明:在高电流密度下易获得晶粒细小,平均晶粒尺寸为120 nm,具有较强(100(择优取向的Ni镀层;而在低电流密度下所得的Ni镀层晶粒较粗大,平均晶粒尺寸为925 nm,具有较弱的(111(择优取向.在腐蚀气氛下,低电流密度下所得的Ni镀层在高温腐蚀后有利于生成晶粒粗大、且具有完整"八面体"结构的NiAl2O4尖晶石相;而高电流密度下所得Ni镀层表层腐蚀层的晶粒细小,且主要为NiO相.     

高温高压氯离子环境对螺杆钻具硬铬镀层腐蚀行为的影响

目的研究螺杆钻具表面硬铬镀层在高温高压氯离子环境下的腐蚀行为。方法利用高温高压反应釜模拟螺杆钻具的井下环境,对螺杆钻具表面硬铬镀层进行腐蚀和检测,通过正交实验法研究温度、压力和氯离子浓度对硬铬镀层腐蚀状态的影响。采用动电位扫描、腐蚀失重法,研究硬铬镀层的电化学参数及腐蚀特征。通过扫描电镜(SEM)和能谱(EDS),分析镀层腐蚀后的微观形貌和表面成分的变化。结果影响硬铬镀层腐蚀速率的最大因素是氯离子浓度,其次是温度,再次是压力。年腐蚀深度最严重为0.8925 mm/a,最大的腐蚀速率为1.9026 g/(m~2·h)。腐蚀速率随着氯离子浓度的升高而降低,随着温度和压力的升高而升高。结论推断在温度180℃、压力15 MPa和Na Cl质量浓度30 g/L的条件附近,硬铬镀层腐蚀最严重。氯离子是影响镀铬层腐蚀速率的主要因素,因为氯离子优先在敏感位置(钝化膜的薄弱点处,如裂纹)引发孔蚀核。在闭塞腐蚀电池催化作用下,镀层表面不断形成孔蚀,裂纹被加宽,最终导致少部分区域镀层剥落,影响镀层整体保护性能。     

环保彩锌镀层在NaCl介质中的腐蚀行为研究

采用Tafel直线外推法、加速腐蚀试验,研究了环保彩锌镀层在NaCl溶液中的腐蚀行为,利用扫描电镜和能谱分析表征彩锌镀层的腐蚀形貌和腐蚀产物。结果表明:随着NaCl浓度的升高,彩锌镀层腐蚀电流密度增大;在-1.2~-0.7 V区域内,彩锌镀层发生阳极钝化;镀锌层的3价铬钝化膜可阻碍Cl-腐蚀,在随后的加速腐蚀试验所产生的腐蚀产物可再次阻碍Cl-腐蚀;由于Cl-存在强吸附和强穿透性,使得钝化膜产生破裂并使Zn腐蚀;随着时间的增加,在Cl-的进一步作用下,钝化膜被破坏殆尽,甚至有些已经侵入基体形成Zn-Fe原电池加速了Zn的腐蚀。     

Al—Zn热浸镀层在H2S—NaCl—H2O体系中的腐蚀行为

采用表面钝化助镀法进行热浸镀,获得了55％Al－Zn镀层。研究了溶液温度、H2S浓度、NaCl浓度、pH值及试验时间对55％Al－Zn镀层在H2S－NaCl－H2O体系中的腐蚀行为。分析了镀层腐蚀前后的表面组织形貌及腐蚀产物,阐述了镀层的腐蚀机理。结果表明,55％Al－Zn镀层具有Zn镀层的电化学保护作用,其耐蚀性是镀锌钢的2－3倍,是风Q235的10－11倍。     

稀土铈对化学镀复合镀 Ni-P-PTFE 镀层耐蚀性能的影响

为了进一步提高化学镀Ni-P-PTFE复合镀层的耐蚀性能,采用在化学镀液中添加稀土铈的方法在45号碳钢试片表面制备了稀土铈Ni-P-PTFE复合镀层。用扫描电镜观察了镀层的表面形貌,并研究了稀土铈浓度对镀层中PTFE含量的影响,通过浸泡失重法分别研究了在3.5%NaCl和3.5%NaOH溶液中稀土铈浓度对镀层耐蚀性能的影响。结果表明:适量稀土铈的加入提高了镀层中PTFE的含量,降低了镀层的腐蚀速率,提高了复合镀层的耐蚀性能,在铈质量浓度为0.02 g/L时,在3.5%NaCl和3.5%NaOH溶液中镀层的腐蚀速率分别为0.402 mg/cm2和0.235 mg/cm2。     

钙铁离子对Cu-Ni-Cr复合镀层耐蚀性影响的研究

针对某汽车供应商提供的Cu-Ni-Cr镀层试样,采用电化学阻抗、动电位极化曲线等方法,研究了不同钙铁离子浓度以及在特定温度下铁离子对Cu-Ni-Cr镀层耐蚀性的影响。结果表明,在浸泡初期Ca2+对Cu-Ni-Cr镀层起钝化作用对镀层具有一定防护作用,在浸泡中后期,主要以Cl~-的腐蚀作用为主;Fe~(3+)对Cr为加速腐蚀作用,而且随着温度升高会加速Cr的腐蚀,Fe~(3+)对Cu-Ni-Cr镀层的腐蚀反应主要发生在Ni-Cr层。     

铝和铝合金的大气腐蚀研究现状

综述了铝和铝合金的大气腐蚀特点和大气主要污染组分对铝的大气腐蚀影响. 暴露于大气中的铝表面呈现三层结构, 即氧化铝和氢氧化铝层、其上的腐蚀产物层和最上层的污染物沉积形成的污染物层. 铝的硫酸盐是大气腐蚀层最丰富的腐蚀产物, 其次是铝的氯化物. 着重阐述了SO2, NO2, NO, O3, Cl-和存在的痕量大气有机物对铝的大气腐蚀行为影响.     

Corrosion behavior of composite brake materials

It is very important to study the corrosion behavior of composite brake materials for their design, manufacture, and application. In the study, one kind of composite brake material used in engineering machinery, two kinds used in automobiles, and gray cast iron HT200 were selected as tested materials. Their corrosion behavior in typical acid solution, alkali solution, salt solution, running water, and air were investigated. The results showed that some components of composite brake materials, such as iron matrix, steel fiber, and iron powder, were easily subject to corrosion in acid solution. Corrosive pitting, net‐like cracking, and breakage appeared at their corrosion surfaces, and in the solution of 3.5% NaCl, corrosive pitting took place and corrosion holes of 2–8 µm diameter formed at the corrosion surface of these components. But when brake materials were exposed to the solution of 5% NaOH, the organic binder was corroded seriously, nearly parallel cracks formed at the corrosion surface and some samples even became loose powders because the corrosion makes the binder lose its adhering function. In running water and air, the tested samples have an excellent corrosion resistance, and the composite brake material containing organic binder has a better corrosion resistance compared with other tested materials. The investigation has also indicated that the interface between ingredients easily corrodes.     

Inhibitoren der Korrosion 23 (1) – Gibt es eine Struktur- Wirkungs-Beziehung bei organischen Inhibitoren der Korrosion von Aluminium?

Corrosion inhibitors 23 (1) – Does there exist a structure-efficiency relation in the organic inhibitors of aluminium corrosion? Over 400 organic compounds have been routinely tested as potential inhibitors for the corrosion and dissolution of aluminium in In HCl/2,5% NaCl solution, using 10^?2 m/l as the concentration of the organic compound being tested. It was attempted to derive a relationship between efficiency of the inhibitor with molecular structure. Particular attention was devoted to the following classes of compound: organoarsenic; phosphonic and phosphinic acids; aromatic aldehydes and ketones; aromatic and aliphatic carboxylic acids; dihydric phenols; tetrazolium salts and formazan compounds; sulphoxides and aromatic sulphonic acids; sulphonamides and sulphones. For a selected number if inhibitors, the dependence of concentration and the effect of an oxygen-containing atmosphere were studied. Compounds which show good inhibition in the corrosion of aluminium are consistently even better in the protection of zinc surfaces. The mechanism of the corrosion inhibition is not clear, but the results suggest that the total molecular structure of the inhibitor must be considered, with particular importance paid to the nature and the spatial relationship of the different functional groups.     

船舶用碳钢表面镀Zn及其耐蚀性

为了提高船舶舱内碳钢制品的使用寿命，以20#碳钢 为例对其表面采用无氨、无氰溶液镀Zn以及钝化处理.研究了镀Zn试样在中性盐雾以及含有 机物质气氛中的耐蚀性能.结果表明：有机物质气氛是造成船舶舱内碳钢制品腐蚀的主要 原因，而无氨、无氰溶液进行镀Zn能在很大程度上解决碳钢表面的电化学腐蚀问题.     

Korrelation zwischen der beschleunigten Bewitterung im Laboratorium und der Freibewitterung eines kohlenstoffarmen Stahls in Meeresatmosphäre

Correlation between laboratory and weathering tests with a low carbon steel in maritime atmosphere The work presented here shows a possible correlation of the corrosion behaviour of a low carbon steel in maritime atmosphere and in a salt spray chamber. The corrosion tests in maritime atmosphere have been conducted in the open air and in a covered cabin at the coast of the Black Sea over two years. The laboratory corrosion tests have been conducted in a salt spray chamber and had a duration of 70 days. The correlation between laboratory and weathering tests is represented graphically. The chemical composition of the corrosion products is given.     

不锈钢在海洋环境中的腐蚀

在海洋大气区含铬大于１７％的不锈钢基本不腐蚀,在飞溅区,在含铬大于１７％的不锈钢腐蚀较轻,耐蚀性没有明显的差别。２Ｃｒ１３在海洋大气区和飞溅区不能维持钝态。不锈钢在潮 汐区的腐蚀较重,耐蚀性有明显差别。不锈钢在全浸区的腐蚀业重,耐蚀性判别很大。海生物污损对不锈钢的腐蚀有明显的影响。     

The Properties of Bright Nickel Electrodeposits in Relation to the Period of Service of the Plating Bath

Atmospheric exposure tests at industrial and marine sites and accelerated tests in a moist atmosphere containing sulphur dioxide showed no tendency for the corrosion resistance of organic bright nickel + chromium coatings to vary with increasing length of service of the nickel bath. The pattern of attack was very similar in atmospheric and accelerated tests. Crazing of the chromium occurred to about the same extent in an industrial atmosphere as in the sulphur dioxide test. Extended salt spray tests had almost no effect on the coatings.     

Novel,water-based high-performance primers that can replace metal pretreatments and chromate-containing primers

In previous research it was demonstrated that simple rinses with organofunctional silanes can be used to protect metals against various forms of corrosion. Such treatments also improve paint adhesion. However, when unpainted, the silane filsm are too thin to provide long-term corrosion protection. In this paper it will be shown that much thicker, primer-like coatings can be obtained from silanes if the silanes are mixed with organic resins and small particles, preferably nanosize. Self-priming coatings of up to 20 μm in thickness have been obtained with outstanding adhesion and corrosion protection properties. The components of such “superprimer” systems are all water-based, and they do not contain chromates or other toxic ingredients. Thus, they are environmentally friendly. This paper describes several successful superprimers and presents their performance data. This paper was presented at the 2nd International Surface Engineering Congress sponsored by ASM International, on September 15–17, 2003, in Indianapolis, Indiana, and appears on pp. 374–81 of the Proceedings.     

7475高强铝合金在海洋和乡村大气环境中的腐蚀行为研究

目的研究海洋和乡村大气环境对7475高强铝合金腐蚀行为的影响,为7475高强铝合金环境适应性设计提供支撑。方法在万宁和北京大气环境试验站开展了7475高强铝合金为期36个月的户外暴露试验,通过腐蚀失重分析方法研究了7475高强铝合金在我国2种典型大气环境中的腐蚀动力学规律;借助环境扫描电镜(ESEM)、金相显微镜和X射线光电子能谱(XPS)等表征技术研究了7475高强铝合金的微观腐蚀形貌和锈层成分。结果2种大气环境中,铝合金腐蚀都呈现出初始阶段腐蚀迅速发展,之后腐蚀速率减慢,最后进入腐蚀扩展相对平稳时期的变化规律。在海洋大气环境中户外暴露36个月后,7475高强铝合金呈现明显的点腐蚀特征,腐蚀产物组成为Al(OH)_3、Al_2O_3和Al_2Cl_3。7475高强铝合金在乡村大气环境中表面腐蚀非常轻微,个别表面出现非常小且浅的腐蚀点。结论在乡村大气环境和海洋大气环境中,7475高强铝合金腐蚀动力学遵循幂函数规律。相比较乡村大气环境,7475高强铝合金在海洋大气环境中表现出非常强的腐蚀敏感性。