电弧喷涂Al-Zn-Si-RE合金涂层与Al-Zn伪合金涂层的耐蚀性能对比

为研究Al-Zn-Si-RE合金涂层和相同Al含量的Al-Zn伪合金涂层耐蚀性能的不同,采用电弧喷涂技术在Q235钢表面制备了此两种合金涂层。通过盐水全浸实验和电化学测试技术对比研究了两种涂层的耐腐蚀性能,并将两种涂层的极化曲线与纯Zn、纯Al、Zn-15Al合金涂层进行了对比分析。使用扫描电镜、金相显微镜和X-射线衍射仪等手段测试分析了两种合金涂层腐蚀前后的微观组织形貌和相组成。结果表明,Al-Zn-Si-RE合金涂层的自腐蚀电位和自腐蚀电流密度分别为-0.995V和3.319×10-6 A/cm2,腐蚀电位更正,腐蚀电流密度更低,耐蚀性更好,原因可能是致密的腐蚀产物膜抑制了腐蚀作用;Al-Zn-Si-RE合金涂层与伪合金涂层微观组织成分和相结构的不同引起腐蚀行为的差异,且Al-Zn-Si-RE合金涂层表现出更好的耐盐水腐蚀性能;稀土元素的存在有利于提高Al-Zn-Si-RE合金涂层的耐蚀性。     

热镀Al-Zn合金镀层在模拟工业污染大气环境中的腐蚀试验及数学模型分析

1 引言 不同Al-Zn合金镀层在不同环境中的耐蚀性能差异很大,但研究它们在不同环境中腐蚀失重(ΔW)与腐蚀时间(T)关系的报道还很少见,本工作通过模拟工业污染大气环境,根据大气腐蚀常用数学模型ΔM=K×T~n,对不同Al-Zn合金热镀层的腐蚀数据进行曲线拟合,为选择大气腐蚀模拟试验方法与评价Al-Zn合金热镀层的耐蚀性提供依据。     

Co-28Mo-8Cr-2Si涂层在去离子水和人工海水中的气蚀性能

服役于海洋中的多种零部件往往因腐蚀-气蚀联合作用而严重损坏。文中采用超音速火焰喷涂(HVOF)技术制备了Co-28Mo-8Cr-2Si涂层,使用光学显微镜、X射线衍射仪、显微硬度计等设备分析涂层的组织结构和力学性能,使用电化学工作站考察涂层的腐蚀性能,使用超声波振动气蚀试验机评价了涂层分别在去离子水和人工海水中的气蚀性能,利用扫描电镜(SEM)观察涂层腐蚀和气蚀后的形貌。结果表明:在去离水中,涂层的气蚀机理主要是孔隙周围的扁平粒子大片剥落,气蚀6h后,涂层的累积体积损失高达4.15mm3;在人工海水中,腐蚀产物有效地填充了涂层表面的孔隙,大大降低了扁平粒子剥落情况的发生,气蚀6h后,涂层的累积体积损失仅为1.83mm3。     

海洋工程用钢表面喷涂Zn、Al和Zn-55%Al伪合金涂层的耐蚀性

热喷涂金属涂层是当前海洋环境下钢结构件防腐的首选方法,利用电弧喷涂技术在新型海洋工程结构用钢(Q345B钢)表面制备了Zn-55%Al伪合金热喷涂涂层,并与纯Zn涂层和纯Al涂层的耐蚀性进行了对比。结果表明:纯Zn涂层能提供较好的电化学阴极保护作用,但电化学性能欠佳;纯Al涂层表现出优良的电化学性能,但腐蚀后期产生点蚀;Zn-55%Al伪合金涂层具有更优越的耐蚀性和腐蚀防护性能。     

工程机械用Cu-Ni合金的腐蚀行为研究

对Cu-Ni合金进行了全浸腐蚀、电化学腐蚀和冲刷腐蚀性能测试。研究了全浸时间、冲刷流速对Cu-Ni合金腐蚀速率、腐蚀类型和电化学性能的影响,并分析了腐蚀反应的作用机理。结果表明,全浸腐蚀过程中Cu-Ni合金表面会形成Cu_2O氧化膜,而全浸腐蚀时间达到720 h后表面膜中的Cu_2O会与腐蚀介质中的氧气和氯离子发生反应形成Cu(OH)_3Cl;Cu-Ni合金表面氧化膜的形成可有效抑制腐蚀介质与基体的接触,从而对合金基体起到保护作用。随着全浸腐蚀时间的延长,腐蚀深度速率的变化趋势与全浸腐蚀速率的变化趋势保持一致,即采用线性极化方法测试Cu-Ni合金在静态3.5%Na Cl溶液中的腐蚀速率是可行的;在冲刷流速低于临界流速下的Cu-Ni合金具有较低的腐蚀速率,可起到对材料良好的保护作用。     

Zn-Al伪合金涂层的耐蚀性能研究

目的提高电弧喷涂锌铝合金涂层中Al的含量。方法用纯铝丝和Zn80Al20合金丝在Q235钢表面制备Zn-Al伪合金涂层,通过中性盐雾试验和电化学试验,与纯铝涂层和Zn-Al合金涂层进行对比,分析比较三种涂层在氯离子存在环境中的腐蚀行为。结果 Zn-Al伪合金涂层表现出了较高的活化能力和较低的腐蚀速度。结论 Zn-Al伪合金涂层的耐蚀性能优于纯铝涂层和Zn-Al合金涂层。     

钢在流动人造海水中的冲刷腐蚀行为与防护研究

目的 研究钢在流动人造海水中的冲刷腐蚀行为及防护方法.方法 采用自制的冲刷试验平台,利用扫描电镜、电化学阻抗、电化学噪声、最大熵值变换等方法,分析钢在流动人造海水中各阶段的冲刷腐蚀行为特征,验证材料表面涂覆新型环氧涂层的方法对提高钢耐流动人造海水冲刷腐蚀的有效性.结果 钢在2 m/s流动人造海水中30 d的冲刷腐蚀行为特征可以分为三个阶段,第一阶段,金属开始发生点蚀,生成网状腐蚀产物,反应电阻上升后持续减小至400?,电化学噪声电位发生负移,SE值较大,电化学腐蚀速率增强;第二阶段,点蚀速率减弱,开始出现颗粒状腐蚀产物,反应电阻相对稳定在300? 左右,电化学噪声电位发生正移,SE值数值较小,电化学腐蚀速率保持相对稳定;第三阶段,外层腐蚀产物剥离,反应电阻和SE值发生较大的波动,冲刷作用导致了腐蚀产物的快速形成和脱离.涂覆绝缘涂层的钢试样总电阻稳定在6.0×105?左右,高出无涂层裸露试样总电阻(1.0×103?)2个数量级.结论 钢在2 m/s流动人造海水中30 d的冲刷腐蚀行为特征可以分为加速腐蚀-动态平衡-平衡破坏三个阶段,新型环氧涂层具有较好的耐冲刷腐蚀性能.     

微弧表面处理对AZ31B镁合金耐腐蚀及耐腐蚀疲劳性能的影响

采用微弧表面处理技术(微弧氧化MAO和微弧复合MCC)在AZ31B镁合金基体上制备出不同断面结构的防护涂层。通过电化学腐蚀及腐蚀疲劳测试方法,研究了MAO、MCC涂层的电化学腐蚀及腐蚀疲劳性能。结果表明,生长10 min的MAO涂层具有较好的耐电化学腐蚀性能。MAO涂层表面存在微孔和微裂纹,在应力条件下微孔和微裂纹作为疲劳断裂的裂纹萌生点,可加速裂纹的萌生与扩展,使其腐蚀疲劳寿命相较AZ31B合金基体降低了55%。而具有MCC涂层的AZ31B合金试样腐蚀疲劳极限为(64.0±5.4) MPa,比AZ31B合金基体提高了59%。在低应力载荷下(＜80 MPa),微弧复合涂层试样的腐蚀疲劳强度得到明显提高。     

Mg-4.0Zn-2.0Sr-0.4Ca合金复合涂层的耐腐蚀性能

通过环保型阳极氧化工艺及聚合沉积技术在生物材料Mg-4.0Zn-2.0Sr-0.4Ca合金表面逐层制备阳极氧化膜、SiO₂溶胶凝胶、聚多巴胺(PDA)和壳聚糖(CS)复合涂层。采用扫描电镜(SEM)、X射线衍射仪(XRD)观察涂层形貌并确定相组成,采用电化学测试、SBF浸泡试验比较涂层对合金耐蚀性能的影响。结果表明,制备的复合涂层致密完整无缺陷。在SBF溶液中,复合涂层随腐蚀时间的延长逐渐产生裂纹并破碎,产生较小的腐蚀坑,腐蚀在一定程度上被控制在表面,而无涂层Mg-4.0Zn-2.0Sr-0.4Ca合金在SBF溶液中的腐蚀以点蚀和局部腐蚀为主,且腐蚀程度随腐蚀时间的延长而加剧。复合涂层在SBF溶液中的腐蚀电流密度、腐蚀电位和平均腐蚀速率分别为5.7039 μA/cm²、-1.4203 V(vs SCE)和0.163 g/(m²·h),均优于无涂层镁合金,且平均腐蚀速率降幅达50%以上,说明制备的复合涂层可显著提高Mg-4.0Zn-2.0Sr-0.4Ca合金的耐腐蚀性能。     

氯离子浓度对Ni-P合金涂层失效过程影响的SECM实验和COMSOL模拟研究

目的发展具有空间分辨的腐蚀电化学研究方法。方法用电沉积方法在铜基体上制备Ni和Ni-P涂层,应用扫描电镜和XRD检测涂层表面形貌和晶体结构,采用扫描电化学显微镜(SECM)研究Ni和Ni-P涂层在不同浓度Na Cl溶液中的失效行为,并结合COMSOL多物理场软件建立二维和三维模型,模拟量化活性点大小和反馈机制。结果低浓度Cl-对于纯Ni涂层具有活化作用,增加Cl-浓度会促进腐蚀发生。Ni-P合金涂层在低浓度Na Cl溶液中,短时间内保持良好的稳定性,浸泡6 h后,低P合金涂层出现典型的活性点和腐蚀产物,而高P合金涂层在浸泡24 h后出现腐蚀产物和活性区域。0.1 mol/L的Na Cl溶液促进低P合金涂层局部腐蚀的发生,而涂层在0.3 mol/L Na Cl溶液中则以发生均匀腐蚀为主。逼近曲线及其模拟结果表明,腐蚀产物对于Fc Me OH的电化学过程完全失活,而新鲜Cu表面对Fc Me OH氧化还原过程受扩散控制。三维模拟结果显示,低P合金涂层失效过程中活性点大小接近10μm。结论 Ni和Ni-P合金涂层的失效过程中活性点的形成、腐蚀产物的生成和累积过程与SECM面扫描图谱中正负反馈效应相关,Cl-促进腐蚀发生,其浓度影响腐蚀类型。COMSOL多物理场模拟明确反馈效应与探针和基底的距离有关,Ni-P涂层失效活性点大小在微米级。     

Operational based corrosion analysis in naval ships

Life extension of ageing steel structures such as naval ships requires consideration of plate thickness losses due to corrosion, particularly when protective measures such as paint coatings and sacrificial protection are not entirely effective. Traditionally, corrosion prediction models for ships take no account of the operational profile. Consequently, the corrosion models have an inherently high variability with poor corrosion prediction capability. A new corrosion model for the prediction of corrosion loss in the seawater ballast tanks of naval vessels has been developed. The model incorporates previously available corrosion models for immersion corrosion and atmospheric corrosion and takes account of operational and environmental variables. Experimental validation is presented for a trial on an operational naval vessel.     

海洋船舶冷却水系统阴极保护的注意事项

本文主要论述了阴极保护技术在海洋船舶冷却水系统应用的方案选择和实际应用中需要注意的问题，对指导海洋结构冷却系统防腐蚀具有特别的意义。     

The use of potentiostatic techniques in the development of improved stainless steels for chemical plant

It is possible by potentiostatic methods to exactly forecast the behaviour of unusual material/corrodent systems; such methods may, consequently, be used for the development of corrosion resistant alloys. A new alloy on iron base (with, %, 25 Cr, 5.5 Ni, 3.0 Cu, 2.5 Mo) combines very good mechanical properties with resistance to general corrosion, pitting and crevice corrosion. Industrial applications include impellers for pumps operating in acid slurries (30% P₂O₅, 30% CaSO₄ as solids, 2% H₂SO₄, HF, H₂SiF₆; 60–80°C, three years without corrosion); pump impeller for sulfuric acid and other corrosive products shipped in tank ships; impeller for a sea water pump (no corrosion after 4 years' operation).     

A time-dependent corrosion wastage model for seawater ballast tank structures of ships

For assessment of time-dependent reliability or risk of aging ship structures, it is essential to have a mathematical model which provides the statistical characteristics (mean, variance, distribution) of corrosion wastage as a function of time (i.e., ship age). The aim of the present work is to develop such a model for low alloy carbon steel plates used for the structure of seawater ballast tanks in ships. Measurement data of structural wastage due to corrosion for such ship steel plates is collected and the statistical characteristics of corrosion loss and rate are quantified by statistical analysis in terms of ship age. The results and insights developed in the present study will be useful for predicting the wastage of corrosion in seawater ballast tank structures of ships. They will also be useful for designing corrosion tolerant structures subjected to the seawater environment.     

气体多元共渗技术及应用

气体多元共渗技术适合在使用过程中高磨损、易腐蚀的机械零件、金属模具、金属切削工具等部件的热处理。另外,对于在大气下服役、要求抗含氯化钠、二氧化硫湿空气的钢铁材料及其构件的表面防腐蚀处理也十分有效。此技术能够在轻型装甲车辆履带等传动部件,舰船装甲及离合器,刹车磨擦片等得到更广泛的应用,给社会带来更大的效益。铁道线路、机车车辆、汽车配件的另部件中,大幅度提高其耐磨性能与抗蚀性能。     

Corrosion of mild steel in porous media

The corrosion process in large-particle porous media is investigated with particular reference to corrosion in bulk carriers (ships). Examples of large-particle porous media include raw materials such as coal and iron ore which typically have particle sizes ranging up to approximately 50 mm diameter. It is proposed that the corrosion process is dominated by finer particles which co-exist with the larger particles. A mathematical model of the corrosion process is developed and used to estimate corrosion rates. These are shown to compare well with experimental results. The analysis indicates that to minimise corrosion it is desirable to maintain the moisture content of porous media in contact with mild steel either to less than 50%, or to more than 80%, of the maximum water holding capacity of the media.     

苛刻环境下材料表面防护技术的研究进展

近年来,材料表面防护技术已由普通环境下的材料保护技术向苛刻环境下的特种防护技术发展,主要包括高速、高温、高压、重载环境下的长寿命润滑与强化技术,严酷海洋大气、深海环境、辐射环境下的腐蚀与防护技术,以及面向重大装备的维修与再制造技术等。这些技术的发展促进了磁控溅射、多弧离子镀、冷喷涂、热喷涂、智能防腐涂层等多项新技术的发展,并在航空、航天、船舶、兵器、核电等多个重点行业中得到应用。文中对近年来苛刻环境下材料表面防护技术的发展现状和趋势进行了研究,以我国重大工程装备为出发点,重点对材料的腐蚀与防护、减摩与润滑、耐磨与强化以及维修与再制造4个领域技术的新成果、新观点、新方法和新技术进行了综述,为相关的研究工作提供技术参考。     

舰船冷却设备腐蚀特点及选材

对舰船冷却设备的典型腐蚀破损原因作了详细分析， 阐明了舰船冷却设备的腐蚀机理和特点，提出了舰用冷却设备的材料选取和搭配原则，实践证明合理的选材设计是防止舰船冷却设备异常腐蚀的重要环节.     

Zur Entwicklung der elektrochemischen potentiokinetischen Reaktivierungsmethode – des EPR‐Tests

On the development of the electrochemical potentiokinetic reactivation method – the EPR‐test Electrochemical potentiokinetic reactivation methods, but also other polarisation methods, are suitable as quasi non destructive testing methods to describe the corrosion resistance of steels and alloys without needing a very pretentious surface preparation. They may be used also to check finished components or even on site such in service, especially welding areas or weld overlays. Compared to standard tests they are quicker, more sensitive, more objective and quasi quantitative. They may be applied not only with austenitic standard steels but also with high alloyed ferritic, martensitic or duplex steels as well as with nickel based alloys. After any case of heat treatment the sensitivity to intergranular corrosion but also to pitting or selective attack can be determined by these testing methods. They may inform on the general corrosion resistance or the microstructural changes which may occur with materials, too. Based on the experience of many years with such methods which, starting from the early developments, have now been applied to very different materials, one may attend new fields of application in research and also as a nationally and internationally testing standard.     

激光熔覆修复青铜零件的实验研究和工程应用

青铜具有极好的耐海水腐蚀性和耐磨损性能,在舰艇、船舶中大量存在青铜零件,但对这些零件进行修复非常困难。由于青铜对激光的强烈反射及其优良的热传导性,给激光熔覆修复青铜零件带来了很大的困难。通过激光熔覆修复实验,优化了激光熔覆修复工艺参数。在对激光熔覆修复过程进行最优控制的条件下,获得了界面结合良好、耐腐蚀性和耐磨损性均符合要求的激光熔覆修复试样。在此基础上,实现了对实际舰船青铜零件的激光熔覆修复。