船舶外加电流阴极保护用辅助阳极组件

阴极保护和优质涂层相结合是防止海水中金属结构物腐蚀的有效方法。在船舶外加电流阴极保护系统中 ,辅助阳极组件是其中的关键组成部分。介绍了船舶外加电流阴极保护用辅助阳极组件的研究发展及工程经验 ,评述了铅银阳极、铂阳极和混合金属氧化物阳极的性能特点。     

海水输送管阴极保护装置改造的跟踪检查

1999年 6月 ,我厂在停役期间对海水一泵至海水二泵阴极保护装置进行保护检查。首先对前期工作不够稳定的南 4号参比电极和北 12号辅助阳极进行更换。其次 ,调换观测井的所有挂片。最后 ,根据挂片的外观和重量 ,将 2年来测得的数据与 1997年以前测得的数据加以比较和分析。本文记述了本次海水管阴极保护检查情况 ,按有关设计、标准、规范的要求通电调试 ,根据检查获得的数据 ,讨论了 1997年对海水管阴极保护装置改造的合理性、可靠性及对海水输送管外壁增加牺牲阳极的必要性。参考执行标准 :ＧＢ 310 8— 82 ,ＧＢ 7387— 8,ＧＢ 32 2 0— 84…     

厂区埋地管网外加电流阴极保护

华能大连电厂埋地主冷却海水管网外加电流阴极保护系统，采用近管道线状路灯式分散阳极埋设方案，解决了厂区内管网保护近距离埋设阳极电位分布不均匀及工艺实施困难问题。     

牺牲阳极在舰船阴极保护中的应用和进展

分别论述了铝合金牺牲阳极、锌合金牺牲阳极、铁合金牺牲阳极的研究和发展过程,总结了各种阳极的研发现状、研发热点和相应的阳极产品研发成果,指出了针对特殊环境和细分领域的各种阳极,是阳极新材料未来发展的主要方向。对于铝合金牺牲阳极,介绍了常规铝合金牺牲阳极和包括海水环境低驱动电位阳极、油污海水低驱动电位牺牲阳极、适用于干湿交替环境的阳极和适用于高温环境中的阳极等在内的针对特殊环境和特殊材料的铝合金牺牲阳极在舰船阴极保护领域的应用,总结了船舶用铝合金牺牲阳极的研究进展;对于锌合金牺牲阳极,主要介绍了锌合金牺牲阳极的发展历史、研究现状和相应的阳极产品;对于铁合金牺牲阳极,主要总结了铁合金牺牲阳极的研究现状和在舰船上的实际应用。     

牺牲阳极在舰船阴极保护中的应用和进展

分别论述了铝合金牺牲阳极、锌合金牺牲阳极、铁合金牺牲阳极的研究和发展过程,总结了各种阳极的研发现状、研发热点和相应的阳极产品研发成果,指出了针对特殊环境和细分领域的各种阳极,是阳极新材料未来发展的主要方向。对于铝合金牺牲阳极,介绍了常规铝合金牺牲阳极和包括海水环境低驱动电位阳极、油污海水低驱动电位牺牲阳极、适用于干湿交替环境的阳极和适用于高温环境中的阳极等在内的针对特殊环境和特殊材料的铝合金牺牲阳极在舰船阴极保护领域的应用,总结了船舶用铝合金牺牲阳极的研究进展;对于锌合金牺牲阳极,主要介绍了锌合金牺牲阳极的发展历史、研究现状和相应的阳极产品;对于铁合金牺牲阳极,主要总结了铁合金牺牲阳极的研究现状和在舰船上的实际应用。     

海底管线牺牲极保护设计

本文论述了在海水和海泥介质中遭受强烈电化学腐蚀的海底管线的牺牲阳极保护方法，所用阳极及其性能，设计与安装。     

某型艇海水管路牺牲阳极保护选材设计与寿命预测

针对某型潜艇海水管系腐蚀严重的现状,提出采用管路铁阳极保护,对管路牺牲阳极的材料选择和结构设计进行了研究,分析评估了管路铁阳极的保护寿命。预测设计的六种规格牺牲阳极至少具有2.7年以上的保护寿命,其中五种规格的保护寿命可达3年以上。     

35钢牺牲阳极性能及其对铜管阴极保护的可行性

采用恒电流试验测试了35钢在海水和淡水中的牺牲阳极性能,并结合紫铜的极化曲线测试和阴极保护试验分析了35钢用于铜管牺牲阳极保护的可行性。结果表明:35钢在海水和淡水中都具有良好的牺牲阳极性能,工作电位稳定,电流效率高,溶解均匀,消耗慢;对紫铜管进行阴极保护有足够的驱动电压,达200 mV以上;短期阴极保护试验结果显示35钢对紫铜管有良好的保护效果。     

海水介质中阴极保护用涂层钛阳极的制备及其性能研究

为了提高钛阳极在阴极保护中应用的可靠性和使用寿命,用热分解方法制备了复合金属氧化物(MMO)涂层钛阳极,研究了阳极寿命与基材表面处理、涂敷量、温度、电流密度及涂层损耗率之间的关系.结果表明:基材喷砂增强了钛基体与涂层的结合力,增加涂敷量能够提高阳极寿命,而提高温度和电流密度对阳极寿命有不利影响,阳极涂层损耗率几乎为0.所研制的RuIrTiSnCo涂层钛阳极具有良好的电化学稳定性和较长的寿命,强化寿命达到96 h,约为次氯酸钠发生器标准的5倍,是海水介质外加电流阴极保护中比较理想的辅助阳极.     

舰船铜合金海水管路铁基牺牲阳极阴极保护研究

采用电化学测试、电偶腐蚀试验和腐蚀仿真计算方法综合研究了铁基牺牲阳极在海水环境下对铜合金管路提供阴极保护的效果。研究结果表明,海水环境下铁合金牺牲阳极与铜合金开路电位差值合理,在提供充分的阴极保护驱动电位的前提下,能够有效降低阳极材料的溶解速率,比锌合金阳极更适合于铜合金的阴极保护;铁基牺牲阳极在铜合金管路阴极保护过程中,保护电流发散受管路尺寸影响,一般可保护10倍管径范围区域。研究成果对于提高海水环境下铜合金管路的腐蚀安全性具有参考意义,具有良好的工程应用价值。     

316L不锈钢在海水中的阴极极化行为研究

为了探索316L不锈钢阴极保护有效控制电位,利用动电位极化曲线及恒电位极化法研究了316L不锈钢在天然海水和模拟闭塞液中的阴极极化行为,通过失重法研究了不同电位恒电位极化对316L不锈钢在模拟闭塞液中腐蚀控制的效果.研究表明:316L不锈钢在海水中适宜的阴极保护电位为-0.6～-0.9 V(vs.SCE),模拟闭塞液中...     

Layer-by-layer self-assembled mesoporous PEDOT-PSS and carbon black hybrid films for platinum free dye-sensitized-solar-cell counter electrodes

A thin film of poly(3,4-ethylenedioxythiophene)-poly(4-styrenesulfonic acid) (PEDOT-PSS), which is an alternative cathodic catalyst for Pt in dye-sensitized solar cells, was prepared using the layer-by-layer self-assembly method (LbL). The film is highly adhesive to the substrate and has a controllable thickness. Therefore, the PEDOT-PSS film prepared using LbL is expected have high performance and durability as a counter electrode. Moreover, when carbon black was added to the PEDOT-PSS solution, highly mesoporous PEDOT-PSS and carbon black hybrid films were obtained. These films showed high cathodic activity. In this study, we investigated the change in morphology in the obtained film with increasing carbon black content, and the influence of the porosity and thickness on the performance of the cells. In this study, a Pt-free counter electrode with performance similar to that of Pt-based counter electrodes was successfully fabricated. The achieved efficiency of 4.71% was only a factor of 8% lower than that of the cell using conventional thermally deposited Pt on fluorine-doped tin oxide glass counter electrodes.     

Rißfortschritt an Baustählen in Meerwasser

Crack Growth Behaviour of Structural Steels in Seawater The influence of a synthetic seawater environment upon the crack growth behaviour of two structural steels was investigated. The results were presented in terms of the stress intensity fracture toughness parameter. Data were generated in air and in seawater with or without a cathodic protection. Results show that seawater environment and a cathodic protection influence the crack propagation at the applied frequencies of 0,04 and 0,25 Hz. The use of cathodic protection raises questions concerning the resistance to hydrogen embrittlement of the two steels. Some fractographic examinations of selected specimens show the microstructure of the two steels at various test conditions.     

THE EFFECTS OF CATHODIC POTENTIAL AND CALCAREOUS DEPOSITS ON CORROSION FATIGUE CRACK GROWTH RATE IN SEA WATER FOR TWO OFFSHORE STRUCTURAL STEELS

The effects of cathodic protection potential, corrosion products and stress ratio on corrosion fatigue crack growth rate have been studied on offshore structural steels. These materials were cathodically polarised in seawater and 3% sodium chloride solution at three potentials of -0.8, -1.0 and -1.1 V(SCE). The corrosion fatigue crack growth rate in seawater was greater than that in air and increased with more negative potentials. The maximum acceleration of crack growth rate in seawater was observed at the crack growth plateau which was independent of ΔK. Calcareous deposits precipitated within the cracks resulted in an increase of crack opening level and contributed to a reduction of the corrosion fatigue crack growth rate. Such a corrosion-product-wedging effect could be evaluated by using an effective stress intensity range, ΔK_eff. The estimation of corrosion fatigue crack growth rate in terms of ΔK_eff clarified the effect of hydrogen embrittlement under a cathodic potential. Thus the processes of cracking in seawater at cathodic potentials resulted from mechanical fatigue and hydrogen embrittlement with calcareous deposits reducing the crack growth rate. All these three mechanisms were mutually competitive.     

电解海水对环氧涂层防腐蚀性能的影响研究

通过在天然海水及3种不同余氯浓度的电解海水中进行静态浸泡试验，研究了环氧涂层吸水率、附着力、划痕剥离、耐阴极剥离等防腐蚀性能。结果表明，在所试验的3种浓度电解海水中，环氧涂层均未起泡或剥落，试验后的涂层附着力>3.5 MPa，涂层仍保持良好的防腐性能。当电解海水中余氯浓度不超过10 mg/L时，电解海水对涂层划痕剥离及耐阴极剥离性能影响不显著，涂层失效主要是由于海水介质沿着金属-涂层界面渗透导致涂层从基材脱附；当余氯浓度达到15 mg/L时，涂层划痕剥离及耐阴极剥离性能随着试验时间的延长显著下降，高浓度余氯会加速涂层失效。      

Real-time determination of picomolar free Cu(II) in seawater using a fluorescence-based fiber optic biosensor

We report real-time, in situ determination of free copper ion at picomolar levels in seawater using a fluorescence-based fiber optic biosensor. The sensor transducer is a protein molecule, site-specifically labeled with a fluorophore that is attached to the distal end of an optical fiber, which binds free Cu(II) with high affinity and selectivity. The transducer reports the metal's concentration as a change in fluorescence intensity or lifetime, using a frequency domain approach. The transducer's response time is diffusion-limited, with a typical measurement requiring 30 s. The sensor demonstrates a detection limit of 0.1 pM free Cu(II) in a seawater model. Accuracy and precision of the sensor were at least comparable to cathodic ligand exchange/adsorptive cathodic stripping voltammetry. Measurements of tidal flushing of a copper-contaminated inlet are shown.     

THE EFFECT OF CATHODIC PROTECTION POTENTIAL ON CORROSION FATIGUE CRACK GROWTH RATE OF AN OFFSHORE STRUCTURAL STEEL

Abstract— Duplicate tests have been performed to determine the effect of cathodic protection potential on corrosion fatigue crack growth rate of a modern offshore structural steel, produced by thermo-mechanically controlled processes. The experiments were carried out using compact tension specimens exposed to artificial seawater at 10°C and subjected to constant amplitude loading at 0.35 Hz. Reproducible results showed that the merits of cathodic protection potentials are strongly dependent on stress intensity ratio R and stress intensity range Δ K . It appears that a specific value of cathodic potential may not give comprehensive protection against corrosion fatigue within the spectrum of variable amplitude loading experienced in service. Fractography showed the initiation of secondary cracks on the fracture surface to be associated with the dissolution of calcium sulphide inclusions, regardless of imposed cathodic potential.     

THE EFFECTS OF A MARINE ENVIRONMENT ON THE CORROSION FATIGUE CRACK PROPAGATION RATE OF PURE TITANIUM AND ITS WELD METAL

The effects of stress ratio and microstructure on fatigue crack growth rate in air and natural seawater were investigated for pure titanium and its weld metal. The corrosion fatigue characterization of pure titanium was also studied under a cathodic potential in natural seawater. In air, the fatigue crack growth rates of pure titanium and its weld metal increased with increasing stress ratio. In natural seawater, the effect of stress ratio was similar to that in air. However, the crack growth rates were greater for pure titanium than for the weld metal. These results indicate that the corrosion action is sensitive to the microstructure in front of the crack tip. When the crack growth rate for the weld metal was plotted using the effective stress intensity factor range, the crack growth rate in natural seawater was coincident with that in air, regardless of stress ratio. For the base metal, there is a significant difference in the crack growth rate between natural seawater and air.