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1.
INTRODUCTIONBesidesprotectivecoatingandcathodicprotectionmethodsagainstcorrosionoflowalloysteelconstructuresinmarineenvironment,itisalsoimportanttoimprovethecorrosionresistanceofthelowalloysteelitself.Therearefewreportsontherelationshipofalloyelementandthecorrosionre sistanceofsteel .Larrabee (1 958)’s 5-9yearsseaexperimentusinglong scalesteelshowedthatthecorrosionresistanceof 0 .5%Ni-0 .5%Cu -0 .1 %Psteelwasthehighestinthesplashzone .HouandZhang (1 980 )consideredthataproperrelationshi…  相似文献   

2.
Study on rust layers on steel in different marine corrosion zone   总被引:1,自引:0,他引:1  
IrmODUCnONTheMossbaureffect(ME)isalsoknOWnasrecoil-thenuclearresonaneabsorp-hon.MossbaursPeCboscoPy(MS)haspIDvedtobeaveryuSefultecheqUeforstudytngcormsionPimessesandcedon-cts.TheInainadvantagsofMSincormsionre-enhare:(l)thenon-deStrutivechateroftheteCboqUe;(2)possibilltyforquali-tativeandqUanitativephaanalsis;(3)uSehassinidenificationofPOOrlycrystal-lizedoramorphouscormsionpnhats.WththedeVfoPmntofInarineresomees,InansteelconstrUctionswerebulltatsea'MSwasusedforanalfongcormsion~t…  相似文献   

3.
ImooUcr0NCormsinnofsodinconatisnowrognindasaseriousproblemwithlargeere-nondconSequenas.Thecormsionproducofondatthesurfaeeofrenfontin-dutaltenSioninthernaterial,resultinginfraCtureandspillingoftheconcretefromtherenfoot(Madrinaldetal.,l99l).Asaasult,theconCretestructure'sIneCanhalstwthisgreatiytalued.0wingtothephyShaldfultyofconduCtingforchdricalexperiInentsinconare,muCoftheworkintheaasofndanisticdCtendnationsforcormsionofstalincon-~wereconduedinalkalinesolution,generallyofporewatCr(Romirz…  相似文献   

4.
STUDY ON THE CORROSION PEAK OF CARBON STEEL IN MARINE SPLASH ZONE   总被引:3,自引:0,他引:3  
lNTRODUCTI0NSincetheoonceptofrnarinesplashzone(MSZ)wasfirstproposedbyHumble,rnanyresearchesprovedthatthecorrosionofsteelinthesplashzoneisthemostseriousinthemarineenvironninetandthatthisMSZcorrosionhasapeak(Zhu,l995).Howevertheenvironmentalfactorscatisingthecorrosionpeakwasnotkn0wnthen(Niat0,l975,Atsushi,l994)andtherangeoftheMSZwasnotyetdeariydefinedopzkaki,l985).ThispaperexplainsthemaincauseofthecormsionpeakanddefinestheexaCtrangeoftheMSZinsomeofChina'sharbours.MATERIALSANDMET…  相似文献   

5.
Chemical means were used to extract polyphenols from healthy brown algae collected in littoral seawater. Experiments on corrosion of A3 steel, the time-potential curve, and polarization curve in polyphenols seawater showed stronger cathodic polarization compared with that in common seawater. This indicates that brown algae polyphenols might feasibly be used as corrosion inhibitor in seawater. Contribution No. 3763 from the Institute of Oceanology, Chinese Academy of Sciences. Project 59471054 supported by NSFC and National “Nineth Five Year” Project 96-916-04-01.  相似文献   

6.
INTRODUCTIONBrownalgaepolyphenol (BAP)isadistinctivenaturalproduct,anactiveorganicmatterre leasedfromnormalgrowingbrownalgaeintoseawater.TheBAPoutputfromthelivingbrownalgaeis 1g (m2 ·d) (Craigieetal.,1 964 ) .About3 7%ofdissolvedorganicmatter(DOM)inseawateralongshoreisthesecretionfromseaweedcells,andcanreach 70 %oftotalDOMinseawaterifor ganicmatterreleasedbydeadalgaeisincluded (Raganetal.,1 979) .BAP (mainlycomprisingtheyellowmatter)inseawateralongshore ,canreach 2 .5mg L (Rashida…  相似文献   

7.
The effect of barnacles on corrosion of low alloy (16Mn) steel was studied by immersing steel panels in seawater at Zhonggang.Qingdao, for 41 months. It was found that the secondary attachment on this kind of steel by barnacles had less effect on its corrosion while the primary attachment had a greater effect; that different seasons have different effects on the form and extent of local corrosion in this steel, and that primarily attached barnacles cause more serious local corrosion in high breeding seasons when there are more attachments.  相似文献   

8.
INTRODUCTIONItwasgenerallyconsideredpreviouslythatthecorrosionofsteelinseamudwasnotserious.However,itwaslaterfoundthatthecorrosionrateofsteelinsomeseamudwashigherthanthatinseawater(King,1980;Sehmide,1982;Guoetal.,1997;Hou,1998).Therearesomereportsthatthecorrosionr…  相似文献   

9.
The high strength low-alloy steels are welded by underwater wet welding with stainless steel electrodes. The micro-structural and electrochemical corrosion study of base metal (BM), weld zone (WZ) and heat affected zone (HAZ) are carried out to understand the influence of the corrosion product layer generated on the high strength low-alloy steels welded by underwater wet welding with stainless steel electrodes, methods used including, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). The results indicate that the WZ acts as a cathode and there is no corrosion product on it throughout the immersion period in seawater. The HAZ and BM acts as anodes. The corrosion rates of the HAZ and BM change with the immersion time increasing. In the initial immersion period, the HAZ has the highest corrosion rate because it has a coarse tempered martensite structure and the BM exhibites a microstructure with very fine grains of ferrite and pearlite. After a period of immersion, the BM has the highest corrosion rate. The reason is that the corrosion product layer on the HAZ is dense and has a better protective property while that on the BM is loose and can not inhibit the diffusion of oxygen.  相似文献   

10.
Copper has long been utilized as a disinfectant for bacteria,but its impact on microbial communities attached to the steel surface in seawater remains unknown.In the present study,3 mooring chain steels of different copper contents are subjected to a 3-month marine field exposure,and the corrosion rate increases in the order of BR5 steel(without copper) BR5 CuH steel(0.8% copper) BR5 CuL steel(0.4% copper).The microbial community results show that copper introduction does not result in an obvious change in microbial quantity,but it alters the diversity,richness,and structure of microbial communities due to the variation in copper-resistance of different species.BR5 CuH steel holds microbial communities with the highest percentage of some well-known corrosive microbes including sulfate-reducing bacteria,sulfuroxidizing bacteria,and iron-oxidizing bacteria,but possesses the lowest community diversity/richness owing to the toxicity of copper.The microbial community diversity/richness is stimulated by the low-copper content of BR5 CuL steel,and this steel also carries an intermediate proportion of such corrosive bacteria.Both well-known corrosive bacteria and microbial community diversity/richness seem to be involved in the corrosion acceleration of copper-bearing mooring chain steels.  相似文献   

11.
The through one year corrosion potential and polarization resistance for 3 kinds of steels in seabottom sediment of Liaodong Bay were measured with the “MD” method. The measurements will have some theoretical and practical values. The theoretical value lies in that the recorded changing process of the practical corrosion case can be basis for indoor discussion and electrochemical research on the corrosion process. The practical value lies in that the obtained data can be basis for designing and controlling electrochemical protection systems. In fact, it is very difficult to measure in situ the corrosion parameters of steels in sea sediment. Contribution No. 2611 from the Institute of Oceanology, Chinese Academy of Sciences. This study is a major project of the Chinese Academy of Sciences.  相似文献   

12.
The tbough one year cormsion potential and polarisation resistanoc for 3 kinds of stals in seabottomedment of Liaodong Bay were measured with the “MD” method.The measurements wiIl have some thoretical and pndital talues. The thooretical valoc lies in thatthe reoorded changing process of the practital corrosion case can be basis for indoor discussion andeectrochemical on the corrosion practical value lies in that the obtained datu canbe basis for designing and controlling elatrochemical protation syttems. In fact, it is very difficult tomeasure in situ the cornosion parnders of steeIs in sea sediment.  相似文献   

13.
INTR0DUCnONAlloycoatingscandetivelyproteCtsteelagainstcormsioninseri0uscormsionenvir-orunent,suchasthedrinesplashandtidalzones-TwoInainhodiptincaldrinumalloycOaingswidelyusedcommroiallyareGalfancoaing(contalningZn-5wt%kl-us)devel-oPedbytheIntemaionaltalZincReenhheZaionandhocoating(c0n-talningZn-55Wt%Al-1.6Wt%Si)develoPedbytheBethlehemSteelCorpOration-Anewrinc-basedalloycOaingdevel0PedbyNortheaStemUniversityisdiscussedinthesPaperbyelecthehendcalmethod.FromSun(l996),welmOWthecorms…  相似文献   

14.
Considering the continuous exploitation of marine resources,it is very important to study the anticorrosion performance and durability of zinc coated streel(ZCS) because its increasing use as reinforcements in seawater.Tafel polarization curves and linear polarization curves combined with electrochemical impedance spectroscopy(EIS) were employed to evaluate the corrosion performance of ZCS at Qingdao test station during long-term immersion in seawater.The results indicated that the corrosion rate of the ZCS increased obviously with immersion time in seawater.The corrosion products that formed on the zinc coated steel were loose and porous,and were mainly composed of Zn_5(OH)_8Cl_2,Zns(OH)_6(CO_3)_2,and ZnO.Pitting corrosion occurred on the steel surface in neutral seawater,and the rate of ZCS corrosion decreased with increasing pH.  相似文献   

15.
The Al—basic sacrificial anode is widely used to protect steel construction from corrosion in seawater, but is not suitable for protecting steel in freshwater. In the estuary area, seawater and freshwater mix and different seawater salinity can be formed in different mixing sites between freshwater and seawater. Based on the requirements of the Shengli Petroleum Administrative Bureau of China, the effect of seawater salinity on electrochemical properties of Al—basic anode was studied under laboratory conditions by the method given in National Standard GB 4948-85 (China Starndard Bureau, 1985). No obvious effect was found when seawater salinity was 30 to 10, but obvious effect on anodic open circuit potential, closed circuit potential and current efficiency was found when seawater salinity was 5. These values are lower than those given in the National Standard. Contribution No. 2681 from the Institute of Oceanology, Chinese Academy of Sciences. This study is a major project (Ky85-11-5) and a key project (A14920416) of the Chinese Academy of Sciences, and also received support from the Shengli Oil Field.  相似文献   

16.
The Al-basic sacrificial anode is widely used to protect steel construction from corrosion in seawater,but is not suitable for protecting steel in freshwater. In the estuary area, seawater and freshwater mix anddifferent seawater salinity can be formed in different mixing sites between freshwater and seawater. Basedon the requirements of the Shengli Petroleum Administrative Bureau of China, the effect of seawatersalinity on electrochemical properties of Al-basic anode was studied under laboratory conditions by themethod given in National Standard GB 4948-85 (China Starndard Bureau, 1985). No obvious effectwas found when seawater salinity was 30 to 10, but obvious effect on anodic open circuit potential, closedcircuit potential and current efficiency was found when seawater salinity was 5. These values are lowerthan those given in the Naional Standard.  相似文献   

17.
Electrochemical reduction of dissolved oxygen in seawater on metals is of great importance for corrosion studies. The present paper studied cathodic reduction of dissolved oxygen on Q235 carbon steel in 3. 5% sodium chloride(NaCl)solutions by cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS), rotating disk electrode(RDE)and rotating ring-disk electrode(RRDE). The cyclic voltammetric results demonstrated the cathodic process on Q235 carbon steel in O2-saturated 3. 5% NaCl solution contains three reactions:dissolved oxygen reduction, iron oxides reduction and hydrogen evolution. The peak potential of oxygen reduction reaction(ORR)is-0. 85 V vs Ag/AgCl, 3 molL-1 KCl. The E1S results indicated that the ORR occurring on Q235 carbon steel is a 4-electron process and that no finite diffusion is caused by the intermediate of H2O2 produced by ORR. The RDE and RRDE voltammograms confirmed the EIS results and it was found that the number of transferred electrons for ORR was nearly 4, I. E. , dissolved oxygen reduced to water.  相似文献   

18.
为了研究不同腐蚀条件下的焊缝磁记忆特征信号,对20号钢板状焊缝试件进行残余应力腐蚀、35kN恒拉伸应力腐蚀和35kN静载、25kN动载拉拉腐蚀疲劳对比实验,分析焊缝正、反面磁记忆信号的变化规律,获得焊缝腐蚀发展进程中应力腐蚀与腐蚀疲劳各自对应的磁记忆特征信号.结果表明:在应力腐蚀状态下,不同拉伸载荷对应的磁记忆信号特征不同,35kN恒拉伸应力腐蚀与残余应力腐蚀相比,焊缝区磁记忆信号峰峰值及其梯度更大,磁记忆曲线分布的分散度更大;35kN静载、25kN动载拉拉腐蚀疲劳与35kN恒拉伸应力腐蚀相比,焊缝区磁记忆曲线上下波动多,过零点次数多,磁记忆曲线分布的分散度小.这为磁记忆技术在焊缝工程检测的定性与定量分析提供基础数据.  相似文献   

19.
设计一种新型光纤光栅锈蚀传感器,主要由锈蚀体、不锈钢体和2段串联的光纤布拉格光栅(FBG)组成。缠绕于锈蚀体表面的FBG监测钢筋的锈胀应变,缠绕于不锈钢体表面的FBG用作温度补偿器,消除温度变化对锈胀应变监测的影响。此外,设计电化学加速腐蚀实验,探究该传感器在不同强度等级混凝土中的工作性能。结果表明,该传感器监测质量腐蚀率的灵敏度为0.02%,监测范围大于1%,可实时监测混凝土中钢筋的锈蚀过程及特征,为预警钢筋锈蚀引起的钢筋混凝土结构耐久性损失提供阈值,在结构健康监测领域具有较大的应用价值。  相似文献   

20.
The surface of ZrO2 nanoparticles was modified by styrene coupling grafting method to improve the dispersion and interaction of the nanoparticles with the epoxy coating in which the modified ZrO2 nanoparticles were used as an additive. The grafting performance and microstructure of the nano- ZrO2/epoxy coating were analyzed by Fourier transformation infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The corrosion behavior of the nano-ZrO2/epoxy coating on mild steel was evaluated in neutral 3.5 wt% NaC1 solution using electrochemical impedance spectroscopy (EIS). Both the coating capacitance and coating resistance fitted by the equivalent circuit from EIS were used to evaluate the protective performance of the coating towards the mild steel. The results show a superior stability and efficient corrosion protection by the modified ZrO2 nanoparticles. The epoxy coating containing 2 wt% modified ZrO2 nanoparticles exhibited the best corrosion performance among all the coating specimens. This research may provide an insight into the protection of mild steel using modified epoxy coatings.  相似文献   

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