Fe41Co7Cr15Mo14C15B6Y2块体非晶合金在HCl溶液中的腐蚀行为

采用电化学极化曲线和电化学阻抗(EIS)测试方法研究Fe_(41)Co_7Cr_(15)Mo_(14)C_(15)B_6Y_2块体非晶合金在0.5,1,2以及4 mol/L HCl溶液中的腐蚀行为,并比较了1 mol/L HCl溶液中非晶合金和不锈钢的腐蚀行为.极化曲线测试结果表明,Fe_(41)Co_7Cr_(15)Mo_(14)C_(15)B_6Y_2块体非晶合金在各种浓度的HCl溶液中都具有很好的耐蚀性,阳极极化曲线表现出明显的钝化特征.随着HCl溶液浓度的增大,其耐蚀性能逐渐下降.在1 mol/L HCl溶液中,非晶合金的自腐蚀电位高于不锈钢,自腐蚀电流密度比不锈钢小1个数量级.EIS结果显示,在开路电位下,Fe_(41)Co_7Cr_(15)Mo_(14)C_(15)B_6Y_2非晶合金和不锈钢的Nyquist图均由单一的容抗弧构成,但非晶合金的电化学转移电阻Rt比不锈钢的大2个数量级,这一结果与极化曲线结果一致,说明非晶合金在HCl溶液中的耐蚀性能优于不锈钢.     

变形量对 690 合金在核电一回路水环境中电化学腐蚀行为的影响

目的研究变形量对690合金电化学行为的影响。方法采用动电位极化、电化学阻抗和高温高压浸泡实验,结合扫描电子显微镜(SEM)、X射线光谱仪(EDX)和X射线光电子能谱(XPS),研究不同变形量的690合金传热管在核电模拟液中的腐蚀行为。结果在常温常压下,50%变形量试样的自腐蚀电位比25%变形量试样正140 m V,维钝电流密度显著降低,阻抗模值高出约10倍。高温高压下浸泡后,XPS分析显示,50%变形量试样表面腐蚀产物膜中的Cr2O3含量远高于25%变形量试样,其富Cr内层致密,氧化层更厚。结论 50%变形量的690合金表面形成的钝化膜及腐蚀产物膜对基体的保护作用更强。     

690合金在ETA和AVT水工况下的电化学特性

采用Tafel极化曲线法和电化学阻抗法研究了690合金在乙醇胺(ETA)和全挥发处理(AVT)两种水工况下的电化学行为,并着重考察了pH值、温度、Cl-和SO42-对690合金电化学性能的影响.结果表明,在两种不同水工况下,pH值升高会提高690合金的耐蚀性,而温度升高和Cl-,SO42-的加入则均会加速690合金的腐蚀.在相同条件下,690合金与ETA水工况有更好的兼容性,ETA的缓蚀性能优于NH3.     

690合金在NaCl溶液中的电化学行为研究

利用动电位极化曲线、电化学阻抗谱和电流-时间响应曲线对690合金在NaCl溶液中的电化学行为进行了研究。结果表明,690合金在不同浓度的NaCl溶液中均表现出阳极钝化现象,腐蚀速率随NaCl浓度的升高而增加。钝化后690合金的耐蚀性提高,在1%NaCl溶液中生成的钝化膜较致密。钝化时间小于1096 s时690合金在0.1%NaCl中的腐蚀电流密度低于其在1%NaCl中的腐蚀电流密度,当钝化时间大于1096 s时690合金在0.1%NaCl中的腐蚀电流密度反而高于其在1%NaCl中的腐蚀电流密度。     

316L不锈钢、690合金在氢氧化钠溶液中的电化学性能

采用动电位极化、电化学阻抗和电容测量等方法研究了316L、690合金在NaOH溶液中的电化学行为及生成钝化膜的半导体性质.在NaOH溶液中,316L不锈钢存在明显的钝化区间;316L不锈钢、690合金在NaOH溶液中电化学阻抗谱的阻抗模值相近.动电位电化学阻抗谱(DEIS)表明,随扫描电位正移,钝化膜的阻抗在测试溶液中...     

锌电积工业用新型泡沫铝/Pb-0.6 wt%Ag合金复合阳极电化学性能研究

为改善传统锌电积阳极存在的高析氧过电位和高银含量的缺陷,本文发明了一种新型泡沫铝/Pb-0.6 wt%Ag复合阳极。采用计时电位法,扫描电镜,交流阻抗和塔菲尔测试方法对比研究了在160 g/L H2SO4极化72 h后泡沫铝/Pb-0.6 wt%Ag复合阳极和Pb-0.6 wt%Ag阳极的电化学性能。结果表明：泡沫铝/Pb-0.6 wt%Ag复合阳极的阳极膜比Pb-0.6 wt%Ag阳极的更平整,且抗腐蚀能力更强。此外,泡沫铝/Pb-0.6 wt%Ag复合阳极的稳定阳极电位更小,与其通过计时电位法和交流阻抗获得的高PbO2,低PbO, PbO?PbSO4含量和低Rct值一致。而且还发现泡沫铝/Pb-0.6 wt%Ag复合阳极具有更优异的析氧反应行为。     

恒电位阳极氧化对锆合金表面钝化膜的影响

采用动电位扫描极化曲线、电化学阻抗谱、Mott-Schottky曲线等电化学测试方法,研究了在室温0.1 M Na_2SO_4溶液条件下,不同极化电位对锆合金钝化膜性能的影响。结果表明,锆合金表面钝化膜表现出n型半导体性质,随着极化电位的增加,锆合金钝化膜缺陷密度下降,半导体性质减弱,阻抗值增大。阻抗谱可以用RQ并联后与溶液电阻Rs串联的等效电路来拟合。在相同的极化电位下,含Nb的N18合金表面钝化膜的缺陷密度要小于出厂退火态Zr-4合金。     

乙醇胺ETA浓度对核电站二回路碳钢和镍基合金690腐蚀的影响

利用扫描电镜（SEM）、X射线光电子谱（XPS）、X射线衍射（XRD）分析以及电化学实验研究了乙醇胺（ETA）浓度对碳钢和690合金浸泡腐蚀和电化学腐蚀行为的影响。结果表明,碳钢的点蚀随着浓度的增加明显减少,碳钢表面腐蚀产物的主要成分为Fe₃O₄,690合金表面膜中没有观察到双层膜结构;在浓度为40、50、80 mg/L时观察到Cr的富集峰。在280 ℃条件下的电化学实验结果表明,ETA浓度为20 mg/L和40 mg/L时,对碳钢和690合金的电化学腐蚀行为影响不大。而在80 mg/L时,两种材料的腐蚀电流密度下降较多,极化电阻显著增大。     

Electrochemical Behavior of 2205 Duplex Stainless Steel in NaCl Solution with Different Chromate Contents

The electrochemical behavior of 2205 duplex stainless steel in NaCl solution with different chromate contents were investigated by potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), Mott-Schottky analysis, and scanning electron microscope (SEM). The effect of chromate on passivity and pitting behavior of stainless steel was also studied. The results showed that pitting susceptibility as well as semiconducting properties of passive film is heavily dependent on the chromate concentration. There exists a critical chromate value (about 0.03?M in 1?M NaCl solutions) below which the pitting corrosion on the stainless steel would be inhibited and above which it would be accelerated.     

磷酸钠在NaCl溶液中对AZ31镁合金的缓蚀作用

采用电化学阻抗法、动电位极化曲线法、全浸泡失重法和扫描电镜,研究了在3.5%(质量分数)Na Cl溶液中磷酸钠(Na3PO4)对AZ31镁合金腐蚀的抑制作用。结果表明:Na3PO4对3.5%Na Cl溶液中的AZ31镁合金具有缓蚀作用,其缓蚀率随着Na3PO4含量增大逐渐提高,当Na3PO4质量浓度为1.0 g/L时,缓蚀率达到81.5%。结合扫描电镜分析表明,Na3PO4在镁合金表面形成含有Mg(OH)2和Mg3(PO4)2的保护层,这层致密的膜减少了基体与Cl-接触,抑制了镁合金的阳极反应。     

载波处理对AZ91D镁合金耐蚀性能的影响 Ⅰ-载波处理对AZ91D镁合金腐蚀行为的影响

对AZ91D镁合金进行载波钝化,利用正交试验确定载波钝化工艺的最佳工艺参数。使用扫描电子显微镜(SEM)观察载波钝化后的AZ91D镁合金表面形貌;采用极化曲线、电化学阻抗谱(EIS)、扫描电化学显微镜(SECM)、Mott-Schottky曲线等电化学方法研究了载波钝化对合金耐蚀性能的影响。结果表明:载波钝化后,AZ91D镁合金表面生成了一层非常致密的膜,其耐蚀性能显著提高。     

Zr-Cu-Al-Ni-Sr非晶合金的腐蚀行为研究

通过与18-8不锈钢对比,研究了Zr-Cu-Al-Ni-Sr非晶合金的腐蚀行为,用XRD、极化曲线、电化学交流阻抗谱研究了其非晶合金的结构、耐蚀性能和电极反应动力学过程,并用Mott-Schottky曲线法研究了其钝化膜的半导体特性.结果表明,与18-8不锈钢相比,该非晶合金的钝化膜不具备半导体特性,Sr的加入降低了锆基合金的玻璃态形成能力,进而急剧地降低该非晶合金耐蚀性,特别是耐氯离子侵蚀能力.     

Transgranular SCC mechanism of thermally treated alloy 600 in alkaline water containing lead

This work aims to understand a SCC failure mode of thermally treated steam generator tubing materials in high temperature water containing lead. The effect of lead contents on the anodic polarization curves of alloy 600 (UNS NO6600) and alloy 690 (UNS NO6900) has been studied in a solution of pH 10 at 200 °C and 315 °C. Lead increased the active peaks of alloy 600 and alloy 690 in mild alkaline water at high temperatures. A reduction of PbO to a metallic lead in alloy 690 is easier than that of alloy 600. When lead was added into the solution, a relative ratio of Cr from among the main metallic elements (Cr, Fe, and Ni) of alloy 600 and alloy 690 decreased in the outer corrosion film. Alloy 690 TT showed a transgranular stress corrosion cracking (TGSCC) in a 10 M NaOH solution with 5000 ppm of lead. Intergranular stress corrosion racking (IGSCC) was observed in the 100 ppm lead condition, and some TGSCC was detected on the fracture surface of the alloy 600 MA cracked in the 10,000 ppm lead solution. IGSCC seemed to be retarded by a crack blunting around the grain boundaries, and the TG cracking mode of the thermally treated alloy 600 and 690 seemed to be related to a crack blunting at the grain boundary carbide and a film dissolution by lead in an alkaline solution.     

空蚀对20SiMn在3%NaCl溶液中的电化学腐蚀行为的影响

利用带电化学测试系统的磁致伸缩空蚀试验机研究了 20SiMn低合金钢在3%NaCl水溶液中的电化学腐蚀行为，通过空蚀和静态条件下的自腐蚀电位变化以及交流阻抗谱和动电位极化曲线的比较，分析了空蚀加速20SiMn低合金钢电化学腐蚀的机理.结果表明，空蚀使20SiMn低合金钢的自腐蚀电位正移200 mV，并显著降低电荷转移电阻和线性极化电阻，使电化学腐蚀速率增大约54倍；随着空蚀的进行，电荷转移电阻和线性极化电阻减小，空蚀3 h后逐渐趋于稳定.     

Corrosion electrochemical behaviors of silane coating coated magnesium alloy in NaCl solution containing cerium nitrate

Sol–gel coatings cannot provide adequate corrosion protection for metal/alloys in the corrosive environments due to their high crack‐forming potential. This paper demonstrates the possibility to employ cerium nitrate as inhibitor to decrease the corrosion development of sol–gel‐based silane coating on the magnesium alloy in NaCl solution. Cerium nitrate was added into the NaCl solution where the silane coating coated magnesium alloy was immersed. Scanning electron microcopy (SEM) was used to examine surface morphology of the silane coating coated magnesium alloy immersed in NaCl solutions doped and undoped with cerium nitrate. The corrosion electrochemical behaviors were investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests. The results showed that the introduction of cerium nitrate into NaCl solution could effectively inhibit the corrosion of the silane coating coated magnesium alloy. Moreover, the influence of concentration of cerium nitrate on the corrosion inhibition and the possible inhibiting mechanism were also discussed in detail.     

氯化铈对镁合金在NaCl溶液中的缓蚀作用

采用电化学阻抗法和动电位极化曲线法研究了氯化铈对镁合金AZ31在3.5％NaCl溶液中腐蚀行为的影响,用扫描电镜(SEM)和能谱仪(EDS)分析了腐蚀产物膜的形貌和成分.结果表明,当NaCl溶液中加入50～200mg/L氯化铈时,镁合金的腐蚀速率均有降低,当稀土含量为l00mg/L时,腐蚀速率最低;加入适当的稀土,腐蚀...     

690TT合金在高温含铅碱液中的腐蚀行为

室温条件下690TT合金的极化曲线表明,加入氧化铅能导致合金表面钝化膜不稳定。静态高压釜高温含铅碱液中的浸泡实验表明,在330℃的10% NaOH+10 g/L PbO含铅碱液中,690TT合金发生晶间腐蚀,试样失重,且试样表面越粗糙,腐蚀越严重。其中线切割样品由于残余应力和腐蚀产物楔入应力的综合作用,晶间腐蚀发展成为沿晶应力腐蚀开裂。在330℃的10% NaOH碱液中,690TT合金没有发生晶间腐蚀。     

碳钢在含热稳定性盐的N-甲基二乙醇胺介质中的腐蚀行为

利用阳极极化曲线法、Tafel曲线法和电化学阻抗谱法等技术,研究含有各种模拟热稳定性盐(HSS)的N-甲基二乙醇胺(MDEA)溶液在含氧与除氧条件下以及不同温度下对碳钢的腐蚀行为.结果表明,HSS的存在使碳钢的腐蚀速度加快.常温下HSS中的Cl-对碳钢的腐蚀性最强、可导致碳钢发生孔蚀;溶解氧的存在有利于降低既定HSS的腐蚀性.温度升高,碳钢的全面腐蚀速度增加,宏观孔蚀受到抑制;在含HSS的MDEA溶液中,碳钢腐蚀反应的阴极过程为电化学反应和扩散传质混合控制,阳极过程为电化学反应控制.     

X80管线钢钝化膜在各种高浓度NaHCO3溶液中的电化学行为

采用动电位极化曲线、恒电位极化曲线、电化学阻抗谱(EIS)、Mott-Schottky分析等电化学方法研究了X80管线钢在各种高浓度的NaHCO₃溶液中形成钝化膜的电化学行为。结果表明, X80管线钢钝化膜的稳定性和耐蚀性会受到NaHCO₃溶液浓度的影响。钝化膜电化学性质随HCO₃^-浓度升高而降低;内层Fe₃O₄的厚度不随HCO₃^-浓度变化,推测其形成与成膜电位有关;内外膜层厚度比随HCO₃^-浓度的升高而增大,钝化膜的稳定性和耐蚀性主要受外层γ-Fe₂O₃的影响。根据点缺陷(PDM)理论的分析认为,NaHCO₃溶液浓度升高时钝化膜稳定性和耐蚀性的降低与溶液电导率的升高和HCO₃^-在缺陷点处吸附作用的增强有关。     

Role of lead in electrochemical reaction of alloy 600, alloy 690, Ni,Cr, and Fe in water

It has been reported that lead causes stress corrosion cracking (SCC) in the secondary side of steam generators (SG) in pressurized water reactors (PWR). The materials of SG tubings are alloy 600, alloy 690, or alloy 800, among which the main alloying elements are Ni, Cr, and Fe. The effect of lead on the electrochemical behaviors of alloy 600 and alloy 690 using an anodic polarization technique was evaluated. We also obtained polarization curves of pure Ni, Cr, and Fe in water containing lead. As the amount of lead in the solution increased, critical current densities and passive current densities of alloy 600 and alloy 690 increased, while the breakdown potential of the alloys decreased. Lead increased critical current density and the passive current of Cr in pH 4 and pH 10. The instability of passive film of steam generator tubings in water containing lead might arise from the instability of Cr passivity.