X70管线钢在酸性和近中性模拟海水溶液中的腐蚀行为

为对比X70管线钢在酸性(pH=3)和近中性(pH=7.7)模拟海水溶液中的腐蚀机制,采用极化曲线,通过电化学阻抗谱(EIS)和腐蚀失重实验对X70管线钢在不同模拟海水溶液中的腐蚀行为进行了研究。结果表明,X70管线钢在酸性溶液中浸泡168 h后腐蚀失重约为近中性模拟海水溶液中的16倍,大部分表面发生均匀腐蚀,局部形成以夹杂物为中心的腐蚀圆环,随着浸泡时间的延长,容抗弧半径和低频区阻抗值|Z|均呈增大趋势,先发生吸附而后出现微弱的扩散,电荷转移电阻R_ct值增大,腐蚀速率减小;近中性模拟海水中形成较厚的腐蚀产物膜,氯离子聚集破坏形成小点蚀坑,局部聚集形成大的点蚀,电荷转移电阻减小,腐蚀速率增大,而后趋于稳定;X70管线钢在模拟海水溶液中处于活性溶解状态,与酸性海水溶液相比,管线钢在近中性模拟溶液中自腐蚀电位E_corr正移137 mV,自腐蚀电流密度i_corr为酸性海水溶液中的0.047倍。因此,X70管线钢在酸性模拟海水溶液中的腐蚀规律可为其应用于海底管线的腐蚀控制提供理论支撑,对其安全服役具有十分重要的意义。     

镍基合金CMSX-4在3.5wt.% NaCl溶液中的腐蚀行为

研究二代镍基合金CMSX-4在质量分数为3.5% NaCl溶液中的腐蚀行为,对该类合金在海洋性环境条件下的应用具有深远意义。通过动电位极化方法研究室温条件下镍基合金CMSX-4在3.5 wt.% NaCl溶液中的电化学行为,利用扫描电子显微镜（SEM）、能谱分析仪（EDS）和X射线光电子能谱仪（XPS）对合金表面阳极腐蚀产物进行微观形貌观察及成分分析。研究表明,CMSX-4合金具有一定的钝化能力,钝化区间比较宽广;在镍基合金CMSX-4表面上形成的腐蚀产物可大致分为两层,表层主要由Ni （OH）₂、Cr （OH）₃、Co （OH）₂和Al （OH）₃等氢氧化物组成,内层主要分布着NiO、Al₂O₃、CoO、Cr₂O₃和CrO₃等氧化物及组成合金基体的各种金属;由Ni （OH）₂和Cr （OH）₃等氢氧化物组成的腐蚀产物膜外层能够在腐蚀介质和金属之间产生较好的屏蔽效果;构成腐蚀产物膜内层的NiO、Al₂O₃、Cr₂O₃和CrO₃等氧化物有利于产物膜内层与外层之间建立一定的空间电荷区,对稳定腐蚀产物内层有很大帮助。研究表明CMSX-4合金在海洋性环境中具有一定的耐蚀性能。     

Mg-2.4Nd-0.5Sr-0.3Zr生物镁合金表面耐蚀抑菌层的制备与表征

以AgNO_3溶液为介质,采用水热法在Mg-2.4Nd-0.5Sr-0.3Zr生物镁合金表面制备具有抗菌性能的耐蚀膜层,通过XRD、SEM、EDS等技术,对不同水热温度及时间条件下所制膜层的形貌及物相结构进行表征,结合电化学测试及抑菌试验,考察了水热条件对膜层耐蚀性和抗菌性能的影响。结果表明,Mg-2.4Nd-0.5Sr-0.3Zr合金表面膜层主要由层片状Mg(OH)_2和颗粒状Ag/Mg(OH)_2聚集混合组成,随着水热温度的升高及反应时间的延长,膜层厚度逐渐增加。电化学测试结果显示,膜层能有效改善合金的耐蚀性,且随着表面膜层厚度的增加,对应合金样品的耐蚀性增强。此外,经过水热处理制得的合金样品在金色葡萄球菌培养24h后,产生了明显的抑菌圈,表现出了良好的抗菌效果。     

N80油管钢的CO_2高温高压腐蚀电化学行为与机理研究

在高温高压釜中模拟油气井腐蚀环境 ,采用电化学交流阻抗和动电位扫描极化曲线测试技术 ,研究了N80钢在温度为 10 0℃ ,CO2 分压为 1.18MPa条件下的腐蚀电化学行为和阳极与阴极反应机理 ,实时监测了腐蚀产物膜对腐蚀行为和腐蚀反应机理的影响 .研究结果表明 :N80钢的阳极反应过程服从Bockris机理 ;N80钢的阴极反应以H2 CO3的还原为主 ;反应中间产物吸附与腐蚀产物膜覆盖的竞争导致交流阻抗谱随腐蚀时间而变化 ,影响着钢的腐蚀行为 ,产物膜对钢基体具有一定的保护作用     

Effect of H2S concentration on the corrosion behavior of pipeline steel under the coexistence of H2S and CO2

The effect of H2S concentration on H2S/CO2 corrosion of API-X60 steel was studied by scanning electron microscopy, a weight-loss method, potentiodynamic polarization tests, and the electrochemical impedance spectroscopy technique. It is found that the cor-rosion process of the steel in an environment where H2S and CO2 coexist at different H2S concentrations is related to the morphological structure and stability of the corrosion product film. With the addition of a small amount of H2S, the size of the anode reaction region is de-creased due to constant adsorption and separation of more FeS sediment or more FeHS＋ions on the surface of the steel. Meanwhile, the dou-ble-layer capacitance is diminished with increasing anion adsorption capacity. Therefore, the corrosion process is inhibited. The general cor-rosion rate of the steel rapidly decreases after the addition of a small amount of H2S under the coexistence of H2S and CO2. With a further increase in H2S concentration, certain parts of the corrosion product film become loose and even fall off. Thus, the protection provided by the corrosion product film worsens, and the corrosion rate tends to increase.     

外加电位对X80管线钢模拟海岸土壤腐蚀的影响

为探究双相X80管线钢在沿海土壤模拟溶液环境中的腐蚀机理，采用极化曲线、慢应变速率拉伸试验(SSRT)和交流阻抗(EIS)法对不同外加电位(-750,-900和-1 050 mV vs.饱和甘汞电极(SCE))下双相X80管线钢的应力腐蚀和电化学腐蚀行为进行研究。结果表明，双相X80管线钢在-1 050 mV电位下对应力腐蚀(SCC)最为敏感。慢应变拉伸呈现为脆性断裂，断口可见铁素体区域圆形或椭圆形的凹坑，这是由于过度阴极反应产生的氢原子扩散进入到钢中在铁素体晶界聚集，氢气析出产生的较高氢压超过材料的强度产生圆形孔洞，在拉伸应力作用下变为椭圆形。在此电位下EIS模拟电阻最小，耐腐蚀性最差。-750 mV的外加电位可起到一定的电化学保护作用，但不足以防止X80管线钢应力腐蚀的发生。-900 mV的外加电位可有效抑制X80管线钢的阳极溶解，SSRT的强度和延展性均高于0 mV电位试样，表现出韧性断裂特征，EIS模拟电阻最高，因此双相X80管线钢在模拟海岸土壤环境下最佳的阴极保护电位约为-900 mV vs. SCE。双相X80管线钢在沿海土壤模拟环境中的应力腐蚀行为的研究可对其在实际使用过...     

油套管用钢P110的CO_2腐蚀动力学研究

利用高温高压腐蚀试验及电化学原位测量技术,并辅以SEM、EDS和XRD等微观分析手段研究了油套管用钢P110在CO2分压为2 MPa、温度为100℃的3.5%NaCl水溶液中的腐蚀失重、界面反应电化学特性、腐蚀产物膜的微观形貌、成分和结构特征,探讨了油套管用钢CO2腐蚀动力学.研究结果表明:油套管用钢P110的CO2腐蚀产物为FeCO3;随腐蚀时间的延长及腐蚀产物膜的形成,平均腐蚀速率逐渐降低、趋势变缓,产物膜生长满足抛物线生长规律;腐蚀产物晶粒逐渐长大并堆垛紧密,逐渐成膜覆盖于金属表面,膜厚先增加后逐渐趋于稳定,对基体保护能力增强;不同腐蚀时间交流阻抗图谱(EIS)的拟合结果表明,极化电阻随着腐蚀时间增加逐渐增大,电极反应由最初的活化控制变为扩散控制.     

Mo,Ti离子注入不锈钢耐水溶液腐蚀改性研究

用电化学测试和俄歇电子能谱分析研究了离子注入不同剂量的Ｍｏ、Ｔｉ对３０４Ｌ奥氏体不锈钢在Ｈ２ＳＯ４、ＮａＣｌ水溶液中的腐蚀行为。结果表明：注入Ｍｏ、Ｔｉ可使不锈钢的耐水溶液腐蚀性能提高，并改善材料的钝性和耐小孔腐蚀能力；在腐蚀过程中，注入元素在膜中富集，膜中Ｃｒ／Ｆｅ比值提高，从而达到耐蚀性能改善之目的；在适当的注入剂量下，可获得最佳的耐蚀改性效果。     

Short-term exposure of low-alloyed steels in Qinghai Salt Lake atmosphere

The rusts formed on carbon steel and weathering steel exposed in Qinghai Salt Lake atmosphere for 6 months were characterized by X-ray diffraction （XRD）, infrared transmission spectroscopy （iRS）, scanning electron microscopy （SEM）, electron probe micro analyzer （EPMA） and electrochemical po- larization techniques. The two kinds of steels showed the similar corrosion rate, corrosion product composition and electrochemical polarization behavior. Their rusts were mainly composed of β-FeOOH, Fe8（O,OH）16Cl1.3 and a little γ-FeOOH. Cl^- played an important role during the corrosion process of low-alloyed steels. The alloyed elements Cr, Ni and Cu in weathering steel were detected in the rusts; however, they showed no remarkable protective ability.     

铁素体不锈钢在盐酸溶液中的腐蚀过程

利用电化学工作站,结合微观腐蚀形貌分析,研究了铁素体不锈钢在盐酸溶液中的腐蚀过程.结果表明:铁素体不锈钢在盐酸溶液中的腐蚀过程分为3个阶段:表面钝化膜的穿透、腐蚀产物膜的增厚以及阴阳极反应平衡.不锈钢在表面钝化膜的穿透和腐蚀产物膜的增厚阶段仅发生均匀腐蚀,而在反应平衡阶段不锈钢表面出现大量的晶间腐蚀和少量的点蚀.当盐酸质量分数大于10%时,铁素体不锈钢在盐酸溶液中的极化曲线钝化区完全消失,其腐蚀过程主要受阳极控制.随着盐酸质量分数的增大,溶液电阻Rs和电极反应的电荷转移电阻Rt均逐渐减小,同时腐蚀电极表面双电层结构中的充放电能力不发生改变.     

冷凝液硫含量对SUS444铁素体不锈钢腐蚀行为的影响

利用冷凝液浸蚀-高温氧化循环腐蚀法模拟汽车排气系统内部服役环境,借助失重分析、腐蚀形貌观察及腐蚀产物分析,研究了SUS444不锈钢在不同硫含量的冷凝液中的腐蚀行为。结果表明,随着腐蚀循环次数的增加,不锈钢表面不断沉积的FeSO_4·7H_2O、Fe(NH_4)(SO_4)_2及Fe_4(SO_4)_5(OH)_2·18H_2O等硫酸盐物质加速了不锈钢的腐蚀进程,其点蚀深度及腐蚀速率均随冷凝液中硫含量的升高而增加。     

Comparative study on the corrosion behavior of X52, 3Cr,and 13Cr steel in an O2–H2O–CO2 system: products,reaction kinetics,and pitting sensitivity

The corrosionbehaviors of X52, 3Cr low-alloy steel, and 13Cr stainless steel were investigated inanO2–H2O–CO2 environment at varioustemperaturesand O2–CO2partial-pressure ratios. The results showed thatthe corrosion rates of X52, 3Cr, and 13Cr steels in-creased with increasing temperature. The corrosion ratesslowly increased at temperaturesless than100℃ and increased sharply when the temperature exceeded100℃. In the absence of O2, X52, 3Cr, and 13Cr exhibited uniform corrosion morphology and FeCO3 was the main corrosion product. When O2 was introduced into the system, various forms of Fe2O3 appeared on the surface of the samples. The Cr content strongly influenced the corrosion resistance. The 3Cr steel with a low Cr content was more sensitive to pitting than the X52 or 13Cr steel. Thus, pitting occurred on the surface of 3Cr when 1.25 MPa of O2 was added; this phenomenon is related to the non-uniform distribution of Cr in 3Cr.     

3Cr低合金管线钢及焊接接头的CO_2腐蚀行为

采用高温、高压反应釜和电化学技术对3Cr低合金管线钢及焊接接头的CO2腐蚀行为进行研究.结果表明,3Cr低合金管线钢在高温、高压CO2腐蚀环境中表面生成致密的富Cr腐蚀产物膜,这是其抗CO2腐蚀性能优于X65钢的主要原因.3Cr低合金管线钢焊接接头中母材、热影响区和焊缝的腐蚀产物膜特征相似,结构致密,均存在Cr元素的富集.与X65钢相比,3Cr低合金管线钢的自腐蚀电位较正,自腐蚀电流密度较低.在CO2腐蚀介质中,3Cr低合金管线钢焊接接头的母材区域作为阳极首先发生腐蚀,焊缝和热影响区作为阴极受到保护.     

超临界水中310-ODS钢表面氧化膜形成机制和性能

采用腐蚀增重方法研究310-ODS钢在600℃低溶氧的超临界水中的全面腐蚀敏感性,取样周期分别为100、300、600、1 000、1 500h,对试样表面氧化膜进行扫描电镜、能谱仪和X射线衍射仪分析.结果表明:310-ODS钢在浸泡早期(300h)已经在表面形成较为致密的氧化膜,腐蚀速率快速降低;氧化膜为双层结构,内层致密富Cr,外层多孔富Fe,随着浸泡时间的增加,内层变得均匀,外层变化不大.310-ODS钢在600℃超临界水中的氧化过程满足固态生长机制,晶界处的Y2O3改善了材料的耐腐蚀性能.     

Study on the passive film formed on 2205 stainless steel in acetic acid by AAS and XPS

The properties of the passive film formed on 2205 stainless steel in acetic acid at high temperature that contained chloride ions were studied by atomic absorption spectrometry (AAS), X-ray photoelectron spectroscopy (XPS), and electrochemical polarization measurements. AAS results show that molybdenum is enriched on the surface as the passive film is dissolved. This enrichment decreases the corrosion resistance because it hinders chloride adsorption and Fe ion dissolution, and acts as a local pH buffer because it consumes protons. The dissolution ratio of Fe/Cr is approximately 10 during the active dissolution of the passive film. XPS results indicate that when the potential is in the passivation region, Cr comprises about 50% of the metal cations in the near-surface region of the passive film and is the main metal constituent in this region. When the polarization potential is much greater than the transpassivation potential, the Mo content accounts for approximately 45% of the metal cations in the nearurface region; Fe and Ni have no obvious influence on the formation, dissolution, or puncture of the passive film.     

碳钢油气输送管道不同沉积物下的腐蚀行为

利用失重法、电化学测试、丝束电极和微观分析手段研究了在CO2饱和地层水中X65碳钢覆盖不同沉积物的腐蚀行为。结果显示，覆盖沙粒、黏土和碳酸亚铁可减轻X65钢的腐蚀，而覆盖硫化亚铁、元素硫和混合物则明显加速钢的腐蚀。尤其是覆盖元素硫，试样的腐蚀速率急剧增大。覆盖混合物试样的腐蚀速率也有显著的增大，混合物中元素硫起主导作用。试样表面沉积的元素硫可自催化阴极反应而大大加速钢的腐蚀。丝束电极的电位和电流分布显示，覆盖混合沉积物的电极，其电极电位比无沉积物覆盖电极的电极电位正。随着腐蚀进行，沉积物覆盖下电极发生严重的局部腐蚀。丝束电极的电位和电流分布图能够有效反映沉积物下局部环境变化而导致的局部腐蚀行为差异。     

Electrochemical behavior of 304 stainless steel with electrodeposited niobium as PEMFC bipolar plates

In order to enhance the corrosion resistance of 304 stainless steel, niobium was electrodeposited on its surface in air- and water-stable ionic liquids. The electrochemical behaviors of bare and niobium-coated 304 stainless steel were evaluated by electrochemical tests in a simulated proton exchange membrane fuel cell (PEMFC) environment. The results showed that niobium could be electrodeposited on the surface of 304 stainless steel from ionic liquids, and a smooth and strong chemical inert compound film was obtained on the surface of 304 stainless steel, which was mainly composed of NbO and Nb₂O₅. The thin composite film acted as a barrier and remarkably improved the corrosion resistance of 304 stainless steel in the PEMFC environment.     

阳离子类型对钢筋腐蚀临界氯离子浓度的影响

采用饱和Ca(OH)2溶液和水泥浸泡液2种混凝土模拟孔溶液,选用NaCl,KCl,MgCl2和CaCl2等4种氯盐,通过逐级添加氯盐方式腐蚀钢筋,以半电池电位法测得的自腐蚀电位和电化学阻抗技术测得的腐蚀电流密度分别判定钢筋起始腐蚀对应的临界氯离子浓度.研究结果表明:阳离子类型对钢筋腐蚀的临界氯离子浓度有明显影响;在饱和Ca(OH)2溶液中,Mg2+和Ca2+降低了钢筋腐蚀的临界氯离子浓度;在水泥浸泡液中,Mg2+和Ca2+则提高了钢筋腐蚀的临界氯离子浓度;在2种混凝土模拟孔溶液中,同价阳离子的临界氯离子浓度相同.     

镍基合金UNS N08028钝化膜的耐蚀性研究

采用高温高压腐蚀试验方法使镍基合金028在100 ℃、130℃和150℃条件下形成钝化膜,利用阳极极化曲线和电容测量法(Mott-Schottky曲线),研究镍基合金钝化膜在不同温度同时含CO2和Cl-的腐蚀介质中的电化学行为和半导体性质.结果表明:在130℃条件下形成的钝化膜对基体的保护作用较强;在3个条件下形成的钝...     

化学镀非晶态Ni-P及Ni-Sn-P镀层在弱酸性介质中耐蚀性研究

以紫铜为基体,采用化学镀制备了非晶态Ni-P,Ni-Sn-P镀层.采用X射线衍射(XRD)、扫描电子显微镜(SEM)和X射线能谱(EDS)等对镀层的结构、微观形貌及元素组成进行分析.通过Tafel极化曲线、电化学阻抗谱(EIS)、开路电位监测及室内加速腐蚀试验,研究两种镀层在pH=5.5,w_(NaCl)=3.5%,以及pH=5.5,wS=20%的土壤介质中的耐蚀性能.结果表明,化学镀非晶态Ni-P及Ni-Sn-P镀层的自腐蚀电流密度是裸铜的4.5%和1.2%,两种镀层在酸性腐蚀介质中具有比金属铜更好的耐蚀性,并且化学镀Ni-Sn-P镀层耐蚀性优于Ni-P镀层.两种镀层的自腐蚀电位均负于铜.