HSn70-1A 黄铜的原始表面膜特征及其海水腐蚀行为

采用俄歇电子能谱分析、电子探针Ｘ射线能谱分析、扫描电镜、金相显微镜和数学回归分析等方法研究了ＨＳｎ７０－１Ａ黄铜的原始表面膜特征及其海水腐蚀行为。证实了原始表面膜对黄铜的初期海水腐蚀行为的影响,而长期的腐蚀行为则是由实海暴露过程中形成的腐蚀产物膜特征决定的。     

应用

BNF已研制出保护铝-黄铜和90/10铜-镍的两种新的涂层并已被批准取得专利权。这两种合金很普遍地用于世界各地的海水冷凝器,当接触未污染的海水时,在最初几个星期内铜合金管生长一保护层,这层膜能保护合金管免遭腐蚀长达10～20年,     

Cr元素对耐海水腐蚀钢腐蚀性能的影响探讨

在涟钢开发耐海水腐蚀钢过程中,为了解Cr元素对耐海水腐蚀钢腐蚀性能的影响,进行了不同成分试样耐海水腐蚀性能比较,通过室内加速实验、电化学和腐蚀产物分析等方法进行了耐海水腐蚀性能比较。通过试验得到在钢中加入合金元素Cr可以提高钢的耐腐蚀性能,因为在腐蚀过程中会形成含Cr2O3的致密的保护膜;合金元素Cr的加入会使钢发生点蚀。     

HSn62-1铜合金海水腐蚀行为特征的扫描电镜研究

利用ＪＳＭ８４０扫描电镜及ＴＮ５５００能谱仪，采用ＳＳＱ（无标样定量分析程序）和ＩＰＰ图像处理程序，研究和分析了未经腐蚀样品和腐蚀后样品的微区成分变化及添加微量合金元素对其腐蚀性能的影响，并观察了在腐蚀过程中不同阶段的微观组织形貌变化。发现ＨＳｎ６２１铜合金的腐蚀过程是从基体表面的β相开始，以沿晶腐蚀的方式形成多孔铜而优先进行脱成分腐蚀，然后通过α相界达到另一个β相晶粒开始新的腐蚀。当β相腐蚀后，α相形成“孤岛”并开始腐蚀，进一步向纵深发展。锡元素向晶界富集，使腐蚀过程大大减缓。     

铜管在羧酸环境下的腐蚀行为和腐蚀机理研究

铜管是空调及制冷行业用热交换器的核心部件,在服役过程中常由于蚁穴腐蚀导致设备提前失效。本文采用蒸气腐蚀、电化学腐蚀方法研究了铜管在羧酸环境下的腐蚀行为,通过金相显微镜（OM）、扫描电镜（SEM）、 X射线粉末衍射仪（XRD）观察和分析了表面腐蚀形貌和腐蚀产物的结构,通过接触角测量仪研究了羧酸与铜管的界面行为。结果表明,与CH3COOH蒸气腐蚀相比,铜管在HCOOH蒸气环境下的腐蚀速度慢,腐蚀产物更致密。在HCOOH蒸气环境下,铜管容易出现蚁穴腐蚀。铜管表面的腐蚀产物主要由羧酸铜和氧化亚铜组成。蚁穴腐蚀属于电化学腐蚀,腐蚀机理复杂。腐蚀初期,表面氧化膜被聚集在铜管表面的羧酸溶解,暴露的铜基体作为微观阳极,之后,腐蚀坑内产生的微裂纹的尖端作为微观阳极,使腐蚀加速,直至贯穿管壁。     

钛铜共用的海水冷却器的牺牲阳极保护

钛在海水中具有优异的耐蚀性,而铜合金由于严重腐蚀则不能适应生产需要．用钛制作海水冷却器,能确保其安全稳定可靠运行,随着钛管制造工艺与焊接技术的进步,使得选用钛材制作海水冷却器变得更为容易．但由于钛材一次性投资相对较高,为了节省费用,在老设备改造时,只将省换为钛管,管板仍采用铜合金;或者管子与管板采用钛,而保留原铜合金复层的封头,但这样由于电偶接触会加速铜合金的腐蚀,仍须采用原有的电化学保护,而如果保护电位过负,即过度阴极极化,又会促使钛管口部位吸氢而致脆．上海石化公司1号乙烯装置的许多钛制海水冷…     

低温多效海水淡化装置换热管腐蚀原因分析

对国内低温多效蒸馏海水淡化装置在生产运营中出现的铜合金换热管腐蚀问题进行了深入的研究和分析。发现铜管腐蚀原因为管板与换热管材质不同形成电位差,铵离子与铜离子发生络合作用,造成部分区域腐蚀;同时,海水的冲刷对管表面形成冲击力,络合产物随运动的海水被冲走,加快腐蚀速率。     

钛制海水冷却器及凝汽器的应用

1前言滨海地区的石化企业发电厂、炼油化工厂的展汽器与冷却器常常采用海水冷却．由于海水，特别是污染海水造成铜合金管的腐蚀，使凝汽器与冷却器生产运行处于经常泄漏、防不胜防的被动局面．虽采用注入硫酸亚铁、涂膜、电化学保护等措施，但从环保和控制等方面考虑，这些措施     

耐海水腐蚀钢的腐蚀性能评价与机理研究

通过适量添加Cu、Ni、Cr、Mo、Sn等元素,某钢厂成功开发耐海水腐蚀钢NHYNE36。周期浸润腐蚀试验和盐雾腐蚀试验表明:耐海水腐蚀钢NHYNE36的腐蚀性能接近或优于船级社的相应要求。光学显微镜和扫描电镜分析表明:耐海水腐蚀钢表面内锈层中发现的Cr元素可形成致密氧化膜,有利于钢板耐蚀性的提高;基体组织为单相多边形铁素体精细组织或含有极少量珠光体,可有效降低钢中原电池的数量,从而提高基体的抗电化学腐蚀能力。     

铜对碳钢耐大气腐蚀性能的影响

通过实验室干湿周浸加速腐蚀试验，研究了模拟工业大气环境下，合金元素Cu对碳钢耐腐蚀性能的影响。利用XRD测定腐蚀产物的相组成，通过SEM观察腐蚀试样表面及截面形貌。结合失重法及电化学方法对Cu提高碳钢耐腐蚀性能的机理进行研究分析。结果表明：Cu对碳钢耐腐蚀性能具有明显的促进作用，添加025％的Cu使碳钢的腐蚀速率明显下降，腐蚀抗力平均提高65％以上，含铜钢的腐蚀产物主要由稳定的aαFeOOH及少量γ-FeOOH构成，锈层较碳钢锈层更加致密，腐蚀电流较小。     

Corrosion resistance of new copper alloy containing 29Zn, 10Ni and up to 5Mn vis-a-vis Cu-10Ni in sulphide polluted synthetic seawater

Cu-10 Ni alloy suffers from accelerated corrosion in sulphide-polluted seawater. New copper alloys containing 29% Zn, 10Ni and 3 or 5% Mn have been found to be more corrosion resistant than Cu-10Ni alloys in sulphide polluted synthetic seawater. The studies were carried out in synthetic seawater (ASTM D 114–75) and sulphide was added through Na₂S (1 gpl ≈ 41ppm S²⁻). Testing was carried out using cathodic and anodic potentiodynamic polarization methods. Corrosion product film formed on the Cu-29Zn-10Ni-5Mn alloy in sulphide polluted synthetic seawater was characterized using SEM and XRD. The film was found to contain Cu₂O, Cu₂S, NiS and ZnS. Better corrosion resistance of new alloys as compared to that of Cu-10Ni alloy is attributed to formation of ZnS, a bad conductor, in the film and incorporation of Mn³⁺ cations in Cu₂O and Cu₂S lattice.     

Effect of Zn addition on corrosion resistance of Cu-10Ni alloy in clean and sulphide contaminated seawater

Cu-10Ni alloy has an outstanding resistance to corrosion in seawater due to formation of protective Cu₂O film. However, in presence of S^2? ions, it suffers accelerated corrosion. The present paper investigates the corrosion behaviour of Cu-10Ni, Cu-10Ni-6Zn and Cu-10Ni-12Zn alloys using weight loss, electrochemical impedance spectroscopy and potentiodynamic polarisation technique. The experiments were performed in clean seawater and sulphide contaminated seawater. The Cu-10Ni-6Zn and Cu-10Ni-12Zn alloys were found to exhibit lower corrosion rate than Cu-10Ni alloy in clean and sulphide contaminated seawater. Lower corrosion rate of Zn containing alloys in clean seawater is attributed to the incorporation of Zn²⁺ ions in Cu₂O lattice. Lower corrosion rate of Zn containing alloys sulphide contaminated seawater is attributed to formation of ZnS in the film.     

Effect of zinc addition to copper in improving its corrosion resistance in sulfide polluted synthetic seawater

In an endeavor to develop a cost effective substitute of Cu-10Ni alloy for seawater application (especially for sulfide polluted seawater) few Cu-Ni-Zn-Mn alloys were developed in our laboratory. The Cu-Ni-Zn-Mn alloy was found to have better corrosion resistance than Cu-10Ni both in clean and sulfide polluted synthetic seawater. Resistance to sulfide in Synthetic Seawater was attributed to the formation of ZnS. To ensure that the resistance to sulfide attack is due to Zn alone, a series of studies were carried out with binary alloys of Cu and Zn with increasing weight percentage of Zn (12% and 36%). Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) was used for the purpose. Polarization studies gave the corrosion data and EIS was effective in depicting the nature of corrosion product (film). It was found that among the test alloys, Cu-36Zn is most corrosion resistant in sulfide polluted seawater due to formation of ZnS in the film. As it is a binary alloy, the corrosion resistance against sulfide is attributed to Zn alone.     

Stress corrosion cracking of alpha brass in a tarnishing ammoniacal environment: Fractography and chemical analysis

Alloy 260 brass specimens under stress were exposed at room temperature to 15 N aqueous ammonia solution with 8 g/1 of cupric copper predissolved. This environment causes tarnishing of the brass surface and intergranular stress corrosion cracking. Scanning electron microscopy, energy dispersive X-ray analysis, and Auger electron spectroscopy were employed to study fractography, corrosion product composition and distribution within the stress corrosion crack, and fracture surface chemistry characteristic of stress corrosion cracking in this system. A thin oxidized film was detected by Auger spectroscopy at the leading edge of the propagating crack. With continued exposure to the corrosive environment, deposits form on the fracture surface, then coalesce to form a continuous tarnish film that is depleted of zinc. No bulk depletion of zinc was detected in the alloy at the stress corrosion crack leading edge. No evidence of noncrystallographic crack arrest marks was found on the intergranular fracture surface.     

Development of single-phased copper alloy for seawater applications: As a cost-effective substitute for Cu-10Ni alloy

Cu-10Ni alloy is a standard material for seawater application. Under Indian scenario, where half of copper and whole of Ni (and Cu-Ni) requirement is met by imports, search for a cheaper substitute is obvious. An attempt has been made to develop a single-phased copper alloy containing 10 wt% Ni, 29 wt% Zn, up to 5 wt% Mn and 1 wt% Fe as a substitute to Cu-10wt% Ni-1wt% Fe alloy. Studies on Corrosion resistance of test alloys were carried out in synthetic seawater (ASTM D 114-75) by electro-chemical methods (cathodic and anodic polarization). Corrosion product film formed on alloy containing 5wt% Mn was characterized by SEM and XRD. A film of Cu₂O was found to form on the surface of the alloy, which accords corrosion protection. The test alloys containing 29 wt% Zn and 3 or 5 wt% Mn have exhibited better corrosion resistance in synthetic seawater than Cu-10Ni alloy. The role of Mn and Zn addition has been discussed.     

铜合金的腐蚀与防护研究进展

铜合金具有良好的导电性和导热性,是应用最广泛的工业材料之一。铜合金服役过程中常与酸、碱、盐等腐蚀介质接触,易引起铜合金的腐蚀,最终导致失效,对生产制造带来危害。提高铜合金的耐腐蚀性有利于进一步扩展其应用领域。本文主要归纳了Cr, Pb, Ti, Al,Mn, Ni以及稀土元素的添加对合金耐蚀性能的影响,通过合金元素的添加可以改变铜合金表面腐蚀产物膜的组成和形貌,减小相与相之间腐蚀电位差,以及减少有害杂质的存在,以此来改善铜合金的耐蚀性能。塑性变形和热处理是改善铜合金力学性能的常用手段,经塑性变形和热处理过后的铜合金,其微观组织形貌和分布发生了变化,因此对合金耐蚀性能也有一定的影响。本文主要从合金化、塑性变形及热处理3个方面对铜合金耐蚀性能影响进行综述,最后对铜合金的腐蚀防护研究进行总结和展望。     

Influence of silicon coating on the corrosion resistance of Zn-Al-Mg-RE-Si alloy

The electric arc spraying method was used to prepare the Zn-Al-Mg-RE-Si alloy coating with different content of silicon.The corrosion resisting property was measured by copper accelerated salt spray(CASS) and corrosion weightless test.The influence of silicon content on the corrosion resisting property was investigated by XRD,SEM,polarization curve and electrochemical impedance spectroscopy(EIS) and the electrochemical property of coating in the corrosion process was analyzed.The results showed that the density of coating was improved significantly since the major nonequilibrium glass-like state phase was composed of silicon and other metals existed in the Zn-Al-Mg-RE-Si alloy coating,which prevented the corrosive medium and retarded the corrosion velocity because of compact corrosion products in the corrosion embryo.The Zn-Al-Mg-RE-Si coating had better corrosion resistance than the Zn-Al-Mg-RE because of more positive potential,half corrosion current density and double electrochemical reaction resistance.     

Engineering Defect-Free Nanoporous Pd from Optimized Pd-Ni Precursor Alloy by Understanding Palladium-Hydrogen Interactions During Dealloying

Thin films of nanoporous palladium (np-Pd) were produced from binary palladium-nickel (Pd-Ni) precursor alloys. A suitable precursor alloy and a method of dealloying to yield optimum nanoporosity (average pore/ligament size of 7 nm) were developed by studying the effects of various processing parameters on final microstructure. To obtain crack-free np-Pd, a 100 nm thin film of 20 at. pct Pd (80 at. pct Ni) can be dealloyed for ~5 hours in a 1 M solution of sulfuric acid, with oleic acid and oleylamine added as surfactants. Both shorter and longer dealloying times, as well as heating, inhibit the formation of crack-free np-Pd. Stress measurements at different stages of dealloying revealed that the necessary dealloying time is determined by the diffusion-controlled corrosion reaction occurring within the thin film during dealloying. Strong interaction between hydrogen and np-Pd was reflected in the stress evolution during dealloying. A mechanism is proposed for the formation of a Ni-rich dense top layer that results from H-induced swelling during initial dealloying and permits the development of defect-free np-Pd beneath, by limiting the speed of dealloying.     

Influence of silicon coating on the corrosion resistance of Zn-Al-Mg-RE-Si alloy

The electric arc spraying method was used to prepare the Zn-Al-Mg-RE-Si alloy coating with different content of silicon. The corrosion resisting property was measured by copper accelerated salt spray (CASS) and corrosion weightless test. The influence of silicon content on the corrosion resisting property was investigated by XRD, SEM, polarization curve and electrochemical impedance spectroscopy (EIS) and the electrochemical property of coating in the corrosion process was analyzed. The results showed that the density of coating was improved significantly since the major nonequilibrium glass-like state phase was composed of silicon and other metals existed in the Zn-Al-Mg-RE-Si alloy coating, which prevented the corrosive medium and retarded the corrosion velocity because of compact corrosion products in the corrosion embryo. The Zn-Al-Mg-RE-Si coating had better corrosion resistance than the Zn-Al-Mg-RE because of more positive potential, half corrosion current density and double electrochemical reaction resistance.