3A21、5A05和6063铝合金在低电导率乙二醇冷却液中的腐蚀行为

采用极化曲线、电化学阻抗谱(EIS)以及浸泡实验等手段,对比研究了3A21、5A05和6063 3种铝合金在低电导率乙二醇冷却液中的腐蚀行为。结果表明,在低电导率乙二醇冷却液中,5A05铝合金的耐蚀性最好,其腐蚀类型为全面腐蚀+轻微的局部腐蚀;3A21和6063的腐蚀类型则为点蚀,且6063铝合金的耐点蚀性最差,其207 d后减薄速率与蚀坑生长速率均最快。5A05与3A21和6063 3种铝合金在低电导率乙二醇冷却液中腐蚀行为差异主要源于5A05中含较其它两种铝合金高的Mg和适量的Mn。     

乙二醇冷却液中BAl86SiMg钎料的腐蚀行为研究

为了调查BAl86SiMg钎料在乙二醇冷却液中的腐蚀行为,测量了BAl86SiMg钎料及其与3A21/6063铝合金构成电偶对时在乙二醇冷却液中的腐蚀速率,并利用扫描电子显微镜(SEM)、X射线能谱仪(EDS)和X光电子能谱(XPS)对腐蚀形貌和腐蚀产物进行了分析。结果显示:试样表面形成的Ca/Zn难溶性磷酸盐沉淀膜使BAl86SiMg钎料在乙二醇冷却液中的腐蚀为增重腐蚀,且腐蚀速率较低。BAl86SiMg钎料与3A21/6063铝合金可形成电偶对,加速钎料的腐蚀。     

乙二醇对阀冷系统6063铝合金的腐蚀影响

通过浸泡腐蚀试验及电化学测试研究了乙二醇对换流站阀冷系统6063铝合金的腐蚀影响。结果表明:不论通电与否,乙二醇均加速6063铝合金的腐蚀,乙二醇含量越大,腐蚀越严重,且通入10mA直流电流后,腐蚀速率更大;同时,乙二醇被氧化生成乙醇酸、乙二酸等腐蚀性物质,加快6063铝合金腐蚀。因此,阀冷系统在实际应用中,应重视乙二醇对6063铝合金的腐蚀问题,并采取相应对策。     

摩擦搅拌焊AA2024铝合金在盐雾条件下的腐蚀性能（英文）

2024铝合金是一种重要的工程材料,被大量应用于航空工业。但是在含氯介质中,2024铝合金易于腐蚀。本研究对5 mm厚AA2024铝合金轧板进行摩擦搅拌焊接。通过Na Cl溶液盐雾腐蚀试验对试样在不同p H值、氯离子浓度和喷雾时间条件下的腐蚀性能进行评价。建立一个经验关系式对摩擦搅拌焊AA2024铝合金的腐蚀速率进行预测。采用含有3因素5水平的中心复合旋转设计以减少实验次数。采用响应曲面法研究实验参数间的关联关系。在中性p H条件下,腐蚀速率降低;而在碱性和酸性条件下,腐蚀速率增加。随着喷雾时间的增加,腐蚀速率降低,但腐蚀趋于均匀,而随着氯离子浓度的增加,腐蚀速率增加。     

痕量Cl-和Cu2+对3A21铝合金在乙二醇冷却液中腐蚀行为的影响

针对3A21铝合金在乙二醇冷却液中的腐蚀问题,采用浸泡实验和表面分析技术系统研究了痕量Cl-和Cu2+对3A21铝合金在50℃乙二醇-水冷却液中腐蚀行为的影响.结果表明,Cl-引发了铝合金的点腐蚀,随着Cl-浓度增大,铝合金点蚀敏感性增大.Cu2+促进铝合金钝化膜的破裂,并与Al发生置换反应沉积在铝合金表面,电偶作用加...     

3A21铝合金在乙二醇水溶液中的腐蚀行为

采用电化学方法研究了3A21铝合金在乙二醇水溶液中在不同浓度、温度和浸泡时间条件下的腐蚀电化学行为。采用扫描电子显微镜研究了腐蚀前后3A21铝合金的形貌及表面腐蚀产物。结果表明,随着乙二醇水溶液浓度的增加,铝合金腐蚀速率下降;随着溶液温度升高,铝合金腐蚀速率增大;随着铝合金浸泡时间的延长,一方面,氧化膜的生成和溶解达到动态平衡,另一方面氧化膜薄弱区出现点蚀,点蚀的发展伴随着点蚀的自愈合,并向点蚀加剧方向发展。     

铝及铝合金在南疆沙漠大气环境中的腐蚀行为

将铝及铝合金L3、LF21和LY12置于在南疆沙漠大气环境下进行现场暴露试验,利用扫描电镜(SEM)、能谱仪(EDS)和红外光谱仪(FTIR)分析腐蚀形貌、元素分布和腐蚀产物组成.结果表明:在南疆沙漠大气环境中,铝及铝合金发生较严重的大气腐蚀,主要腐蚀产物为Al2O3和水合Al(OH)3;铝及铝合金的腐蚀质量损失随暴露时间的变化遵循幂函数C=Ktn,短期内随着暴露时间的延长腐蚀速率会不断下降;地表浮土中的MgCl2 等成分的存在增加了金属表面的湿润时间,浮土中较高的pH值以及氯离子和硫酸根离子等的共同作用促进了铝及铝合金在南疆沙漠大气环境下的腐蚀.     

混合树脂粉末对换流站阀冷系统6063铝合金腐蚀的影响

通过浸泡腐蚀试验及电化学试验研究了混合树脂粉末对阀冷系统6063铝合金腐蚀行为的影响。结果表明:随着浸泡时间的延长,阴阳树脂分解产物与溶出物含量增多,溶液酸化,表现为溶液电导率上升,pH下降;混合树脂粉末、电流均会加速6063铝合金的腐蚀;电化学测试表明混合树脂粉末使6063铝合金的自腐蚀电位负移,自腐蚀电流密度增大;随着浸泡时间的延长,电化学阻抗谱中容抗弧半径减小,极化电阻减小,即混合树脂粉末溶液中铝合金的耐腐蚀性能降低,腐蚀加快。因此,在实际应用中应该考虑阀冷系统中混合树脂粉末对6063铝合金的腐蚀问题,并采取相应的防护措施。     

6063铝合金阳极氧化膜的耐碱腐蚀性能

铝合金建筑型材阳极氧化膜耐碱性能是衡量其质量的重要指标。采用自行研制的耐蚀性电位测量仪对预制不同厚度的6063铝合金建筑型材阳极氧化膜进行耐碱腐蚀性能测试,并用金相显微镜、扫描电子显微镜对氧化膜的腐蚀形貌进行观察。结果表明:随着6063铝合金阳极氧化膜膜层厚度的增加,其耐碱腐蚀时间逐渐增长;当腐蚀电位达1mV时停止试验,不同膜层厚度的试样腐蚀形貌大致相同。     

镁合金在汽车发动机冷却液中的耐蚀性

在浓度为50％和85％的乙二醇自制冷却液及商用冷却液中对镁及镁合金和纯铝进行了全浸腐蚀测试。结果表明：纯铝比纯镁更耐蚀;在同一浓度的冷却液中,AZ91D的腐蚀率小于AZ31的腐蚀率,而随着乙二醇浓度的提高,镁合金的腐蚀率下降。     

合金元素对铝合金在泰国曼谷地区初期腐蚀行为的影响

在泰国曼谷地区对5083、6063和7020 3种铝合金进行为期1 a的暴晒实验,采用SEM、电化学实验、XPS和扫描Kelvin探针显微镜(SKPFM)对3种铝合金初期腐蚀形貌及腐蚀机理进行研究。结果表明:6063铝合金中Mg、Si、Fe等合金元素含量较少,腐蚀电位相对较高,约为-0.66 V (vs SCE),腐蚀产物膜较为致密,耐蚀性较好,在泰国曼谷地区的腐蚀速率约为0.7 g/(m²·a)。7020铝合金含有较多Mg、Zn等合金元素,腐蚀电位约为-0.78 V (vs SCE),腐蚀最为严重,腐蚀速率约为3.26 g/(m²·a)。3种铝合金均含有Mn、Si、Fe等合金元素,从而形成Fe-Si-Al或Fe-Si(Mn)-Al第二相,第二相表面电位高于基体225～280 mV,在大气环境中第二相作为阴极相,周围的基体Al优先溶解脱落,成为点蚀坑。     

复配缓蚀剂在50%乙二醇冷却液中对AZ91D镁合金的缓蚀作用

采用电化学试验、表面形貌观察、腐蚀产物分析等方法研究了磷酸氢二钠(DSP)和D-葡糖酸钠(GS)两种物质复配后对镁合金在50%(体积分数,下同)乙二醇型冷却液中的缓蚀作用。结果表明:DSP对AZ91D镁合金在50%乙二醇冷却液中是一种混合抑制型缓蚀剂,GS对AZ91D镁合金在50%乙二醇冷却液中没有缓蚀作用;DSP和GS之间存在缓蚀协同效应,复配后的缓蚀剂是一种以抑制阳极过程为主的混合型缓蚀剂;GS的添加量存在极值,而DSP和GS的质量浓度比达到4∶1时,即复配缓蚀剂E,其缓蚀率趋于稳定;随着复配缓蚀剂E加入量的增大,缓蚀率增大,其加入量为2.5g/L时,缓蚀率高达90%以上;复配缓蚀剂E对AZ91D镁合金起到缓蚀作用主要表现为形成了MgHPO4沉淀物,通过GS络合在镁合金表面,从而抑制了镁合金在乙二醇冷却液中的腐蚀。     

Effects of Trace Cl-, Cu2+ and Fe3+ Ions on the Corrosion Behaviour of AA6063 in Ethylene Glycol and Water Solutions

The effects of Cl^-, Cu²⁺ and Fe³⁺ ions and their combinations on the corrosion behaviour of aluminium alloy 6063 (AA6063) in ethylene glycol and water solutions at 50 °C were investigated by electrochemical and immersion methods. Cl ^- resulted in pitting corrosion of the alloy. In the Cl^--free solutions, Fe³⁺ was prone to accelerate uniform corrosion, while Cu²⁺ tended to accelerate pitting corrosion. Severe pitting corrosion of AA6063 was observed in the cases of Cl^- combined with Cu²⁺ or Fe³⁺, especially in the case of Cl^- combined with Cu²⁺ and Fe³⁺ ions.     

Effects of coolant chemistry on corrosion of 3003 aluminum alloy in automotive cooling system

In this work, effects of coolant chemistry, including concentrations of chloride ions and ethylene glycol and addition of various ions, on corrosion of 3003 Al alloy were investigated by electrochemical impedance spectroscopy measurements and scanning electron microscopy characterization. In chloride‐free, ethylene glycol–water solution, a layer of Al‐alcohol film is proposed to form on the electrode surface. With the increase of ethylene glycol concentration, more Al‐alcohol film is formed, resulting in the increase in film resistance and charge‐transfer resistance. In the presence of Cl^? ions, they would be involved in the film formation, decreasing the stability of the film. In 50% ethylene glycol–water solution, the threshold value of Cl^? concentration for pitting initiation is within the range of 100 ppm to 0.01 M. When the ethylene glycol concentration increases to 70%, the threshold Cl^? concentration for pitting is from 0.01 to 0.1 M. In 100% ethylene glycol, there is no pitting of 3003 Al alloy even at 0.1 M of Cl^?. Even a trace amount of impurity cation could affect significantly the corrosion behavior of 3003 Al alloy in ethylene glycol–water solution. Addition of Zn²⁺ is capable of increasing the corrosion resistance of Al alloy electrode, while Cu²⁺ ions containing in the solution would enhance corrosion, especially pitting corrosion, of Al alloy. The effect of Mg²⁺ on Al alloy corrosion is only slight.     

Microbial Activities’ Influence on Three Kinds of Metal Material Corrosion Behaviors

The corrosion behaviors of copper, 6063 aluminum alloy, and Q235 steel were investigated by open-circuit potential (OCP), anodic polarization curve analysis, and electrochemical impedance spectroscopy (EIS). Scanning electron microscopy revealed that a small number of translucent rod-shaped bacterial colonies on the copper surface of copper, whereas plenty of rod-shaped microbes colony were detected on the surface of 6063 aluminum material. Moreover, rod-shaped bacteria and mold colonies attached to the surface of Q235 steel. The decrease in the OCP of copper, 6063 aluminum alloy, and Q235 steel led to higher corrosion tendency. EIS analysis showed that bacteria can reduce the value of AC impedance of copper, the polarization resistance, and the surface resistance, thereby accelerating corrosion. Moreover, the polarization resistance of aluminum alloy in bacterial seawater is lower than that in non-bacterial seawater, indicating the existence of bacteria accelerated the corrosion of 6063 aluminum alloy. The adherence of microbes on Q235 steel surface accelerated the dissolution of the surface layer, and then the passive film is replaced by incompact biofilm layer. Q235 steel corrodes faster under the influence of bacteria because the polarization resistance in bacterial seawater is much lower than that in non-bacterial seawater.     

Corrosion behaviour of magnesium in ethylene glycol

Corrosion of magnesium engine components by coolant is an important issue in the automotive industry where magnesium alloys may be used. It is of significance to understand the corrosion behaviour of pure magnesium in ethylene glycol solutions, as this can provide a basis for developing new coolants for magnesium alloy engine blocks. In this paper, through corrosion and electrochemical tests, it was found that the corrosion rate of magnesium decreased with increasing concentration of ethylene glycol. Individual contaminants, such as NaCl, NaHCO₃, Na₂SO₄ and NaCl can make aqueous ethylene glycol solution more corrosive to magnesium. However, in NaCl contaminated ethylene glycol, NaHCO₃ and Na₂SO₄ showed some inhibition effect. The solution resistivity played an important role in the corrosion of magnesium in ethylene glycol solutions, and the competitive adsorption of ethylene glycol and the contaminants on the magnesium surface was also responsible for the observed corrosion behaviours. The corrosion of magnesium in ethylene glycol can be effectively inhibited by addition of fluorides that react with magnesium and form a protective film on the surface.     

6063铝合金着色钛锆转化膜结构和耐蚀性能的研究

为了获得性能优异的有色钛锆转化膜层,利用正交试验确定了组分为六氟钛酸、六氟锆酸、含锰成膜剂和有机酸的6063铝合金转化处理液的较佳配方,并分析了转化膜的表面形貌、成分及耐蚀性能.分析结果表明:生成的转化膜为淡黄色,且均匀、连续;转化膜中含有钛、锆元素,其腐蚀电位和腐蚀电流密度比裸6063铝合金明显降低,说明钛锆转化膜可以更好地抑制铝合金的阴极反应,从而更有效地提高铝合金的耐蚀性能.     

铝合金化学镀镍工艺对镀层沉积速度的影响

针对铝合金的特点,采用一种无机酸处理工艺对铝合金进行前处理,然后直接进行化学镀镍。讨论了主盐、还原剂、络合剂、pH值等因素对化学镀镍反应沉积速度的影响,得到了较优的工艺配方。验证试验所得Ni-P合金镀层表面均匀,耐蚀性好,结合力强。     

Corrosion mechanism of aluminum alloy by ethylene glycol‐based solution

Corrosion and failure mechanisms on an aluminum (Al) alloy by ethylene glycol base solution have been studied. Extensive crevice corrosion damage and localized scale deposition are clearly observed between the failed Al alloy surface and the rubber hose, in which the leakage of ethylene glycol‐based solution occurred under an actual operating. In addition, many micro‐cracks are found at the rubber hose which is clamped with the Al alloy. The scales on the Al surface appear to be due to the occurrence of Al corrosion, followed by the precipitation of additives of ethylene glycol‐based solution in the crevice between Al alloy and rubber hose. The mechanisms that can account for the crevice corrosion and solution leakage on the Al alloy surface are discussed.