基于SECM研究5083铝镁合金在不同pH NaCl溶液中的腐蚀行为

采用扫描电化学显微镜(SECM)中的极化曲线法和交流阻抗图谱法研究5083铝镁合金在不同pH NaCl溶液中的腐蚀行为,结果表明:在酸性体系(pH 3~7),随着pH的增加,其腐蚀电位正移,点蚀电位相差不大,维钝电流密度减小,电化学阻抗谱中仅有1个容抗弧且呈现收缩趋势.同时,阻抗和相位角减小,电荷传递电阻升高,耐腐蚀性能增大.在碱性体系(pH 9~12),随着pH的增加,腐蚀电流密度增加,而腐蚀电位减小,腐蚀速度由0.000 9mm/a增加到0.025 6?mm/a.电化学阻抗谱中有2个容抗弧,在pH=12处出现感抗弧.同时,阻抗和相位角减小,金属化合物颗粒溶解过程加快,合金耐腐蚀性能降低.      

5083铝镁合金在不同浓度NaCl溶液中的腐蚀研究

采用扫描电化学显微镜（SECM）中的极化曲线法和交流阻抗图谱法研究5083铝镁合金在不同浓度NaCl溶液中的腐蚀行为,结果表明:合金在中性NaCl溶液中的腐蚀为钝化材料体系,随着盐度的增加,Cl-对合金基体的破坏加剧,腐蚀电位正移,点蚀电位减小,其电化学阻抗谱中仅有1个容抗弧且呈现收缩趋势.同时,阻抗减小,相位角增加,弥散指数降低,合金的耐腐蚀性能下降.溶液中存在强活化作用的Cl-,会损坏合金表面的氧化膜,逐渐取代腐蚀产物Al（OH）₃中的OH-,生成新的腐蚀产物AlCl₃.      

Al_(88)Ce_8Co_4非晶合金在NaCl溶液中的腐蚀行为研究

利用极化曲线测试方法、交流阻抗技术研究了Al88Ce8Co4非晶合金在NaCl溶液中的电化学腐蚀行为。研究结果表明,Al88Ce8Co4非晶合金在NaCl溶液中具有很好的耐腐蚀性能。NaCl溶液浓度严重影响Al88Ce8Co4非晶合金的抗腐蚀性能,在所研究的浓度范围内,极化曲线都表现出明显的钝化趋势,EIS图谱均由单一的容抗弧构成。在浓度为0.5mol/L~2mol/L范围内,随浓度的增加,自腐蚀电位有向负方向移动的趋势,腐蚀电流密度逐渐降低,电荷转移电阻逐渐增大,当浓度达到4mol/L时,自腐蚀电位向负方向移动较大,相较于2mol/L时,腐蚀电流密度又有所升高,电荷转移电阻有所降低。     

球磨过程中水性咪唑啉类缓蚀剂对铝粉性能的影响

在对缓蚀剂的缓蚀机理进行分析探讨的基础上,研究了水性咪唑啉类缓蚀剂A在铝粉颜料制备过程中对铝粉性能的影响规律,发现水性咪唑啉类缓蚀剂A在水介质中制备铝粉颜料的最佳用量为3%(缓蚀剂与原料之质量比).在此基础上进一步研究了水性咪唑啉类缓蚀剂A复配后对铝粉性能的影响,结果表明:在同样条件下,复配缓蚀剂制备的铝粉的各项性能更好.这对进一步研究水性铝粉颜料的制备具有一定的参考价值.     

坡莫合金在pH=2.14的氯化钠溶液中的电化学腐蚀行为研究

针对金属薄膜复合板的金属膜选材问题,对坡莫合金进行成分、物相及显微硬度分析,同时研究了坡莫合金在pH=2.14氯化钠溶液中的电化学腐蚀行为,结果表明:镍成分(50%wt)的坡莫合金中的主物相为正方晶系的FeNi(97.7%wt)物相,多边形奥氏体组织;动电位极化曲线表明:镍成分(50%wt)的坡莫合金在pH=2.14的酸性氯化钠溶液中腐蚀以阳极的电化学反应为主,腐蚀速率控制在10~(-3)A/cm~2;交流阻抗表明:电化学腐蚀反应分两步,第一步为阳极的活化反应形成中间腐蚀产物并覆盖在电极表面,第二步为覆盖在电极上的中间腐蚀产物的活化溶解,腐蚀行为及腐蚀机理随着时间的延长未发生变化。     

新型铸造合金的组织及其腐蚀行为的研究

本文设计了新型铸造合金的化学成分，采用金相显微镜、X射线衍射、电于探什（EMPA）、透射电镜（TEM）、扫描电镜（SEM）及扫描隧道显微镜（STM）研究了新型铸造合金的组织及其腐蚀行为。试验结果表明，该合金经1200t固溶处理后，可得到单一的奥氏体组织，具有良好的耐蚀性能。通过STM的观测，得到了新型合全的超高分辨三维腐蚀形貌图象。     

温度对Q235钢在大港土中腐蚀行为和机理的影响

利用极化曲线、线性极化和电化学阻抗谱(EIS)研究了Q235钢在20~70℃、含水20%的大港土中的腐蚀行为.实验表明:Q235钢的腐蚀电流密度随温度升高而增大,线性极化电阻R_p及电荷转移电阻R_t随温度升高而减小;在阳极极化100~200 mV区间,Q235钢的电极过程受到了一定阻滞,E~lgI曲线在该极化区间内的斜率随温度升高而呈指数衰减;利用腐蚀电流密度和线性极化电阻所计算的Stern公式中的B值要大于活性区均匀腐蚀所对应的B值,在实验温度范围内,其数值基本维持在44.2 mV左右;线性极化电阻R_p是整个电极反应过程的综合体现,在含水20%的大港土中,由于受扩散过程控制,R_p的数值要比电荷转移电阻R_t大得多.     

表面纳米化对Ti-6Al-4V合金腐蚀行为的影响

<正>法国学者对Ti-6Al-4V合金进行表面机械磨损处理(SMAT),通过极化曲线及电化学阻抗能谱(EIS)研究了其在林格氏溶液中的腐蚀行为。实验用Ti-6Al-4V合金化学成分(质量分数)为:C 0.08%,N 0.05%,Fe 0.3%,Al 5.5%,V 3.5%,O 0.08%,H 0.015%。试样尺寸为20 mm×10 mm×3 mm,经过抛光、丙酮与蒸馏水溶液超声波清洗、烘干后进行表面机械磨损处理,试样状态为热加工态,未经过预处理或时效。SMAT处理在空气中进行,采用牌号为100Cr6的小球,第一组处理时     

Ce含量对Al在3.5％NaCl溶液中腐蚀行为影响的研究

稀土元素及其含量对铝合金耐腐蚀性能的影响及其机制是铝合金开发利用的重要研究课题,采用高频熔炼方法制备Al1-xCex(x=0,0.2％,2.0％(原子分数))合金,通过X射线衍射、金相分析、电化学测试、扫描电镜和能谱等分别对制备的Al1-xCex合金的结构、动电位线性扫描极化曲线、浸泡与电化学腐蚀前后表面形貌的变化进行了研究;对Al1-xCex在3.5％ NaCl溶液中耐腐蚀性能与铈含量的关系进行了系统的分析.结果表明:由于Cl-离子的存在,铝在3.5％ NaCl溶液中发生点蚀破坏;稀土Ce的加入能够细化晶粒,改善合金微观结构,减弱Cl-离子对点蚀的影响;Ce元素在腐蚀表面层富集,有利于形成连续钝化膜,提高合金在NaCl溶液中的耐蚀能力;微量稀土Ce(0.2％)的加入使合金的自腐蚀电位升高,腐蚀电流密度降低,耐腐蚀性能改善明显;但随着Ce含量的增加,即含量高于铈在铝中的溶解度后,铝与铈将形成金属间化合物,基底与金属间化合物相界面的存在使合金的耐腐蚀性能有所降低,Ce含量为0.2％合金的耐腐蚀性能比Ce含量为2.0％的合金要好.所有合金腐蚀后的主要产物为Al2O3.     

NH3对CuZnAl合金在3.5%NaCl溶液中腐蚀行为的影响

通过对CuZnAl舍金在3．5％NaCl和3．5％NaCl＋NH，溶液中的腐蚀速率和电化学参数的测试及CuZnAl合金腐蚀形貌的观察，分析了NH3对CuZnAl合金在3．5％NaCl溶液中腐蚀行为的影响。结果表明：NH3能改变CuZnAl舍金的腐蚀形貌，使合金的腐蚀电位负移。腐蚀电流增加，合金的腐蚀速率增大。     

Stress corrosion cracking of an Al-Li alloy

Stress corrosion cracking (SCC) has been studied in an Al-Li alloy with variables of orientation of specimen, heat treatment, and applied potentials. The distribution of the electrochemical potential resulting from precipitate clusters was measured, and the hydrogen content on the specimen surface was detected. The results showed that the SCC susceptibility under the peak- aged (PA) condition was higher than that under the natural (NA) and overaged (OA) conditions. The transverse (TL) specimen was more susceptible to SCC propagation than the longitudinal (LT) specimen. The SCC susceptibility and the hydrogen content on the specimen surface were dependent on the applied potentials. The hydrogen content increased when the applied potential changed to positive or negative directions. There was a critical hydrogen content, below which local anodic dissolution (LAD) plays an important role, above which hydrogen embrittlement (HE) plays an important role.     

Stress corrosion cracking of an Al-Li alloy

Stress corrosion cracking (SCC) has been studied in an Al-Li alloy with variables of orientation of specimen, heat treatment, and applied potentials. The distribution of the electrochemical potential resulting from precipitate clusters was measured, and the hydrogen content on the specimen surface was detected. The results showed that the SCC susceptibility under the peakaged (PA) condition was higher than that under the natural (NA) and overaged (OA) conditions. The transverse (TL) specimen was more susceptible to SCC propagation than the longitudinal (LT) specimen. The SCC susceptibility and the hydrogen content on the specimen surface were dependent on the applied potentials. The hydrogen content increased when the applied potential changed to positive or negative directions. There was a critical hydrogen content, below which local anodic dissolution (LAD) plays an important role, above which hydrogen embrittlement (HE) plays an important role.     

Cr对低合金钢在流动NaCl溶液中耐蚀性的影响

对碳钢和Cr含量不同的实验钢在流速为0.8m/s的流动的3.5％(质量分数)NaCl溶液中的腐蚀行为进行研究,最长腐蚀周期为192h.对4种实验钢的腐蚀失重进行了比较,并利用动电位极化曲线、SEM、EPMA和TEM等分析手段,对实验钢表面形成锈层的特征进行了系统研究.结果表明,含Cr实验钢的腐蚀失重低于碳钢,并且随Cr的质量分数由0.5％提高至2％,腐蚀失重亦降低.Cr元素在内锈层中的富集是含Cr钢耐蚀性改善的重要原因.这种富集可使腐蚀产物颗粒获得细小的尺寸,致密内锈层形成的原因就是由于这种尺寸细小的腐蚀产物的形成,使内锈层的保护性获得明显的改善.     

Composition and corrosion resistance of cerium conversion films on 2195Al-Li alloy

The Ce conversion films on 2195Al-Li alloy without and with post-treatment were studied and the corrosion resistance was evalu-ated as well. The surface morphology was observed by scanning electron microscopy (SEM), and the chemical composition was characterized by X-ray photoelectron spectroscopy (XPS). The corrosion behaviors of 2195Al-Li alloy and conversion coating were assessed by means of potentiodynamic polarization curves. The experimental results indicated that after post-treatment the surface quality was improved signifi-cantly. According to XPS, the conversion coating after post-treatment was mainly composed of CeO2, Ce2O3, Ce-OH and a little MoO3 and MoO2. The results of potentiodynamic polarization curves revealed that the conversion coating with post-treatment possessed better corrosion resistance than bare alloy and Ce conversion coating without post-treatment.     

碳钢在NaCl溶液中初始腐蚀行为的探讨

采用电化学极化与金相显微镜原位观察相结合的方法,对Q235钢在3%NaCl溶液中腐蚀的初始行为进行了研究。借助原子力显微镜对初始腐蚀的试样观察分析,发现试样在-900 mV(vs SCE)就出现了点蚀,点蚀优先在晶界附近的铁素体上生成。蚀坑长大后,优先沿轧制方向发展,而形成腐蚀沟槽。钢中夹杂没有发生活性溶解,导电性夹杂物作为阴极仅对腐蚀过程起促进作用。     

Mg-5Gd-3Y-0.8Zr合金的微观组织及耐NaCl溶液腐蚀性能研究

系统研究了Mg-5Gd-3Y-0.8Zr合金的微观组织和耐蚀性能,通过静态失重法测定了其在NaCl溶液中的腐蚀速率。结果表明:铸态合金主要由基体α-Mg和方块状β相(Mg_5Gd、Mg_(24)Y_5)组成,时效处理后分布在晶界处的共晶β相数量明显增加;在NaCl溶液中腐蚀12 h以后镁合金的腐蚀速率明显增加,在3.5%Na Cl(质量分数)溶液中腐蚀24 h后,镁合金已被严重腐蚀,表面布满腐蚀坑和未脱落的白色腐蚀产物;镁合金易产生沿晶腐蚀,方块状共晶β相颗粒可有效阻止表面腐蚀沿晶界向镁合金内部扩展,从而提高镁合金的耐蚀性。     

Effect of solid-solution treatment on corrosion and electrochemical behaviors of Mg-15Y alloy in 3.5 wt.% NaCl solution

The effect of solid-solution treatment on corrosion and electrochemical mechanisms of Mg-15Y alloy in 3.5 wt.% NaCl solution was investigated by electrochemical testing,immersion testing and SEM observation.The results indicated that the corrosion resistance of Mg-15Y sample gradually deteriorated with immersion time increasing,which was consistent with the observation of corrosion morphologies.The solid-solution treatment decreased the amounts of second phase Mg24Y5.The Ecorr and corrosion rate of as-cast samples were both lower than those of solid solution-treated samples,and both increased with increment of solid solution-treated time.The corrosion mechanism was proposed for the galvanic,pitting and filiform corrosion which varied with the immersion time and solid-solution treatment.     

时效制度对2A97铝锂合金腐蚀行为和微观组织的影响

通过拉伸性能测试、晶间腐蚀(IGC)和剥落腐蚀实验(EXCO)以及透射电镜(TEM)观察,研究时效制度对2A97铝锂合金力学性能、晶间腐蚀行为、剥落腐蚀行为和微观组织的影响.结果表明:135℃/36 h+175℃的双级时效比135℃的单级时效更有利于提高2A97铝锂合金的力学性能和耐腐蚀性能;随着175℃下的第二级时效...     

Comparative study on the corrosion behavior of low alloy steels in sulfuric acid solution

The corrosion behavior of a weathering steel SPA-C and two acid resistance steels( S-TEN1 and ND) in sulfuric acid solution was investigated by using potentiodynamic polarization and weight loss measurement techniques.Both potentiodynamic polarization and weight loss measurement tests indicated that corrosion resistance of these three alloy steels was as follows: ND ≈ S-TEN1 SPA-C.Surface analysis of the corroded samples conducted after the immersion test indicated that two layers were formed on the substrates,with the outer layer comprising Fe SO_4·H_2O and the inner layer mainly comprising iron oxides.The addition of Cu,Cr,and Sb refined the corrosion products and improved the adhesion ability between the rust layer and the substrate.