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。     

稀土镁合金、AZ31及AZ91负极材料耐腐蚀性能及放电行为的比较

通过对动电位极化曲线、电化学阻抗谱图、SEM形貌的分析,研究了AZ31、AZ91和稀土镁合金在8.0%(质量分数)Na Cl溶液中的腐蚀行为。并将上述三种镁合金组装成电池,在8.0%Na Cl溶液中进行恒流放电测试。结果表明:三种负电极的耐蚀性是稀土合金AZ31AZ91;浸泡48 h后稀土镁合金的表面裂纹最少,腐蚀程度最轻,而AZ91负极的腐蚀程度最严重,表面裂纹较深;稀土合金的放电时间最长,达到800 min,AZ31为710 min,AZ91为660 min。     

钨铜合金化学镀镍磷镀层的腐蚀行为

采用浸渍失重试验法和动电位极化曲线研究了钨铜合金基材和钨铜合金表面化学镀Ni-P合金镀层在不同腐蚀介质溶液中的腐蚀行为.浸渍失重试验结果表明:Ni-P合金在质量分数为3.5%的NaCl溶液、人工模拟汗液和体积分数为10%的H2SO4溶液中的耐腐蚀性能好于钨铜合金;动电位极化曲线研究表明:化学镀Ni-P合金浸入3.5wt.%NaCl溶液后不久其表面便开始形成钝化膜,但此钝化膜不完整,随着浸泡时间的延长,钝化膜不断生长,能在较长时间内(29d)对钨铜合金起到保护作用.     

AM60压铸镁合金表面ZrO_2微弧氧化陶瓷层的制备方法研究

为了改善镁合金的微弧氧化膜层的性能,利用两步法在AM60压铸镁合金表面制备了ZrO_2微弧氧化膜层.研究了膜层在恒电压控制方式下的生长规律,测量了膜层在w(NaCl)=3.5%溶液中的极化曲线,分析了膜层的物相组成.结果表明:在400 V恒压微弧氧化处理时,微弧氧化膜层的平均生长速度最高可达3.5 μm/min:试样在w(NaCl)=3.5%溶液中的极化曲线显示,镁合金经过两步法在锆盐溶液中微弧氧化后,其腐蚀电位正移,腐蚀电流降低,腐蚀速度大幅降低,其耐蚀性得到了大幅度提高.两步法制备微弧氧化膜层主要由ZrO_2、ZrP_2、Mg_3(PO_4)_2、MgF_2相组成,在溶液中添加的Zr元素可以通过微弧氧化处理时的复杂反应进入膜层中,膜层表现出的优异耐蚀性主要源于膜层中存在ZrO_2陶瓷.     

硫酸锰掺杂聚吡咯膜的制备和其耐腐蚀性能

采用直接接触氧化技术在不锈钢表面制备了硫酸锰掺杂聚吡咯膜。采用循环伏安曲线、显微形貌观察、动电位极化曲线和电化学阻抗谱研究了硫酸锰掺杂聚吡咯膜的微观形貌及耐腐蚀性能。结果表明:硫酸锰的掺杂改变了聚吡咯的结构,增强了膜结构的致密性,从而使硫酸锰掺杂聚吡咯膜具有较好的耐腐蚀性能,对不锈钢起到保护作用;与裸不锈钢相比,表面涂覆硫酸锰掺杂聚吡咯膜后,不锈钢的自腐蚀电位提高了约1.0V,自腐蚀电流降低了约3个数量级。     

AZ31镁合金表面聚吡咯-钼酸盐膜的腐蚀性能（英文）

在水杨酸钠溶液中采用循环伏安法在AZ31镁合金表面分别电聚合聚吡咯(PPy)膜和聚吡咯-钼酸根膜(PPy-MoO_4~(2-))。利用扫描电子显微镜(SEM)观测PPy膜和PPy-MoO_4~(2-)膜层腐蚀前后的表面形貌,衰减全反射红外光谱(ATR-IR)反映了PPy膜和PPy-MoO_4~(2-)膜的特征吸收峰,研究了MoO_4~(2-)的存在对PPy特征吸收峰的影响。使用四探针法测量薄膜的表面电阻;采用开路电位(OCP),电化学交流阻抗谱(EIS)和动电位极化曲线测试PPy膜和PPy-MoO_4~(2-)膜在3.5%Na Cl溶液中浸泡12 h后的耐腐蚀性能。结果显示,PPy-MoO_4~(2-)膜层更紧凑,PPy-MoO_4~(2-)膜层的腐蚀电流密度比PPy膜的低3个数量级。钼酸根的存在使得PPy-MoO_4~(2-)膜的表面电阻比PPy膜小,且PPy-MoO_4~(2-)膜的耐腐蚀性能较好。     

AZ31镁合金表面聚吡咯-钼酸盐膜的腐蚀性能

在水杨酸钠溶液中采用循环伏安法在AZ31镁合金表面分别电聚合聚吡咯(PPy)膜和聚吡咯-钼酸根膜(PPy-MoO42-)。利用扫描电子显微镜（SEM）观测PPy膜和PPy-MoO42-膜层腐蚀前后的表面形貌,衰减全反射红外光谱（ATR-IR）反映了PPy膜和PPy-MoO42-膜的特征吸收峰,研究了MoO42-的存在对PPy特征吸收峰的影响。使用四探针法测量薄膜的表面电阻;采用开路电位（OCP）,电化学交流阻抗谱（EIS）和动电位极化曲线测试PPy膜和PPy-MoO42-膜在3.5%NaCl溶液中浸泡12h后的耐腐蚀性能。结果显示,PPy-MoO42-膜层更紧凑,PPy-MoO42-膜层的腐蚀电流密度比PPy膜的低三个数量级。钼酸根的存在使得PPy-MoO42-膜的表面电阻比PPy膜小,且PPy-MoO42-膜的耐腐蚀性能较好。     

聚苯胺/聚吡咯复合薄膜的制备及其抗腐蚀性能研究

采用循环伏安法在不锈钢表面电聚合聚苯胺/聚吡咯复合薄膜.利用动电位极化曲线法和电化学阻抗法研究了聚苯胺/聚吡咯复合薄膜的耐蚀性及其影响因素.结果表明:在3.5%NaCl溶液中,不锈钢表面覆盖复合膜以后,其自腐蚀电位比无膜和纯聚苯胺膜时提高,耐蚀性能增强,且复合膜的耐蚀性受电解液浓度、扫描次数、扫描速率及扫描上限等因素的影响.电解液中苯胺和吡咯的浓度比及硫酸浓度的高低,都会影响膜的致密度,从而影响膜的耐腐蚀性.电化学参数的改变会影响复合膜的聚合速率,使得复合膜的抗腐蚀能力不同.当苯胺和吡咯浓度比为7:3时,硫酸浓度为1.1 mol/L,扫描次数为25次,扫描速率为60 mV/s,扫描上限为1.2 V时,采用循环伏安法共聚合苯胺和吡咯,可形成沉积致密度高、耐蚀性好的复合膜.     

化学镀纳米晶铜层的显微组织与腐蚀特性

利用化学镀技术在石英玻璃表面制备了致密光亮的纳米晶铜层。随着化学镀时间由10min延长至60min,铜层平均晶粒尺寸由22nm增大到75nm,(111)晶面织构减弱,表面团簇聚集程度增加。采用极化曲线和浸泡失重实验对比分析了纳米晶铜层和粗晶铜的腐蚀特性。结果表明:在3.5%NaCl(质量分数)溶液中,纳米晶铜层的耐蚀性能较好。腐蚀溶液沿点蚀坑逐渐进入铜层与玻璃基体的界面处,导致铜层脱落失效。在10%NaOH(质量分数)溶液中,纳米晶铜层的腐蚀速率较高,由于应力腐蚀产生大量微裂纹而迅速失效。     

镀锌钢板表面硅烷膜的制备及性能研究

目的提高镀锌钢板的耐腐蚀性能。方法在镀锌钢表面制备双-[γ-(三乙氧基硅)丙基]四硫化物(BTESPT)和乙烯基三乙氧基硅烷(VTES)单一硅烷膜和双硅烷膜,并掺杂缓蚀剂和稀土盐改性制备复合膜,用动电位极化曲线测试研究各种硅烷膜在3.5%Na Cl溶液中对镀锌钢的腐蚀防护性能。结果 VTES硅烷膜的最佳工艺条件为:V(VTES):V(乙醇):V(水)=7:30:70,p H=4.5,水解2 d,成膜时间20 min,固化温度100℃,固化时间30 min,VTES硅烷膜耐蚀性比BTESPT硅烷膜略差,但更经济。双层硅烷膜能够提高物理屏障作用,可以进一步增加耐蚀性。当铈盐和硅烷混合水解再成膜时,硅烷膜的耐蚀性最好。在硅烷水解溶液中加入0.01 mol/L的吡咯,可以制得耐蚀性优良的缓蚀剂掺杂硅烷摸。结论铈盐和吡咯改性硅烷膜对镀锌钢具有良好的保护作用。     

Corrosion study of PVD coatings and conductive polymer deposited on mild steel: Part I: Polypyrrole

Electrochemical deposition of polypyrrole on mild steel substrate was carried out by cyclic voltammetry and galvanostatic technique from neutral aqueous sodium tartrate medium. Homogenous polypyrrole layer for further studies was achieved by galvanostatic technique at constant current density of 5 mA/cm². TiN, CrN and diamond-like carbon (DLC) coatings deposited by physical vapor deposition (PVD) technique on mild steel were used for comparison of corrosion properties with polypyrrole film. Electrochemical synthesis of polypyrrole was also applied as a solution for the PVD coatings porosity problem. Polypyrrole film was successfully deposited on all studied PVD coatings by the galvanostatic technique under special conditions. The protection against corrosion was studied by several methods — measurement of potentiodynamic polarization curves, Tafel plot analysis and electrochemical impedance spectroscopy in 3% NaCl solution.     

The role of chromium and molybdenum in passivation of amorphous Fe-Cr-Mo-P-C alloys in deaerated 1 M HCl

The effect of open circuit immersion on the passivation behavior of amorphous Fe-8Cr-Mo-13P-7C alloys with 0, 2 and 6 at.% molybdenum by potentiostatic polarization in de-aerated 1 M HCl was investigated. The polarization was made at 400 mV (SCE) which is in the passive region of chromium but in the transpassive region of molybdenum, whereas the open circuit potential of these alloys is in the passive region of molybdenum but in the active region of chromium. Open circuit immersion of molybdenum-bearing alloys results in the formation of molybdenum-enriched passive film, but passivation at 400 mV is based on the formation of chromium-enriched passive film and the molybdenum-enriched film formed by open circuit immersion is converted to the chromium-enriched film at 400 mV. Polarization at 400 mV immediately after immersion leads to rapid enrichment of chromium to the level of 50% cations within 100 s, but polarization after open circuit immersion of molybdenum-bearing alloys for 10 min results in a gradual increase in chromium content to the level of 50% of cations in 5 h. The current density of molybdenum-bearing alloys after open circuit immersion is always higher than that of the alloys polarized immediately after immersion. Open circuit immersion of molybdenum-free alloy for 10 min gives rise to serious damage of the alloy surface and hence prevents passivation even if prolonged polarization is carried out.     

Influence of hydrolysis time on the structure and corrosion protective performance of (3-mercaptopropyl)triethoxysilane film on copper

Films of (3-mercaptopropyl)triethoxysilane with different hydrolysis time were formed on copper surface. To evaluate the influence of hydrolysis time on structures and corrosion resistance of these films, Fourier-transform infrared spectroscopy, polarization curves, cyclic voltammetry and electrochemical impedance spectroscopy tests were performed on covered and uncovered copper specimens. Results indicate that the optimum hydrolysis time is 48 h. The film obtained in this case shows the best corrosion resistance in 3.5% (w) NaCl solution.     

TA2纯钛酒石酸钠溶液阳极氧化膜层微观形貌对腐蚀性能的影响

选择酒石酸钠环保电解液,用恒电势法在不同浓度条件(1,5,15,30和50 g/L)下制备TA2纯钛阳极氧化膜。采用原子力显微镜分析膜层的微观三维形貌,使用电化学工作站研究试样在3.5%NaCl溶液低电位下的极化曲线和电化学交流阻抗谱,探讨微观三维形貌对耐腐蚀性能的影响。结果表明:15 g/L浓度时,氧化膜层细小均匀,生长完整,粗糙度较低,具有宽广的钝化区,最大的极化电阻值,较小的致钝电流值和自腐蚀电流值,耐腐蚀性能最佳。     

电化学合成聚吡咯及其腐蚀防护性能研究

    采用循环伏安法在304不锈钢(304SS)基体上电化学合成聚吡咯(PPy)膜层,并通过Tafel极化曲线、电化学交流阻抗谱法(EIS)研究聚吡咯膜层的腐蚀防护性能.结果表明,聚吡咯膜层使304不锈钢基体的自腐蚀电位正移60 mV,腐蚀电流密度由10^-6 A/cm² 变化到 10^-7 A/cm²;覆有聚吡咯膜层的304不锈钢在腐蚀液中浸泡的过程中,由于聚吡咯的氧化还原能力,在金属表面加速钝化层的形成及修复破坏的钝化层,进一步提高了金属的抗腐蚀性能;聚吡咯膜层的防腐机制归结为物理屏蔽作用和钝化机制.     

Polypyrrole electrodeposited on copper from an aqueous phosphate solution: Corrosion protection properties

Highly adherent and homogenous polypyrrole films were electrodeposited at copper from a dihydrogen phosphate solution. The polypyrrole films were electrosynthesized in the overoxidized state by cycling the copper electrode from -0.4 to 1.8 V (SCE) in a pyrrole-containing phosphate solution. The growth of the polypyrrole films was facilitated by the initial oxidation of the copper electrode in the phosphate solution to generate a mixed copper-phosphate, copper oxide or hydroxide layer. This layer was sufficiently protective to inhibit further dissolution of the copper electrode and sufficiently conductive to enable the electropolymerization of pyrrole at the interface, and the generation of an adherent polypyrrole film.Potentiodynamic polarization measurements, Tafel analyses and open-circuit potential data revealed that the polypyrrole coating effectively protects the copper substrate from corrosion in a chloride solution. However, the corrosion protection properties were reduced with longer immersion times.     

Characteristics and formation of corrosion product films of 70Cu-30Ni alloy in seawater

The corrosion product films of 70Cu-30Ni alloy, composed of recrystallized grains or deformed and recrystallized grains, were investigated in 3.5% NaCl and natural seawater by electrochemical techniques, SEM, EDX and AES. The recrystallized alloy displayed a steady increase in the polarization resistance while the alloy of incomplete recrystallization kept its polarization resistance at a low level as increasing the immersion time in 3.5% NaCl. The films formed on the recrystallized alloy in seawater were thin, uniform and rich in nickel. After long-term immersion, the films, still thin and protective, consisted of convex lines and smooth zones between the lines. The convex lines were richer in nickel and contained more seawater species than the zones, so this led the lines to preferentially dissolve and new lines to appear where the film grew slower. Immersed in seawater, the alloy of incomplete recrystallization showed thick, loose and porous films, of which the inner layer was denickelified and the outer layer contained a great amount of seawater species, and of which the underlying substrate was found with severe intergranular corrosion. The tube specimens of incomplete recrystallization for four-year immersion were perforated by intergranular corrosion.     

聚噻吩的电化学合成及其对不锈钢的抗腐蚀性研究

通过恒电位法在三氟化硼乙醚（BFEE）溶液中以不锈钢片为基底合成了聚噻吩薄膜（PTh）。采用傅里叶红外光谱（FT-IR）、扫描电镜（SEM）、热重（TGA）等测试技术对产物的结构、形貌、热稳定性进行了表征。在3.5mass% 的NaCl溶液中采用塔菲尔（Tafel）极化曲线和电化学阻抗（EIS）方法对聚噻吩薄膜进行了抗腐蚀性能检测。结果表明,所制得的聚噻吩膜形貌均匀,热稳定性好,附着聚噻吩薄膜的不锈钢片（PTh/SS）抗腐蚀电位相对于裸不锈钢片（SS）正移约220 mV,腐蚀电流密度下降了2个数量级,具有良好的抗腐蚀性能。     

Corrosion behaviors and galvanic studies of microarc oxidation films on Al-Zn-Mg-Cu alloy

Corrosion-resistant films were fabricated by the microarc oxidation technique on the LC4 zinc-containing aluminum alloy in silicate electrolyte. The electrochemical corrosion behaviors of LC4 alloy, with and without films, were evaluated using potentiodynamic polarization curves. Galvanic currents and galvanic potentials of bare and coated alloys coupled with copper were measured using the zero-resistance technique. Scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX) was used to analyze the microstructure of films and the corrosion morphology before and after corrosion testing. After microarc discharge treatment, the corrosion potential was increased and the corrosion current was significantly reduced. For a thin film sample, the galvanic current is similar to that of the bare alloy. However, a thick film can protect the LC4 alloy against galvanic corrosion.     

Corrosion Performance of Anodized AZ91D Magnesium Alloy: Effect of the Anodizing Potential on the Film Structure and Corrosion Behavior

Die-cast AZ91D magnesium alloy samples have been submitted for anodizing at different potentials. Anodizing was conducted in an environmentally friendly solution which comprised 3 M KOH + 1 M Na₂SiO₃ at room temperature. The surface treatment was performed electrolytically at four different potentials: 3, 5, 8, and 10 V. The corrosion resistance was evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization curves obtained after 7 days of immersion in a 3.5 wt.% NaCl solution at room temperature. The porosity of the anodic films was estimated by means of the linear polarization method. SEM images revealed that the surface oxide was thicker for the anodic films obtained at 3 and 5 V. The films obtained at these potentials were more porous than those formed at 8 and 10 V. The results showed that the thickness of the anodic film had a significant effect on the corrosion behavior of the AZ91D, whereas the influence of the initial porosity was not significant.