烷基硫醇自组装膜对铝合金的缓蚀性能研究

采用浸泡法,在含水量不同的十四烷基硫醇/乙醇-水溶液中,使2024铝合金表面自组装烷基硫醇膜,通过动电位扫描、电化学交流阻抗、原子力显微镜以及光电子能谱研究了硫醇自组装膜在铝合金表面的吸附行为及缓蚀性能。结果表明,十四烷基硫醇自组装膜对铝合金在Harrison溶液中的腐蚀具有一定缓蚀作用,且缓蚀效果随着自组装溶液中含水量的增加而增强。     

溶液中含水量对铝合金表面自组装TDPA膜缓蚀行为的影晌

用含水量不同的正十四烷基膦酸（TDPA）／乙醇-水混合溶液在2024铝合金表面制备TDPA自组装膜。采用动电位扫描、电化学交流阻抗（EIS）、傅里叶红外（FTIR）、俄歇能谱（AES）以及原子力显微镜（AFM）等手段,研究白组装膜在0．1mol／L硫酸溶液中对铝合金的吸附及缓蚀性能的影响。傅里叶红外以及俄歇能谱测试结果表明：TDPA分子成功吸附于合金表面,且吸附密度随着溶液中水含量的增加而增加。电化学测试以及腐蚀形貌观察结果表明：4h的自组装能够获得最佳缓蚀效率;自组装溶液中水含量越高,得到的自组装膜缓蚀性能越好;白组装溶液中水对白组装膜性能的影响与金属表面的水化反应有关。     

自组装硅烷膜对 6061 铝合金表面耐蚀性影响的研究

采用自组装方法,在6061铝合金表面制备十二氟庚基丙基三甲氧基硅烷自组装膜层,对制备工艺进行了优化,并对自组装膜层进行了表面形貌分析,通过极化曲线和电化学阻抗谱研究了自组装膜层的耐蚀性能。结果表明:与铝合金基体相比,自组装膜的腐蚀电流密度减小了3个数量级,电化学阻抗值增大了近1倍,达到了提高铝合金表面耐蚀性能的目的。     

K2L-SAMs对碳钢在饱和CO2油田水中的缓蚀行为与量子化学研究

利用邻氧乙酸苯甲醛缩对氨基苯磺酸钾盐席夫碱(K2L)缓蚀剂在20#碳钢表面制备自组装单分子膜(SAMs),并通过电化学方法研究缓蚀剂自组装膜的最佳组装时间;采用电化学测试技术和表面分析技术研究K2L-SAMs对碳钢在饱和CO2油田水介质中的缓蚀行为;采用密度泛函理论分析缓蚀剂分子的前线轨道、Mulliken电荷和分子静电势。结果表明:缓蚀剂在碳钢表面自组装3 h后,可以形成稳定、致密的缓蚀膜;在碳钢表面形成的K2L-SAMs能有效抑制碳钢的阴极还原过程,最高缓蚀效率达87.55%;K2L的吸附行为符合Langmuir吸附等温式,吸附机理为典型的化学吸附。量子化学计算结果表明:羧基是K2L分子的主要吸附活性区域,能与碳钢表面铁原子作用形成稳定的配位键。     

430 不锈钢表面月桂酸自组装膜的探究

采用浸泡法在430不锈钢表面制备了月桂酸自组装膜,通过电化学方法、接触角测试及微观形貌分析,研究了该自组装膜在430不锈钢表面的吸附行为及缓蚀作用。研究结果表明:经过简单的浸泡,月桂酸分子能够稳定地吸附在不锈钢表面,自组装时间、组装液浓度以及基底表面前处理对组装膜的缓蚀效率有较大影响,自组装时间4 h、月桂酸浓度5 mmol/L、组装温度35℃为最佳自组装条件;基底在组装之前进行钝化处理,有利于形成致密的自组装分子膜,提高不锈钢的耐蚀性能。     

430不锈钢表面十四烷基膦酸自组装膜的制备与耐蚀性

用浸泡法在430不锈钢表面制备了十四烷基膦酸自组装膜,利用Fourier反射红外,动电位扫描、接触角测试、电化学阻抗及X射线光电子能谱研究了该自组装膜在430不锈钢表面的吸附行为和对点蚀电位的影响。结果表明:吸附有十四烷基膦酸分子的430不锈钢表面由亲水性转为疏水性,自组装时间为6 h时不锈钢的点蚀电位较高;氧化处理能够提高不锈钢基底的点蚀电位,且氧化处理后的不锈钢表面也能在十四烷基膦酸溶液中形成保护性的自组装膜。     

Cu表面氨基酸混合组装体系的缓蚀作用

考察了半胱氨酸自组装膜Cu电极在0.5 mol/L HCl溶液中的电化学行为,结果表明半胱氨酸自组装膜导致Cu电极的自腐蚀电位负移,能够在一定程度上抑制Cu电极的阴极电化学过程｡在此基础上,通过静电沉积技术,将十二酸接枝到Cu表面半胱氨酸分子上｡结果显示,十二酸修饰的半胱氨酸自组装膜对Cu电极的阴极电化学过程抑制作用进一步增强,提高了对Cu的保护｡     

铜表面吡咯烷二硫代氨基甲酸铵自组装膜的拉曼光谱和缓蚀作用

应用表面增强拉曼光谱(SERS)和电化学方法,对铜电极表面吡咯烷二硫代氨基甲酸铵(APDTC)的自组装单层结构、缓蚀性能和吸附行为进行研究。SERS光谱表明:APDTC分子通过硫原子垂直吸附在铜表面形成APDTC自组装单分子膜(APDTC SAMs)。交流阻抗和极化曲线实验表明:在3%NaCl(质量分数)溶液中APDTC SAMs对铜具有很好的缓蚀作用,最高缓蚀效率可达98%;APDTC的吸附行为符合Langmuir吸附等温式,吸附机理是介于化学吸附和物理吸附之间的一种吸附。     

聚多巴胺自组装膜对316L不锈钢缓蚀性能的影响

通过浸泡组装法在316L不锈钢表面成功组装制得聚多巴胺自组装膜,并用动电位扫描、电化学阻抗测试、扫描电镜SEM观察及傅立叶反射红外FTIR研究了多巴胺的吸附行为及其对316L不锈钢在0.9%NaCl溶液中腐蚀行为的影响。结果表明,多巴胺发生氧化和聚合反应,并以氧原子吸附组装于试样表面;多巴胺加量较低时加速腐蚀,大于10g/L可起到缓蚀作用。组装时间24h,组装质量浓度为20g/L时可获得最佳缓蚀效果。     

十八硫醇自组装膜对青铜的缓蚀作用

在乙醇体系中采用十八硫醇(ODT)在青铜表面制备自组装膜(SAMs),采用循环伏安法、极化曲线和交流阻抗谱等电化学方法研究该膜在0.5 mol/LNaCl溶液中对青铜电极的缓蚀性能。结果表明:ODT在青铜表面形成了SAMs,能够有效抑制青铜的腐蚀。随着成膜温度和ODT浓度的增高,ODT自组装膜的缓蚀效率和覆盖度提高。当ODT浓度为0.1 mol/L、成膜温度为60℃时,缓蚀效率为98.1%,覆盖度为98.7%;十八硫醇在青铜表面的吸附行为符合Langmuir吸附等温式,吸附机理是典型的化学吸附。     

Impurity effects on the macromorphology of electrodeposited zinc III: Potential sweep analysis

The potential sweep method has been employed to analyse the impurity effects in zinc electrodeposition from solutions of its chloride. It has been pointed out that the peak for zinc deposition from its binary systems disappears because of mutual codeposition with hydrogen and continuous exchange of the reaction rates during the cathodic sweep. It has also been pointed out that a black “burned” zinc deposit always appears at electrode reaction rates higher than the limiting current for zinc electrogrowth in intense hydrogen evolution. The distinction between the spongy and burned zinc has also been made: the former is an autocatalytic mass-transfer process promoted by some impurities, while the latter represents the kinetic effects of the local current density, both being electrocatalytic for the hydrogen evolution reaction. Finally, it has been pointed out that the individual deposition peak for more positive metals disappears whenever intermetallic phase formation occurs and that it naturally leads to underpotential deposition.     

表面膜对点阵结构Ti6Al4V表面超疏水特性的影响

采用激光加工在Ti6Al4V试样表面加工不同间距的点阵结构,采用自组装技术制备4种自组装分子膜。通过表面形貌和接触角的测量表征试样的表面特性。结果表明:通过激光点阵加工和沉积自组装分子膜,可显著增加Ti6Al4V试样的水接触角。长链分子FDTS、FOTS和OTS制备的自组装分子膜,使Ti6Al4V试样的接触角均大于150?,形成超疏水表面,其中沉积FDTS自组装分子膜时,试样的接触角最大,可达164.5?。沉积短链分子MPS自组装分子膜时,只有当激光加工间距为50μm时,试样方可形成超疏水表面;间距增大后,试样表面变成疏水表面。沉积4种自组装分子膜时,试样的接触角均随激光点阵加工间距的增大而减小。     

An electrochemical study on the influence of sodium molybdate on electrodeposition process and phase composition of ternary Zn–Ni–Mo alloy coatings

Ternary Zn–Ni–Mo alloy coatings were deposited from a citrate-sulphate bath at pH 5.7 containing different amounts of sodium molybdate. The content of molybdenum in the coatings (from 0.3 to 5.2?at.-%) can be easily controlled by increasing sodium molybdate concentration in the plating bath from 0.0025 to 0.05?mol?dm^??3, which results also in deposition of smoother deposits. An increase in molybdate concentration leads to the shift of reduction potentials towards more negative values and to the decrease in current efficiency of deposition process. XRD analyses and anodic linear sweep voltammetry (ALSV) measurements demonstrated that at least two phases are formed in the Zn–Ni–Mo alloy: a hexagonal zinc phase or solid solution of nickel in zinc and Ni₅Zn₂₁ intermetallic compound. Furthermore, the XRD analyses revealed a third phase, which could be assigned to the oxidised species of molybdenum or other alloying metals.     

Modification of copper surfaces with cathodic arc aluminum plasma

In the present study, surfaces of copper substrates were modified with aluminum plasma using cathodic vacuum arc (CVA) physical vapor deposition based technique. Surface treatments were carried out as a function of bias voltage for various time intervals. The effect of long and short durations of ion bombardment on the resulting microstructural features of the treated surfaces were studied and discussed. It was observed that surface alloying and diffusion processes were enhanced by the application of the ion bombardment and thick (10-15 μm) modified zones were achieved in a relatively short processing time (15-20 min). In the experiment executed with long bombardment duration, the modified zone consisted of a mixture of martensitic β₁-AlCu₃ phase and (Cu) solid solution, accompanied with a minor amount of γ₁-Al₄Cu₉ intermetallic phase, whereas, in the experiment involving short total bombardment duration, the modified surface predominantly consisted γ₁-Al₄Cu₉ intermetallic phase, accompanied with martensitic β₁-AlCu₃ phase at the copper aluminum interface.     

Characterisation of industrially produced galvannealed coating by open circuit potential (OCP) measurement technique

An attempt has been made to characterise the industrially produced galvannealed coating by the open circuit potential (OCP) measurement technique. It confirms that the industrially produced galvannealed coating consists of four iron–zinc intermetallic phases, Fe3Zn10, Fe5Zn21, FeZn10 and FeZn13, in layers on the steel substrate. The OCP results are compared with other characterisation techniques such as galvanostatic scan EIS and glow discharge optical emission spectroscopy (GDOES). The additional advantage of this technique is not only to confirm different iron–zinc intermetallic phases in the coating but also to identify the stability of all these phases in an aggressive chloride environment. It was established that the dissolution rate of the Fe3Zn10 phase which contains the maximum amount of iron is the slowest whereas the dissolution rate of the FeZn13 phase which contains the minimum amount of iron is the fastest. This can be explained by the fact that the phase containing more of the more active metal (zinc) is dissolved faster than the phase containing more of the less active metal (iron).     

Characterization of hot-dip galvanized coating on dual phase steels

This work explored the microstructure of continuous hot-dip galvanized zinc coating on two dual phase steels, focusing on the sample preparation methods for cross-sectional microstructure and Fe-Al intermetallic compound observation. Based on the microstructure revealed by proper method, we established a relationship between the annealing atmosphere and coating microstructure. The experimental results showed that the coating thickness and Fe-Al intermetallic compound's size are relevant to the annealing atmosphere. And the coexistence of Fe-Al intermetallic compound and Fe-Zn phase has proved indirectly that the aluminothermic reduction is working during hot-dip galvanizing.     

Effect of Ultrafine Powders of Copper Alloys in Lubrication on Mating Surfaces under Friction

The effect of ultrafine powders of copper alloys in lubrication on friction surfaces is considered. It is shown that friction is accompanied by structural changes in the copper alloys with formation of intermetallic compounds and deposition of copper on the mating surfaces. The amount of copper depends on the chemical composition of the ultrafine alloys and microdistortions of their crystal lattices.     

2-Mercaptobenzothiazole monolayers on zinc and silver surfaces for anticorrosion

Anticorrosive behaviors of 2-mercaptobenzothiazole (MBT) self-assembled monolayers (SAMs) on silver and zinc electrodes were comparatively studied by means of electrochemical impedance spectroscopy (EIS). The promising inhibition effect of the MBT for silver and zinc from corrosion had been confirmed. The adsorption geometries of MBT monolayers on zinc and silver electrodes were observed by surface enhanced Raman scattering (SERS) technique. The SERS spectra implied that monolayers of MBT could be self-assembled on Ag surface through S¹⁰ and N³ atoms and the molecular plane should be tilted with respect to the surface. On Zn surface, MBT molecules formed monolayers via both S atoms and the other moieties of the molecule away from the surface. From the in situ electrochemical SERS results it can be found that MBT monolayers on both Ag and Zn surfaces experienced the changes of adsorption fashions as the potential shifting to more negative direction.     

激光熔化沉积NiTi/Ni3 Ti金属间化合物合金的显微组织和耐磨性

利用激光熔化沉积技术制备出分别以NiTi和Ni3Ti为初生相的NiTi/Ni3Ti金属间化合物耐磨合金,采用XRD、OM、SEM、EDS等手段分析合金的组织,测试合金的室温干滑动磨损性能。结果表明,其室温干滑动磨损机制为软磨料磨损和氧化磨损;对于以Ni3Ti为初生相的合金,其室温干滑动磨损机制在中低负荷下为氧化磨损和显微切削,在高负荷下则是Ni3Ti的显微切削;以NiTi为初生相的NiTi/Ni3Ti金属间化合物合金具有更好的抗室温摩擦磨损性能。     

Influence of zinc on intermetallic compounds formed in friction stir welding of AA5754 aluminium alloy to galvanised ultra-high strength steel

In this study, lap joints between AA5754 and DP1000 ultra-high strength steels were produced by friction stir welding. In order to investigate the roles of zinc on intermetallic phase formation and joint properties, steel substrates were used, two being galvanised coated and one uncoated. Joint performance has been evaluated in term of maximum tensile shear loading. The effects of the process parameter, translational speed; chemical compositions; and intermetallic phase formation on the mechanical properties have been investigated. The results show that joints with a galvanised layer exhibit higher strength as compared to the non-coated steel. A thicker galvanised layer promotes the presence of zinc in the aluminium matrix, resulting in better joint properties. The level of zinc contents in the aluminium matrix depends on process temperature and material circulation characteristics. Two stable Al-rich intermetallic phases, Al₅Fe₂ and Al₁₃Fe₄, were detected at the interface regardless of the coating conditions.