油管镀Ni-Fe-W合金层的耐疲劳和耐蚀性能

目前,不同腐蚀环境中油管选用Ni-Fe-W合金镀层时存在一定的盲目性。对QT-900油管电镀Ni-Fe-W合金,模拟某油田腐蚀环境,通过疲劳试验、高温高压腐蚀试验以及金相显微镜、SEM、EDS等分析手段,研究了Ni-Fe-W镀层对QT-900油管的耐疲劳及耐CO2酸性腐蚀的影响。结果表明:Ni-Fe-W合金镀层具有良好的耐CO2酸性腐蚀性能,其均匀腐蚀速率较低,且随CO2分压增加变化不大;Ni-Fe-W合金镀层显著提高了油管的疲劳寿命;疲劳失效的Ni-Fe-W合金镀层油管,裂纹均起源于表面镀层,贯穿镀层扩展至基体,刺口附近裂纹较为密集,距刺口350 mm处裂纹较为稀疏。     

Ni—W非晶态合金电沉积方法及结构研究

研究了Ｎｉ－Ｗ非晶态合金的电沉积方法，讨论了电解液组成、温度及ｐＨ值对镀层组成及镀层结构的影响，获得了Ｎｉ－Ｗ合金镀层结晶－非晶区域图。根据镀层的Ｘ射线衍射实验结果，研究了镀层结构及非晶态结构的形成机理。     

稀土对硫酸盐体系电沉积Zn-Fe合金阴极极化的影响

为了深入地探讨Zn-Fe合金镀层的电沉积机理,实验在了三电极体系下,采用动电位法测定硫酸盐体系电沉积Zn-Fe合金镀层的阴极极化曲线,探讨了该合金镀层的电沉积机理,以及镀液成分和稀土盐的加入对电沉积阴极极化的影响.通过实验发现,Zn-Fe合金镀层的沉积属于异常共沉积,结果表明镀液中加入稀土盐Ce2(SO4)3后,对Zn-Fe合金镀层电沉积的阴极极化行为有较大影响.     

三价铬脉冲电沉积纳米晶Ni-Cr合金工艺

采用脉冲电沉积方法对三价铬电沉积Ni-Cr合金镀层工艺进行研究,确定并优化三价铬脉冲电沉积Ni-Cr合金的最佳镀液配方及工艺参数。研究镀液中各成分及工艺参数对三价铬脉冲电沉积Ni-Cr合金厚度及合金镀层中铬的影响,利用扫描电镜和电子能谱分析Ni-Cr合金镀层的形貌、微观结构和化学组成。结果表明,镀层厚度和Ni-Cr合金中铬含量在不同浓度的络合剂、稳定剂、乙酸钠及不同的电流密度、温度、pH值、占空比和脉冲频率下都存在极大值,且Ni-Cr合金厚度随合金中铬含量的增加而减少。当铬含量为24%时,镀层的厚度大于10μm,无裂纹,其晶粒为纳米球状晶粒。     

《表面技术》2009年第1期摘要及目次

稀土对电沉积Zn-Fe-La三元合金性能影响的研究为了获得更加光亮、致密的Zn-Fe-La三元合金镀层,针对电沉积Zn-Fe-La三元合金镀液组成及工艺条件,系统地研究了稀土对镀层成分含量、镀液稳     

电沉积锡镍合金的工艺研究

研究在氰化络合物中电沉积Sn-Ni合金的新方法,评述了合金电沉积的机理和合金镀层的性能。它的美丽的“黑珍珠”彩色外观,将在装饰件上获得广泛应用。文章还详细报道了电沉积Sn-Ni合金的工艺过程。     

碱性电镀锌镍合金的研究

采用恒电流沉积方法和X射线能谱(EDS)技术,研究了碱性Zn-Ni合金的主要电沉积工艺参数对镀层组成的影响规律,获得了Ni含量稳定为(11~13)mass%的Zn-Ni合金镀层,证实了Zn-Ni合金的共沉积过程遵循异常共沉积机制。采用扫描电镜(SEM)、原子力显微镜(AFM)和X射线衍射仪(XRD)等对优化的Zn-Ni合金镀层进行了表征,发现镀层主要具有γ相(NiZn₃)结构,其表面平整、致密、光亮;腐蚀测试表明Zn-Ni合金镀层具有优良的耐蚀性能。     

电沉积Zn-Ni合金镀层的阴极极化

为了研究Zn-Ni合金镀层的电沉积机理,采用三电极体系下的动电位法测定了电沉积Zn-Ni合金镀层的阴极极化曲线,并研究了添加剂浓度对阴极极化的影响.结果表明:添加剂DZN的最佳用量是15mL/L.当电流密度在0.32～20A/dm2区间时,Zn-Ni合金镀层的沉积属于异常共沉积,添加剂通过复配,效果好于单独添加,这是由于DZN型添加剂具有良好的选择性吸附作用.     

非晶态Al-Mn合金镀层的性能与组成

通过熔盐电沉积方法,获取了非晶态Al-Mn合金镀层,对非晶态Al-Mn合金镀层的组成、表面状态、硬度和耐蚀性进行了研究.结果表明,镀层的结构、耐蚀性及硬度与镀层含Mn量有关.非晶态Al-Mn合金镀层具有很高的硬度和优良的耐蚀性.     

电沉积Ni-Fe合金镀层腐蚀性能研究

本文采用失重、阳极极化和电化学阻抗谱等方法研究了电沉积Ni-Fe合金镀层腐蚀性能和镀层的破坏过程.结果表明：Ni-Fe合金镀层具有良好的耐酸腐蚀性;在3.5%（质量）NaCl溶液中,腐蚀发生之前的镍铁合金镀层的电化学阻抗谱由一个高频容抗弧和一个低频的感抗弧组成;随着浸泡时间的延长,容抗弧半径快速减小,感抗弧减弱并消失.     

电沉积超薄金刚石切割刀片背面结瘤缺陷的形成机理

用扫描电子显微镜(SEM)、原子力显微镜(AFM)和能谱仪(EDS)对切割刀片背面结瘤的形貌、电沉积前铝合金基体处理过程中的表面形貌及成分演变等进行观察和分析,得出刀片背面结瘤缺陷的形成机理。结果表明:铝合金基体前处理过程中,其表面析出物周围的铝合金逐渐溶解,析出物脱落,2次浸锌后的铝基体表面留下0～6 μm的孔洞;镍-金刚石复合电沉积过程中的镍在孔洞处沉积,去除部分铝合金基体后,在刀片背面形成0～6 μm的凸起,即镍瘤。      

Synthesis and characterization of electrodeposited Ni-Pd alloy electrodes for methanol oxidation

A wide compositional range of Ni-Pd alloy catalysts were prepared by electrodeposition for use as anode materials for methanol oxidative fuel cells in alkaline conditions. Structural characterization of the electrocatalysts in their as-plated condition revealed that the Ni-Pd catalysts synthesized were nanocrystalline, single phase, face centered cubic materials, indicating the formation of complete solid solution in the alloy. Compositional analysis of the alloys indicated that the palladium composition of the alloy increased with decrease in current density. This change in the composition of the alloy resulted in a shift in the X-ray diffraction peaks. The percentage shift in the d-spacing calculated from X-ray diffraction is in good agreement with percentage of palladium in the alloy. The electrocatalysts prepared are active for methanol oxidation in alkaline medium.     

Studies on electrochemical deposition of novel Zn–Mn–Ni ternary alloys from an ionic liquid based on choline chloride

Ternary Zn–Mn–Ni alloy coatings were electrodeposited for the first time from a choline chloride based ionic liquid with the aim of collecting properties of binary Zn–Mn and Zn–Ni alloys into one alloy system. The effect of electrodeposition potential on the composition and corrosion performance of the obtained ternary Zn–Mn–Ni deposits was investigated and contrasted with the characteristics of Zn–Mn and Zn–Ni deposits. Cyclic voltammetry revealed that the deposition of ternary Zn–Mn–Ni alloys behaved differently from the deposition of binary Zn–Mn and Zn–Sn alloys and that Mn deposition takes place at positive potentials in the Zn–Mn–Ni electrolyte than in the Zn–Mn electrolyte due to the presence of Ni²⁺ ions in the electrolyte. X-ray diffraction studies showed that the Zn–Mn–Ni ternary alloys consist of a lattice of Zn (with Mn and Ni imbedded inside) at low electrodeposition potentials and MnZn(with Ni imbedded inside) phase at high electrodeposition potentials. Chemical composition analysis show that the Mn content in the ternary Zn–Mn–Ni alloy increased with increase in electrodeposition potential, whereas Zn and Ni contents are suppressed. The corrosion tests results indicate that through addition of Ni into the Zn–Mn binary alloy, the Zn–Mn–Ni alloy tailored are more corrosion resistant than the Zn–Mn binary alloy whilst the passivation behavior is still preserved.     

Electrodeposition of ternary Zn–Ni–Sn alloys from an ionic liquid based on choline chloride and their characterisation

Ternary Zn–Ni–Sn alloy coatings with a range of compositions were potentiostatically electrodeposited on steel substrates from a deep eutectic solvent-based electrolyte. The effect of electrodeposition potential on the morphology, chemical and phase compositions, and corrosion behaviour of the deposits was analysed. The co-deposition mechanism of Zn–Ni–Sn alloys was found to be normal whereby increasing the electrodeposition potential enhanced the ternary alloy Zn content (active element) and greatly suppressed the alloy Sn and Ni content (noble elements). The X-ray diffraction phase analyses showed that Ni in the deposits exists in the form of metal compounds including β-Ni₃Sn₂ as well as γ-NiZn₃. The improved corrosion resistance observed in all ternary alloys was attributed to their compact morphology, phase content and chemical composition. Comparison of corrosion performances shows that ternary Zn–Ni–Sn alloys are superior for sacrificial corrosion protection of steel metallic substrates compared to binary Zn–Sn and Zn–Ni alloys.     

Ternary Zn–Mn–Sn alloy electrodeposition from an ionic liquid based on choline chloride

Zinc–manganese–tin (Zn–Mn–Sn) ternary alloys have been successfully prepared, for the first time, by electrochemical deposition from a choline chloride-based ionic liquid. The influence of electrolyte composition and electrodeposition potential on the ternary Zn–Mn–Sn alloy surface morphology, composition and corrosion resistance were investigated and contrasted with the characteristics of binary Zn–Mn and Zn–Sn electrodeposits. It was found that the composition of the plating bath and deposition potential have a significant influence on the alloy content, morphology and corrosion properties of the Zn–Mn–Sn alloys. The content of Sn in the ternary alloy increased with a decrease in electrodeposition potential and an increase in concentration of Sn²⁺ in the electrolyte. The corrosion studies showed that the Zn–Mn–Sn alloys have a synergistic property combining the barrier behaviour afforded by Sn and the strong passive behaviour of Mn, while the sacrificial characteristics are still preserved.     

电沉积电位对锌镍合金镀层耐蚀性的影响

采用电化学沉积方法在DH36船板钢表面制备了锌镍合金镀层。采用扫描电镜(SEM),能谱仪(EDS)和X射线衍射仪(XRD)等研究了电化学沉积电位对锌镍合金镀层形貌、化学成分和晶体结构的影响。结果表明:随着沉积电位的升高,锌镍合金镀层由无法覆盖整个基底表面到均匀致密覆盖,再到较大微纳米颗粒层覆盖,证明沉积速率越来越大。由EDS和XRD分析可知,在较低电位下沉积,锌镍电沉积过程属于正常共沉积,而在较高电位沉积时,锌镍电沉积过程属于异常共沉积。电化学极化曲线测试表明,在电沉积电位为-1.2 V时所获得的锌镍合金镀层的耐腐蚀性最好。     

Studies on the Mechanism,Structure and Microhardness of Ni-W Alloy Electrodeposits

The electrodeposition of Ni-W alloy has been studied on the glassy carbon electrode by the cyclic voltammetry and potentiostatic step methods. It has been found that electrodeposition of Ni-W alloy involves an intermediate valence tungsten oxide which inhibits hydrogen evolution. Ni-W alloy electrodeposition occurs by a mechanism involving progressive nucleation followed by three dimensional growth.

The structures of nickel-tungsten alloy deposits were analyzed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The XRD results from Ni-W alloy deposits reveal a face-centered cubic solid solution, the microstructure of the deposits exhibit (111) preferred orientation. The lattice constant and microhardness of Ni-W alloy deposit increase as the tungsten content increases, the XPS results of Ni-W alloy deposits indicate that the nickel and tungsten of the deposits exist in the metallic state, but the Ni-W alloy deposit with a tungsten content of 40.7% is an intermetallic compound. The XPS results of the deposit with tungsten content of 40.7% show that the atomic ratio of Ni to W is 4:1, so β-Ni₄ W alloy can be obtained by electrodeposition and its microhardness (Hv) is as high as 672.8.     

The Kinetics of Electrode Reactions III Practical Aspects

Abstract

To study the electrodeposition of Cr–Co alloy, as a possible alternative to the deposition of pure Cr, in particular from hexavalent Cr baths, Cr(III) formate–urea electrolyte containing various concentrations of CoCl₂ was used. The deposition rate, composition, phase state and structure of Cr–Co deposits were investigated. The data obtained suggest that the electrodeposition of Cr–Co alloy occurs under acceleration of Cr(III) and inhibition of Co(II) ions electroreductions. It was found that the presence of 1–2 g L^–1 CoCl₂ in Cr(III) bath has an optimum effect on the electrodeposition of the good quality thick (30 μm) Cr–Co alloy obtained. The X-ray diffraction data reveal that the Cr–Co alloy deposit has an X-ray amorphous structure with a grain size of ～1·3 nm. The morphology of the deposit shows a significant dependence of the nodular structure on the percentage of Co. X-ray photoemission spectroscopic spectra indicate the presence of oxide and metal phases for both metals in the top layers of as deposited Cr–Co alloy.     

电沉积Ni-W-P三元合金层工艺的研究

研究了Ni-W-P三元合金层的电沉积方法;讨论了电沉积液的温度,pH值和阴极电流密度(Dk)对镀层结构及成分的影响;同时对电沉积液的pH值和阴极电流密度对镀层的硬度及耐蚀性的影响进行了研究。     

The Electrolytic Preparation and Characterization of Ni-Fe Alloys

The electrodeposition of nickel rich Ni-Fe alloys from an alkaline (pH 8.5) bath containing serine and sodium pyrophosphate has been studied. The functional properties (hardness, coercivity and corrosion resistance) and their dependence on plating variables (bath composition and working conditions) are discussed. The deposited alloy under optimum plating conditions is fine grained with fcc structure. The composition of the alloy varied with cd, pH and composition of the bath solution. The solution affords 90% current efficiency and 35% throwing power under some experimental conditions. The anomalous co-deposition of Ni-Fe alloy is minimized considerably by the presence of complexing agents in the solution. Spectral studies (UV-Visible) indicated the presence of Ni^2- ions in the complex state in preference to Fe^2- ions.