Co/Cu纳米多层膜的电化学制备及其微观结构的表征

以(110)高择优的Cu片为基底,在硫酸盐镀液中采用单槽双脉冲控电位电沉积法制备了Co/Cu纳米多层膜。采用X射线衍射(XRD)和扫描电镜(SEM)分别对多层膜的微观结构和形貌进行了表征。结果表明,Co/Cu多层膜具有良好周期性,多层膜的微结构和表面形貌与表层的金属层紧密相关,也与Co和Cu镀层厚度及其相对厚度、周期数相关。硼酸的加入有利于改善Co/Cu多层膜的层状结构。     

新型整平剂TS-L对铜电沉积的影响

通过极化曲线、电化学阻抗谱、计时电流等电化学测量方法研究了整平剂TS-L对铜电沉积的影响。基础镀液组成为:Cu SO_4·5H_2O 75 g/L,H_2SO_4 240 g/L,Cl~-60 mg/L。结果表明,TS-L会抑制铜的电沉积,有利于得到平整、光亮的镀层。随TS-L用量增大,其抑制作用增强。TS-L的用量为50 mg/L时,铜的电沉积由基础镀液的三维瞬时成核转变为三维连续成核。随TS-L质量浓度的增大,镀液的深镀能力提高。在电镀液中添加50 mg/L整平剂TS-L、10 mg/L光亮剂TS-S和600 mg/L抑制剂TS-W时,深镀能力为87%,铜镀层的延展性和可靠性满足印制线路板行业的应用要求。     

单晶硅上电沉积Cu/Co纳米多层膜及其巨磁电阻效应

采用双脉冲控电位技术在单晶硅上沉积了一系列Cu/Co纳米多层膜,调制波长从200nm到5nm不等.用扫描电镜及X射线衍射对多层膜的调制结构进行了表征.采用四探针法测试多层膜的巨磁电阻（GMR）效应,研究了GMR与调制波长（λ）、铜的子层厚度（δ_Cu）的关系：λ较大时,没有观察到明显的GMR效应;λ＜30nm时,GMR效应随λ减小而增大;而λ＜8nm时,GMR值随铜层厚度的变化周期性振荡.     

Cr~(3+)电镀溶液中Cr电结晶机理

用计时电流法研究了Ｃｒ３＋镀液中Ｃｒ在玻璃碳电极上的电结晶机理,并根据理论推导出瞬时成核和连续成核的理论模型．实验结果和理论模型的分析表明,Ｃｒ在玻璃碳电极上的沉积按瞬时成核和三维生长机理进行,其法向生长速度常数Ｋ′和混合速度常数Ｋ２Ｎ０随过电位的增大而明显增大．     

不同添加剂对Ni-Sn-Mn合金电沉积行为的影响

采用阴极极化曲线、循环伏安曲线、电化学阻抗和电位阶跃等电化学方法,研究了糖精(BSI)、1,4-丁炔二醇(BYD)及两种添加剂组合对Ni-Sn-Mn合金电沉积行为的影响。结果表明:加入不同添加剂均使Ni-Sn-Mn合金电沉积的阴极极化增大,沉积电位负移,对合金电沉积起阻化作用;不同添加剂作用下电沉积过程均为不可逆;加入BSI的电荷转移电阻大于加入BYD的电荷转移电阻,而加入BSI+BYD的电荷转移电阻最大;在不同添加剂作用下Ni-Sn-Mn合金电沉积无因次曲线接近理论连续成核曲线,电沉积结晶过程遵循三维生长方式的连续成核机制。     

电镀级焦磷酸钾品质快速评价的电化学方法研究

应用线性扫描伏安法和计时电位法分别测量绘制阴极极化曲线和恒电流电位-时间曲线,研究了铜电极上焦磷酸盐镀铜的电化学行为。结果表明,焦磷酸盐镀液的组成、pH和温度都会影响铜电极电镀过程的阴极极化和恒电流电位。在镀液中,在焦磷酸根与Cu2+质量比为8∶1,Cu2+浓度为0.28～0.39mol/L,镀液pH值为8.8～9.3,镀液温度为45～48℃条件下,有利于得到结晶质量较好的铜镀层。阴极极化越大,恒电流电位越负,对应镀液越容易得到致密的金属镀层,与赫尔槽实验效果一致。阴极极化曲线和恒电流电位-时间曲线可用于电镀级焦磷酸钾品质的快速评价。     

焦磷酸盐铜-锡合金镀液性能的研究

以焦磷酸铜和锡酸钠为主盐,焦磷酸盐为配位剂,加入一种自制的铜-锡合金添加剂组成焦磷酸盐镀液,通过赫尔槽实验优选出最佳镀液配方和工艺条件,并对镀液的分散能力、深镀能力、阴极电流效率和沉积速率等性能进行测试。结果表明:镀液的分散能力为98.05%,深镀能力为100%,平均电流效率为86.65%,平均沉积速率为59.2μm/h。加入添加剂后明显改善了镀液的极化性能,提高了铜离子及锡离子的析出电位,得到均匀致密、结晶细致、光亮整平的铜-锡合金镀层。     

十二烷基硫酸钠对铁电沉积行为的影响

为了解铁的电结晶机理及润湿剂十二烷基硫酸钠(SDS)对铁电沉积阴极过程的影响,采用线性扫描伏安法、单电位阶跃计时电流法、交流阻抗谱等手段对由200 g/L Fe SO4·7H2O、20 g/L H3BO3、50 g/L Mn Cl2和30 g/L配位剂组成的基础镀液和含0.2 g/L SDS的镀铁溶液中铁在玻碳电极上的电沉积行为进行了对比研究。结果表明,润湿剂的加入使铁电沉积的阴极极化增强。不管镀液中是否含有润湿剂,铁在玻碳电极上的电结晶都遵循三维瞬时成核理论,且在含有润湿剂的镀液中的结晶过程与理论模型有着更好的吻合程度。润湿剂的加入使反应物离子的扩散受阻,电荷传递电阻增大。这些变化可能与SDS在镀层表面的吸附和对表面张力的影响有关。     

电沉积Ni80Fe20/Cu纳米多层膜及其巨磁电阻效应

采用单槽控电位双脉冲技术在n-Si（111）晶面上制备了［Ni₈₀Fe₂₀/Cu］_n多层膜,用SEM观测了多层膜的断面形貌,利用X射线衍射（XRD）表征了多层膜的超晶格结构。采用四探针法研究了多层膜的巨磁电阻（GMR）性能,结果表明,多层膜的GMR值随着Cu层厚度的变化发生周期性振荡,随着NiFe层厚度的增加先增大后减小;当样品结构为［NiFe（1.6 nm）/Cu（2.6 nm）］₈₀时,GMR值可达6.4%;多层膜的最低饱和磁场仅为750Oe。磁滞回线测试结果表明,反铁磁耦合多层膜具有较小的矩形比,更适宜作为磁头材料。     

氟硼酸铅镀液中电沉积钛基二氧化铅

以电沉积法从氟硼酸铅镀液中制备Ti基PbO2阳极(FB/PbO2)及其掺杂氟离子的FB/F - PbO2阳极.应用计时电位法研究了所制备阳极的电沉积成核速率,发现氟硼酸铅镀液在钛基表面电沉积二氧化铅的结晶速度比硝酸铅镀液更快.采用XRD和SEM技术对这两种电极进行了表征,并与传统的硝酸镀液制备的钛基二氧化铅对比,发现电...     

Effect of sub-layer thickness on magnetic and giant magnetoresistance properties of Ni-Fe/Cu/Co/Cu multilayered nanowire arrays

Ni–Fe/Cu/Co/Cu multilayered nanowire arrays were electrodeposited into anodic aluminum oxide template by using dual-bath method at room temperature. Scanning electron microscopy and transmission electron micros-copy were used to characterize the morphology and structure of the multilayered nanowire arrays. Vibrating sample magnetometer and physical property measurement system were used to measure their magnetic and giant magnetoresistance (GMR) properties. The effect of sub-layer thickness on the magnetic and GMR proper-ties was investigated. The results indicate that magnetic properties of electrodeposited nanowires are not affect-ed obviously by Cu layer thickness, while magnetic layers (Ni–Fe and Co layers) have significant influence. In addition, GMR ratio presents an oscillatory behavior as Cu layer thickness changes. The magnetic and GMR properties of the multilayered nanowire arrays are optimum at room temperature for the material structure of Ni–Fe (25 nm)/Cu (15 nm)/Co (25 nm)/Cu (15 nm) with 30 deposition cycles.     

Preparation and Characterisation of Electrodeposited Ni—Cu/Cu Multilayers

Ni–Cu/Cu multilayers have been, grown from a single electrolyte under potentiostatic conditions at different electrolyte pH values. The current-time transients recorded during deposition indicated different growth modes of the Ni–Cu layers. Structural characterisation by X-ray diffraction revealed that the multilayers have the same crystal structure and texture as their (1 0 0) textured polycrystalline Cu substrate. Scanning electron microscopy showed that the films grown at low pH (2.2) have smoother surfaces than those grown at high pH (3.0). Energy dispersive X-ray analysis revealed that the magnetic layers of the multilayers electrodeposited at high pH contain much more Cu compared to those deposited at low pH. Anisotropic magnetoresistance was found for nominal Cu layer thicknesses below 0.6 nm, and giant magnetoresistance (GMR) above 0.6 nm. The shape of the magnetoresistance curves for GMR multilayers indicated the predominance of a superparamagnetic contribution, possibly due to the discontinuous nature of the magnetic layer. For multilayers with the same bilayer and total thicknesses, the GMR magnitude decreased as the electrolyte pH increased. Besides possible structural differences, this may have come from a strong increase in the Cu content of the magnetic layers since this causes a nearly complete loss of ferromagnetism at room temperature.     

Electrochemical behaviour and physical properties of Cu/Co multilayers

Cobalt/copper multilayer formation was analysed over different substrates in order to control the bilayer thickness and quality of coatings. Using a sulphate-citrate bath, at pH 4.7, electrodeposition conditions were optimised to prepare good alternate Cu/Co layers with high efficiency, by minimising the oxidation of cobalt layers during copper deposition. For multilayers with cobalt and copper layers of several nanometers, direct observation by scanning electron microscopy (SEM) or tapping mode-atomic force microscopy (TMAFM) gives layer thickness in agreement with the value calculated from deposition charges. Therefore, this calculation has been used to estimate the thickness of the thinner layers for which direct observation was difficult or impossible. A relation between the response of different characterisation methods was found. When the thickness of each layer in Cu/Co multilayers is >1.8-2 nm, potentiodynamic stripping experiments show separate peaks related to cobalt and copper oxidation. In these conditions, magnetoresistance of the coating is low. For thinner layers, the stripping response shows overlapping peaks or even a single oxidation peak. In these conditions the magnetoresistance begin to increase.     

Electrochemical Surface Modification of Aluminium Sheets for Application to Nano-electronic Devices: Anodization Aluminium and Electrodeposition of Cobalt-Copper

A nano-porous anodized aluminium oxide layer was synthesized on the surface of bulk aluminium at a wide range of anodization voltages. The barrier layer at the pore bottom of anodized aluminium oxide layer was chemically etched to make good electrical contact for nanowires electrodeposited in the pores thus formed on metallic aluminium substrates. Cathodic polarization was examined at a wide range of cathode potentials to investigate the electrodeposition behaviour of Cu and Co into the pores. Co₈₁Cu₁₉/Cu multilayered nanowires were fabricated using a pulse-plating technique into the templates. Co-alloy layer and Cu layer thicknesses were adjusted to 10 nm, by controlling the deposition times. The temperature dependence of the resistance of Co₈₁Cu₁₉/Cu multilayered nanowires grown on the template presented clean metallic characteristics and a giant magnetoresistance (GMR) of 23% was reached at 4 K.     

金属添加剂对Ni-B非晶态合金催化剂邻氯硝基苯加氢性能的影响

研究金属添加剂（Cr、Mn、Fe、Co、Cu、Mo和Zn）负载的Ni-B非晶态合金催化剂催化加氢制备邻氯苯胺的影响。结果表明,适量的Zn、Cr和Mo能提高催化剂的活性和选择性,Mn对催化剂的活性和选择性影响不大,Fe、Co和Cu降低催化剂的活性。这与能和硝基形成多位吸附的单元镍以及电子因素有关。     

Electrochemical nucleation and growth of Co and CoFe alloys on Pt/Si substrates

Electrochemical nucleation and growth of Co and CoFe alloys on Pt/Si(1 0 0) surface from watts (mixed chloride sulfate) baths were studied by voltammetric, chronoamperometric and AFM measurements. The CoFe alloys were deposited from solution with molar ratio of (1/1) and (10/1). The Scharifker and Hills model was employed to analyse the current transients. For both Co and CoFe (10/1) alloys the nucleation was a good agreement with the instantaneous model followed by 3D diffusion-limited growth. Inversely, for CoFe (1/1) alloy the nucleation was an agreement with the progressive model. It is evident that the compositions of the electrolyte influence greatly the type of nucleation. The atomic force microscopy (AFM) images revealed a compact and a granular structure of the electrodeposited Co layers and CoFe alloys.     

纳米金属多层膜的巨磁电阻效应

磁电阻效应是指材料的电阻随外加磁场变化而变化的现象。介绍了金属多层膜的制备及磁性检测方法。阐述了金属多层膜结构对巨磁电阻的影响．综述了金属多层膜巨磁电阻效应的研究现状、理论解释，并展望了其研究方向，