电沉积法制备组分调制Zn－Ni合金多层镀层

研究了Zn－Ni合金镀液中主盐的组成、电镀工艺参数对Zn－Ni合金镀层中的含镍量及镀层性能的影响，结果表明，电流密度是影响Zn－Ni合金镀层中含镍量的主要因素.在电沉积过程中，利用计算机控制电流输出的电镀电源，通过调整施镀电流密度，制备出了由2种组成不同的Zn－Ni合金薄层交替叠加而形成的Zn－Ni合金多层镀层.SEM表面及断面显微分析结果表明：Zn－Ni合金多层镀层表面无缺陷，断面呈清晰的层状结构.      

Effect of the plating parameters on the electrodeposition of Ni matrix coatings containing Ti nanoparticles

This work focuses on the production of electrodeposited nickel matrix composite coatings containing Ti nanoparticles and on the modification of the process parameters in order to maximise the codeposited particles content as well as obtaining a uniform distribution along the coating thickness. The deposition was carried out using a Ni sulphamate plating bath with different amounts of Ti nanoparticles. The plating parameters such as current density, current type (direct, DC, or pulsed, PC) and the use of ultrasound during the deposition have been modified. The specimens produced have had their microstructure, chemical composition and microhardness analysed. It was found that the increase of the particle concentration in the plating bath up to 40?g?L^?1 leads to an increase of the amount of codeposited particles. The use of ultrasound prevents agglomeration of the particles, leads to a more uniform distribution and increases the Ti content. However, it induces microstructural defects in the matrix. These defects can be limited by increasing the current density or by using pulsed current.     

Evaluation of corrosion resistance of electrodeposited nanocrystalline Ni–Fe alloy coatings

Nickel–iron alloys with a compositional range of 24–80?wt-% iron were electrodeposited on a copper substrate from a sulphate-based bath and using a stirring rate of 100?rev?min^?1. The effect of applied current density and Ni²⁺/Fe²⁺ metal ion ratio of plating bath on the properties of alloy coatings was examined. Crystal structure and grain size of Ni–Fe alloy coatings were investigated using X-ray diffraction technique. Field emission scanning electron microscopy and energy dispersive X-ray spectroscopy were used to analyse the surface morphology and chemical composition of coatings. Microhardness test was applied to evaluate the hardness of the coatings. Finally, the electrochemical behaviour of the Ni–Fe alloy coatings was studied by a polarisation test in 10?wt-% H₂SO₄ solution. Results revealed that current density and plating bath composition had a strong effect on the characteristics of coatings. As the iron content of alloys produced increased, their corrosion resistance improved with the best corrosion resistivity being achieved at a metal ion ratio of 0.5 and applied current density of 2.5?A?dm^?2.     

28CrMo钢的Ni-P合金镀工艺

研究了制备工艺对28CrMo钢Ni-P合金镀层性能的影响。结果表明,镀液成分中的氯化镍和稀土含量及电流密度和镀液温度都会影响镀层的厚度和硬度。本试验条件下的最佳制备工艺是镀液成分为含50 g/L的氯化镍+2 g/L的稀土(镀液中其他成分为硫酸镍180 g/L、磷酸45 g/L、亚磷酸10 g/L),电流密度为8 A/dm2,镀液温度为65℃。在此条件下得到的镀层为非晶态,镀层性能最好。     

Zinc–nickel alloy coatings electrodeposited from a chloride bath using direct and pulse current

Zinc–nickel alloys were electrodeposited on steel from chloride bath by direct and pulse current. Some electric variables (average current density, pulse frequency, duty cycle) and some important bath conditions (ratio of Ni²⁺/Zn²⁺ in bath, temperature) on chemical compositions, current efficiency, microhardness and surface appearance of coatings were studied. At low current densities, transition from anomalous to normal co-deposition was observed for both direct and pulse current. Pulse current seems to increase brightness of the coating and to decrease the precipitation of zinc hydroxide at the cathode surface. In addition, applied pulse current increases the percentage of nickel in deposits. Pulse frequency and duty cycle had little effect on the chemical composition of deposits. The polarization curve of zinc–nickel deposition with pulse current is shifted to positive potentials in comparison with direct current curves. The temperature of the plating bath had a very strong effect on the composition of the deposits. This is primarily the result of intrinsically slow nickel kinetics. The hardness of Zn–Ni alloy coatings (approx. 220 VHN) was greater than the hardness of zinc coating (approx. 161 VHN). The hydroxide suppression mechanism for Zn–Ni co-deposition has been confirmed.     

Electrodeposition,characterisation and mathematical model of nickel–iron film in a parallel plate flow system

Abstract

Nickel–Iron alloy films were electrodeposited in a parallel plate flow system. The volumetric flow rate of electrolyte was fixed at 12 dm³ min^?1 through the 1 cm thick and 9 cm wide slit parallel plate. Fluid velocity was ca 0.22 m s^?1 under fully turbulent convective flow. Alloy films with iron content varying from 7·5 to 40 wt-% were deposited as a function of solution pH, temperature, bath ingredient concentration and applied current density. It is shown that the magnetic property is strongly correlated to the alloy content: the saturation moment, B _s, increases with the iron composition, while the coercivity, H _c, increases with nickel content. Current efficiency increases with pH and applied current density. The nickel deposition rate is inhibited in the presence of ferrous ion in the plating bath. The microhardness of the deposit is increased as the iron content is increased over the range studied. A mathematical model that considers the convective mass transfer of Fe(II) and Ni(II) species in the diffusion layer, the competition of adsorbed metal species on surface active sites, and Tafel electrochemical kinetics describe the alloy plating system well.     

Effect of plating time on electrodeposition of thick nanocrystalline permalloy foils

Thick foils of nanostructured permalloy were electrodeposited by applying a current density of 100?mA?cm^?2 for 48 hours. The bath contained nickel sulphate, iron sulphate, a complex agent, a grain refiner, a stress reducing agent, a buffer and a wetting agent. The bath pH was 3·8. Different parameters were controlled to get thick (approximately 860?µm), uniform permalloy coatings. To investigate the effect of electroplating time on the surface morphology, thickness and structure of foils, scanning electron microscopy, optical microscopy and X-ray diffraction were used. Chemical compositions of foils and the bath were investigated by quantometry and ultra violet–visible spectroscopy. The composition of the coatings was constant during the long period of electroplating, which was attributed to the bath stability. The cathode current efficiency of the electroplated permalloy foils increased slightly on increasing the plating time. Existence of chloride ions, complex agent and saccharin in the bath influenced efficiency.     

Ni-ZrO2纳米复合电镀工艺研究

采用正交实验法,对铜表面电沉积镍基纳米ZrO2复合镀层的工艺进行了研究,观察了复合镀层的表面及截面形貌,并对其耐磨性能进行了测试分析。所涉及实验条件下的最优工艺为:阴极电流密度4A/dm2,镀液温度60℃,极间距为12cm。采用此最优工艺条件,得到了晶粒细小,表面平整、光滑,显微组织致密、均匀的Ni-ZrO2纳米复合镀层,且复合镀层的显微硬度比纯镍镀层有明显提高。     

Electrodeposition of Nickel from Perchlorate Based Electrolytes

Nickel is usually electrodeposited from the Watts bath. Other baths like sulphamate and fluoborate are also of industrial importance but are used less commonly. Perchlorate solutions, though examined to some extent in the case of cadmium and lead deposition, have not been experimented upon for deposition of nickel. In this paper certain operational data on Perchlorate nickel deposition are presented. As a consequence, the following bath composition is recommended: Nickel 29.2 g/l, perchloric acid 201.0 g/l, ammonium chloride 60–120 g/l, pH 5.5-6.8. The useful current density is 1–5 A/dm² and optimum temperature 50°C.     

NiCl2 含量对电沉积 Ni-纳米 TiN 复合镀层过程的影响

目的针对氨基磺酸镍体系镀镍液,优化活化剂NiCl2的用量,提高Ni-纳米TiN复合镀层的性能。方法采用超声-脉冲电沉积工艺制备Ni-纳米Ti N复合镀层,研究NiCl2含量对镀液的电导率及复合镀层的厚度、显微硬度、表面微观形貌等的影响。结果镀液的电导率及复合镀层的厚度、显微硬度均随NiCl2含量的增加呈现先增大、后减小的变化趋势。当NiCl2的用量为30 g/L时,镀液的导电性能最佳,电导率值为61.3 m S/cm,复合镀层的厚度及显微硬度均达到最大值,分别为84μm和760HV,并且复合镀层表面平整光滑,晶粒尺寸最小。结论 NiCl2含量对镀液及复合镀层的性能有很大影响,适量的NiCl2可以防止阳极钝化,提高镀液的导电能力及沉积速率,使复合镀层的厚度增加,显微硬度提高,晶粒细化,微观形貌获得改善,性能提高。适宜的NiCl2用量为30 g/L。     

Electrodeposition of Amorphous Iron-Nickel-Phosphorus Alloy Coatings

The effects of plating parameters on the composition and structure of electrodeposited Fe-Ni-P alloys have been studied. A sulfate electrolyte containing sodium hypophosphite with an acetate buffer was used. Deposits were plated onto both planar and rotating cylinder electrodes. Alloy deposits that were amorphous over a wide range of iron:nickel ratios were achieved. The anomalous deposition typical of Ni-Fe alloy plating was not observed in these studies where phosphorus was codedeposited. The deposit composition was dependent on both the plating bath composition and current density.     

The Properties of Nickel Electrodeposited from a Sulphamate Bath

The properties of nickel electrodeposited from a nickel sulphamate bath and the effect of some experimental variables upon them are described. The optimum conditions for minimum internal stress are defined. The tensile properties of sulphamate nickel deposits and their effect on the fatigue strength of En 25 (Ni/Cr/Mo) steel of 80 ton/in² U.T.S. are directly compared with the properties of nickel deposited from a Watts type solution.     

铜含量对镁合金化学镀Ni-Cu-P镀层性能的研究

为研究镀液中不同铜离子含量对镁合金AZ91D化学镀Ni-Cu-P镀层性能的影响,采用硫酸镍为镍源,在镁合金化学镀Ni-P的镀液中加入不同含量的铜离子,可直接得到不同的Ni-Cu-P镀层,但都较均匀致密,结合力良好.经过耐醋酸腐蚀、磨粒磨损试验,结果表明:在硫酸铜含量为0.5g/L的镀液中获得的Ni-Cu-P镀层,较基体的耐蚀性提高了0.84倍,耐磨性提高了0.56倍.由此得出结论:镀液中硫酸铜含量为0.5g/L,所得到的镀层性能最佳.     

镀镍槽液中镍含量的在线监测系统研究

目的研发一种能够在线监测镀镍槽液中镍离子含量的测试系统,并将此方法推广至镀铬、镉、铜等槽液。方法利用计算机VC++语言编程技术、Modbus通讯技术、西门子PLC技术组成监控系统,通过耐酸碱计量泵和耐酸碱流量计对镀镍槽液取液量进行控制和校正,采用电化学测试方法对待测槽液在线监测,采用VC++语言编程技术采集电化学测试数据,最终实现对镀镍槽液中镍离子含量的自动监测。结果采用此自动控制系统测量镀镍槽液中镍离子的质量浓度,其与极化曲线中-1.0 V(vs.SCE)电位下的极化电流之间的线性拟合方程为:I=0.002 01+6.90×10-5ρ。以120 g/L待测溶液为分析对象,采用此自动检测系统测得镀镍液中Ni2+质量浓度为115.5 g/L,而采用EDTA直接滴定分析测得Ni2+质量浓度为113.7 g/L,测量误差分别为3.78%和5.25%。结论该镀镍槽液中镍离子含量的在线监测方法可靠性高,除了对镀镍槽液状态进行监控分析外,还能对镀铬槽液、镀镉槽液等进行监控分析,可适应较恶劣的生产环境。     

Ce（SO4）2对化学镀镍液及镀层性能的影响

采用电化学方法研究了Ce（SO4）2对化学镀镍液及镀层性能的影响。结果表明：Ce（SO4）2的添加总体上提高了化学镀镍层的耐腐蚀性能和沉积速率,当加入量为2mg·L^-1时,镀层具有最高的沉积速率;当加入量为5mg·L-1时,镀层具有最好的耐蚀性能;Ce（SO4）2能够在电极表面吸附,对次亚磷酸根氧化的促进作用表现在提高了其氧化电流密度,并通过影响化学镀镍的阳极反应来影响化学镀镍层的沉积速率;Ce（SO4）2的加入增大了化学镀镍反应的活化能,提高镀液的稳定性。     

Nickel Electroplating

NICKEL ELECTROPLATING has been practicallyused for decades.There is an unknown part in theplating,although this is easy to plate.Applications ofthe plating are described from the practical viewpoint.Purpose of Nickel Electroplating(1)Decorative,and corrosion resistanceNickel electroplating is deposited on iron,cupper,zinc and aluminum substrate etc.,and chromiumplating is usually deposited on nickel plating.Hexavalent chromium plating has an important effecton the corrosion resisitan…     

工艺参数对连续碳纤维表面电磁搅拌化学镀镍的影响

目的解决连续碳纤维在镀覆过程中易出现黑心现象以及无法完全浸泡于镀液中的问题,制备镀层均匀的连续碳纤维镍镀层。方法引入外加电磁搅拌对连续碳纤维进行化学镀镍,研究了施镀时间、镀液温度、镀液pH值以及电磁搅拌转速对连续碳纤维表面微观形貌及镀层沉积速率的影响规律。结果当搅拌转速一定时,随着施镀时间、镀液温度、镀液pH值的不断增加,碳纤维表面镀层逐渐变得均匀完整,且镀层厚度逐渐增大。但当施镀时间超过20 min,镀液温度超过75℃,镀液pH值超过8时,镀层表面沉积了大量形状不一的胞状镍颗粒,形成粗糙的表面形貌。镀层的沉积速率随着镀液温度、镀液pH值的升高而增大。当搅拌转速由200 r/min增加到300 r/min时,镀层的沉积速率随着搅拌转速的增加而不断增大;当搅拌转速由300 r/min增加到400 r/min时,镀层的沉积速率随着搅拌转速的增加而不断减小。结论电磁搅拌辅助连续碳纤维化学镀镍的最佳施镀工艺参数为:施镀时间15~20 min,镀液温度75℃,镀液pH为8,搅拌转速200~250 r/min。采用此工艺参数能获得表面致密、均匀完整的镍镀层。     

Nickel and nickel-phosphorous matrix composite electrocoatings

Nickel and nickel-phosphorous matrix composite coatings reinforced by TiO₂, SiC and WC particles were produced under direct and pulse current conditions from an additive-free Watts' type bath. The influence of the variable electrolysis parameters (type of current, frequency of current pulses and current density) and the reinforcing particles properties (type, size and concentration in the bath) on the surface morphology and the structure of the deposits was examined. It is demonstrated that the embedding of ceramic particles modifies in various ways the nickel electrocrystallisation process. On the other hand, Ni-P amorphous matrix is not affected by the occlusion of the particles. Overall, the imposition of pulse current conditions leads to composite coatings with increased embedded percentage and more homogenous distribution of particles in the matrix than coatings produced under direct current regime.     

金属化竹纤维的8mm微波干扰性能研究

为研制一种轻质毫米波干扰材料,试验以化学镀的方式对竹纤维进行表面金属化改性(镀覆的金属为铜和镍);并检测了金属化竹纤维的8mm波衰减性能.测试结果显示金属化竹纤维的8mm波衰减性能较好:20mg镀铜竹纤维可衰减17.5dB,30mg镀镍竹纤维可衰减24.2dB.化学镀工艺对金属化竹纤维的衰减性能有一定影响,在相同工艺下所制备试样的8mm波衰减分贝值随测试用量的增加而增加.试验结果表明金属化竹纤维可望成为一种新型毫米波干扰材料.     

Electrodeposition of Copper-Nickel Alloys from a Citrate Bath Containing Boric Acid

Copper-nickel alloys have been electrodeposited on steel substrates from a bath containing copper sulphate, nickel sulphate, sodium sulphate, sodium citrate and boric acid. Galvanostatic cathodic polarization, cathodic current efficiency and composition of the alloys were studied as influenced by bath composition, current density and temperature.

The bath is characterized by high cathodic current efficiency. Current density is found to strongly influence the composition of the deposits. At low current densities (lower than a certain transition current density), a copper-rich alloy is deposited with copper (the more noble metal) being the preferentially deposited metal. At larger current densities, nickel becomes the nobler metal and is deposited preferentially. The magnitude of the transition current density depends upon the bath composition and temperature. The structure and surface morphology of the as-deposited alloys were examined by XRD and SEM. The results reveal the presence of a single solid solution phase with face centred cubic structure. The morphology of the deposits is mainly controlled by the alloy composition.