双向脉冲电镀对银层抗变色能力的影响

以镀银层抗变色特性为主要指标，优选了光亮镀银的双向脉冲参数，并与直流光亮镀银进行了比较，脉冲镀银层的抗变色特性优于直流电镀。     

激光重熔纳米晶镍镀层的研究

介绍了喷射电镀的基本原理,采用自行设计制造的喷射电镀设备制备纳米晶镍镀层,并对镀层进行激光重熔处理.重点研究了在直流电源和脉冲电源作用下,电流密度对镀层金属的微观结构的影响,以及采用激光重熔处理对直流纳米晶镍镀层形貌的影响;考察了金属基体、喷射电镀层以及激光重熔后的镀层的显微硬度的变化.研究结果表明:与基体金属相比,喷射电镀层的显微硬度有明显提高;经过激光重熔处理后镀层的显微硬度得到进一步提高.     

316L不锈钢表面脉冲电镀钯的性能

以316L不锈钢为基体,分别采用脉冲电镀和直流电镀法制备了钯膜层。对比研究了脉冲电镀钯和直流电镀钯的微观结构、显微硬度、孔隙率、耐蚀性等性能。与直流电镀钯膜层相比,脉冲电镀钯膜层更为均匀、致密,晶粒尺寸更小,孔隙率更低,显微硬度更高,附着力更强。另外,脉冲电镀钯膜层在80°C的20%H2SO4和20%H2SO4+0.001 mol/L Cl-中的耐腐蚀性均优于直流电镀钯膜层。     

脉冲电镀银层组织与性能

脉冲电镀银技术具有细化晶粒,孔隙率低,电阻率低的优点。采用脉冲电镀银技术在2A12铝合金基体上制备了银层并进行了镀层组织与性能测试。结果表明,镀银层为单一的面心立方结构,显微硬度为160 HV,银层具有良好的防变色能力与较小的回路电阻。     

脉冲镀铬镀层性能的研究

为了提高铬镀层性能,简化工艺流程,提高电镀效率,本文对比了直流镀铬和脉冲镀铬工艺,研究了电镀工艺对镀层厚度均匀性、硬度、孔隙率、结合力、表面和截面微观形貌及镀层电镀效率的影响。结果表明,脉冲镀铬的镀层性能明显优于直流镀铬,其镀层硬度与直流镀层相比提高约8%。脉冲镀铬的电镀效率远高于直流电镀工艺,其可缩短电镀周期约53%。     

通信腔体类零部件电镀铜/银工艺

介绍了通信腔体类零部件电镀光亮Cu/Ag的工艺流程和关键事项，并分析了光亮镀铜层和镀银层的外观、厚度、结合力和显微硬度。通过反复试验，探索了不同电流密度下镀层厚度与电镀时间的关系，为实际生产中腔体类零部件电镀提供参考。     

脉冲电镀中脉冲参数对镍镀层显微硬度的影响

采用传统的瓦特镀液通过脉冲电镀制得纯镍镀层。研究了脉冲参数对镀层微观形貌与显微硬度的影 响。结果表明:镀层表面形貌为胞状结构;随着脉冲峰值电流密度的增加,胞状结构的尺寸逐渐变小,镀层显微硬度先增 加后减小;随着占空比的减小,最大显微硬度值对应的峰值电流密度增大,占空比减小到一定值后,峰值电流密度的改变 对显微硬度影响不再明显。     

一起铝合金镀银起泡质量问题的研究探讨

本文通过一起铝合金镀银生产中出现的镀层起泡问题,研究了铝及铝合金快速镀银工艺对银镀层结合力的影响.通过显微硬度计测量镀银层硬度,表征了镀层起泡的定性特征,通过霍尔槽实验确定了有效的改进措施,优化了快速镀银工艺.结果表明,采用优化后的工艺,镀银层的显微硬度达到了一个合理的数值范围,镀层达到了稳定的合格率.     

硫代硫酸盐无氰脉冲镀银工艺研究

对无氰镀银工艺进行了优选,找到一种无氰光亮镀银添加剂的配方,并对其工艺参数进行优选,得出最佳脉冲参数为：脉宽1ms,占空比为10％,电流密度为0．6A／dm^2。在最佳工艺参数下得到的银镀层镜面光亮,与直流镀银相比,抗变色性和耐蚀性均显著提高,并通过扫描电镜观察了镀层的表面形貌。     

防渗氮脉冲镀镍工艺研究

本文采用正交试验法优选脉冲镀镍工艺参数。对所制备的试片拍摄扫描电镜照片考察表面形貌；采用贴滤纸法对镀层进行孔隙率试验；采用磨损试验机进行耐磨损性试验。并进行了防渗氮效果测试，结果表明脉冲电镀试片结晶细致、结合力良好、孔隙率低，耐磨性及防渗氮效果优于直流电镀。     

Effect of pulse plating on composition of Sn–Pb coatings deposited in fluoroborate solutions

Galvanostatic pulsed current (PC) and pulse reverse (PR) plating of Sn–Pb coatings onto copper rotating disks from fluoroborate solutions has been conducted to obtain alloy compositions otherwise not achievable by DC plating. PC plating investigated over a wide range of pulse frequencies (20 Hz–200 kHz) and duty cycles produces coatings with compositions that differ only slightly from those obtained by DC plating at the same current density. On the other hand, the use of PR plating can be dramatic, producing Pb contents both well above and below that achievable by DC plating. Varying the frequency from 20 Hz to 200 kHz with the duty cycle and average current density fixed at 80% and 3.78 A dm^–2 yields compositions between 2.5 and 28 wt.% Pb. The Pb:Sn ratio in the deposit is always lower than that in the plating bath when a PR frequency of 20 Hz is imposed, but generally exceeds it at a frequency of 20 kHz. Alloy composition appears to be closely related to the working electrode potential reached during the anodic pulse. A higher frequency leads to less positive potentials during the anodic pulse and shorter anodic pulse times, which may enhance Sn dissolution and enrich the coating in Pb.     

Catalyst electrode preparation for PEM fuel cells by electrodeposition

The preparation of catalyst electrodes by electrodeposition for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs) has been studied. This work looks at the potential to apply the electrodeposition technique, in the forms of direct current (DC) and pulse plating electrodepositions, to prepare Pt and Pt–Co alloy catalysts for membrane electrode assemblies (MEAs). The preparation of the non-catalyst layer was found to be important for the electrodeposition of Pt catalysts. The activities of the electrodeposited catalysts, both pure Pt and Pt–Co alloy, produced by pulse plating are substantially higher than that of the Pt catalyst produced by DC electrodeposition. The improvement in electroactivity towards the ORR of the electrodeposited catalysts produced by pulse plating is likely due to the finer structures of electrodeposited catalysts which contain smaller catalyst particles compared to those produced by DC electrodeposition. A maximum performance towards the ORR in PEMFCs was achieved from the catalysts prepared by pulse plating using a charge density of 2 C cm⁻², a pulse current density of 200 mA cm⁻², a 5% duty cycle and a pulse frequency of 1 Hz.     

脉冲镀和直流镀对钨镀层性能的影响

在耐热钢基体上用Na2WO4-ZnO-WO3体系熔盐镀钨,比较了脉冲镀与直流镀对钨镀层性能的影响.在相同镀液配比条件下,脉冲镀可扩大电流密度范围,钨镀层的表面形貌、厚度、结晶度、纯度等都优于直流电镀.     

脉冲镀金层耐磨性能的研究

研究了脉冲电镀在微氰镀金，无氰镀金体系中脉冲频率、脉冲占空比对镀金层耐磨性的影响。在最佳冲条件下得到的镀金层的耐磨性能比直流电镀的好。     

Influence of pulse plating parameters on the electrocodeposition of matrix metal nanocomposites

Electrocodeposition of alumina particles with copper and nickel from acidic electrolytes has been investigated using different deposition techniques. Compared to direct current (DC) deposition, both pulse plating (PP) and pulse-reverse plating (PRP) facilitated higher amounts of particle incorporation. With conventional DC plating the maximum alumina incorporation is ∼1.5 wt% in a nickel and ∼3.5 wt% in a copper matrix. However, the implementation of rectangular current pulses can give considerably higher particle contents in the metal layer. A maximum incorporation of 5.6 wt% Al₂O₃ in a copper matrix was obtained by PP at a peak current of 10 A dm⁻², a duty cycle of 10% and a pulse frequency of 8 Hz. In general, low duty cycles and high pulse frequencies lead to an enhanced particle codeposition. The microstructure and the hardness of both pure metal films and nanocomposite coatings showed only a weak dependence on the PP and PRP conditions.     

脉冲电沉积工艺参数对Ni-W-P合金镀层性能的影响

针对传统镀硬铬沉积速率低、污染环境等问题,采用脉冲电沉积方法在碳钢表面制备Ni-W-P代铬镀层。采用显微硬度计、扫描电子显微镜、X射线衍射仪和电化学工作站研究了脉冲频率、平均电流密度和占空比对镀层性能的影响。结果表明:随着脉冲频率、平均电流密度和占空比的增加,镀层的硬度和耐蚀性均呈现出先增大后减小的变化规律;当脉冲频率为250Hz,平均电流密度为4.0A/dm2,占空比为30%时,镀层为非晶态结构,表面光滑、平整,结构致密,硬度可达5 140MPa,耐蚀性较好。     

Preparation of Pt–Co alloy catalysts by electrodeposition for oxygen reduction in PEMFC

Direct current (DC) and pulse current (PC) electrodeposition of Pt–Co alloy onto pretreated electrodes has been conducted to fabricate catalyst electrodes for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFC). The effect of plating mode and pulse plating parameters on the Pt–Co alloy catalyst structure, composition and electroactivity for the ORR in PEMFC has been investigated. The electrodeposited Pt–Co alloy catalyst indicates higher electrocatalytic activity towards the ORR than the electrodeposited Pt catalyst. The activity of the electrodeposited Pt–Co catalysts is further improved by applying the current in a pulse waveform pattern. The electrodeposition mode and the pulse plating parameters do not have the significant effect on the Pt:Co composition of deposited catalysts, but show the substantial effect on the deposit structures produced. The Pt–Co catalysts prepared by PC electrodeposition have finer structures and contain smaller Pt–Co catalyst particles compared to that produced by DC electrodeposition. By varying the Pt concentration in deposition solution, the Pt:Co composition of the electrodeposited catalyst that exhibits the highest activity is found. The Pt–Co alloy catalyst with the Pt:Co composition of 82:18 obtained at the charge density of 2 C cm⁻², the pulse current density of 200 mA cm⁻², 5% duty cycle and 1 Hz was found to yield the best electrocatalytic activity towards the ORR in PEMFC.     

镍钨合金电沉积的电流效率和镀层显微硬度

通过调节镀液中不同的Ｎｉ／Ｗ比例、温度和沉积电流密度,研究在焦磷酸盐体系中镍钨合金电沉积的电流效率、沉积层和组成和显微硬度。实验结果表明：合金共沉积的电流效率不高。为了尽量提高合金的沉积电流效率,主要途径宜增大镀液中硫酸镍和钨酸钠的浓度;提高合金沉积电流密度,降低镀液中［Ｎｉ］／［Ｗ］比例,则镀层中的钨含量增大;合金沉积层的显微硬度随镀层中的Ｗ含量提高而增大。     

Copper electrodeposition in sulphate solutions in the presence of benzotriazole

DC and pulse plating of copper in acidic sulphate solutions containing benzotriazole (BTA) has been studied. When BTA is the only additive present, it generally has a stronger effect than the plating mode and significantly enhances deposit morphology and surface brightness over that produced in additive-free solutions. XPS and voltammetry analyses indicate that BTA is present at the surface of the deposit, but not through the entire coating, and does not become depleted within the solution over the course of plating. This may help explain why the initial surface smoothness and brightness is maintained as the coating grows beyond 5 μm thick. Plating mode does have a strong effect on deposit morphology under specific conditions. Pulse current plating at low frequency (50 Hz) and low duty cycle (20%) produces deposits with poorer quality than that obtained by DC plating. Pulse reverse plating yields very coarse and dull coatings when the frequency is low enough for metal dissolution to occur during the reverse time. Regardless of the plating mode, the addition of Cl⁻ eliminates most of the beneficial effects of BTA and leads to very rough and dull deposits. The observed effects are discussed in light of previous research on the electrodeposition and corrosion of the Cu–BTA and Cu–BTA–Cl systems.