脉冲电沉积镍-铜合金

采用脉冲电沉积技术在304不锈钢表面制备Ni-Cu合金镀层,镀液组成和工艺条件为:NiSO4ꞏ6H2O 200g/L,CuSO4ꞏ5H2O 10 g/L,十二烷基硫酸钠0.2 g/L,柠檬酸钠80 g/L,糖精0.2 g/L,pH 4.0,温度25°C,搅拌速率30 r/min,平均电流密度40~120 mA/cm2,脉冲频率0~100 Hz,占空比20%~90%,时间30 min。研究了平均电流密度、脉冲频率和占空比对Ni-Cu合金镀层的元素组成、表面形貌和显微硬度的影响,得到较优的工艺参数为:平均电流密度40 mA/cm2,脉冲频率50 Hz,占空比60%。该条件下所得Ni-Cu合金镀层由质量分数分别为56.53%和43.47%的Ni和Cu组成,呈“菜花”状形貌,结晶细致、均匀,显微硬度为614.4 HV。     

浅谈压延铜箔光面色差的成因

针对压延铜箔在表面处理过程中光面易出现色差的问题,从设备、工艺、人员操作等方面进行成因探讨,并给出了应对措施。     

Meniscus-confined electrodeposition of metallic microstructures with in-process monitoring of surface qualities

Meniscus-confined electrodeposition is a potential approach to fabricate three-dimensional (3D) metallic microstructures. However, the quality of the deposited microstructures by this approach, which is conventionally checked by a scanning electron microscope (SEM) used off-process, cannot be well in-process qualified. This paper presents a study on meniscus-confined electrodeposition of metallic microstructures with in-process monitoring of deposition qualities. Firstly, to understand the fabrication mechanism in meniscus-confined electrodeposition which formed the fundamental for quality control, mathematical model was derived to study the geometric shape of the meniscus. Multi-physical field simulation was carried out to investigate the effect of several process parameters on the deposition results, including the micropipette aperture, biased voltage and solution concentration, etc. Meniscus-confined electrodeposition of metallic micro-wires by utilizing a micropipette was carried out. The ionic current during the electrodeposition is in-process monitored for contact point detection and fabrication quality monitoring. The corresponding relationship between the quality of the fabricated micro-wires and the in-process monitored ionic currents was investigated. This study provides a potential way for in-process quality control with the local electrodeposition method.     

One-step fabrication of heterostructured CoNi-LDH@NiCo alloy for effective alkaline hydrogen evolution

Construction of heterostructured electrocatalyst with interface effect is an effective strategy for enhancing the alkaline hydrogen evolution efficiency, whereas this process often requires complex treatments. Herein, we proposed a one-step electrodeposition method to obtain heterostructured CoNi-LDH@NiCo alloy on Ni foam (NF) through a competition reduction between NO₃^? group and metal cations in the electrolyte. The HER performance for the CoNi-LDH@NiCo alloy achieved the current density of 10 mA cm^?2 at overpotential of 69 mV in 1 M KOH solution, improved 60% for η₁₀ by comparing with the pristine NiCo alloy. Utilizing the specialized adsorption of CoNi-LDH for H₂O and the featured attractiveness of NiCo alloy for H atom, the interface effect of the heterostructure electrocatalyst accelerated the dissociation of water molecules and elevated the catalytic kinetics dramatically. This work points out a potential approach towards the easy construction of inexpensive heterostructured electrocatalysts for HER activity in alkaline medium.     

Polypyrrole and platinum deposited onto carbon substrate to enhance direct methanol fuel cell electrodes behaviour

The aim of this work is to study the ability of polypyrrole to reduce the platinum load of low temperature methanol fuel cell electrodes. Platinum was deposited onto carbon paper and a layer of polypyrrole electrodeposited onto carbon paper, using electron beam evaporation and electrodeposition by pulses. Subsequently, the morphology and electrochemical behaviour of the synthesised samples were analysed in sulphuric acid solution, determining their electrochemically active surface area; and in a solution of sulphuric acid and methanol, to analyse their catalytic performance. The electrochemical measurements showed that the electrochemically active surface area and the catalytic performance of the electrodes prepared by evaporating platinum are increased when prepared on the polypyrrole film. Electrodes prepared using the pulse electrodeposition technique presented fairly homogeneous coatings that led to the reduction of the oxidation potential of methanol and the increase of their resistance to CO poisoning.     

Facile preparation of ultra-low Pt loading graphene-immobilized electrode for methanol oxidation reaction

Pulse current electrodeposition (PCE) technique was used to prepare graphene-supported platinum nanoparticles (GN-PtNPs) electrodes for the methanol electro-oxidation reaction in acidic media. The influences of the PCE parameters (applied current density, concentration of the Pt precursor, and duty cycle) upon the as-prepared GN-PtNPs electrodes for the methanol oxidation reaction (MOR) in terms of catalytic activity and tolerance against poisoning were studied using the Taguchi design of experiment (DOE). The analysis of variance (ANOVA) and signal-to-noise (S/N) ratio analysis provided prediction of optimal electrodeposition conditions to yield GN-PtNPs electrode which give the best MOR performance. The values of confirmatory experiment were demonstrated close to the values predicted using the Taguchi method. Transmission electron microscopy images showed that the Pt crystallites in flower-like structure were deposited evenly on the surface of graphene sheet. The Pt crystallites were predominantly in a zero-valent, metallic Pt state based on the X-ray photoelectron spectroscopy analysis.     

Design of tailored biodegradable implants: The effect of voltage on electrodeposited calcium phosphate coatings on pure magnesium

Magnesium, as a biodegradable metal, offers great potential for use as a temporary implant material, which dissolves in the course of bone tissue healing. It can sufficiently support the bone and promote the bone healing process. However, the corrosion resistance of magnesium implants must be enhanced before its application in clinical practice. A promising approach of enhancing the corrosion resistance is deposition of bioactive coating, which can reduce the corrosion rate of the implants and promote bone healing. Therefore, a well-designed substrate-coating system allowing a good control of the degradation behavior is highly desirable for tailored implants for specific groups of patients with particular needs. In this contribution, the influence of coating formation conditions on the characteristics of potentiostatically electrodeposited CaP coatings on magnesium substrate was evaluated. Results showed that potential variation led to formation of coatings with the same chemical composition, but very different morphologies. Parameters that mostly influence the coating performance, such as the thickness, uniformity, deposits size, and orientation, varied from produced coating to coating. These characteristics of CaP coatings on magnesium were controlled by coating formation potential, and it was demonstrated that the electrodeposition could be a promising coating technique for production of tailored magnesium-CaP implants.     

脉冲占空比对Ni-W合金镀层耐蚀性的影响

采用脉冲电沉积方法在纯铜基体上制备出Ni-W合金镀层。研究了脉冲占空比(30%~60%)对镀层表面形貌、结构、成分和耐蚀性的影响。结果表明:制得的Ni-W合金镀层表面致密、平整,W的质量分数在46.84%~49.24%范围内窄幅波动,具有非晶态结构。脉冲占空比为50%时制得的镀层的耐蚀性最好。在3.5%的NaCl溶液中,自腐蚀电位较正,自腐蚀电流密度最小,电荷转移电阻最大。     

磁场下电沉积制备Co-Pt-P磁性薄膜

在磁场下电沉积制备Co-Pt-P磁性薄膜。研究了电流、温度、磁场强度对薄膜性能的影响。结果表明:磁场对镀层的成分、微观结构及磁性能有一定程度的影响。     

氧化处理对电沉积吸液芯性能的影响研究

目的 通过研究自然氧化、过氧化氢氧化和130℃氧化处理对电沉积吸液芯润湿性和毛细性能的影响,探究吸液芯毛细性能在空气中衰减的原因。方法 通过电沉积在铜表面制备一层多孔铜吸液芯,分别对吸液芯进行自然氧化、过氧化氢浸泡和130℃烘烤处理,利用接触角测量和毛细上升法分析吸液芯表面的润湿性和毛细性能,通过扫描电镜(SEM)观察吸液芯微观形貌,采用X射线光电子能谱(XPS)和傅里叶红外光谱分析吸液芯表面成分。结果 3种氧化处理后,吸液芯的润湿性与毛细性能有明显差异。自然氧化处理和过氧化氢处理的吸液芯均表现为超亲水,接触角为0°,而130℃烘烤的吸液芯表现为超疏水,接触角高达150.49°。水在过氧化氢处理的吸液芯表面的运行速度比在自然氧化的表面更快。3种不同状态的吸液芯微观形貌都为树枝状结构,没有明显差异。XPS图显示,自然氧化处理的吸液芯表面部分氧化,存在76.4%(质量分数)Cu₂O;130℃烘烤的试样表面全部氧化,为60.6%的Cu₂O和39.4%的CuO;而过氧化氢浸泡的表面为100%的CuO₂。结论 3种氧化处理不会改变...