碱性介质中脉冲镀非晶态Ni-Mo-W合金镀层的电化学性能(英文)

采用脉冲电镀技术获得了高活性Ni-Mo-W析氢合金阴极。以析氢反应过电位为考察指标,确定了脉冲镀Ni-Mo-W合金的最佳电镀条件,如Na2WO4·2H2O浓度、平均电流密度和占空比等。同时,系统研究了Mo和W含量对Ni-Mo-W合金镀层成分和组成的影响规律。结果表明,在二元合金中添加W能有效提高电极的析氢反应活性(η200=80 mV);非晶态Ni-Mo-W合金的组织结构主要取决于Mo含量;与非晶态Ni-Mo合金镀层相比,Ni-Mo-W合金析氢阴极的电化学稳定性得到一定程度的提高。     

钛基Ni-Co-P非晶合金镀层电极的析氢性能

通过电沉积在钛基体上制备了非晶态Ni-Co-P合金镀层.在7mol/L NaOH溶液中进行的电化学测试结果表明,Ni-Co-P合金电极的析氢过电位明显低于镀镍阴极和纯钛阴极;计算了电极析氢反应的电化学动力学参数,表明非晶态Ni-Co-P合金电极具有较好的析氢电催化活性.     

镀液pH值对Ni-Mo-C合金镀层析氢性能的影响

通过电沉积法在纯铜表面制备Ni-Mo-C合金镀层,采用能谱仪(EDS)、扫描电镜(SEM)、线性伏安扫描法(LSV)和电化学阻抗谱(EIS)等方法研究了镀液pH值对Ni-Mo-C合金镀层元素组成、沉积速率、表面形貌及析氢性能的影响。结果表明:随着镀液pH值的增大,镀层中Ni、C的含量先减小后增大,Mo的含量先增大后减小;当镀液pH=4.5时,电沉积速率最大;能量因素和几何因素的优化均可增强合金镀层的析氢性能,能量因素对析氢性能的促进作用大于几何因素;当镀液pH=4.5时,镀层中Mo含量最大,吸附氢的脱吸附能力最强,析氢性能最好。     

电沉积非晶/纳米晶Ni-Mo-La合金电极的析氢性能

在非晶/纳米晶Ni-Mo合金镀液中添加适量的LaCl3溶液,获得了非晶/纳米晶混合结构的Ni-Mo-La合金电极。结果表明:稀土La元素的加入,有利于镀层Mo含量的提高,形成非晶态Ni-Mo合金,细化镀层晶粒,减小镀层微应变,并使镀层表面积增加。在25℃、7 mol/L的NaOH溶液中的电化学实验表明:Ni-Mo-La合金电极比Ni-Mo合金电极具有更高的析氢催化活性,在电流密度为150 mA/cm2条件下,Ni-Mo-La合金电极的析氢过电位比Ni-Mo合金电极的降低了约80 mV。Ni-Mo-La合金具有储氢材料的特性,其析氢过程含有吸氢—储氢—脱附的过程。     

Mo含量对Raney Ni—Mo活性阴极析氢过电位的影响

利用喷涂技术在Raney Ni-Mo活性阴极的基础上研制出了RaneyNi-Mo活性阴极,该阴极的析氢过电位比Raney Ni低,电化学特性比Raney Ni稳定.Raney Ni-Mo中的Mo含量不同,其析氢过电位不同,Mo含量存在一个最佳值,此值与Raney Ni合金中Ni/Al比有关,而与涂层厚度无关.     

电沉积工艺参数对镍-钼-锌三元合金电极析氢催化性能的影响

目的采用直流电沉积法在铜基底上制备镍-钼-锌三元合金电极,提高电解水析氢过程中阴极电极的效率。方法使用电化学工作站研究不同电沉积工艺参数对镍-钼-锌三元合金镀层析氢性能的影响,使用扫描电镜(SEM)、X射线衍射分析仪(XRD)、能谱仪(EDS)对合金镀层表面形貌、相结构及元素含量进行表征。通过线性扫描伏安法(LSV)对析氢过电位进行测量,采用塔菲尔极化获得塔菲尔斜率,采用电化学阻抗法(EIS)表征合金镀层的析氢催化性能。结果最佳工艺参数为:温度45℃,p H=10.5,电流密度100 mA/cm~2。该合金在10 mA/cm~2下相对氢标电位仅为139 mV,塔菲尔斜率为103 mV/dec,活化电极电阻(Rct)随着电压的升高而降低。合金中Ni、Mo和Zn的原子比分别为68.23%、10.09%和21.68%。合金镀层为非晶结构,表面是纳米级颗粒堆叠而成的粗糙形貌。结论不同的工艺参数对Ni-Mo-Zn电极析氢性能有着重大影响,其析氢性能随着p H值的升高而上升,随着电流密度的升高而先增后减,随着电沉积温度的升高而上升。Ni-Mo-Zn高的析氢性能源于其元素协同作用、非晶结构和粗糙表面。     

光电子器件外壳脉冲电镀镍钴合金工艺及其耐蚀性

目的开发一种脉冲电镀镍钴合金工艺,并研究其镀层的耐腐蚀性能,以期将其应用于光电子器件外壳电镀领域。方法采用脉冲电镀的方式获得电镀镍钴合金镀层,通过腐蚀失重试验、极化曲线测试以及电化学阻抗谱测试等方法考察镀层的耐腐蚀性能,通过场发射扫描电子显微镜、能谱仪和X射线衍射仪等设备对镀层的表面微观形貌、成分和晶体结构进行了表征,并与传统的电镀氨基磺酸镍工艺进行了抗腐蚀性能的比较。在耐腐蚀性能最优的工艺条件下,对公司某型号光电子器件外壳进行了镍钴合金电镀,并对产品的镀层进行一系列考核。结果随着Co含量的增加,脉冲电镀镍钴合金镀层的结晶更均匀致密,晶粒、镀层孔隙更小。在3.5%NaCl溶液中,随着Co含量的增加,脉冲电镀镍钴合金镀层的自腐蚀电位正移,自腐蚀电流密度减小,电荷转移电阻增加。Co含量25%的脉冲电镀镍钴合金镀层的自腐蚀电位和自腐蚀电流密度分别为-331 mV和2.26μA/cm~2,电荷转移电阻是212.62 kΩ。产品的镀层质量、引线涂敷强度、引线疲劳等考核均满足相关标准要求。结论脉冲电镀镍钴合金镀层的耐蚀性随着Co含量的增加而增强。在3.5%的NaCl溶液中,Ni-Co(25%)的镀层自腐蚀电流仅是Ni镀层的44%。开发的脉冲电镀镍钴合金工艺可以应用于光电子器件外壳电镀领域。     

电沉积制备Cu-Ni-Mo三元电极及其析氢性能

目的 制备一种在碱性溶液中具有高效、低成本等优点的铜基析氢阴极材料。方法 在35 ℃下采用直流电沉积法，在泡沫镍(NF)表面分别沉积Cu-Ni、Cu-Ni-Mo镀层，制备Cu-Ni/NF、Cu-Ni-Mo/NF析氢电极。利用X射线衍射分析仪(XRD)、扫描电镜(SEM)和能谱仪(EDS)表征电极的表面形貌、结构元素含量及物相。通过电化学阻抗技术(EIS)、线性扫描伏安法(LSV)、循环伏安法(CV)测定电极的析氢性能和催化活性。结果 经Mo掺杂后，Mo在Cu-Ni-Mo三元合金中以置换型固溶体的形式存在，与二元镀层相比，增大了镀层的晶格常数。Cu-Ni-Mo/NF三元电极在电流密度10 mV/cm²下，过电位仅为116 mV，塔费尔斜率为104 mV/dec，电荷转移电阻为15.34 Ω，电化学活性比表面积(ECSA)为22.33，相较于Cu-Ni/NF二元电极，分别降低了68 mV、27 mV/dec、15.48 Ω，ECSA值提高了7.95，且循环稳定性较好。结论 引入第3种元素Mo，改变了Cu-Ni二元电极的镀层形貌，使晶粒细化，表现为微粒紧密堆积而成的球胞状结构，从而提升了电极材料的比表面积，为析氢反应提供了更多的活性位点，有助于提高析氢反应效率。由于三金属间的协同作用，与Cu-Ni二元电极相比，Cu-Ni-Mo三元电极显示出更优异的析氢催化性能。     

晶化温度对非晶态Cr-Fe-C合金镀层的影响

采用三价铬电镀液,在4Cr10Si2Mo钢工件表面电沉积非晶态Cr-Fe-C合金镀层.通过改变络合剂的含量、电流密度和电镀时间,在阴极上沉积了不同厚度的非晶态Cr-Fe-C层.用扫描电子显微镜和光学显微镜、X射线衍射仪、能谱仪测定、显微硬度计研究了从三价铬镀液中电沉积Cr-Fe-C镀层的工艺以及镀层的形貌、结构与性能.结果表明,利用该工艺获得了厚度为30 μm、27 wt%Fe的非晶态Cr-Fe-C合金镀层.该镀层耐蚀性较好,经600℃×1 h晶化处理后硬度最高可达1 800 HV0.05.     

热处理对混晶结构Ni-Mo合金镀层电化学性能的影响

对获得的非晶/纳米晶混合结构形态的镍钼合金镀层在氮气保护条件下作热处理实验,研究热处理后合金镀层的电化学性能.结果表明,非晶/纳米晶的Ni-Mo合金具有较好的析氢催化活性,与镀层中的非晶态含量及镀层的真实接触面积有关.在350℃以下热处理,镀层结构仍具有混晶结构形态,具有良好的析氢催化活性;当温度高于450℃以上时,合金镀层开始以晶态合金出现,析氢催化活性降低.     

Electrolytic Synthesis of Ni-W-MWCNT Composite Coating for Alkaline Hydrogen Evolution Reaction

Nickel–tungsten multi-walled carbon nanotube (Ni-W-MWCNT) composite films were fabricated by an electrodeposition technique, and their electrocatalytic activity toward hydrogen evolution reaction (HER) was studied. Ni-W-MWCNT composite films with a homogeneous dispersion of MWCNTs were deposited from an optimal Ni-W plating bath containing functionalized MWCNTs, under galvanostatic condition. The presence of functionalized MWCNT was found to enhance the induced codeposition of the reluctant metal W and resulted in a W-rich composite coating with improved properties. The electrocatalytic behaviors of Ni-W-MWCNT composite coating toward HER were studied by cyclic voltammetry (CV) and chronopotentiometry techniques in 1.0 M KOH medium. Further, Tafel polarization and electrochemical impedance spectroscopy (EIS) studies were carried out to establish the kinetics of HER on the alloy and composite electrodes. The experimental results revealed that the addition of MWCNTs (having a diameter of around 10-15 nm) into the alloy plating bath has a significant effect on the electrocatalytic behavior of Ni-W alloy deposit. The Ni-W-MWCNT composite coating was found to show better HER activity than the conventional Ni-W alloy coating. The enhanced electrocatalytic activity of Ni-W-MWCNT composite coating is attributed to the MWCNT intersticed in the deposit matrix, evidenced by surface morphology, composition and phase structure of the coating through SEM, EDS and XRD analyses, respectively.     

电刷镀工艺对 Ni-Mo 合金镀层表面形貌与硬度的影响

目的优化电刷镀制备Ni-Mo合金镀层工艺,并分析对镀层表面形貌和硬度的影响。方法改变电极相对速度和工作电压,获得不同电刷镀条件下的Ni-Mo合金镀层。采用金相显微镜观察镀层的表面形貌,采用显微硬度计测试镀层的显微硬度。结果最佳工艺为:工作电压14 V,电极相对速度11.3m/min。镀层光亮致密,显微硬度达到503.90HV。结论适当提高电极相对运动速度、工作电压,能有效改进Ni-Mo合金镀层的沉积速度、表面形貌及显微硬度。     

Characterisation of tungsten coatings by pulsed current plating from molten salt in air atmosphere

Pure and compact tungsten coatings with high (200)-orientation were successfully electrodeposited from Na₂WO₄–WO₃ binary oxide molten salt by direct and pulse current techniques on copper based alloy substrate in air atmosphere at 1173 K. The tungsten coatings and copper alloy substrates combined well with no obvious voids and cracks. In addition, the influence of pulse plating on the microstructure, crystal structure and Vickers microhardness of coatings, adhesive strength between coatings and substrates as well as the current efficiency was investigated. It was also observed that applied pulse current led to tungsten coatings with better mechanical properties than those obtained by direct current plating. In addition, a tungsten coating of 500 μm which had lower oxygen content and higher adhesive strength than the coating obtained by the plasma spray method was obtained.     

Studies of Structure and Electrocatalytic Hydrogen Evolution on Electrodeposited Nanocrystalline Ni-Mo Alloy Electrodes

Nanocrystalline Ni-Mo alloy deposits were obtained by electrodeposition. The structures of the alloy deposits were analyzed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The XRD shows that Ni-Mo alloy deposit with 15·2% molybdenum exhibits (111) preferred orientation, the lattice constant is larger than that of nickel metal. The XPS results on nanocrystalline Ni-Mo alloy deposits indicate that the nickel and molybdenum of the deposits exist in the metallic state, the binding energy of the alloyed elements increase to some extent. The nanocrystalline Ni-Mo alloy deposit electrode may offer better electrocatalytic activity than the polycrystalline nickel electrode. The electrochemical impedance spectra from the nanocrystalline Ni-Mo alloy electrode indicate that hydrogen evolution in 30% (m/m) KOH is in accordance with the Volmer-Heyrovsky mechanism.     

镁锆合金表面Ni-P非晶化学镀工艺研究

镁锆合金是一种轻质、高阻尼的新型合金,但耐蚀性极差.采用化学镀方法,系统研究了Mg-0.57Zr合金表面Ni-P非晶化学镀的预处理及施镀工艺.研究结果表明:1)采用复合酸洗,有利于提高镀层与基体的结合力、镀层的沉积均匀性和金属光泽度;2)直接化学镀镍比预浸锌后再化学镀镍的工艺方案,更利于提高镀速、降低镀层孔隙率;3)采用所推荐的化学镀工艺,获得了与基体结合力高、孔隙率低、耐蚀性较好的Ni-P非晶镀层,其平均镀速为11.44 μm/h,镀层硬度比合金基体提高10.7倍.     

化学镀 Ni-Mo-P 合金镀层的组织结构与防垢性能研究

目的采用材料测试方法和防垢实验,研究不同工艺条件下的化学镀Ni-Mo-P合金镀层的组织结构与防垢性能。方法在化学镀Ni-P镀层基底上,添加含有钼酸根离子杂多酸盐,在不同工艺条件下化学沉积Ni-Mo-P合金镀层,研究化学镀Ni-Mo-P合金镀层的表面形貌和组织结构,分析镀液中硼酸含量和钼酸铵含量对镀层沉积速率的影响,观测镀层在结垢实验后的表面形貌并分析结垢速率。通过SEM,XRD和EDS对化学镀Ni-Mo-P合金镀层的表面形貌和组织结构进行检测,研究在酸性镀液中硼酸含量对化学镀Ni-Mo-P工艺条件的影响。采用防垢实验测试化学镀Ni-Mo-P合金镀层的防垢性能。结果在化学镀Ni-Mo-P过程中,钼酸根离子杂多酸盐具有稳定作用。化学镀Ni-Mo-P合金镀层的化学沉积镀液的最佳工艺条件为:Ni SO4·6H_2O 16.5 g/L,Na H_2PO_2·H_2O 20 g/L,钼酸钠0.5~0.8 g/L,硼酸2 g/L,乙酸钠7.5 g/L。化学镀Ni-Mo-P合金镀层的结垢速率明显低于化学镀Ni-P镀层,具有良好的防垢能力,形成了非晶态的镀层。结论采用化学镀Ni-P镀层基底上沉积得到非晶态的Ni-Mo-P合金镀层,硼酸具有调节镀液p H值和络合作用,非晶态的Ni-Mo-P合金镀层平均结垢速率最小值为0.58μm/h,具有良好的阻垢能力。     

STRUCTURE OF ELECTRODEPOSITED Ni-Mo OR Ni-W ALLOY

研究了电镀条件对电镀Ni-Mo和Ni-W合金结构的影响,发现各个因素中pH值的变化对镀层形成晶态或非晶态起着决定性的作用.这些结构上的变化,仍可用作者在解释Ni-P镀层结构时发展的模型加以解释.     

钨铜合金表面化学镀Ni-P镀层性能研究

从钨铜合金表面化学镀Ni-P镀层的表面形貌及成分,镀层结构,外观,结合力.硬度,耐磨性,孔隙率,纤焊性等方面进行了检测和表征.结果表明,化学镀Ni-P合金层磷含量为11.37%,属于高磷镀层,主要为非晶型结构,在钨铜合金表面化学镀Ni-P合金可以大大提高钨铜合金的硬度和耐磨性,且Ni-P合金镀层与钨铜合金基体结合强度好,孔隙率低,纤焊性好.     

Fabrication, thermal stability and microhardness of sputtered Ni–P–W coating

Ternary Ni–P–W alloy coating was fabricated by the RF magnetron sputtering technique with dual targets of electroless nickel alloy and tungsten metal. The composition of both the alloy deposited and the sputtered targets were evaluated by electron probe microanalysis. The homogeneity of Ni–P targets fabricated by electroless nickel plating on copper plates was revealed from cross-sectional line profile analysis. Transitions in microstructure, in terms of the tungsten content in the as-deposited alloy deposit, were discussed using X-ray diffraction analysis. Results of microhardness tests showed that the surface hardness could be engineered by controlling the composition and microstructure in the Ni–P–W coating. A relatively high microhardness of approximately 1900 HK was observed for the ternary coating with high tungsten contents of 65 wt.%. The thermal stability could be enhanced by addition of tungsten into the deposit compared to the binary Ni–P sputtered coating.     

Pretreatment-free Ni−P plating on magnesium alloy at low temperatures

Electrochemically promoted electroless plating (EPEP) was used for the application of pretreatment-free Ni?P coating on AM60B magnesium alloy at low temperatures and the obtained coating was characterized by SEM, AFM, EDS and XRD techniques. Compact, uniform, and medium-phosphorus Ni?P coating with mixed crystalline?amorphous microstructure was obtained by applying a cathodic current density of 4 mA/cm² at 50 °C. Also, island-like nickel clusters were deposited on the alloy surface under the same plating condition but without applying the cathodic current. In addition, the durability of the magnesium alloy against corrosion was strongly improved after plating via EPEP technique which was revealed by electrochemical examinations in 3.5% NaCl (mass fraction) corrosive electrolyte. The results of the electrochemical examinations were confirmed by microscopic observations. Thickness, microhardness, porosity and adhesive strength of the deposits were also qualified.