Ni—WC复合电极的结晶结构及其电化学性能的研究

本文在优选的工艺条件下制备了Ｎｉ－ＷＣ复合电极。其ＳＥＭ观察和ＸＲＤ测试结果表明：复合电极中的Ｎｉ是以比Ｎｉ电极的Ｎｉ更微小的晶粒存在。复合电沉积过程中，导电性的ＷＣ微粒的存在，对基质金属Ｎｉ的电沉积方式产生了影响，使基质金属Ｎｉ几乎无择优取向性。采用循环伏安法对其电化学性能进行研究，实验结果表明：Ｎｉ－ＷＣ复合电极在碱性水溶液析氢反应中与Ｈ质子之间的吸附作用及吸附量高于Ｎｉ电极，对硝基苯的电还原反应具有比Ｎｉ电极更良好的催化活性。     

Co—WC电极

从钴镀液中添加ＷＣ微粒复合电沉积制备Ｃｏ－ＷＣ镀层，ＷＣ微粒的加入，加快了阴极电化学反应。Ｃｏ－ＷＣ复合电极在碱性溶液中具有优越的电催化析氢性能，并经受了长期间断电解的试验，电极性能稳定。     

复合镀层中ZrO2微粒对基质Ni晶体结构的影响

采用复合电沉积方法制备了Ｎｉ－ＺｒＯ２复合镀层，探讨了ＺｒＯ２微粒引起的基质金属Ｎｉ的晶体择优取向及点阵常数的变化，及其对析氢电催化活性的影响。结果表明，ＺｒＯ２微粒的存在改变了Ｎｉ的电沉积层结构，使基质金属Ｎｉ产生新的沿（２２０）晶面的择优取向。这一新的择优取向不利于析氢反应。择优取向的改变说明复合电沉积过程中，Ｎｉ与ＺｒＯ２微粒是以一定的界面匹配进入复合镀层的，基质金属Ｎｉ点阵参数的改变也证明     

Co-WC电极

从钴镀液中添加ＷＣ微粒复合电沉积制备Ｃｏ－ＷＣ镀层,ＷＣ微粒的加入,加快了阴极电化学反应．Ｃｏ－ＷＣ复合电极在碱性溶液中具有优越的电催化析氢性能,并经受了长期间断电解的试验,电极性能稳定     

电沉积Ni-PSZ梯度镀层过程中阴极电流效率的研究

采用动电位扫描,电化学交流阻抗及扫描电子显微镜研究电沉积Ｎｉ－ＰＳＺ梯度镀层过程中阴极电流效率的变化规律及其机理．结果表明,Ｎｉ－ＰＳＺ复合镀层对氢的析出反应具有催化作用,在镀液中加入ＰＳＺ微粒后,能增大镍还原过电位,降低氢析出过电位,从而不断降低电沉积梯度镀层过程中的阴极电流效率．在电沉积Ｎｉ的过程中,有中间吸附相Ｎｉ＋ａｄｓ生成,ＰＳＺ微粒的加入能优先催化Ｈａｄｓ,加速氢气析出     

Ni-W-WC复合电极在碱性介质中的电催化析氢

氢能源作为高效、洁净和理想的二次能源,已受到世界各国广泛的重视［１］．电解水制氢是实现大规模生产氢的重要手段,为降低电解能耗,最行之有效的办法是降低氢的阴极析出电位,因此开发新型廉价高催化性能的析氢材料具有十分重要的意义．具有高催化析氢活性的单一金属和合金材料已广为报导［２－８］．近二十年来,通过复合电沉积技术将一种或数种不溶性固体微粒渗杂到金属材料中所形成的复合镀层,如Ｎｉ－ＷＣ［９］、Ｎｉ－ＰＴＴＥ［１０］、Ｎｉ－ＲｕＯ_２［１１］、Ｎｉ－ＬａＮｉＯ３［１２］等,这些复合镀层因其高比表面而表…     

PbO2—WC复合物阳极的研究

采用复合电沉积技术制备了ＷＣ微粒弥散于ＰｂＯ２中的ＰｂＯ２ＷＣ复合电极，研究了相结构及在Ｈ２ＳＯ４介质中阳极析氧反应的性能。结果表明，与不含ＷＣ微粒的ＰｂＯ２电极比较，ＷＣ微粒改变了ＰｂＯ２电沉积的方式，复合电极的结晶更为细小和致密，α－ＰｂＯ２的含量更高，晶体产生了择优取向，该复合电极在０．５ｍｏｌ／ＬＨ２ＳＯ４溶液中阳极析氧的电催化活性提高近１倍，其化学稳定性和电化学稳定性良好。     

PbO_2－WC复合物阳极的研究

采用复合电沉积技术制备了ＷＣ微粒弥散于ＰｂＯ_２中的ＰｂＯ_２－ＷＣ复合电极，研究了相结构及在Ｈ_２ＳＯ_４介质中阳极析氧反应的性能。结果表明，与不含ＷＣ微粒的ＰｂＯ_２电极比较，ＷＣ微粒改变了ＰｂＯ_２电沉积的方式，复合电极的结晶更为细小和致密，α－ＰｂＯ_２的含量更高，晶体产生了择优取向。该复合电极在０．５ｍｏｌ／ＬＨ_２ＳＯ_４溶液中阳极析氧的电催化活性提高近１倍，其化学稳定性和电化学稳定性良好。     

p—Si上电沉积Ni—W—P薄膜的结构与热稳定性

研究了ｐ－Ｓｉ上恒电流沉积Ｎｉ－Ｗ－Ｐ合金薄膜组成与结构的关系，讨论了镀层的组成、结构随沉积时间的变化．测定了非晶合金的晶体结构随热处理温度的改变以及ＤＴＡ曲线，结果表明，非晶Ｎｉ－Ｗ－Ｐ合金在晶化过程中形成两个纳米超微晶相，非晶Ｎｉ－Ｗ－Ｐ薄膜的热稳定性远高于通常使用的非晶Ｎｉ－Ｐ薄膜．     

Ni—La2O3复合镀层的氧化行为及机制

通过对金属镍、镍镀层及Ｎｉ－Ｌａ２Ｏ３复合镀层于９００℃、１０００℃时的恒温氧化实验，发现Ｎｉ－Ｌａ２Ｏ３复合镀层的氧化行为明显改善。高分辨电子显微镜（ＨＲＥＭ）的观测研究表明，Ｎｉ－Ｌａ２Ｏ３复合镀层氧化时，纳米尺寸的Ｌａ２Ｏ３颗粒掺入到氧化层中，形成了ＮｉＯ－Ｌａ２Ｏ３复合氧化物层；在氧化层晶界发现了异常原子排列的新现象。由此认为，Ｎｉ－Ｌａ２Ｏ３复合镀层抗高温氧化性能的提高，主要归因于小尺寸     

α-Al2O3纳米粒子对Co-Ni合金异常共沉积电化学行为的影响

为了研究在电化学复合共沉积过程中,惰性纳米粒子和金属离子、电极表面的相互作用,以及由此产生的对合金电化学共沉积行为的影响.本文从两个吸附过程出发: 电解液中的金属离子和H＋在纳米粒子表面的吸附；纳米粒子迁移到阴极表面,在电极表面的吸附.采用Zeta电势和稳态极化以及电化学交流阻抗（EIS）研究了纳米Al2O3粒子和电解液中的金属离子，和电极表面的相互作用,进而分析了纳米粒子对Co2＋和Ni2＋还原沉积的影响规律.通过对阻抗数据的拟合,讨论了Al2O3纳米粒子对等效电路中各物理参数的影响.在H＋和不同金属离子在纳米粒子上发生竞争吸附的基础上,提出了纳米粒子和合金共沉积的可能反应历程.     

Ni/ZrO2复合电沉积机理的研究

研究了在Ｗａｔｔｓ镀镍液中ＺｒＯ２颗粒与镍复合电沉积的阴极电流密度以及颗粒在镀液中分散量对颗粒共析量的影响，探讨了复合电沉积的过程与模型。研究表明，在小的颗粒分散量下，复合电沉积为颗粒向阴极的传输所控制，导致共析量随电流密度增大而减少。在大的颗粒分散量，小电流密度时复合电沉积为颗粒的强吸附过程所控制，致使共析量随电流密度增大而增加；大电流密度时，复合电沉积为颗粒向阴极的传输所控制，造成共析量随电流     

Ni/ZrO2复合电沉积机理的研究

研究了在Watts镀镍液中ZrO     

Electrodeposition and characterization of chromium–tungsten carbide composite coatings from a trivalent chromium bath

The electrodeposition of chromium from a trivalent chromium bath has been described in this work. The electrocomposite coatings of chromium with hard abrasive particles were investigated. The chromium–tungsten carbide (Cr? WC) composite coatings were obtained by suspending different concentrations of WC particles in a trivalent chromium plating solution to improve the various properties of the chromium deposit layers. The effect of operating conditions on the deposit layers has been studied. On the other hand, the effect of non‐ionic polymeric surfactant [nonyl phenol ethoxylate with 12 units of ethylene oxide (NPE)] as an additive in enhancing the incorporation of the WC ceramic particles in the chromium metal matrix was investigated. It was found that the co‐deposition of the WC ceramic particles depends on the concentration of the additive and its efficiency in reducing the surface tension of the electroplating solution. The mechanism of incorporation of WC particles into a growing deposit was suggested and discussed in view of the zeta potential and degree of wetability of WC particles in the plating solution. Furthermore, the adsorption behaviour of the additive on WC particles was analysed according to the Frumkin isotherm. The surface morphology and the distribution of WC in the chromium metal matrix were investigated. The properties of the deposit layers, hardness, corrosion resistance and wear resistance were determined and compared with free chromium deposits. The test results reveal that the Cr? WC deposit layer shows better performance compared with the chromium‐free deposit. Copyright © 2005 John Wiley & Sons, Ltd.     

Ni-Mo合金电沉积层织构及形成机理

在组成为：０．２２ｍｏｌ／Ｌ硫酸镍、０．０６ｍｏｌ／Ｌ钼酸钠和０．３ｍｏｌ／Ｌ柠檬酸钠的溶液,于纯铜片上采用恒电流沉积,所得Ｎｉ－Ｍｏ合金沉积层经Ｘ射线衍射测定,结果表明在温度为２５℃～５０℃,电流密度为１０ｍＡ·ｃｍ－２～３０ｍＡ·ｃｍ－２范围,Ｎｉ－Ｍｏ合金沉积层表现为（１１１）择优取向．循环伏安和电位阶跃实验表明镍钼合金电结晶过程按照连续成核和三维生长方式进行．Ｎｉ－Ｍｏ合金电沉积过程的电化学交流阻抗谱表明Ｎｉ－Ｍｏ共沉积过程经历了吸附中间产物步骤,由于吸附态物种氢氧化镍和钼的氧化物将阻化晶粒（１１１）晶面的生长,从而使镍钼沉积层表现为（１１１）择优取向．     

Adsorption and Decomposition of NH3 on Ni/Pt(111) and Ni/WC(001) Surfaces: A First-Principles Study

Density functional theory was used to study the NH₃ behavior on Ni monolayer covered Pt(111) and WC(001). The electronic structure of the surfaces, and the adsorption and decomposition of NH₃ were calculated and compared. Ni atoms in the monolayer behave different from that in Ni(111). More dz2 electrons of Ni in monolayer covered systems were shifted to other regions compared to Ni(111), charge density depletion on this orbital is crucial to NH₃ adsorption. NH₃ binds more stable on Ni/Pt(111) and Ni/WC(001) than on Ni(111), the energy barriers of the first N-H bond scission were evidently lower on Ni/Pt(111) and Ni/WC(001) than on Ni(111), these are significant to NH₃ decomposition. N recombination is the rate-limiting step, high reaction barrier implies that N₂ is produced only at high temperatures. Although WC has similar properties to Pt, differences of the electronic structure and catalytic activities are observed for Ni/Pt(111) and Ni/WC(001), the energy barrier for the rate-determined step increases on Ni/WC(001) instead of decreasing on Ni/Pt(111) when compared to Ni(111). To design cheaper and better catalysts, reducing the N recombination barrier by modifying Ni/WC(001) is a critical question to be solved.     

氢原子在Ni(111)次表面和Ni(211)、(533)台阶面上的吸附与振动

应用原子与表面簇合物相互作用的五参数Morse势(5-MP)方法对氢原子在Ni(111)表面和次表面以及Ni(211), (533)台阶面进行了系统研究, 得到了氢原子在上述各面的吸附位、吸附几何、结合能和本征振动频率. 计算结果表明, 在Ni(111)面上, 氢原子优先吸附在三重位, 随着覆盖度的增加会吸附在次表面八面体位和四面体位. Ni(211), (533)的最优先吸附位都是四重位, 当氢原子的覆盖度增大时占据(111)平台的三重吸附位. 靠近台阶面的吸附位受台阶和平台高度的影响很大. 此外, 我们计算了氢原子在各表面的不同吸附位的扩散势垒, 获得氢原子在各表面的最低能量扩散通道.     

氮原子在Ni平坦和缺陷表面上的吸附和振动

 构造了氮－镍相互作用的5－参数Morse势，研究了氮原子在Ni（\r\n100），Ni（110）和Ni（111）平坦表面的吸附和振动，获得了氮原子\r\n在三个低指数表面的吸附位、吸附构型、结合能和本征振动等数据，计\r\n算结果与实验结果非常吻合．同时，与Ni（100）表面对比，系统研究\r\n了氮原子在Ni（510）台阶面的吸附和扩散．计算结果表明，氮原子在\r\n台阶下部形成最稳定的吸附态，台阶对下台面上扩散的氮原子形成捕获\r\n势，对上台面上扩散的氮原子形成反射势．     

Reactivity of nanocolloidal particles gamma-Fe2O3 at the charged interfaces. Part 1. The approach of particles to an electrode

We are interested here in the reactivity of magnetic nanoparticles at the electrode-electrolyte interface with the aim of the electrochemical synthesis of magnetic and conductive liquids (electronic conduction). The reactivity of charged colloidal particles occurs through a two steps process, the first being the approach toward the electrode with a possible adsorption phenomenon and the second step, the electron transfer. In this first paper we focus on the approach and the deposition of well-defined gamma-Fe(2)O(3) nanoparticles onto conductive substrates like mercury and gold under different conditions in order to vary the interactions particle/substrate especially the electrostatic interactions. The approach of the particles near the electrodes is estimated from the electrochemical currents related to the transformation of the particles. This electrochemical method is validated by coupling several techniques on gold electrodes: direct imaging by atomic force microscopy and study of kinetics by reflectometry. The results show that the electrochemical currents are always associated to adsorption of the particles, so that the electrochemical method can be used to estimate the adsorption of the particles, thus to follow the kinetics. The influence of the electrostatics on the occurrence of adsorption highly depends on the nature of the substrate and on the nature of the colloidal suspension. (ions, pH, ionic strength): whereas electrostatics governs the deposits in some cases, it is totally dominated by other interactions in other cases. Therefore, it seems difficult to predict a priori the existence of adsorption. However, when a deposit occurs, the kinetics and the maximal coverage of the substrates are controlled by the electrostatic interactions between the particles already adsorbed and those, close to the interface, in the bulk of the solution.