共查询到17条相似文献,搜索用时 265 毫秒
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为了进一步弄清常用镀镍添加剂邻磺酰苯酰亚胺、1,4-丁炔二醇及2者的混合物对酸性镀镍中镍电沉积的作用机理,通过循环伏安、交流阻抗和电势阶跃等电化学方法进行了试验研究.结果表明:加入有机添加剂后均能使镍电沉积电位负移,且该电极过程不可逆;同时镍沉积过程经历了2个电子转移步骤和中间产物吸附步骤;当2种添加剂联合使用时,镍电沉积的阴极过电位增大约650 mV,并能有效增大成核数密度,更有利于得到光亮镍层;加入有机添加剂后镍电沉积,I2/Im2-t/tm曲线均靠近瞬时成核理论曲线,说明在有机添加剂作用下镍的沉积遵循瞬时成核三维生长的电结晶机理. 相似文献
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本文在ChCl/CrCl3.6H2O离子溶液体系中,采用循环伏安法和恒电位阶跃法研究了Cr(Ⅲ)在玻碳电极上的电化学成核机理。研究结果表明,Cr(Ⅲ)的电化学成核机理是三维成核并与过电位有关。当过电位较小时,Cr(Ⅲ)的电结晶过程为三维连续成核,其扩散系数为(2.56±0.33)×10-11m2/s。当过电位较大时,Cr(Ⅲ)的电结晶过程趋向于三维瞬时成核过程,其扩散系数和晶核数密度均与过电位无关,分别为(3.04±0.3)×10-11m2/s和(4.47±0.05)×1011/m2。两种成核方式的法向生长速率常数均与过电位成线性关系,晶体法向的生长没有受到任何阻滞。 相似文献
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目前,添加剂对镀锌的作用及其机理说法不同.用线性扫描法、循环伏安法和计时电流法分别研究了聚乙二醇400(PEG400)及其与苄叉丙酮(BA)复配在氯化钾(KCl)溶液中对锌电沉积的影响;根据Scharifker-Hills成核模型拟合了电流-时间数据.结果表明:PEG400和BA混合比单加更能增大锌在KCl溶液中电沉积的过电位,能更有效地抑制析氢反应;锌的电沉积机理在一定程度上取决于所加入的添加剂,仅添加PEG400,锌电沉积机理与无添加剂的一样,都是晶核瞬时形成和成长的过程,PEG400和BA同时加入,锌的电沉积机理是晶核连续形成后转为晶核瞬时形成.本研究结果有助于氯化钾镀锌高效添加剂的开发. 相似文献
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为研究Cr3+在金属电极表面的电结晶行为,在氯化物三价铬电镀溶液中,采用电化学工作站测试了Cr3+沉积的时间电流曲线,并利用扫描电镜(SEM)分析镀层形貌。结果表明:在镍电极、铜电极和铬电极表面,Cr3+的电沉积均经历了成核过程;铜电极和镍电极表面表现为连续成核转为瞬时成核的机理,铬电极的(I/Im)2-t/tm曲线偏离理论曲线较大,但其表现出较正的形核阶跃电位(-1.1 V);随着阶跃电位的负移,3种电极电沉积的电流极大值逐渐增加,电结晶的扩散速率增加,成核数密度减少,镀层由平整光滑逐渐转变为球状晶胞紧密堆砌,晶胞尺寸逐渐增大;在相同的阶跃电位下,铬电极的沉积电流值更小,成核数密度更大,晶胞尺寸更小。 相似文献
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超声波对泡沫镍抗拉强度和延伸率的影响 总被引:2,自引:2,他引:0
针对导电胶法制造泡沫镍存在的抗拉强度、延伸率低,结果不均匀等问题,在制造泡沫镍的浸涂石墨导电胶和电沉积镍的过程中,首次采用超声波发生装置,对比研究了有无超声波的4种情况下制得泡沫镍的抗拉强度、延伸率及三维网络结构。结果表明:超声波增加了石墨导电胶在泡沫基体上浸涂的均匀性;大大提高了镍在石墨导电层上初期沉积和后期沉积的均匀性;增大了Ni的结晶过电位,使Ni的临界晶核半径变小,结晶更加致密;泡沫镍的三维网络结构更加均匀,抗拉强度、延伸率大大提高。在自行设计制造的生产线上,验证了本文的试验结果。 相似文献
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The electrochemical behavior from n-Al2 O3 or n-SiO2 composite brush plating system and quick nickel solution were investigated using cyclicvoltammetry. The interaction between nanoparticle and matrix metal nickel was researched by X-ray Photoelectron Spectrometry. The electrochemical experimental data indicated that nanoparticles lead to increasing of the current efficiency as well as decreasing of overpotential. The results showed that the nanoparticle took part in the electrode reaction during nickel electrocrystallization and could catalyze the nickel electrodeposition. During the electrocrystallization process, some of nanoparticles were captured effectively on the growing metal surface. As the absorbed nickel atoms were diffusing on metal growth surface, some of them arrived at the interface between the captured nanoparticle and the growing metal surface. The unsaturated bond of oxygen on nanoparticle surface could capture some of the absorbed nickel atoms and form nickel-oxygen chemical bond. It was proved that the chemical bond interaction exists in the interface between nanoparticles surface and matrix metal nickel. 相似文献
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M.A. Raso M.J. González-TejeraI. Carrillo E. Sanchez de la BlancaM.V. García M.I. Redondo 《Thin solid films》2011,519(8):2387-2392
The potentiostatic electropolymerization of poly-N-Methylpyrrole on Cu at 1.5 V, 2.0 V and 2.5 V vs saturated calomel electrode potentials has been carried out to establish the successive steps of polymer coating generation. The chronoamperograms obtained allow the different steps of the nucleation and growth mechanism to be analyzed by fitting the experimental data to the mathematical equations established in the electrocrystallization theory. In all cases a mechanism consisting of a two-dimensional growth at short time followed by a three-dimensional diffusion controlled growth and at longer times a subsequent two-dimensional growth mechanism, with progressive nucleation, is suggested. Scanning electron microscopy micrographs support this mechanism. 相似文献
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This paper discusses recent experimental and numerical results from the authors'' labs on the effects of moderate magnetic (B) fields in electrochemical reactions. The probably best understood effect of B fields during electrochemical reactions is the magnetohydrodynamic (MHD) effect. In the majority of cases it manifests itself in increased mass transport rates which are a direct consequence of Lorentz forces in the bulk of the electrolyte. This enhanced mass transport can directly affect the electrocrystallization. The partial currents for the nucleation of nickel in magnetic fields were determined using an in situ micro-gravimetric technique and are discussed on the basis of the nucleation model of Heerman and Tarallo. Another focus of the paper is the numerical simulation of MHD effects on electrochemical metal depositions. A careful analysis of the governing equations shows that many MHD problems must be treated in a 3D geometry. In most cases there is a complex interplay of natural and magnetically driven convection. 相似文献
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Yu. I. Golovin D. Yu. Golovin A. V. Shuklinov R. A. Stolyarov V. M. Vasyukov 《Technical Physics Letters》2011,37(3):253-255
The process of nickel nanoparticle nucleation and growth during galvanochemical deposition on the surface of multiwalled carbon
nanotubes has been studied. The dependences of the morphology, size, and spacing of nickel nanoparticles on the deposition
time at a current density of 5 and 0.5 A/dm2 are determined. 相似文献
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镍衬底上定向金刚石膜的成核与生长 总被引:2,自引:0,他引:2
提出了一种包括晶粒接种、高温退火、成核、生长四过程的薄膜沉积新方法 ,用射频等离子体增强热丝化学气相沉积系统 ,在Ni衬底上制备了定向金刚石膜。通过对成核和生长两过程工艺条件的研究 ,掌握了提高成核密度和金刚石定向生长规律。实验还表明 ,膜与Ni衬底之间未见Ni C H界面层的形成 相似文献
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Dayong Liu Shan Ren Hui Wu Qingtang Zhang Lishi Wen 《Journal of Materials Science》2008,43(6):1974-1978
Nickel nanoparticles with different morphologies have been synthesized with polyvinylpyrrolidone (PVPK30) as structure-directing
agent through a chemical reduction process. SEM, TEM and selected-area electron diffraction (SAED) were employed in the analysis
of morphological characteristics of nickel nanoparticles. It was found that nickel nanoparticles are formed by the aggregation
of nanoscale nickel crystallites, and particle morphology was strongly dependent on the PVPK30 concentration. In addition,
crystallite size and formation time of nickel nanoparticles increased with the increasing PVPK30 concentration. PVPK30 additive
seems to influence the three steps of nickel particle precipitation: nucleation, crystal growth and aggregation. The resultant
spherical nickel nanoparticles showed high coercivity. 相似文献