共查询到18条相似文献,搜索用时 171 毫秒
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峰值电流密度对脉冲电沉积Ni-Co-CNTs复合镀层机械性能的影响 总被引:2,自引:0,他引:2
研究了峰值电流密度对脉冲电沉积Ni-Co-CNTs复合镀层机械性能的影响。结果表明:当峰值电流密度升高时,镀层表面变得粗糙;随着峰值电流密度的增加,镀层中碳的质量分数先增加后下降,当峰值电流密度为80 A/dm~2时,镀层中碳的质量分数达到最大值;镀层的显微硬度和抗拉强度均在峰值电流密度为100 A/dm~2附近时达到其最大值,且高于直流电沉积时所得镀层的显微硬度值和抗拉强度值。说明采用脉冲电沉积工艺可以提高镀层的机械性能。 相似文献
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研究了电流密度对汽车用碳素钢上镍-铁合金箔性能的影响。采用X射线衍射仪分析了合金箔的相结构,并计算出平均晶粒尺寸;采用显微硬度计测量了合金箔的硬度,并用称重法对合金箔在室温和高温条件下的耐磨性进行了评定。结果表明:随着电流密度的增大,合金箔中铁元素的质量分数表现为下降的趋势,平均晶粒尺寸表现为增大的趋势,硬度则表现为减小的趋势。在室温和高温条件下,合金箔的磨损量随电流密度的增大表现出相同的变化趋势。当电流密度为1.5~2.5A/dm~2时,合金箔的硬度达到4 300MPa左右,耐磨性较好。 相似文献
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《现代化工》2017,(4)
在络合-超滤处理含镍废水并得到镍离子质量浓度为418 mg/L浓缩液的基础上,考察了电沉积法处理含镍浓缩液过程中电流密度、初始pH、电解时间、温度、极距、搅拌等参数对电流效率和镍回收率的影响。结果表明:当电流密度、电解时间增加时,电流效率随之下降,而镍回收率增大;当pH、极距增大时,电流效率和镍回收率均先增大后减小;温度升高、低速搅拌均可提高电流密度与镍回收率。在电流密度为3.5 m A/cm~2,pH=4,温度为50℃,电解时间为130 min,极距为10 cm并加入低速搅拌的最优操作条件下,电流效率最高可达42%,镍回收率可达52%,并探讨了电沉积机理。 相似文献
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利用离心旋转加热炉研究了超重力对Al-6%Cu合金凝固组织细化及析出相形貌的影响. 结果表明,超重力场可细化晶粒,在常重力条件下(重力系数G=1),初生铝相主要为粗大的等轴晶,晶粒直径为112 mm;在超重力条件下,当G分别为100, 300, 500和700时,晶粒直径分别减小为85, 77, 70和63 mm,晶粒细化,且超重力越大晶粒细化越明显. 超重力场可改善Al2Cu析出相的形貌,有效提高合金性能,G=1时Al2Cu相主要为粗大的不规则块状,合金硬度为59.9 MPa;当G分别为100, 300, 500和700时,Al2Cu相逐渐转变为细小的块状和球状,硬度分别增大为68.4, 73.2, 74.4和74.9 MPa,且超重力越大,Al2Cu相越细小、致密,合金的硬度也越高. 相似文献
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采用氨基磺酸镍镀液作为电铸的研究体系,并在镀液中加入氨基磺酸钴,对镍钴合金电铸层的内应力、组成、硬度、抗拉强度等进行了测试。结果表明,金属在沉积层中的含量与沉积速度有关,沉积速度与交换电流密度有关;当Co2 质量浓度为8 g/L,pH 3.5~4.4,电铸温度50℃,电流密度6 A/dm2时,得到的电铸层硬度为570HV,抗拉强度为1 487 MPa。 相似文献
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The effects of soluble and insoluble anodes upon the composition and mechanical properties of iron-nickel alloy foil of thickness about 0.1 mm have been studied. The soluble materials include stainless steels, main constituents 17.5–19% Cr, 9–11% Ni or 16–18% Cr, 0.5% Ni, and iron-nickel alloys of composition 60% Fe, 40% Ni or 30% Fe, 70% Ni. The performance of these materials is compared with graphite, an insoluble anode. The presence of chromium as a constituent in soluble anodes has an adverse effect on the electroforming process: the current efficiency of metal deposition is reduced, as is the working current density for the production of foil of acceptable quality and with satisfactory mechanical properties. The nickel content of the alloy foil can be increased, and the quality of the foil improved, by using iron-nickel anodes which are free of chromium. 相似文献
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The effects of nickel and cobalt and their interaction with antimony on the electrowinning of zinc from industrial acid sulphate electrolyte were studied using X-ray diffraction, scanning electron microscopy and cyclic voltammetry. Concentrations of cobalt as high as 20 mgl–1 had no effect on the zinc deposition current efficiency. The current efficiency decreased rapidly when the electrolyte contained >5 mgl–1 nickel. Neither cobalt or nickel had an effect on the morphology of the 1-h zinc deposits. Nickel and cobalt caused characteristic changes in the cyclic voltammograms for zinc deposition. As a result this technique might provide a rapid means for evaluating the electrolyte prior to zinc electrowinning. The combined presence of cobalt and antimony in the zinc electrolyte was more deleterious to zinc electrowinning than was the combined presence of nickel and antimony. The presence of 0.08 mgl–1 antimony in the electrolyte counteracted the effect of nickel both on the current efficiency for 1-h deposits and on the zinc deposition polarization curves. 相似文献
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Thomas Baird 《Fuel》1984,63(8):1081-1088
Carbonaceous materials formed in small quantities (?4 mg) on nickel surfaces by pyrolysis of buta-1,3-diene and propene have been characterized by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in conjunction with electron and X-ray diffraction techniques, laser Raman studies, density measurements, hydrogen microanalysis and plasma gasification experiments. The products identified were nickel carbide, a disordered carbon of columnar morphology, a more-ordered laminar material, filamentous carbon and a polymeric species that condensed out as droplets on the nickel foil surface during cooling. The relative amounts of these products were dependent upon the temperature of reaction as measured at the centre of the foil. The different forms of carbonaceous material could be produced simultaneously on the foil surface as a consequence of the temperature gradient along the length of the foil. The formation of carbon on thin crystalline evaporated films of nickel is also described and compared with deposition on the bulk nickel foils. Carbon growth mechanisms are discussed. 相似文献
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The effect of the presence of commercial organic extractants LIX 84I, Cyanex 272, D2EHPA, Versatic 10 and TBP with or without Mg2+ on various electrodeposition parameters for nickel deposition on stainless steel cathode from aqueous sulphate solutions was investigated. The parameters included cathodic current efficiency, deposit morphology, crystal orientation and cathodic polarization. There was no significant variation in the current efficiency in the presence of these additives, but changes were observed in the deposit morphologies and crystal orientations even though all the deposits were bright, smooth and coherent. Changes were also observed in the cathodic polarization behaviour during nickel electrocrystallization in the presence of these additives. The effect of the additives on the electrokinetic parameter, exchange current density (i
0) has also been investigated. 相似文献
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《Carbon》2015
Carbon films were energetically deposited onto copper and nickel foil using a filtered cathodic vacuum arc deposition system. Raman spectroscopy, scanning electron microscopy, transmission electron microscopy and UV–visible spectroscopy showed that graphene films of uniform thickness with up to 10 layers can be deposited onto copper foil at moderate temperatures of 750 °C. The resulting films, which can be prepared at high deposition rates, were comparable to graphene films grown at 1050 °C using chemical vapour deposition (CVD). This difference in growth temperature is attributed to dynamic annealing which occurs as the film grows from the energetic carbon flux. In the case of nickel substrates, it was found that graphene films can also be prepared at moderate substrate temperatures. However much higher carbon doses were required, indicating that the growth mode differs between substrates as observed in CVD grown graphene. The films deposited onto nickel were also highly non uniform in thickness, indicating that the grain structure of the nickel substrate influenced the growth of graphene layers. 相似文献
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采用电泳沉积法在镍片上沉积Co3O4/碳纳米管(CNT)复合膜。利用XRD、SEM和TEM对Co3O4/CNT复合膜进行物性分析,利用循环伏安和恒流充放电测试表征电容性能。研究表明在CNT表面成功包覆了一层Co3O4壳层,形成独特的核/鞘纳米电缆结构。电化学测试表明,Co3O4/CNT复合膜电极具有较好的电容性能,在充放电电流密度为0.5 mA/cm^2时,比电容高达282 F/g;增加电流密度到15 mA/cm2时,比电容为209 F/g,并具有优异的循环稳定性。 相似文献
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B.C. Tripathy S.C. Das P. Singh G.T. Hefter D.M. Muir 《Journal of Applied Electrochemistry》2001,31(5):573-577
The effects of metal ions such as Mg2+, Li+, Na+ and K+ on the cathodic current efficiency, deposit morphology, crystallographic orientation and polarization behaviour during nickel deposition on stainless steel from aqueous sulfate solutions containing boric acid were investigated. There was virtually no change in current efficiency in presence of these metal ions, but changes were observed in the deposit morphologies and crystal orientations even though all the deposits looked bright, smooth and coherent. Changes were also observed in the polarization behaviour during nickel electrocrystallization in presence and absence of boric acid. An attempt has been made to correlate the effect of these metal ions on various parameters studied. 相似文献