化学镀Ni_P合金镀层对铁细菌微生物污垢的影响

针对化学镀Ni-P合金镀层对换热设备表面常见微生物污垢的影响问题,扩大化学镀层应用范围。通过调整化学镀液工艺制备出多种不同特性的镀层表面,计算了试样的表面能,研究乳酸浓度对镀速及表面能带来的影响;将试样置于OD(光密度)值一定的菌悬液中进行为期5~7天的静置实验,分析镀层表面微生物污垢实验前后宏观和微观形貌,以普通碳钢试样作为对照,研究镀层试样表面能和镀层表面失重量的关联。在实验工艺范围内,制备的镀层表面光滑致密,镀速和镀层试样的表面能均随着乳酸含量的增加而减小;在静置实验结束后,普通碳钢试样表面附着微生物污垢较多,在一个微生物生命周期内,碳钢表面受微生物腐蚀质量呈现逐渐下降的趋势;镀层表面则仍呈金属光泽,质量变化不大,且镀层在微生物污垢实验前后微观形貌变化较小,展现了较好的抗垢效果和耐蚀性;在所制备的镀层试样中,低表面能的镀层试样表面腐蚀失重量最小。制备的Ni-P合金镀层表面可以有效抑制或减轻微生物污垢,其低表面能和表面分布Ni-P非晶结构有效抵抗了微生物污垢生长和腐蚀。     

Ni-Zn-P镀层在黏液形成菌中的结垢和腐蚀特性

利用化学镀层对换热面常用的碳钢材料进行表面改性,得到晶胞细致的Ni-Zn-P镀层。将得到的Ni-Zn-P试样与碳钢试样、Ni-P试样进行比较。在黏液形成菌菌悬液中进行微生物污垢和腐蚀实验,进而分析3种试样的抗微生物污垢特性和腐蚀特性。利用称重法记录3种试样的污垢沉积变化情况和光电比浊法记录黏液形成菌的生长情况。利用扫描电镜观察试样在污垢静置实验后的表面形貌,分析比较实验前后表面形貌的变化。利用电化学方法研究试样在黏液形成菌菌悬液中的腐蚀情况。实验结果表明,Ni-Zn-P镀层抗微生物污垢特性和耐腐蚀性稍好于Ni-P镀层,Ni-Zn-P镀层表面微生物污垢附着量相较于Ni-P镀层和碳钢分别减小24.1%和67.7%,Ni-Zn-P镀层表面腐蚀失重量相较于Ni-P镀层和碳钢分别减小5%和84.6%。由于Ni-Zn-P镀层的保护,碳钢表面抗微生物污垢特性和耐腐蚀性得到明显提高。     

应用于太阳电池的单晶硅上化学镀镍工艺

研究了在P型单晶硅上扩散的N区发射极上选择性化学镀镍工艺,获得了较为优化的化学镀工艺过程,得到了均匀致密的镀层。其中针对单晶硅表面的特点,采取了浓酸浸泡和HF处理以及氯化钯的活化方法,使得镀层质量得以提高。进行了合金化处理温度对合金层的电阻率影响的研究,结果发现在N_2气氛下330℃的热处理将会促进具有最低方块电阻的Ni-Si合金的形成。在方块电阻为45Ω/□的发射极上,化学镀后得到了方块电阻为2Ω/□的Ni-Si合金层。     

Ni-P催化硼氢化钠水解制氢性能研究

文章通过化学镀法成功制备了Ni-P催化剂,并考察了施镀温度以及还原剂浓度对硼氢化钠水解制氢性能的影响。结果表明:试验中Ni-P催化剂的最优制备条件为施镀温度为50℃,还原剂浓度为0.8 mol/L;此条件下制备的Ni-P催化剂催化硼氢化钠水解放氢的速率为639.7 m L/(min·g),活化能为44.5 k J/mol。     

滑动轴承镀层退除工艺的介绍与应用

内燃机的滑动轴承铅、锡、铜三元合金镀层由于种种原因部分不合格需返修而退除镀层。常见的镀层镗除法不能将镀层镗干净且满足不了技术要求,现改用电化学法能有效地退除铅基三元合金镀层。本文还介绍了退除液的配方及操作要求和它们的相互作用与影响。     

Ni-P-BC复合镀层在内燃机上的应用

本文主要研究化学复合镀层在内燃机缸套和活塞环上的应用,在试验过程中摸索出了化学镀的最佳工艺,并且通过对试样不同温度的热处理在MM-200型磨损试验机上观察其磨损情况,本试验结果定将为生产活塞缸套提供重要参考.     

用感应加热技术对带钢镀锌层进行退火（英）

镀锌层退火工艺指的是镀锌带钢离开镀锌锅和镀层厚度控制系统后立即进行再加热,以便使锌铁合金化持续足够长的时间,从而使铁扩散到锌和整个镀层表面。 镀层将因此从纯锌变为均匀的锌—铁合金,这种合金为以后的加工提供了极好的特     

Ni—P—BC复合镀层在内燃机上的应用

本文主要研究化学复合镀层在内燃机缸套和活塞环上的应用，在试验过程中摸索出了化学镀的最佳工艺，并且通过对试样不同温度的热处理在MM-200型磨损试验机上观察其磨损情况，本试验结果定将为生产活塞缸套提供重要参考。     

铜铅轴承合金的金相组织对镀层的影响

为了使从PbsnCu镀层中向铜铅合金层扩散损失的锡减至最少,多数镀层铜铅发动机轴承的镀层下面都有一镍栅层.发动机运转中,大功率发动机曲轴轴承表面承受着较高的动载荷,往往会造成合金层表面铅相上镍栅层破裂,可引起镀层中锡向铜铅合金层扩散,使之锡量减少,导致镀层性能下降.粗大的铅很象似一个裂缝.一种改进的烧结工艺方法有缩小铅相尺寸的效果,并对新的CuPb14Sn3.5合金特别有效.其结果减少了镍栅破裂的频次,可改善镀层在发动机中长期使用的性能.     

国外新型的减摩镀层

用于内燃机滑动轴承的减摩镀层,近年来国外倾向于使用多层镀层及多元镀层。1 多层镀层 据报道,日本近来使用如下镀层:先在铜合金或铝合金衬层上镀1～2μn厚的镍栅;再在镍栅上镀一层含Pb量为63％～82％（重量百分比,以下皆同）,含Sn量为15％～30％,含Cu量为3％～7％的较硬的三元合金,最后再在较硬的三元合金镀层上镀一层含Pb量为85％～90％,含Sn量为8％～12％,含Cu量为2％—3％的较软的三元合金镀层。     

提高摩托车链条耐磨性的试验研究

将纳米技术这一新兴科学应用于摩托车滚子链这一传统机械元件上。将销轴外表面纳米化,套筒内表面进行N i-P化学镀处理,组装成链条,进行了链条磨损性能实验。实验研究表明,这两种表面处理的组合可以进一步提高滚子链的耐磨性。     

Effect of surface treatments on microstructure and electrochemical properties of La–Ni–Al hydrogen storage alloy

Surface treatment by the fluorination treatment with an aqueous solution of KF and HF with a little addition of KBH₄ followed by electroless Ni–P plating has been carried out to modify the surface structure and electrochemical properties of the La–Ni–Al hydrogen storage alloy. The results of scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) show that a Ni-rich and Al-poor layer forms after fluorination treatment. The electroless plating results in the precipitation of the nanometer-scale Ni–P particles with homogeneous distribution on the alloy surface. Both the treatments contribute to an increase in exchange current density, a decrease in charge-transfer resistance and the facility of hydrogen diffusion within the bulk alloy, leading to significant improvements on high rate dischargeability (HRD) of the alloy. The alloy treated by the composite treatment of the fluorination treatment and the following electroless plating possesses best overall electrode performance.     

曲轴铁基合金镀铁再制造技术工艺应用研究

针对曲轴铁基合金镀铁再制造技术,从铁基合金镀铁液的合金成分含量的控制、电控参数的选取、工艺流程的制定等几方面详细介绍了该项技术的实现。试验和实际运用表明:采用该项技术修复的曲轴质量不低于新品,已获得船级社认可;在节约资源的同时取得了较大的经济效益。     

High-rate discharge characteristics of metal hydride modified by electroless nickel plating based on experimental design approach

In this study, a metal hydride (MH) alloy (MmNi_3.81Mn_0.41Al_0.19Co_0.76) is modified by electroless nickel plating with the controlled variables of plating time (A), temperature (B), amount of MH alloy (C), pH (D), concentration of reducing agent (NaH₂PO₂·H₂O) (E), and complex agent (Na₃C₆H₅O₇·2H₂O) (F). Based on the two-level orthogonal array strategy, the Ni loadings on the modified MH alloy of −20.25–11.83% are strongly affected by the variables of A, D, E, and F, as well as the two-factor interactions of AB, AC, AD, BD, and EF. The utility of the unmodified MH alloy used as the negative electrode material of the Ni–MH battery decreases from 100.6 to 7.6% when increasing the discharge rate from 0.2 to 10 C. The utility at the discharge rate of 10 C can be increased to 54.5% for the MH alloy modified by electroless plating Ni when the plating time, temperature, amount of MH, pH, and concentrations of the reducing agent and complex agent are equal to 10 min, 70 °C, 2 g, 7.0, 15 g L⁻¹, and 30 g L⁻¹, respectively.     

Effects of surface coating with Cu-Pd on electrochemical properties of A2B7- type hydrogen storage alloy

La_0.75Mg_0.25Ni_3.2Co_0.2Al_0.1 hydrogen storage alloy, the nickel-metal hydride (MH/Ni) secondary battery negative electrode, was modified by CuSO₄ solution (3 wt% in Cu in contrast with alloy weight) and PdCl₂ solution varied from 1 wt% to 4 wt% in Pd in contrast with alloy weight with a simplified pollution-free replacement plating method, aiming at improving its comprehensive electrochemical properties. The XRD analysis and SEM images combined with EDS results reveal that Cu and Pd nanoparticles are uniformly plated on the pristine alloy surface. The relative amount of Pd on the Cu-Pd coated alloy surface increases notably as the PdCl₂ concentration increases in the plating solution. Electrochemical tests indicate that alloy electrodes modified by Cu-Pd composite coating show perfect activation performance, which achieve the maximum discharge capacity at the first charge-discharge cycle. Moreover, alloy electrodes coated with Cu-Pd perform dramatically enhanced high rate dischargeability (HRD). The enhancement increases firstly and then decreases as the content of Pd increases in the Cu-Pd coating. Meanwhile, the cycle life of modified alloys is also improved significantly. Among all the samples, the Cu-Pd coated alloy with 3 wt% Pd content in the PdCl₂ solution reinforces the comprehensive electrochemical properties most sufficiently, with dischargeability of 86.4% under 1500 mA/g and remaining capacity of 82.7% after 100 cycles.     

Electrodeposition of nickel–copper alloys to use as a cathode for hydrogen evolution in an alkaline media

The electrocatalytic activity of nickel–copper (Ni–Cu) alloy coated electrodes for the hydrogen evolution reaction (HER) in an alkaline media was studied. The Ni–Cu alloys were electrodeposited on a Cu substrate by direct current (DC) and pulse current (PC) electrodeposition in a fixed plating bath. A wide alloy composition range (6–81 mol% Ni) was achieved by controlling the applied current density between 5 and 300 mA cm⁻². It was found that the electrocatalytic activity for the HER depended on the composition of the Ni–Cu alloys, where electrodes having low Ni content gave high electrocatalytic activities. DC electrodeposition resulted in better electrocatalytic performances than PC. Pulse plating parameters other than the magnitude of the applied current density did not substantially influence the electrocatalytic performance of the Ni–Cu alloy electrodes. Ni content was found to have a stronger effect on the electrocatalytic activity for the HER than the deposit morphology.     

Effect of electroless coating of Cu,Ni and Pd on ZrMn0.2V0.2Fe0.8Ni0.8 alloy used as anodes in Ni-MH batteries

In order to improve the electrochemical performance, the alloy represented by the composition ZrMn_0.2V_0.2Fe_0.8Ni_0.8 was microencapsulated with Cu, Ni and Pd. Microencapsulation was done prior to test electrode preparation by electroless plating method. The electrode characteristics such as electrochemical capacity and cycle life were studied for the uncoated and coated alloys. It was found that the coated alloy showed higher discharge capacity and lower activation time in comparison to the uncoated alloy. The phase composition of the alloys was characterized using X-ray diffraction (XRD) and surface morphology was studied using scanning electron microscope (SEM). It was found that the surface microencapsulation of alloy powder was effective in improving the electrode discharge capacity and in reducing the activation time.     

Investigation of corrosion properties with Ni–P/TiNO coating on aluminum alloy bipolar plates in proton exchange membrane fuel cell

Aluminum alloy bipolar plates have unique application potential in proton exchange membrane fuel cell (PEMFC) due to the characteristics of lightweight and low cost. However, extreme susceptibility to corrosion in PEMFC operation condition limits the application. To promote the corrosion resistance of aluminum alloy bipolar plates, a Ni–P/TiNO coating was prepared by electroless plating and closed field unbalanced magnetron sputter ion plating (CFUMSIP) technology on the 6061 Al substrate. The research results show that Ni–P interlayer improves the deposition effect of TiNO outer layer and increase the content of TiN and TiO_xN_y phases. Compared to Ni–P and TiNO single-layer coatings, the Ni–P/TiNO coating samples exhibited the lowest current density value of (1.10 ± 0.02) × 10^?6 A·cm^?2 in simulated PEMFC cathode environment. Additionally, potential cyclic polarization measurements were carried out aiming to evaluate the durability of the aluminum alloy bipolar plate during the PEMFC start-up/shut-up process. The results illustrate that the Ni–P/TiNO coating samples exhibit excellent stability and corrosion resistance.