复合电镀制节能活性阴极的研究──MmNi5活性阴极的研制

本文报导了采用复合电镀法研究制得一种不含ＲａｎｎｅｙＮｉ的ＭｍＮｉ５活性阴极，研究了各种电镀条件（如镀液ｐＨ值、镀液中粉末浓度、镀液温度、电流密度、粉末颗粒大小等）对ＭｍＮｉ５合金粉电沉积速度及镀层结合力的影响，并对ＭｍＮｉ５粉的电沉积机理进行了探讨：一、采用ＮｉＳＯ４电镀液能制得结合力好且镀层均匀的ＭｍＮｉ５活性阴极。镀液ｐＨ值不但影响ＭｍＮｉ５合金粉的沉积速度，而且影响所得电极的活性，镀液ｐＨ值越小，所得电极的活性越好，一般都比铁阴极放氢电位下降３００ｍＶ左右，这是由于采用ｐＨ值较小的镀液可…     

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。     

活塞环Cu-Sn镀层对球墨铸铁缸套摩擦性能影响

针对高强化工况下活塞环Cu-Sn镀层对珩磨球墨铸铁缸套摩擦磨损性能的影响,采用往复式摩擦磨损试验机,选择单层镀Cr活塞环和多层镀Cu-Sn/Cr活塞环开展摩擦磨损试验,测量摩擦系数和缸套磨损量,分析磨损后的摩擦面形貌和成分.结果表明:相比单层镀Cr活塞环,多层镀Cu-Sn/Cr活塞环与球墨铸铁缸套配对时的摩擦系数和缸套磨损量分别降低2.6%和51.8%;磨损后的缸套表面形貌呈现平坦凸峰,形成了更为平整的平台结构.活塞环Cu-Sn镀层在摩擦磨损过程中会镶嵌到缸套表面,有助于在摩擦表面形成化学反应膜,改善摩擦副微凸体间的接触和摩擦状态,提升球墨铸铁缸套的摩擦磨损性能.     

铸铁表面铬基Cr-MoS_2复合电镀层的摩擦磨损性能

在镀铬电镀液中掺杂具有减摩自润滑作用的二硫化钼微粒,在铸铁活塞环表面制成铬基Cr-MoS2复合电镀层。复合镀的工艺是:MoS2微粒浓度15g/L,温度为40-50℃,搅拌强度130r/min,对应的电流密度15A/dm2,间歇搅拌。数据表明,复合镀层Cr-MoS2与基体结合致密,MoS2在铬基体上分布均匀。复合镀层具有优异的摩擦磨损性能,在相同摩擦条件下,磨损仅为纯镀铬层的1/12,摩擦系数为纯镀铬层的1/2。     

活塞环用复合分散镀层：CPN—200

1 前言 汽油机使用有铅汽油作燃料时,活塞环和气缸等的磨损会增加,这是众所周知的。 作为使用有铅汽油的问题是,除气剂分解产生的酸会使腐蚀磨损增加。活塞环和气缸的磨损增大,其结果是使机油消耗量和窜气量增加。 镀铬对腐蚀、磨粒磨损来说,其耐磨性并不很好。作为对增强腐蚀的对策,并减少对气缸的化学侵蚀,且在高温时具有良好的滑动性,因而开发了“新的表面处理材料”,在此介绍已开发的复合分散镀层CPN-200的活塞环。 (CPN-200活塞环作为行业开发先驱,从1984年起就供应给汽车制造厂,其专利号为№1469529、1605397、1670779等) 另外,CPN-200的抗拉缸性优良,常用于抗拉缸的措施。2 CPN-200的特征 对氮化硅不容性微粒子悬浊在镍、钴、磷化合物的电解液中,经充分搅拌均匀镀在被镀件上,共析镍、钴、磷/氮化硅(Ni-Co-P/Si_3N_4)表面处理,再经过热硬化处理的电解复合镀层。(见图1)。     

影响活塞环复合镀铬层网纹特性的因素研究

本文简要介绍了活塞环复合镀铬技术及其主要性能指标和网纹特性定义,重点分析了影响活塞环复合镀铬层网纹特性的因素,试验表明镀铬槽液成份特别是添加剂的种类和含量、镀液温度和特殊处理方法工艺等是影响网纹特性的最主要因素。     

在小型汽油机上采用梯度功能材料的试验研究

通过试验研究,探讨了陶瓷－金属梯度功能材料对小型汽油机性能的影响。采用等离子化学气相沉积技术在摩托车发动机主要零件上渗镀氮化胡和氮化硅,从而形成了陶瓷－金属梯度功能材料。在试验台架上对镀膜处理前后的发动机进行了性能对比试验及耐久性能试验。外特性对比试验结果表明,四冲程发动机的动力性、燃油消耗率和耐久性能均得到了明显改善。分析结果表明,采用陶瓷－金属梯度功能材料可显改善发动机的耐磨性、润滑性和密封性,从而明显降低发动机的摩擦损失、漏气损失和漏气量。     

活塞环外圆短筒镀铬的镀前处理

1前言为延长活塞环及气缸的寿命,对活塞环的镀铬质量提出了较高要求。镀层与基体的结合强度是镀后质量检查的关键内容。由于活塞环材料成分复杂,适镀性差,致使活塞环的镀铬质量问题长期未得到很好的解决。目前国内一些大型活塞环生产厂家为解决镀铬环的质量问题,引进了国外的镀铬设备与工艺——长筒外圆旋转镀铬工艺与液体喷砂工艺。经过液体喷砂处理的活塞环获得     

内燃机缸套—活塞环混合润滑特性及摩擦力分析

本基于二维Ｒｅｙｎｏｌｄｓ方程分析了缸套－活塞环的润滑特性，并且计算了缸套－活塞环间的摩擦力，考虑了表面粗糙度，微凸体接触以及活塞环装入缸套后的变形等影响因素，结果表明，缸套－活塞环间的油膜厚度沿周向是不均匀的，采用二维Ｒｅｙｎｏｌｄｓ方程可以准确地描述缸套－活塞环的摩擦及润滑特性以及润滑特性沿活塞环周向的变化。     

活塞环铬陶瓷复合镀层参数匹配优化研究

针对某型柴油机运行中发生的拉缸故障的分析显示:国产活塞环工作面铬陶瓷复合镀层中陶瓷颗粒大小、含量及表面粗糙度等参数不合理是造成拉缸故障的主要原因。对上述镀层参数开展了优化匹配研究,并进行平台试验及柴油机试验验证。平台试验结果显示:优化后的活塞环其抗拉缸性能显著提高;柴油机运行200 h试验结果显示:活塞环无明显磨损,气缸套珩磨网纹清晰、完整。表明:优化后的活塞环镀层参数匹配合理,优化后的活塞环可满足该型柴油机的使用要求。     

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.     

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.     

Synergetic catalyst effect of Ni/Pd dual metal coating accelerating hydrogen storage properties of ZrCo alloy

Aimed at enhancing the hydrogen absorption/desorption performances of ZrCo system, Ni/Pd dual metal coating is employed on ZrCo alloy combined with the electroless plating and displacement plating. The effects of Ni/Pd dual metal coating on the microstructure, hydrogen storage performance of ZrCo alloys were investigated systematically. The results show that Ni/Pd dual metal coating deposits on the surface of ZrCo sample successfully with the thickness of 500 nm. The hydrogen absorption kinetic property is substantially enhanced for ZrCo alloy after Ni/Pd dual metal coating, which is owing to the catalytic effect of Ni/Pd coating. Further, the activation energies (E_a) for hydrogen absorption and desorption are calculated using the Arrhenius Equation and Kissinger method, respectively. Compared with the bare ZrCo, the activation energies of the Ni/Pd coated samples for hydriding/dehydriding process decrease which facilitate the hydrogenation/dehydrogenation reaction. This work introduces a rational approach by building new catalytic coating on the hydrogen storage materials to improve the hydriding/dehydriding kinetic performance.     

Enhancement of catalytic properties and durability in Ni–B–P/Ni foam for hydrazine electrooxidation

Hydrazine is a promising energy carrier of high power density, high theoretical cell voltage, and zero carbon emission to replace fossil fuel-dominated energy sources. Herein, we present a new Ni–B–P/NF catalyst for hydrazine electrooxidation by a facile electroless plating process. The Ni–B–P/NF catalyst exhibits remarkable catalytic activity (290 mA cm⁻² at 0.3 V) by combining merits of high intrinsic activity, large specific surface area, satisfactory conductivity, and lattice dislocation. Meanwhile, the Ni–B–P/NF catalyst provides excellent long-term durability (5000 s, 94.4%), which is at the leading level among the reported Ni-based electrocatalysts for hydrazine electrooxidation to date. It is found that the phosphorus-containing coating and its tight binding to the substrate contribute to the long-term durability of Ni–B–P/NF. XPS results and electron models are used to elucidate the electron transition mechanism of the Ni–B–P coating. This work presents a novel catalyst for hydrazine electrooxidation and demonstrates its promising application in energy storage and fuel cell systems.     

Decorating carbon nanotubes with Ni particles using an electroless deposition technique for hydrogen storage applications

A facile and low-cost electroless deposition technique is utilized to decorate multi-walled carbon nanotubes (CNTs) with Ni. The obtained composites are attempted to use as hydrogen storage materials, whose performance is evaluated with a high-pressure microbalance. Effects of the concentration of plating solution, deposition time, and reaction temperature on the loading amount, particle size, morphology, and distribution density of Ni are studied using a transmission electron microscope. With proper deposition parameters, highly dispersed Ni nanoparticles with a uniform diameter can be fabricated on CNTs, causing a notable hydrogen spillover reaction on the composite. The optimum hydrogen storage capacity of the prepared Ni-decorated CNTs with a average diameter of 5 nm, measured at 6.89 MPa and 25 °C, is 1.02 wt%, which is almost three times higher than that (0.35 wt%) of pristine CNTs.     

污染颗粒--活塞环--缸套接触数值研究

运用商用软件ANSYS和自编程序,研究了污染颗粒对活塞环和缸套的影响.在求出了接触时间和润滑油膜对污染颗粒的摩擦力的基础上,分析了污染颗粒对活塞环、缸套所受应力以及对环腔气压的影响.计算结果表明：活塞环和缸套所受的Mises应力受到颗粒速度和它所在相对位置的影响;在不同的接触时刻和速度下的活塞环和缸套所受到的接触应力范围和大小均不同,并可能会出现非连续区域的残余应力.同时也发现,较大的污染颗粒速度有增大接触应力和改变最大接触应力点的作用;随着颗粒浓度和速度的增加,活塞环腔内气压会增加.     

Influence of order in stepwise electroless deposition on anode properties of thick-film electrodes consisting of Si particles coated with Ni and Cu

Nickel and copper were coated on Si particles by a stepwise electroless deposition technique in which the coating orders of the metals were exchanged. Thick-film electrodes for Li-ion batteries were prepared by a gas-deposition method using the coated Si particles, and the anode performance of these electrodes was investigated. For (Cu, Ni)-coated Si particles obtained by primary Cu deposition and successive Ni deposition, Cu and Ni metal layers were individually deposited on the Si particles. In contrast, in case of (Ni, Cu)-coated Si particles prepared by primary Ni deposition, Cu layer stacked on Ni layer owing to a high catalytic activity of Ni, forming a thicker coated layer. The latter electrode exhibited notably improved performance with the discharge capacities over 1000 mAh g⁻¹ maintained until 400th cycle. The layer stack of Cu on Ni is probably effective for a release of a stress from the Si particles during charge-discharge reactions.     

渗浸陶瓷活塞环的磨损特性及应用

仪征六方金属渗浸陶瓷公司运用P-CVD技术,在活塞环表面生成BN-SiN陶瓷薄膜,形貌为网络状基体上均匀分布陶瓷超微粒.渗陶活塞环具有良好的磨损特性,优于非渗陶铸铁活塞环,并在发动机上得到应用,改善发动机的整体性能.