Ni-P-纳米TiO2化学复合镀层的制备

采用化学复合镀在40CrNi钢基体上制备Ni-P-纳米TiO2复合镀层,研究了乳酸,柠檬酸、乙酸钠以及表面活性剂对镀层的沉积速度和显微硬度的影响,并通过正交试验,优化了工艺参数。结果表明:当乳酸的体积分数为3%、柠檬酸的质量浓度为25 g/L、乙酸钠的质量浓度为20 g/L、表面活性剂为阴离子型时,镀层具有优良的性能,镀速达到了11.55μm/h,镀层镀态显微硬度为550 HV。     

TC4钛合金低磷化学镀工艺研究

针对TC4钛合金低磷化学镀,在浸锌活化和乳酸-乙酸络合条件下,对镍磷质量浓度比、温度、pH值、乙酸、乳酸等工艺因素对镀速和镀层磷含量的影响进行系列实验研究。用扫描电镜、能谱仪、显微硬度仪、X射线衍射仪对镀层的表面形貌、硬度和物相进行表征。研究结果表明：提高镍磷质量浓度比、温度、pH值,控制络合剂乳酸在20g/L～22g/L,乙酸在19g/L～20g/L范围内,均有利于低磷镀层的形成,平均镀速为25.6μm/h;镀层为晶态的Ni-P过饱和固溶体,平均粒径10μm,磷含量为2.56wt%,硬度为750.2HV.     

无热处理高硬度高耐磨性化学镀镍磷合金

研究了一种无需后续热处理且具有高硬度、高耐磨性的化学镀镍磷合金镀层.采用乳酸和乙酸钠作为络合剂，在理论上完全络合镍离子的前提下，通过改变化学镀镍溶液中乳酸和乙酸钠之间的比例，研究了镀速、镀层表面显微硬度以及镀层耐磨性的变化情况,结果表明,随着乳酸比例的增加，镀速出现先升高后下降的现象，并在n(乳酸提供的配位原子)：n(乙酸钠提供的配位原子)为4∶6时，镀速达到最大值，由此溶液得到的镀层，其表面显微硬度在热处理前达到了HV820，且镀层表面平整、致密，具有很高的耐磨性.     

Ni-P/Al_2O_3复合镀层性能的表征与测试

为了提高镀层的耐磨性和硬度,在45碳钢基材上实施Ni-P/Al2O3化学复合镀,使纳米Al2O3微粒均匀分布于Ni-P基体中.研究了化学复合镀工艺条件和镀液组分对镀层性能的影响.镀件的耐蚀性实验和XRD分析表明:当硫酸镍25 g/L,次亚磷酸钠30 g/L,纳米Al2O3微粒加入量为5 g/L,乳酸20 mL/L和柠檬酸5 g/L,在pH=5.5,施镀温度为(85±2)℃,获得的Ni-P/Al2O3复合镀层表面光滑、胞状物致密,镀层的耐腐蚀性较高、硬度可达600HV,有利于得到综合性能较高的镀层.     

超微金刚石对Ni-P化学复合镀层性能的影响

为改善Ni-P化学镀层的性能,采用化学复合镀的方法在镀层中添加了爆轰合成超微金刚石(Ul-trafine Diamond,UFD).研究了复合镀层的形成机理及镀液中UFD含量对复合镀层显微硬度及耐磨性的影响规律.实验用UFD众数粒径为114.6 nm.镀层显微硬度采用国产71型显微硬度仪进行检测,耐磨性采用国产MM200型磨损试验机进行检测.结果表明:随着镀液中UFD的加入,Ni-P合金粒子会以UFD颗粒为核心形成硬度较高的"包覆球"."包覆球"沉积到镀件表面形成复合镀层.复合镀层的显微硬度及耐磨性均随镀液中UFD含量的不同呈规律性变化.与Ni-P化学镀层相比,当镀液中UFD含量为0.8 g/L时,复合镀层显微硬度可提高0.6倍;当镀液中UFD含量为1.0 g/L时,复合镀层耐磨性可提高4.8倍.     

化学镀液中NiSO4·6H2O浓度对镀速及镀层硬度的影响

在TC4钛合金表面制备了Ni-P低磷化学镀层,研究了镀液中NiSO4·6H2O浓度对镀层沉积速度及镀层硬度的影响.采用紫外可见光分光光度计、扫描电镜及能谱仪、显微硬度仪分别对镀液中的NiSO4·6H2O浓度,镀层的表面形貌和化学成分,镀层的硬度进行测定.结果表明:化学镀液最佳施镀周期为60min.镀液中NiSO4·6H2O浓度对化学反应速率有重要影响,当浓度差达到临界值4.77g/L,沉积速度显著降低.随着反应进行,晶胞尺寸逐渐增大,晶粒粗化;同时镀层磷含量逐渐升高,镀层结构由晶态向微晶态转化,塑性变形抗力降低,硬度降低.     

Ni-SiC纳米复合电镀工艺研究

针对镀液中阴极电流密度、镀液温度以及极板间距,对Ni-SiC纳米复合镀层显微硬度的影响进行了研究.采用正交实验法对各工艺参数进行了优选.并且利用扫描电镜（SEM）对复合镀层的表面形貌及截面形貌进行了观察和分析.结果表明,Ni-SiC纳米复合镀层较纯镍镀层表面平整光滑,显微组织均匀、致密,并且其显微硬度也有明显提高.     

Ni-SiO2复合镀层组织和性能的研究

应用电刷镀技术在45钢表面制备含有微米SiO2的镍基复合镀层,研究了复合镀层表面形貌,测试了镀层的显微硬度和摩擦磨损性能,分析了微米陶瓷颗粒沉积量对镀层摩擦磨损性能的影响.实验结果表明,微米陶瓷颗粒复合镀层较快速镍镀层具有更高的显微硬度和良好的耐磨性.     

添加碳化硼镀铁工艺的优化

为提高镀铁层的硬度和耐磨性,采用了正交实验的方法研究了镀液中碳化硼的浓度、粒度和氯化亚铁的浓度对镀层硬度及耐磨性的影响。结果表明:影响镀铁层耐磨性的因素主次顺序为:B4C浓度B4C颗粒度FeCl2·4H2O浓度;镀铁工艺的优水平为B4C颗粒度1200目、B4C浓度30g/L、FeCl2·4H2O浓度350g/L;影响镀层显微硬度的因素主次顺序为B4C浓度B4C颗粒度FeCl2·4H2O浓度。     

铜/镍磷合金复合镀涤纶电磁屏蔽织物的制备

在化学镀铜涤纶织物表面电镀镍磷合金,制备铜/镍磷复合镀电磁屏蔽织物,研究了硫酸镍浓度、氯化镍浓度和亚磷酸浓度对复合镀织物性能的影响.结果表明,电镀镍磷合金工艺为:硫酸镍浓度240 g/L,氯化镍浓度40 g/L,亚磷酸浓度30 g/L,制备的铜/镍磷复合镀织物表面镀层均匀致密,在300 k~3 000 MHz电磁屏蔽效能在90 dB以上,具有优异的电磁屏蔽效能、抗氧化性和耐蚀性.     

Electroless copper-phosphorus coatings with the addition of silicon carbide （SiC） particles

Cu-P-silicon carbide(SiC)composite coatings were deposited by means of electroless plating.The effects ofpH values,temperature,and different concentrations of sodium hypophosphite(NaH2PO2·H2O),nickel sulfate(NiSO4·6H2O),sodium citrate(C6H5Na3O7·2H2O)and SiC on the deposition rate and coating compositions were evaluated,and the bath formulation for Cu-P-SiC composite coatings was optimised.The coating compositions were determined using energy-dispersive X-ray analysis(EDX).The corresponding optimal operating parameters for depositing Cu-P-SiC are as follows:pH 9; temperature,90℃; NaH2PO2·H2O concentration,125 g/L; NiSO4·6H2O concentration,3.125 g/L; SiC concentration,5 g/L; and C6H5Na3O7·2H2O concentration,50 g/L.The surface morphology of the coatings analysed by scanning electron microscopy(SEM)shows that Cu particles are uniformly distributed.The hardness and wear resistance of Cu-P composite coatings are improved with the addition of SiC particles and increase with the increase of SiC content.     

Preparation of copper-coated fine molybdenum powders with electroless technique

The molybdenum powders with average particle size of 3 μm were coated with copper by electroless plating. The influence of pretreatment,solution composition and plating conditions on electroless copper plating was studied. The copper-coated molybdenum powders were examined by SEM and XRD. Results indicate that a series of optimization methods is used to add activated sites before electroless copper plating. Taking TEA and EDTA as chief and assistant complex agents respectively,2,2’-bipyridyl and PEG as double stabilizers,the Mo powders are coated with copper successfully with little Cu2O contained,at the same time,Mo-Cu composite powders with copper content of 15-85 wt% can be obtained. The optimal values of pH,temperature and HCHO concentration are 12-13,60-65 ℃ and 22-26 mL/L,respectively.     

硫酸锌糖浆稳定性的研究

为解决硫酸锌糖浆贮存期间稳定性下降的问题,以一水枸橼酸—二水枸橼酸钠缓冲液作为硫酸锌糖浆的稳定剂,研究了两者不同的质量浓度比例、质量浓度总量对硫酸锌糖浆pH值稳定的效果,确定加有一水枸橼酸（质量浓度为0.35 g/L）和二水枸缘酸钠（质量浓度为3.15 g/L）缓冲溶液的硫酸锌糖浆,720 d的效期内pH值下降了6.8%,未加pH稳定剂的硫酸锌糖浆pH值720 d的效期内下降了44%,差异显著;结果表明1L硫酸锌糖浆溶液中,一水枸橼酸质量浓度∶二水枸缘酸钠质量浓度=1∶3,两者质量浓度总量为3.5 g/L的缓冲溶液,可明显提高硫酸锌糖浆pH值的效果较好,产品品质得到很的提升     

Mechanism and Microstructure of Electroless Ni-Fe-P Plating on CNTs

Electroless Ni-Fe-P alloy plating on the surface of CNTs was carded out with a bath using citrate salt and lactic acid as complex agents. We proposed a chemical reaction mechanism. The morphology, structure and chemical composition of the Ni-Fe-P/CNTs were studied with the aid of a scanning electronic microscope （SEM）, X-ray diffraction （XRD） and an energy-dispersive X-ray spectral analysis （EDS）. The results show that through a correct pre-treatment and electroless plating, Ni-Fe-P/CNTs composite particles can be obtained. The optimum electroless plating parameters of 35-42℃ and pH of 8.5-9.7 were achieved. The as-plated Ni-Fe-P alloy is amorphous. After a heat treatment at 500℃ for 90 min in H2, the coating is transformed into crystalloid Ni3E Fe2NiP and （Fe,Ni）3R The Ni-Fe-P alloy coating on the surface of CNTs is smooth and unique. The amount of Ni on the surface （mass fraction） of the Ni-Fe-P/CNTs composite particles is 29.13%, that of Fe 3.19% and that of P 2.28%.     

Fabrication of W@Cu composite powders by direct electroless plating using a dripping method

A direct electroless copper (Cu) coating on tungsten powders method requiring no surface treatment or stabilizing agent and using glyoxylic acid (C₂H₂O₃) as a reducing agent was reported. The effects of copper sulfate concentration and the pH of the plating solution on the properties of the prepared W@Cu composite powders were assessed. The content of Cu in the composite powders was controlled by adjusting the concentration of copper sulfate in the electroless plating solution. A uniform, dense, and consistent Cu coating was obtained under the established optimum conditions (flow rate of C₂H₂O₃ = 5.01 mL/min, solution pH = 12.25 and reaction temperature 45.35 °C) by using central composite design method. In addition, the crystalline Cu coating was evenly dispersed within the W@Cu composite powders and Cu element in the coating existed as Cu0. The formation mechanism for the W@Cu composite powders by electroless plating in the absence of surface treatment and stabilizing agent was also proposed.     

The linear regression method for improving magnetic parameter of the electroless CoFeB films

The kinetics equation of deposition rate was implemented to help explain some of the mechanisms responsible for structures observed during the deposition of CoFeB films on poly-ester plastic. The plating rate of electroless CoFeB films is a function of concentration of sodium tetrahydroborate, pH of the plating bath, plating temperature and the metallic ratio. The estimated regression coefficient, confidence interval, residual error and confidence interval were confirmed by computer program. The optimal composition of the plating bath was obtained and the dynamic electromagnetic parameters of films were measured in the 2-10 GHz range. At 2 GHz, the permeability, magnetic loss of the electroless CoFeB films were 304,76.6 respectively as the concentration of reducer is 1 g·L^-1.     

镁合金化学镀及其添加剂研究

精选镁合金化学镀的前处理工艺和镀镍液配方,根据该工艺得到的镀层试验检测表明:该合金具有耐腐蚀性强、硬度高、结构致密、光泽性好,且有一定延展性;并通过实验比较了4种添加剂对镁合金化学镀镀速及镀液稳定性的影响,实验结果表明,钇和铕对镀液的稳定性影响较大,氟化铵和碳酸钠对镀速的影响较为显著,尤其是添加的Y3 浓度为0.02 g/L时,镀液的稳定性提高最多,而碳酸钠在19 g/L左右时加速作用最为明显.文中并分析了它们的影响机理.