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.     

涤纶织物化学镀镍铜合金研究

采用化学镀技术,实现了涤纶织物表面镍铜合金镀,借助SEM、EDX对镀层表面形貌、成份进行了分析,并对化学镀织物的电磁波屏蔽效能、表面比电阻和拉伸性能进行了测试。结果表明,随着增重率的增加,电磁波屏蔽效能开始时增加较快,后又趋于平缓,当增重率基本接近时,屏蔽效能主要受金属镀层成份和致密性的影响。表面比电阻随着增重率的增加而减小。化学镀织物的拉伸曲线同时具有金属和纤维的拉伸特性,主要受金属镀层厚度的影响。     

钡铁氧体表面化学镀Ni-P合金的制备及性能

为提高钡铁氧体的吸波性能,以钡铁氧体为芯材,采用化学镀的方法制备表面包覆Ni-P镀层的钡铁氧体复合粒子.并利用XRD、SEM、EDS及矢量网络分析仪对其晶体结构、表面形貌、成分、电磁吸收性能进行分析.结果表明:钡铁氧体表面包覆完整的Ni-P合金镀层,化学镀工艺显著改善材料的电磁性能,并提高材料对电磁波的吸收能力,镀后复合粒子在2～18GHz频段内,最大反射率为-24.3dB,大于-10dB的吸收频带宽约2.8GHz.     

模板法空心金属微球的制备与表征

以空心玻璃微球作为模板,利用化学镀技术分别在模板表面沉积了一定厚度的铜和镍钴硼涂层,采用碱液溶解法去除模板,成功制备了具有薄壳结构的空心金属微球。分别利用SEM、TEM和XRD等手段对产物进行了表征。     

化学镀蜘蛛丝模板法制备金属微管

研究了以天然蜘蛛丝为模板,利用化学镀工艺制备金属微管的方法。该方法包括模板的预处理、化学镀、去模板以及还原处理。观察不同阶段的产物表面形貌,分析中间产物的热性能,并对镍磷镀层和终产物成分进行了表征。结果表明,利用天然蜘蛛丝为模板通过化学镀的方法可以制备出具有极大长径比的金属微管。     

铜粉表面化学镀银及表征

铜-银复合粉末具有良好的抗氧化性、热稳定性及高电导性,在电子浆料、导电填料等众多领域具有广阔的应用前景.利用化学镀的方法,采用氯化亚锡为敏化剂,甲醛为还原剂,合成了用于电子浆料的铜-银复合粉末.用X射线衍射、扫描电镜表征了复合粒子的晶型和形貌结构,研究了敏化剂氯化亚锡、反应温度、还原剂及镀液的pH值对材料晶型和形貌的影响.结果表明：采用甲醛为还原剂,经过敏化处理后,当镀液pH值为10时,在50℃下,合成的银包铜粉电接触材料有较好的形貌.     

Growth behavior of electroless copper on silicon substrate

The growth behavior containing deposit morphology, growth rate, activation energy, and growth mechanism of copper on silicon substrate, especially at the initial stage, in the electroless plating process was studied. Copper was deposited on the surface of the silicon substrate in an electloless plating bath containing formalin （CH2O 37vol%） as a reducing agent at a pH value of 12.5 and a temperature of 50-75℃. The copper deposit was characterized using a field emission scanning electron microscope and transmission electron microscope. The results showed that after the activation process, nanoscale Pd particles were distributed evenly on the surface of the silicon; in the deposition process, copper first nucleated at locations not only near the Pd particles but also between the Pd particles; the growth rate of electroless Cu ranged from 0.517 nm/s at 50℃ to 1.929 nm/s at 75℃. The activation energy of electroless Cu on Si was 52.97 kJ/mol.     

织物化学镀铜与化学镀镍孰优研究

适于织物化学镀的金属是铜和锋，孰优？通过对化学镀银织物的和化学镀镍织物的质量对比，并对化学投铜和化学镀镍的工艺、生产成本和环保进行分析比较，得出织物化学镀铜优于化学镀镍的结论。     

Preparation of core-shell Cu-Ag bimetallic powder via electroless coating

A novel method of electroless silver coating on copper powders was reported, in which hydrazine was used as the reducing agent, and had some advantages such was used as inhibiting the substitution reaction and reducing consumption of copper powders. In the processes of sensitization and activation, AgNO₃ replaces the conventional PdCl₂, which solves the impurity of bath. Oxide film on the surface of copper powders was tested by chemical analysis. Ag element tested by XRD and XRF is in the form of Ag⁰ and exists on the surface of copper powders, which acts as catalyzer in reduction reaction. Morphology and composition of the coating were characterized by SEM and XRD respectively. Funded by the National Natural Science Foundation of China(50474047)     

Research on Surface Modification of 96 Al2O3 by Ni Ion Implantation

A matrix of 96 Al2O3 ceramics was implanted with Ni ion of different dosages and energies using a MEVVA implanter. Then metallic structures of copper were made on the implanted ceramics, by using selective electroless copper plating. In addition, the characteristics and microstructure of the implanted layer were studied by using the SEM, RBS and XPS. The results show that： 1） the implanted Ni exits as Ni^2, Ni^2＋, and Ni^3＋ in the surface of Al2O3 and metal Ni particles precipitate on ceramics during implantation; 2） the concentration of Ni submits to the Gauss distribution along the direction of implantation on the surface of Al2O3 and high Ni concentration on the surface can be obtained if the Ni is implanted with low energy and a high dosage and 3） Ni ion implantation can activate the surface of Al2O3 and induce electroless copper plating on the ceramics.     

兼容性Cu2+溶液改性EP基材催化铜导电线路沉积

印制电路板(PCB)基材预设位置活化是选择性化学镀铜法制作导电线路的关键工艺。以乙酸铜为催化剂前驱体、硫脲为络合剂、双酚A二缩水甘油醚为环氧树脂(EP)预聚物、试剂593为固化剂和丙二醇甲醚为溶剂,设计出一种基于EP兼容的Cu2+溶液,借助喷墨打印机把兼容性Cu2+溶液印刷在EP基材表面,采用选择性化学镀铜法加成制备了铜导电线路。基于量子化学密度泛函理论,模拟兼容性Cu2+溶液中硫脲分子与Cu2+之间的络合反应,利用红外光谱和拉曼光谱对兼容性Cu2+溶液中特殊官能团进行表征。结果表明:铜线路中晶粒结晶度良好且堆积致密,其电阻率低至2.62×10?6 Ω·cm;在改性层的帮助下,铜线路与EP基材之间的结合力达到5B级别。因此,EP基材兼容性改性催化铜导电线路沉积具有工艺简单、经济环保的优点,这对其他常用树脂基材兼容性改性加成制备PCB具有一定的参考价值。     

Electromagnetic Interference Shielding Properties of Electroless Nickel-coated Carbon Fiber Paper Reinforced Epoxy Composites

Carbon fibers(CFs) were coated with a nickel-phosphorus(Ni-P) film using an electroless plating process. The morphology, elemental composition and phases in the coating layer of the CFs were investigated by scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and X-ray diffraction(XRD), respectively. Wet paper-making method was used to prepare nickle coated carbon fiber paper(NCFP). Vacuum assisted infusion molding process(VAIMP) was employed to manufacture the NCFP reinforced epoxy composites, and carbon fiber paper(CFP) reinforced epoxy composites were also produced as a comparison. Electromagnetic interference(EMI) shielding properties of the composites were measured in the 3.22-4.9 GHz frequency range using waveguide method. Both NCFP and CFP reinforced epoxy composites of 0.5 mm thickness exhibited high EMI shielding effectiveness(SE) at 8wt% fiber content, 35 d B and 30 d B, respectively, and reflection was the dominant shielding mechanism.     

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.     

超细ATC陶瓷制备及其干滑动磨损研究

为提高陶瓷刀具材料的耐磨性能和断裂韧性，制备新型超细Al2O3-TiC-8%Co（ATC）陶瓷样品.采用低温化学镀方法对亚微米级Al2O3和TiC粉末表面进行金属钴包覆，热压烧结复合粉体制备该ATC样品.在销盘式磨损试验机上对ATC陶瓷的耐磨性能进行考察，采用SEM对ATC陶瓷的磨损形貌进行分析.结果表明，干滑动摩擦条件下，断裂韧性对陶瓷材料耐磨性能的影响非常明显.各摩擦副磨损过程中，随磨损时间延长ATC陶瓷样品表面微细突起脱落，磨损面趋于平滑，相对磨损率降低.金属钴的独特复合方式抑制了烧结过程中晶粒长大,并增大ATC陶瓷的断裂韧性和耐磨性能.     

化学镀Ni-P-WC复合镀层的微观结构研究

采用化学镀方法制备了Ni-P-WC复合镀层,并通过扫描电子显微镜的二次电子和背散射电子成像模式以及特征X射线衍射研究了该复合镀层的微观形貌和元素组成及含量。实验结果表明：在Ni-P-WC复合镀层中,纳米WC颗粒与Ni-P组织结合紧密,WC的总含量约27wt.%;与Ni-P镀层的光滑平整表面相比,Ni-P-WC复合镀层表面存在由较多凸出的近球形晶粒所形成的Ni-P胞状组织,其平均粒径约为2-4μm。     

Electroless copper plating process of N, N, N, N′-tetrakis (2-hydroxypropyl) ethylenediamine system with high plating rate

Electroless copper plating process of N, N, N′, N′-tetrakis (2-hydroxypropyl)ethylenediamine(THPED) chelating agent was researched comprehensively. The results indicate that plating rate decreases with the 3H2O has a bad effect on deposits quality, but 2, 2′-dipyridyl and PEG make deposits quality improve greatly. Low concentration of 2-mercaptobenzothiozole (2-MBT) increases plating rate and improves deposits quality, but decreases plating rate and worsens deposits quality when 2-MBT reaches 5 mg/L. The optimal conditions of this electroless MBT are 16.8 g/L, 16.0 mL/L, 13.3 g/L, 0.5 g/L, 5.0 mg/L and 2.0 mg/L, respectively, pH value is 12.75,bath temperature is 30 ℃. Plating rate reaches 9.54 μm/h plating for 30 min in the bath. The SEM images demonstrate that the surface of copper film is smooth and the crystal is fine.     

碳纳米管表面改性工艺参数优化试验研究

利用超声分散法对团聚的原始碳纳米管分散处理后,通过酸化、敏化、活化等步骤对其进行表面改性处理,采用表面化学镀在其表面镀覆镍层,并进行热处理.研究了碳纳米管的分散、表面改性和镀镍工艺对镀层质量的影响.实验结果表明：在乙醇溶液中,利用分散剂进行超声分散可以明显改善碳纳米管之间的团聚状况;经过酸化、敏化、活化处理后其表面可形成密集的活化点;镀镍温度在20℃左右,pH值约8.2时,所得镀层较为均匀,经410℃保温2 h的热处理后,镀层变得光滑、连续、致密,镀层的厚度为12～20 nm.     

化学镀银导电涤纶织物的研究

以葡萄糖为还原剂,采用化学镀银法制备导电涤纶织物,研究了硝酸银浓度、葡萄糖浓度、乙醇浓度及反应时间对涤纶织物导电性能的影响,通过SEM和XRD图谱分析导电织物表面形貌与晶体结构,并测试其电磁屏蔽性能。结果表明,化学镀银涤纶织物具有优异的导电性能,且化学镀银后涤纶织物的电磁屏蔽性能明显增加。     

两步电镀铜对Cf/Cu复合材料的复合效果的影响

通过对碳纤维表面进行空气热氧化短处理,然后采用两步镀铜法对纤维表面进行电镀铜,有效的避免了普通镀铜方法中常见的“黑心”现象,使得纤维束内部单丝获得了均匀连续的镀铜层,而且纤维与镀铜层之间结合牢固．经两步镀铜处理后的碳纤维复合丝与铜基体复合后,碳纤维/铜复合材料中常见的严重纤维偏聚现象得到很大改善,获得了Cf／Cu界面结合良好,纤维分布均匀的铜基复合材料．     

热处理对振动磨损条件下Ni-P化学镀层结合强度的影响

重点研究了热处理对Ni-P化学镀层和复合镀层在冲击振动载荷作用下磨损形态与结合强度的关系．结果表明：振动磨损条件下的磨损形态随热处理温度的升高（400℃），镀层与基体金属间形成内扩散层提高了镀层与基体金属间的结合强度，从而消除了镀态时磨损断口中出现的界面片状剥落和端头部位出现的由界面脱粘所引起的冲击剥落，提高了耐磨性．