Influence of triazole stabilizers on the surface morphology of environmentally benign electroless nano copper deposition

In this work, we report the effect of triazole stabilizers: aminotriazole (ATA), benzotriazole (BTA), and tolytriazole (TTA) on the electroless deposition of copper thin film using xylitol containing copper methanesulphonate bath. Eco-friendly glyoxylic acid was used as reducing agent instead of p-formaldehyde which is carcinogenic. Potassium hydroxide was used for adjusting the pH, since it has the advantage of preventing the formation of insoluble byproducts in electroless bath, which is possible when NaOH is used. The electroless bath was optimized by addition of 1 ppm concentration of stabilizers, at 45°C and pH of 13.25 ± 0.25. Surface roughness, crystallite size and specific surface area of copper deposits were studied by the atomic force microscopy and X-ray diffraction. The anodic peak potential and corrosion current values were analyzed by the cyclic voltammetry and the Tafel plot. ATA was found to inhibit copper deposition while both BTA and TTA accelerated it. The crystallite size and surface roughness values were found to be less than 100 nanometer (nm) compare to the xylitol plain bath. TTA resulted in a better surface, structural, physical and electrochemical property of copper deposition than ATA and BTA.     

新型环金属钌配合物的合成和光物理性能研究

以2,4-二氟苯硼酸、4,4'-二溴-2,2'-联吡啶为原料合成了4,4'-二(2,4-二氟苯基)-2,2'-联吡啶,并以此为N^N配体合成新型离子型环金属钌配合物。采用元素分析、红外光谱、1H-NMR以及质谱表征确认了产物的结构,并考察了其光物理性能。结果表明,联吡啶4,4'-位上取代基团的引入改变了配合物的MLCT态,使其最大发射波长(λmax)较经典配合物Ru(bpy)32+(λmax=590 nm)红移至613 nm;配合物的初始分解温度为356℃,具有较好的热稳定性。     

无铅化学镀镍稳定剂研究

为了研究出一种优良的无铅化学镀镍稳定剂,以传统的化学镀镍基础配方为前提,选择Na2S2O3、S1(一种含硫有机物)、CuSO4和苯并三氮唑作为稳定剂,比较了其对镀液的稳定性能、镀速和镀层性能等影响.结果表明:S1作为化学镀镍液的稳定剂,不仅能使镀液稳定性能良好,而且镀层性能优异.     

Preparation and Electrical Resistance Characteristics of Electroless Copper-Nickel Alloy Deposits

Studies have been made of an electroless copper-nickel-phosphorus alloy from a citrate complex bath using hypophosphite as reducing agent and electroless copper-nickel binary alloy from a triethanolamine complex bath using formaldehyde as reducing agent. With an increase in copper content of alloy, the specific resistance of deposit decreased. The TCR of copper-nickel-phosphorus alloy increased remarkably because of the crystallization of Ni₃P after heat treatment. But the increase in TCR of copper-nickel binary alloy was moderate and not so striking as for the phosphorus containing alloy.     

离子注入陶瓷化学镀Cu工艺的优化

离子注入可作为前处理工艺辅助Al2O3陶瓷表面化学镀铜,优化了离子注入后以甲醛为还原剂、酒石酸钾钠为络合剂的碱性化学镀铜的基本配方.探讨了主盐浓度、甲醛、pH值、温度等对沉铜速度和镀层表面粗糙度的影响.研究了注入不同金属对沉铜速度的影响,结果表明注入铜比注入镍的化学镀铜速度快.     

Role of additives in electroless copper plating using hypophosphite as reducing agent

In electroless copper plating baths using hypophosphite as the reducing agent, nickel ions was used to catalyze hypophosphite oxidation. However, the color of the copper deposits was dark or brown and the electrical resistivity was much higher than that obtained from formaldehyde baths. Polyethylene glycol (PEG) and K₄Fe(CN)₆ were used to improve the microstructure and properties of copper deposits obtained from electroless copper plating bath using hypophosphite as the reducing agent. The effects of PEG concentration on the deposition rate, the microstructure, morphology and electrical resistivity of the copper deposits, and the electrochemical reactions of hypophosphite (oxidation) and cupric ion (reduction) were investigated. The traces of hydrogen escaping from the deposits surface disappeared and the color of the copper deposits changed from dark-brown to dark red when the PEG concentration was 1.67 × 10^− 5 M or more. The deposition rate increased and the electrical resistivity of the copper deposits decreased slightly with the addition of PEG to the plating solution. The electrical resistivity of copper deposits decreased to 2.85 μΩ cm with 1.67 × 10^− 5 M PEG and 4.70 × 10^− 6 M K₄Fe(CN)₆ in the bath. Larger grain size and higher (220) plane orientation were obtained with the increase of PEG concentration in the bath. The electrochemical current–voltage results showed that PEG accelerated the catalytic oxidation of hypophosphite at active nickel sites and had little effect on the reduction reaction of cupric ions on the deposit surface by adsorption on the electrode.     

氧化铝陶瓷基板化学镀铜工艺优化

目的化学镀铜是氧化铝陶瓷基板金属化的一种重要手段,为了进一步优化氧化铝陶瓷基板化学镀铜工艺,研究了化学镀铜液配比(尤其是镀液中铜离子和甲醛含量)对氧化铝陶瓷覆铜板微结构和导电性的影响。方法在对氧化铝陶瓷基板经过前期处理后,采用化学镀铜法在基板上镀铜。采用X射线衍射仪、光学显微镜对氧化铝基板上的化学镀铜层物相和形貌进行观察。采用覆层测厚仪、四探针测试仪对化学铜镀层的膜厚和方阻进行测量。结果 XRD结果表明,不同配比镀液得到的化学镀铜层均具有较好的晶化程度,镀液中甲醛和铜含量较低的镀液可制备出晶粒更为细小的化学镀铜层。甲醛和铜离子含量均较高时,沉积速度过快,使镀铜层的均匀性和致密性不佳。但当甲醛含量较高、铜离子含量较低时,沉积速度适中,从而获得了均匀性和致密性较好的镀铜层,同时这种镀层具有良好的导电性。结论采用表面活性化学镀铜工艺,当镀液中甲醛浓度为0.25 mol/L和硫酸铜质量浓度为1.2 g/L时,无需高温热处理,即获得了均匀性和致密性俱佳的铜镀层,可满足覆铜板的使用要求。     

1.10-菲啰啉在以HCHO为还原剂的化学镀铜体系中的作用

通过实时分析镀液中HCHO含量,结合极化曲线、电化学阻抗谱及扫描Kelvin探针技术,研究了1.10-菲啰啉对化学镀铜液中HCHO利用率及镀层沉积行为的影响;采用SEM,XRD分析铜镀层微观形貌及结构。结果表明：1.10-菲啰啉能够加速HCHO的氧化,提高HCHO利用率;化学镀铜液中加入1.10-菲啰啉,能够明显降低镀液阻抗,提高混合电位下的自腐蚀电流密度,降低Cu在镀液中的表面电势,提高镀层沉积速率。镀液中加入1.5 mgL^-1 1.10-菲啰啉可使HCHO利用率从28%提高到39%,镀速增加50%;1.10-菲啰啉的加入可以提高Cu(111) 晶面的择优取向程度,获得细致均匀的铜镀层。     

镁合金表面化学镀Ni-P合金稳定剂优选试验研究

在合理选择化学镀Ni-P合金配方和工艺条件的基础上,采用对比实验研究了硫脲、Pb(AC)2、KIO3、KI、Bi(NO3)2几种稳定剂及其复合对镁合金化学镀Ni-P合金镀液及镀层性能的影响。研究发现:适合NiSO4体系镁合金化学镀的稳定剂为KI KIO3,采用复合稳定剂的镀液稳定性及镀层性能明显优于单一稳定剂,在优化的稳定剂及相应的工艺条件下,镀液的稳定性好,镀速高,镀层均匀、致密,孔隙率低,耐蚀性能优良。     

Effect of Cd as a stabilizer in the electroless nickel plating system

Bath decomposition is a major problem in the electroless nickel (EN) plating system. Although the stabilization mechanism is far from being fully understood, bath stabilizers are normally added to extend the bath life in a viable EN plating solution. In this study, the effects of Cd²⁺ as a stabilizer on the plating rate, bath stability, and phosphorus content, corrosion resistance and microstructure of the deposits were investigated. The deposited films were examined using a scanning electron microscope (SEM) equipped with energy dispersive X-ray (EDX) spectroscopy and the X-ray photo spectroscopy (XPS). The electronic tunneling mechanism was used to elucidate the effect of the Cd²⁺ stabilizer on the plating system theoretically. The results calculated from theoretical method agreed well with the experimental data.     

Preparation of Fe–Zn alloy deposits by electroless plating

Abstract

Fe–Zn binary alloys have been deposited by electroless plating. The films were prepared on a copper substrate in contact with an aluminium strip. The effects of the concentration of ligand, reducing agent, pH value, temperature of plating bath and plating time on the deposition rate, and structure and morphology of the films have been studied. A practical electroless plating solution has been developed.     

Influence of nickel recovery efficiency on crystallinity and microhardness of electroless Ni–P coatings and optimisation using Taguchi technique

Abstract

This research paper reports on the improvement of nickel recovery efficiency (NRE) and microhardness of the electroless Ni–P coating process. At present, in the electroless nickel coating process, the NRE is very low. Owing to this reason, the coating cost of electroless nickel is very high. Earlier researchers have tried to recover the nickel from the used bath after coating is completed and some achieved success in their attempt by further improving the nickel recovery from 25 to 35%. To overcome the above problem, the excess amount of reducing agent (RA) is supplied to the bath during the coating process to compensate for the consumed amount of electrons. The influence of adding excess amount of RA on NRE and other properties of the deposit have been investigated in this study. The NRE was significantly increased from 35 to 61%.The various coatings parameters used in the electroless bath were optimised to get the high NRE using a Taguchi optimisation technique.     

镁合金微弧氧化涂层上化学镀铜层的显微组织和导电性（英文）

为了赋予镁合金微弧氧化(MAO)涂层以导电特性,对MAO涂层进行化学镀铜处理。通过测试镀层的显微组织、耐蚀性和导电性,研究镀覆温度和络合剂浓度对化学镀铜层性能的影响。结果表明,最优镀覆温度为60℃,最佳络合剂浓度为30 g/L。在此条件下,可获得完整、致密的镀层。分析镀层在镁合金MAO涂层上的形成机制,提出镀覆过程的三阶段模型。镀后试样的表面方阻在经历第三阶段后降低至0.03Ω/。通过化学镀铜,MAO样品在未明显降低耐蚀性的同时获得了良好的导电性。     

Influence of deposition temperature and heat treatment on the performance of electroless Ni-B films

Electroless nickel-boron (Ni-B) was synthesized on mild steel or copper surface. The deposition of thin electroless Ni-B films using an acidic bath having nickel chloride as a source of nickel and dimethylamine borane (DMAB) as a reducing agent and operated at low temperature has been investigated in this paper. The effect of the plating time and temperature on the quality of Ni-B coatings was estimated. The results revealed that the plating rate decreases with increasing plating time and increases with increasing plating temperatures. The boron (B) content of the electroless Ni-B layer increased with increasing temperature. The resulting surfaces were examined and characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). XRD analysis was performed to investigate structural modifications. Microhardness, corrosion and oxidation resistance of electroless as-plated and heat-treated Ni-B coatings, were evaluated. The effect of heat treatment temperature on the phase structure and microhardness of Ni-B coated at different temperatures was discussed. XRD patterns reveal that electroless Ni-B coatings deposited at 60 and 80 °C are amorphous in as-plated condition and undergo phase transformation to crystalline nickel and nickel borides upon heat-treatment. Heat treatment achieved significant improvement in the microhardness and corrosion resistance due to the formation of the Ni-B compound phases (Ni₃B).     

甘油铜络合物溶液化学镀铜的研究

采用单因素优选实验法研究了影响化学镀铜速率和甘油铜镀液稳定性的各因素,确定了适宜的甘油铜化学镀液配方和工艺条件.结果表明,优选出的的镀液稳定性相对较高、沉铜速度快、镀层外观较好.     

表面活性剂在陶瓷化学镀铜工艺中的作用

通过研究在镀液中添加十六烷基三甲基溴化铵(CTAB)、十二烷基硫酸钠(SDS)和吐温-80三种表面活性剂对化学镀铜沉积速率和镀液稳定性的影响,确定出三种添加剂的最优添加浓度。通过扫描电镜、能谱分析仪和X射线衍射仪,对镀层表面形貌、组成成分以及晶体结构分别进行研究。并通过线性伏安扫描法,研究了添加不同表面活性剂镀液的电化学行为。结果表明:表面活性剂可以提高化学镀铜的沉积速率和镀液稳定性。CTAB、SDS和吐温-80的最优添加浓度分别为1mg/L、20mg/L和5mg/L。加入SDS后,由于沉积速率过大,使得镀层颗粒变大。加入CTAB和吐温-80可以细化镀层的颗粒且更加致密。添加不同的表面活性剂后,镀层的晶粒尺寸没有太大改变,含铜量均为100%且镀层的晶粒呈现面心立方晶体结构。表面活性剂主要通过影响甲醛的氧化反应影响化学镀铜过程。     

Monitoring of zincate pre-treatment of aluminium prior to electroless nickel plating

Zincating is used as a pre-treatment for aluminium prior to electroless nickel deposition during preparation of magnetic computer memory discs. Four immersion zincating solutions were evaluated at 22°C using single step or double zincating followed by electroless nickel deposition from a high phosphorus hypophosphite bath at 90°C. The coating process was monitored by potential vs. time curves obtained under open-circuit conditions during zincating then electroless nickel plating. The surface morphology of the aluminium, at various stages, was imaged by scanning electron microscopy and atomic force microscopy. Zero resistance ammetry was used to record galvanic currents between the aluminium and an inert platinum counter electrode during zincating. This, together with potential-time measurements, provided simple and valuable methods for following the zincating process and subsequent electroless Ni plating. Double zincating enabled a shorter induction time for electroless Ni deposition and resulted in a more complete coverage of the surface by Zn.     

Ti3SiC2陶瓷颗粒表面超声波化学镀铜

钛碳化硅（Ti3SiC2）陶瓷导电材料有许多优异的性能,其摩擦系数甚至比石墨更低,完全可以取代石墨用来制备性能更加优良的铜基电接触复合材料,但是由于其与铜基体之间的浸润性不是很好,研究了利用超声波化学镀覆技术在Ti3SiC2颗粒表面均匀镀上一层连续的铜镀层。通过扫描电子显微镜对铜镀层表面形貌的观察表明：通过严格的镀前预处理工艺的优化设计以增加活化点,对传统镀液配方的调整以降低镀速,能够成功的在Ti3SiC2颗粒表面均匀镀覆一层铜微粒,改善了Ti3SiC2和铜基体间的润湿性,从而增强二者之间的界面结合力。     

Formation of electroless Ni–B coatings using low temperature bath and evaluation of their characteristic properties

The formation of electroless Ni–B coatings obtained using a low temperature bath and evaluation of their characteristic properties are addressed in this paper. An alkaline bath having nickel chloride as the source of nickel and borohydride as the reducing agent was used to prepare the electroless Ni–B coatings. The influence of concentration of sodium borohydride in bath on the plating rate and the nickel/boron content of the resultant Ni–B coatings was studied. Selected coatings were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM), respectively, for assessing the phase content, phase transformation behaviour and magnetic properties. XRD patterns reveal that the structure of electroless Ni–B coatings in as-plated condition is a function of the boron content of the coating: higher the boron content, greater the amorphous nature of the coating and vice-versa. DSC traces exhibit two exothermic peaks around 300 and 420 °C, corresponding to the phase transformation of crystalline nickel and Ni₃B phases at 300 °C and the transformation of a higher phase compound to Ni₃B at 420 °C. VSM studies indicate that the magnetic properties of the coating is also a function of the boron content of the coating: higher the boron content, lesser the saturation magnetization.     

Investigation of electroless copper plating on polyurethane foam,as an initial step of open cell foam production process

Abstract

Coating of polymeric foams is known as a method for production of metallic foams, which produces foams with high volume of porosity and controllable pore size. In this research, this method was employed to produce open cell copper foam by use of polyurethane foam with an average pore size of 0.4?mm as the substrate. Since polyurethane foam as a non-conductive material is not able to be coated directly by electrolytic deposition, the substrate was initially metallised by electroless copper plating. In the electroless plating process, the effects of the main parameters such as bath chemical composition, solution pH and temperature on deposition rate and thickness of the coatings obtained were investigated. The results showed that the optimum condition of the process is obtained when CuSO₄ concentration in the deposition bath is 12?g?L^??1, pH is 13 and plating temperature range is 55–60°C.