Study of a pre-treatment process for electroless copper plating on ceramics

In this paper, a pre-treatment process for electroless copper plating on the ceramics was explored. Due to the catalytic activity of gold nanoparticles, the traditional three-step coarsening-sensitization-activation pre-treatment process has been optimized to a two-step coarsening-activation process. In our study, the following results were observed: electroless copper coating on the ceramics was formed after activating the substrate by gold nanoparticles; a more flat and compact nano-composite coating was also obtained by adding gold nanoparticles to the plating solutions. The mechanisms of pre-treatment and composite plating with gold nanoparticles were discussed.     

Fabrication of super-hydrophobic nano-sized copper films by electroless plating

Super-hydrophobic nano-sized copper films were fabricated on smooth glass substrates by an improved electroless plating technology. The copper film deposited for 1 min showed extremely high hydrophobicity with a water contact angle of 138.0^o and super-hydrophobicity with a water contact angle of 152.4^o when it was modified with 1-octadecanethiol (CH3-(CH2)17-SH). Such super-hydrophobicity is attributed to the combined roles of the surface hierarchical structure consisting of the micro-sized island-shaped agglomerates that are composed of the nano-sized copper nodules and the low surface energy formed through the chemical modification.     

Fabrication of silica/platinum core-shell particles by electroless metal plating

An electroless metal plating method was used to form Pt shells on sub-micrometer-sized silica (SiO₂) particles fabricated by a sol-gel method. The electroless metal plating method was comprised of three steps: (1) surface-modification of SiO₂ particles with polyvinylpyrrolidone (PVP) (SiO₂/PVP) or poly-diallyldimethylammonium chloride (PDADMAC) (SiO₂/PDADMAC), (2) pre-deposition of Pt nuclei or Pt fine particles on the SiO₂ particles by reducing Pt ions in the presence of SiO₂/PVP particles (SiO₂/PVP-Pt) or SiO₂/PDADMAC particles (SiO₂/PDADMAC-Pt), and (3) growth of the pre-deposited Pt by immersing the SiO₂/PVP-Pt or SiO₂/PDADMAC-Pt particles in a Pt-plating solution. The pre-deposition of Pt nanoparticles was successfully performed for the surface-modified SiO₂ particles since the surface modification possibly strengthened the affinity between the SiO₂ particle surfaces and Pt ions. The Pt nanoparticles were pre-deposited more uniformly in the case of PVP because the pre-deposition took place more slowly for the PVP, which provided uniform surface-modification followed by the uniform pre-deposition of Pt nanoparticles. The formation of Pt shells was successfully performed on the SiO₂/PVP-Pt particles in the electroless metal plating process because Pt nuclei were generated by the reduction of H₂PtCl₆ and then further deposited on the Pt particle surfaces on the SiO₂/PVP-Pt particles.     

A novel activation for electroless plating on preparing Ni/PS microspheres

A novel and facile surface activation for electroless nickel plating was proposed, avoiding complex surface functionalization or pretreatment. The samples were characterized by XPS, TEM, XRD and SEM. The results indicated that the coatings of Ni/PS microspheres were smooth, compact and uniform, and the Ni coatings thickness was about 0.15 µm. It can be concluded that the novel surface activation was effective for the uniform nickel deposition on the surfaces of PS microspheres, due to more palladium catalytic active sites generated on PS microspheres surfaces.     

Microstructure and friction performance of copper film fabricated by ion implantation assisted electroless plating on PTFE

Abstract

The polytetrafluoroethylene (PTFE), which was implanted with Ni ion to different energy and doses, fabricated metallic structures by selective electroless copper plating. The characteristic and microstructure of the copper film were studied using SEM and X-ray diffraction. Friction performance of the interface between copper film and basal body of PTFE was tested with a CETR UMT-2 (CETR Co., Campbell, CA, USA) multifunction micromechanics instrument. The test loads were 10, 20 and 40 N, while the line velocity was 8 mm s^?1, and the frequency of data acquisition was 1 Hz. The Ni ion implantation replaces the complicated electroless plating surface pretreatment, and it is an assisted technique of electroless plating of copper on the surface of PTFE and plate Cu directly on its surface. Continuous, prepressing and uniformity plating was obtained with proper technique parameters and the dosage of Ni⁺. The frictional performance comprehensive property of copper film was remarkably influenced by different plating methods, annealing treatment and testing loads under unlubricated condition. The friction coefficients and wear rates changed with the varied load. Annealing treatment improves the tightness and uniformity of the copper film, while it decreases its cavity. Friction performance of copper film was thus increased. The mechanisms of friction and wear of copper film under different test conditions are also discussed.     

A vacuum plasma surface pretreatment for refining seeding of Co in electroless copper plating

In this work, various vacuum plasma types, generated by either single gaseous sources (N₂ or H₂) or mixed sources (N₂-H₂) are incorporated into an aqueous-solution electrochemical seeding process to pre-treat the surfaces of SiO₂ dielectric layers. Under the optimal plasma atmosphere (monitored by optical emission spectroscopy), the dielectric surfaces can be modified to terminate by hydrophilic bonds, accelerating the adsorption of a crowd of catalytic seeds as small as 3 nm. Such a seeding refinement allows for the growth of a Co-based barrier layer with thickness as thin as 10 nm using electroless plating. Moreover, the capacity of integrating the plasma surface pretreatment with the seeding and electroless-plating process steps to deposit an ultrathin copper-stacked metallization layer in a selective and sequential manner on blanket wafers will be demonstrated by the fabrication of copper-gated and barrier-interposed capacitors. Finally, a tentative work of filling the seeds and the barrier layer into trenches of a patterned wafer was carried out, demonstrating the potential of the reported technique for advanced technology nodes of 60 nm or less.     

Nickel coating on peptide nanotubes by electroless plating

A cyclic tri-β-peptide, cyclo(4-(4-pyridyl)-β-homoalanine)₃, was synthesized. The cyclic peptide was crystallized into μm-sized rods. Electron diffraction analysis revealed that the rod was composed of peptide nanotubes, which were formed by molecular stacking of the cyclic peptides, with nanotube alignment along the long axis of the rod. Ni coating of the rod crystals was carried out by electroless plating. The pyridyl groups at the side chains of the cyclic peptides were used for immobilization of Pd(II) ions on the surface as catalyst for the reduction reaction. The rod crystals were coated with Ni layers, but the electronic conductivity of the Ni-coated rods was found to be low probably due to the grain boundaries between Ni nanocrystals on the μm-sized rod surface.     

氧化铝陶瓷局部活化及选择性化学镀铜的研究

为解决陶瓷表面局部化学镀存在的问题,研制了一种针对氧化铝陶瓷局部化学镀铜前处理用的活化胶,其由具有活化能力的银盐(或钯盐)和粘稠的复合物有机载体组成.将活化胶印于氧化铝陶瓷表面,经500℃高温烧结形成局部活化层后,可直接置于化学镀液中进行镀铜处理,得到与印刷图形一致的局部镀铜层.利用电化学工作站测定样品在化学镀铜溶液中电位随时间的变化情况,考察不同活化条件对Cu2+还原的催化活性,利用SEM/EDS进行表面形貌及成分分析,确定了活化胶中银盐和钯盐的适宜浓度.结果表明,该两种活化胶应用于氧化铝陶瓷表面化学镀铜的活化工艺,可实现敏化活化的一步化,使陶瓷表面局部化学镀工艺流程简化,成本降低,具有较高的实用价值.     

Preparation of AlN-Cu composite powders by electroless plating of controlled oxidized nitride particles to prevent degradation by hydrolysis

The present work describes the preparation of AlN-Cu composite powders by electroless plating. Initially, the hydrolysis reaction of the ceramic particles in the electroless solution was studied as a reference element for the design of a protective surface barrier that enabled the coating process, with no ceramic phase degradation. The metal source of the electrolytic bath was copper sulfate, with formaldehyde as the reducing agent, under alkaline conditions of pH 12. The microstructural characterization indicated the formation and growth of aluminum hydroxides from AlN particles, inhibiting the coating of Cu by increasing the OH⁻ ions in the solution. As the exposure time increased, the ellipsoidal bayerite grew from AlN and transformed into prismatic particles of the thermodynamically more stable gibbsite phase. To prevent the degradation of AlN, a controlled oxidation stage was implemented to form a protective barrier of non-reactive alumina on the surface through thermal treatment in oxidizing atmospheres. An atmosphere of dry air was found to be more appropriate than pure oxygen for the formation of a continuous and dense layer of crack-free alumina on nitride surfaces, and a temperature of 1000 °C for 1 h enabled the formation of 3.9 by weight of α-Al₂O₃, capable of reducing the hydrolysis reaction of AlN. The process of autocatalytic deposition on the passivated particles, applied in three consecutive steps of metallization, led to AlN-Cu composite powders with 29 wt% Cu. Finally, the coated powders were treated in a hydrogen-reducing atmosphere at 400 °C to remove traces of the Al(OH)₃ phase encountered, as well as to improve the adhesion of the nanostructured deposit of the cauliflower-like structure to the AlN surfaces, obtaining AlN-Cu composite powders suitable for the preparation of metal/ceramic composites.     

The wear and arc erosion behavior of novel copper based functionally graded electrical contact materials fabricated by hot pressing assisted electroless plating

In this study, hot pressing was used to fabricate the novel copper based functionally graded electrical contact materials synthesized by silver, nickel and chrome plated copper core particles. For the fabrication of functionally graded materials (FGMs) by hot-pressing; pure copper, two and three layered metallic powders were used in the lower, middle and upper layer, respectively. The wear and arc-erosion performances of the developed materials increased from 3 to 10 times as compared to that of pure copper. Wear tests showed that the abrasive wear mechanism was dominant for the FGMs including electroless nickel and chromium coating layer. The highest specific wear rate (SWR) value was found in Cu_f-Ag′ (4.9 × 10⁻⁴ mm³/Nm) materials under the load of 20 N while the lowest SWR value belongs to Cu_f-Ag-Ni′ (2.3 × 10⁻⁴ mm³/Nm) materials under the load of 10 N. While severely melted and deformed regions are dominant on arc erosion surfaces of pure copper and copper-silver containing contacts, flatter and relatively less melted regions were detected on the surfaces of FGMs containing nickel and chromium. The arc-erosion loss values (cm³ × 10⁻⁴) measured for FGM₁ sample were 0.75 and 0.70, 0.99 and 0.88, 1.21 and 1.04 at 3000 cycles under the current of 5 A, 10 A and 15 A in fixed and moving contacts, respectively.     

Microstructure and thermal decomposition property of Ni-P/Cr2N composite powder by electroless plating

Cr₂N is the most promising blowing agent for the preparation of steel foam using melt foaming method. In this work, to obtain a blowing agent with suitable density and gas decomposition characteristics for steel melt foaming, Ni-P/Cr₂N composite powder was prepared by electroless plating. The surface morphology, phase, coating thickness, density and decomposition characteristics of Ni-P/Cr₂N composite powder were analyzed. The results indicate that the surface of Ni-P/Cr₂N composite coating powder is covered by the high nickel and low phosphorus layer which has a dense and uniform cell structure. The decomposition rate of the Ni-P/Cr₂N composite powder is 7.46?mW/mg slower than that of the uncoated Cr₂N powder at 1107.4?°C. When the plating time is 30?min, the thickness of Ni-P layer reaches 2.86?μm, the density of the Ni-P/Cr₂N composite powder is 7.45?g/cm³, and maximal decomposition rate temperature reaches 1500?°C. These findings suggested that Ni-P/Cr₂N composite powder meets the requirements of decomposition temperature and density of the blowing agent used to produce steel foam with a uniform pore structure by the melt foaming method.     

空心玻璃微珠表面无钯活化化学镀镍工艺研究

空心玻璃微珠表面进行金属化处理后, 可以作为复合导电填料用于制备电磁屏蔽材料或吸波材料.采用无钯活化工艺在空心玻璃微珠表面实施了化学镀镍磷合金, 对影响镀速和镀液稳定性的因素进行了讨论,并利用环境扫描电子显微镜、X射线能量色散谱仪和X射线衍射对施镀前后空心玻璃微珠的表观形貌、成分和晶形变化进行了表征.结果表明,利用无钯活化法可以得到均匀的非晶态的镍磷合金镀层, 镀层光亮、包覆完整.还对空心玻璃微珠表面化学镀镍活化机理进行了分析.     

Optimization and kinetics of electroless Ni–P–B plating of quartz optical fiber

The preparation of Ni–P–B coatings on surface of quartz optical fibers was carried out using electroless plating method. The effects of the concentrations of nickel chloride, sodium hypophosphite, potassium borohydride, ethylenediamine, cadmium sulfate and temperature on the quality of Ni–P–B coatings were investigated by orthogonal experiment and their optimal values were determined to be: 0.1 mol L⁻¹, 0.094 mol L⁻¹, 0.185 mol L⁻¹, 0.36 mol L⁻¹, 5.68 × 10⁻⁴ mol L⁻¹ and 90 °C, respectively. The effect of coarsening time of the naked fiber on the quality of Ni–P–B coatings was also researched and the optimal coarsening time was determined to be 15 min. Stereomicroscope, Scanning Electron Microscope and X-ray diffractometer were used to characterize the apparentness, morphology and structure of the prepared Ni–P–B coatings. Inductively Coupled Plasma-Atomic Emission Spectroscopy, Thermal Shock Method and Gravimetric Analysis Method were employed to analyze the composition, force of adhesion and solderability of the coatings, respectively. The results showed that a Ni–P–B coating with low surface roughness, good strength of adhesion, low resistivity and good solderability was successfully prepared. The kinetic models (Ni–P–B deposition rate equations) of the process were established as . The theoretical values calculated by the models were proved to be basically consistent with the practical measurements through experimental verification.     

Strain in electroless copper films monitored by X-ray diffraction during and after deposition and its dependence on bath chemistry

X-ray diffraction based strain measurements have been carried out during the deposition and subsequent relaxation of electroless (autocatalytic) polycrystalline copper films. Thin polymer substrates were mounted on the surface of an electrolyte-filled plating cell, and the X-rays traversed the substrate to scatter of the growing Cu layer. The plating cell was rotated back and forth by up to 70° in order to find the strain of Cu crystallites within and perpendicular to the plane of the film (sin²ψ method). Three types of plating solutions were investigated. A Ni-free solution C leads to compressive strain during steady-state film growth, followed by an exponential relaxation of the film to a residual tensile strain. Electrolytes A and B contain Ni ions, and the resulting Cu(Ni) films have nearly constant strain with small counteracting strain variations during and after film growth. Cyanide-stabilized solution A yields films with a slight compressive strain, while solution B, stabilized by an aromatic nitrogen compound, yields films with tensile strain. Different and reproducible evolution patterns observed for these three electrolyte types establishes in situ X-ray diffraction strain monitoring as a method to evaluate chemical formulations for electroless deposition.     

改性塑料表面亚铜化合物的表征及催化化学镀铜作用

在PC/ABS熔融共混的聚合物中掺杂Cu基金属化合物制得改性塑料,运用适当激光参数活化其表面,对此改性塑料表面进行化学镀铜.利用扫描电镜(SEM)、X射线能谱分析(EDS)、X射线光电子能谱分析(XPS)及电子显微镜对其活化层进行表征,结果表明:活化层中Cu元素以亚铜离子(Cu+)的形式构成亚铜化合物.亚铜离子(Cu+)在特定环境下发生歧化反应,对化学镀铜过程起到催化作用;通过镀层形态和性能测试分析,镀层表面光亮平整,结构致密,与基体结合力强,电阻率为:1.8~2.2μΩ·cm.镀层性能良好,表明可以用亚铜化合物来替代传统化学镀铜的贵金属催化剂.     

Effect of plating conditions for electroless Ni deposition on catalytic properties of K2MoO4/Ni-SiO2 catalyst

A series of K₂MoO₄/Ni-SiO₂ catalysts with Ni-SiO₂ as support for methanethiol synthesis from H₂S-rich synthesis gas were prepared and characterized by BET, ESR, XPS and HRTEM techniques. The optimum electroless plating condition was explored for the preparation of Ni-SiO₂ support. Physicochemical characterization results show that the Ni-SiO₂ support prepared under the alkaline condition and relatively high plating temperature makes molybdenum species dispersing more uniformly, leading to an appropriate K/Mo atomic ratio on its surface owing to the advantage of surface morphology. The sulfurized catalyst was found to have a suitable pore diameter distribution and a suitable molar ratio of S₂²⁻/S²⁻ (close to 1) on the surface of the catalyst, which were confirmed to be in favor of the improvement of the catalytic performance of the catalyst.     

Effect of thermochemical and heat treatments on electroless nickel–boron

Electroless nickel–boron synthesized on mild steel was submitted different post-treatments (heat and thermochemical). The resulting surfaces were examined and characterized by scanning electron microscopy. XRD analysis was performed to investigate structural modifications. The samples were also tested under corrosion conditions and polarization measurements were performed.For both the as-plated and treated Ni–B coatings, correlations between electrochemical and microstructural characteristics were observed and it was found that post-treatments transform the coating to a crystalline form that increases corrosion resistance.     

SiCp/Al复合材料表面无钯活化化学镀镍的研究

采用特定的无钯直接活化法在SiCp／A1复合材料表面进行活化,获得了光亮、完整且结合强度良好的Ni—P合金镀层．通过扫描电子显微镜和能谱等测试手段对镀层和活化前后的基体表面形貌、元素组成进行了研究,考察了活化时间、超声波、热处理温度和时间等因素对镀层质量、结合强度及沉积速度的影响,确定了在高体积分数的SiCp／A1复合材料上化学镀镍的最佳前处理工艺．研究表明：本文得到的最佳的无钯活化工艺过程为：直接用由Ni（Ac）2（g）、NaH2PO2（g）、CH,CH2OH（mL）和H2O（mL）以1：1：15：2比例组成的无钯活化液对基体进行活化,在超声波辅助下活化9min,然后在170℃下热处理20min;无钯活化后的基雄表面覆盖了一层Ni—P活化膜,该活化层对化学镀镍具有良好的催化效果．     

化学沉积RE-Ni-Mo-P-WC复合镀层组织结构及性能研究

研究了化学沉积RE-Ni-Mo-P-WC复合镀层的组织结构及性能.结果发现:加入稀土元素能使镀层表面的晶粒急剧细化,分散性大大加强.镀层结构由非晶态转化为晶态结构.镀层的耐蚀性略有下降.硬度随WC浓度增加而增加,钼酸钠浓度为0.05g/L并经过200 ℃热处理后,显微硬度增大.氧化膜的质量随温度的升高逐渐增加,但在600 ℃以下氧化温度对镀层增重不明显.     

聚苯乙烯微球化学制备及镀镍工艺研究

在聚苯乙烯微球表面进行化学镀镍可以制备磁性微球.采用此方法,能将聚苯乙烯的轻质的优点和镍的磁性结合起来.同时,此方法还具有如下优点:操作简单、反应条件易于控制.采用扫描电镜(SEM)表征了微球的表面形貌.考察了施镀温度、镀液浓度、镀液pH值对结果的影响.