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.     

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.     

Facile electroless copper plating on diamond particles without conventional sensitization and activation

Conventional electroless plating of copper on diamond particles needs SnCl₂ sensitization and PdCl₂ activation pretreatments, which needs noble metal and consumes a large amount of reducing agent. In this paper, metallic tungsten coatings were first plated onto diamond particles by microwave-heating salt-bath plating (MHSBP) method, and then copper layer was directly plated onto the out surface of the tungsten layer by an electroless plating method with no need of SnCl₂ sensitization and PdCl₂ activation pretreatments. Composition and morphology of the coatings was analyzed by XRD, SEM, and EDS. The results show that the copper coating on the diamond surfaces can be adjusted by control the concentration of CuSO₄·5H₂O and plating temperature, and a full copper coating is achieved with content of CuSO₄·5H₂O of 19.6 g/L in the plating solution at 60 °C. The bending strength of the coated diamond/Cu composites is as high as 630 MPa, which increases 93.3% than the uncoated composites. This work presents an electroless plating of copper can directly on the surfaces of diamond particles with no need of conventional sensitization and activation, and a strong interface combination between coated diamond and copper.     

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.     

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.     

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.     

Synthesis of polyacrylonitrile/Ag core–shell nanowire by an improved electroless plating method

A simple synthetic route for fabricating continuous Ag shell on electrospun polyacrylonitrile (PAN) nanofibers has been presented via an improved electroless plating method. To avoid the complex steps (wet surface activation, pre-treatment) of the electroless plating methods reported before, UV photoreduction is used to fabricate dense Ag nanoparticles on the outer surfaces of PAN nanofibers. These Ag nanoparticles act as seeds in the following metal electroless plating step for the growth of continuous Ag shell. Additionally, our method can be easily applied to synthesize other metallic shell on the outer surfaces of PAN nanofibers with Ag nanoparticles as seeds.     

化学镀法制备核壳型银-铜双金属粉

为改善超细铜粉的高温抗氧化性能,通过热力学数据理论上分析了液相还原反应取代置换反应的可行性,并以水合肼作还原剂,银以稳定性适中的银氨络合物存在,采用化学镀法制备银包覆超细铜粉的新技术,利用SEM、XRD等手段对双金属粉的形貌和晶相组成进行了分析.研究表明,一次包覆铜粉基体表面银的包覆率为40.22%,二次包覆银的包覆率可达94.98%,在铜粉表面形成了连续的银膜,可以认为是表面包覆结构,拓展了超细铜粉的应用领域.     

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.     

Preparation of Co-plated WC powders by a non-precious-Co-activation triggered electroless plating strategy

In this study, Co nanoparticles were mixed with WC powders by electroless plating with a new non-precious-Co-activation strategy. By soaking WC powders in a mixed solution of cobalt sulfate heptahydrate and sodium hypophosphite and then heat treated at 220 °C, Co active sites were seeded on WC powders to activate the following electroless plating of Co. The effects of reaction conditions on the weight gain and plating rate during electroless plating process were systematically investigated. As is evidenced by results, when the temperature, concentration of CoSO₄ and NaH₂PO₂·H₂O, and pH were 80 °C, 50 g/L, 45 g/L and 11 respectively, WC was evenly coated with Co. Notably, the XPS characterization indicated the content of zero-valence Co was elevated obviously after the plating process due to the effective reduction from two-valence Co.     

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.     

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.     

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.     

Application of response surface method for predicting electroless nickel plating

Electroless nickel plating process has been studied considering pure copper (99.99%) as a substrate material. Deposition per unit area has been considered as a response variable and individual as well as combined effects of process parameters on deposited mass have been studied. Regression analysis and Student’s t test have been used to identify the significant influencing process parameters. It has been observed that reducing agent (NaBH₄), source of metal (NiCl₂ · 6H₂O) and temperature significantly affect the deposition. The interactions among various process parameters have also been observed to be significant. Mathematical modeling has been carried out by a second-order response surface model with central composite design (CCD) to take into account the effect of curvature in the predicted response. Equations for response surfaces have been determined for various deposition times using MATLAB software package. Most of the response surfaces show that deposition thickness increases with increased values of process parameters within the adopted range but with different rates. The test for reliability for predicting response surface equations shows that these equations give an excellent fitting to the observed values.     

Fabrication of nanoscaled silica layer on the surfaces of submicron SiO2-Ag core-shell spheres

A two-step silica deposition process, including prefunctionalization with poly(vinylpyrrolidone) and the following silica deposition, has been used to fabricate silica layer on the surface of nanoscaled silver shell. The influencing parameters of silica coating process were optimized to prevent the precoated silver nanoparticles from desquamating from silica spheres, finally to obtain mono-dispersed silica spheres with silver and silica multilayer films. The resulted silica layer was dense and uniform, its thickness was controllable in the range of 20–50 nm. Such coated silica layer can provide improved thermal stability of the SiO₂-Ag core-shell structural spheres.     

化学镀镍法制备Ni/石墨烯(英文)

采用化学镀镍方法,以氧化石墨烯薄片为基体、NaBH4为还原剂,在NiSO4溶液中制备了Ni/石墨烯。通过X射线衍射、场发射扫描电镜和透射电镜对样品进行了表征,结果表明:沉积在石墨烯片表面Ni的的质量分数高达32.9%时,仍具有高度的分散性;相互堆积Ni/石墨烯片形成了介孔和大孔。氮气等温吸附表明:其介孔和大孔为狭缝型结构,孔的Brunauer-Emmett-Teller比表面积为91 m2/g;吸附支的Barret-Joyner-Halenda平均孔径为3.83 nm,孔容为0.28 cm3/g。     

表面改性离子交换化学镀制备表面覆镍聚酰亚胺纤维

以高强度的聚酰亚胺（PI）纤维为基纤,采用表面改性离子交换和化学镀相结合的方法,成功制备了高强度、高导电性和热稳定性好的聚酰亚胺-Ni （PI-Ni）复合导电纤维,采用SEM观察纤维的微观形貌,通过XRD和EDS表征了镀层组成及相态结构,测试了纤维的力学性能、导电性、界面黏结性能及热性能。结果表明,PI-Ni纤维表面平整光滑,完整致密,镀层为非晶态Ni-P合金。PI-Ni束丝拉伸强度约为1.2 GPa,电阻率为1.76×10^-4 Ω·cm,5%热失重温度为611℃,耐热性能优异,是一种高性能的有机导电纤维。     

Fabrication of raspberry-like superhydrophobic hollow silica particles

Raspberry-like superhydrophobic hollow silica particles were prepared through a sacrificial polymer template method. The Stöber method was adopted to coat silica onto the surface of cationic polymethylmethacrylate(PMMA) particles by electrostatic interaction. The surface of the PMMA-silica composite particles exhibited raspberry-like morphology with high surface roughness. Hollow silica particles were then obtained by calcination to selectively remove the PMMA core. Subsequent modification with nonafluorohexyltriethoxysilane (NFH-silane) conferred superhydrophobicity on the hollow silica particles. The surface property of this particles were investigated by measuring their water contact angle, and the results showed that such perfluorinated raspberry-like hollow particles had unique superhydrophobic.     

Biosensor enhanced by glucose oxidase biomimetic membrane containing the platinum and silica nanoparticles

In this paper, glucose biosensor is fabricated with immobilization of glucose oxidase (GOx) in platinum and silica sol. The glucose biosensor combined with Pt and SiO₂ nanoparticles could make full use of the properties of nanoparticles. A set of experimental results indicates that the current response for the enzyme electrode containing platinum and silica nanoparticles increases from 0.32 µA cm^− 2 to 33 µA cm^− 2 in the solution of 10 mM β-D-glucose. The linear range is 3 × 10^− 5 to 3.8 × 10^− 3 M with a detection limit of 2 × 10^− 5 M at 3σ. The effects of the various volume ratios of Pt and SiO₂ sols with respect to the current response and the stability of the enzyme electrodes are studied.     

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.