Electroless Procedure Research Articles

“Chiralized” Cu and Ni Deposits Obtained Via Electroless Deposition

The study of physicochemical processes at chiral surfaces is a particularly intriguing field of science.1,2 Of course, a logical and natural extension is the study of the electrochemical behavior of a “chiral-electrode”|solution interface, which is the subject of rapidly growing scientific and applicative interest in electrochemistry.3–6 In physics (and biology too), the concept of chirality, and the relevant involvement of physical interactions ruling chiral-systems is fascinating field of science: Maxwell equations, light polarization to mention a few (in biology, the homochirality dilemma7). Besides the purely fascinating scientific aspects, in chemistry chirality means a concept able to rule asymmetric synthesis and enantioselectivity/enantio-recognition (sensors). Within the area of chirality, it was shown that chiral systems are able to interact selectively with spin-polarized electrons8 acting also as spin-filter: chiral induced spin-selectivity (CISS).9 As a rational development, the implementation of the chiral spin-selectivity in electrochemistry, lead to the so-called spin-dependent electrochemistry.10 Quite recently where surfaces functionalized with chiral molecules shown better charge transfer properties if compared with structurally similar achiral compounds.11 Moreover, “chiralized” (which means co-deposition with a chiral-inducer compound) electrodeposited nickel and electropolymerized aniline (PANI), showed both good enantioselectivity as well as spin filtering (magnetoresistance measurements) characteristics.12–14 In this paper we want to prepare “chiralized” metals by electroless co-deposition of a suitable metal (here Cu and Ni) with an enantiopure chiral molecule: asymmetry inducer. This aiming to deposit a chiral conductive (metallic and possibly ferromagnetic) surface on a non-conductive material, in view of applications in both energy (photovoltaic) and spintronics (spin-valve) applications. In general, electroless deposition of both Cu and Ni relies on the use of Pd salts (where the real “catalyst” are Pd metallic nanoparticles), this makes the electroless procedure quite expensive. At present, in our laboratory the electroless deposition of both Cu and Ni was successfully carried out using Ag nanoparticles as the catalyzer, Figure 1. Co-deposition in the presence of enantiopure organic compounds is under investigations. References A. J. Gellman, Acc. Mater. Res., 2, 1024–1032 (2021).D. Avnir, Advanced Materials, 30, 1706804 (2018).C. Wattanakit et al., Nature Communications, 5, ncomms4325 (2014).H. Moshe et al., Chem. Eur. J., 19, 10295–10301 (2013).H. Moshe, G. Levi, D. Sharon, and Y. Mastai, Surface Science, 629, 88–93 (2014).S. Arnaboldi, M. Magni, and P. R. Mussini, Current Opinion in Electrochemistry, 8, 60–72 (2018).G. Laurent, D. Lacoste, and P. Gaspard, PNAS, 118 (2021) https://www.pnas.org/content/118/3/e2012741118.S. Mayer, C. Nolting, and J. Kessler, J. Phys. B: At. Mol. Opt. Phys., 29, 3497–3511 (1996).K. Ray, S. P. Ananthavel, D. H. Waldeck, and R. Naaman, Science, 283, 814–816 (1999).D. Mishra et al., Proceedings of the National Academy of Sciences, 110, 14872–14876 (2013).M. Innocenti et al., Journal of Electroanalytical Chemistry, 856, 113705 (2020).M. Gazzotti et al., Electrochimica Acta, 286, 271–278 (2018).S. Mishra et al., Small Methods, 4, 2070038 (2020).S. Mishra, L. Pasquali, and C. Fontanesi, Appl. Phys. Lett., 118, 224001 (2021). Figure 1

STUDY OF ELECTROLESS NICKEL PLATING ON RAPID PROTOTYPING MODEL USING ACRYLONITRILE BUTADIENE STYRENE

Electroless plating on Acrylonitrile Butadiene Styrene (ABS) is a metallization process that involves a reduction and oxidation reaction between the nickel source and the substrate material. The purpose of this research is to determine the ability of nickel deposition in the nickel electroless plating process with a specific etching time variation. This nickel electroless procedure begins with a chromic acid etching process that can last anywhere from 15 to 55 minutes and is useful for increasing roughness and creating submicroscopic cavities. After the etching process is finished, the surface roughness test is performed with a Mitutoyo SJ-210. Additionally, the activation step is carried out for 5 minutes in order for the polymer to become a conductor, allowing the plating process to proceed. The electroless plating process was then carried out for 55 and 75 minutes, with the goal of depositing nickel metal on the ABS surface. The coating results were analyzed using Fourier Transform Infrared (FTIR) spectroscopy IRSpirit/ATR-S serial No. A224158/Shimadzu to determine the functional groups formed both before and after the coating process, X-Ray Diffraction (XRD) to determine the character of the crystal structure, and phase analysis of a solid material using PANalytical type E'xpert Pro, To determine the surface morphology, the Zeiss EVO MA 10 was used to perform scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) at 1000x magnification. The test findings demonstrate that, based on a range of investigations, etching variations of 15,25,35,45, and 55 minutes etching time 55 minutes are the best nickel deposited substrates, as evidenced by EDS data, where this treatment has the largest weight fraction of nickel. As a result, the longer the etching period, the rougher the surface becomes, affecting the capacity of nickel deposition to increase. Furthermore, it can be demonstrated in this investigation that the nickel deposited is in an amorphous form.

Ni nanoparticle modified graphite electrode for methanol electrocatalytic oxidation in alkaline media

Ni nanoparticles with an electroless procedure were deposited on the graphite rod, and the performance of the proposed electrode was evaluated for electrocatalytic oxidation of methanol in alkaline media. The structure and morphology of the electrode surface were examined with X-ray diffraction, energy dispersive X-ray analysis and scanning electron microscopy techniques. Voltammetric and amperometric studies indicated that the onset potential of the methanol oxidation is low (0.42 V) and the electrode stability is good. In addition to these advantages, due to ease of preparation and low cost, it can be used as an anode in methanol fuel cells.

Electroless gold patterning of CdZnTe crystals for radiation detection by scanning pipette technique

Recently some of the authors have proposed a new technique to deposit contacts on CdZnTe detectors that combines the standard electroless procedure and the scanning pipette technique. In this work it is shown that by using a 15 micron inner diameter alumina pipette it is possible to deposit gold dots, pixels and micro‐stripes without using the standard photolithographic process. Moreover, it is shown that the performances in terms of charge collection efficiency and energy resolution of detectors prepared with the scanning pipette technique are similar to the ones of detectors prepared with the standard electroless procedure.

Metallization on FDM Processed Parts Using Electroless Procedure

Metallization has been studied on flat ABS (acrylonitrile-butadiene-styrene) parts. These parts were fabricated on fused deposition modelling machine using layer by layer deposition principle using ABS as part material. Electroless copper deposition has been performed on these parts using three different surface preparation processes namely aluminium paste (Al paste) coated ABS parts, surface prepared using chromic acid for etching and ABS parts prepared using H2SO4/H2O2 for etching. Surface preparation is followed by Cu (copper) deposition by electroless procedure using four different acidic baths. The acidic baths used are 5 wt% CuSO4 (copper sulphate) with 15 wt% of individual HF (hydrofluoric acid), H2SO4 (sulphuric acid), H3PO4 (phosphoric acid) and CH3COOH (acetic acid) acids. Cu deposition is presented and compared based on their electrical performance, scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The results shows that Al pasted samples demonstrated better electrical performance and more uniform Cu deposition.

Effects of electroplating on the mechanical properties of injection molded thermoplastics

Injection molding (IM) is the most generally used manufacturing process for the fabrication of plastic parts. A wide variety of products are manufactured using injection molding, which vary greatly in their size, intricacy, and application. One of the main limitations of Injection molded parts is the limited strength characteristic of Injection molded materials which in turn limits their scope of application in many areas of engineering. This paper focuses on enhancing the scope of application of IM parts through deposition of thin metallic foils. The ABS and Nylon6 are the materials on which plating is carried out. Through electroless and electrolytic deposition of copper, nickel and chromium layers over the ABS and Nylon6 samples, improvements with respect to strength are evaluated through experimental means. The process of deposition of thin metal foils on ABS substrates involves many steps such as surface activation, etching, catalyzing, electroless deposition, electro plating and surface cleaning, whereas, the electroless procedure is avoided on Nylon6 substrates. Characterization tests such as tensile and compression are conducted on samples in both un-coated and coated conditions.

Energy Efficiency Enhancement of Ethanol Electrooxidation on Pd–CeO2/C in Passive and Active Polymer Electrolyte‐Membrane Fuel Cells

Pd nanoparticles have been generated by performing an electroless procedure on a mixed ceria (CeO(2))/carbon black (Vulcan XC-72) support. The resulting material, Pd-CeO(2)/C, has been characterized by means of transmission electron microscopy (TEM), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and X-ray diffraction (XRD) techniques. Electrodes coated with Pd-CeO(2)/C have been scrutinized for the oxidation of ethanol in alkaline media in half cells as well as in passive and active direct ethanol fuel cells (DEFCs). Membrane electrode assemblies have been fabricated using Pd-CeO(2)/C anodes, proprietary Fe-Co cathodes, and Tokuyama anion-exchange membranes. The monoplanar passive and active DEFCs have been fed with aqueous solutions of 10 wt% ethanol and 2 M KOH, supplying power densities as high as 66 mW cm(-2) at 25 °C and 140 mW cm(-2) at 80 °C. A comparison with a standard anode electrocatalyst containing Pd nanoparticles (Pd/C) has shown that, at even metal loading and experimental conditions, the energy released by the cells with the Pd-CeO(2)/C electrocatalyst is twice as much as that supplied by the cells with the Pd/C electrocatalyst. A cyclic voltammetry study has shown that the co-support ceria contributes to the remarkable decrease of the onset oxidation potential of ethanol. It is proposed that ceria promotes the formation at low potentials of species adsorbed on Pd, Pd(I)-OH(ads), that are responsible for ethanol oxidation.

Metallization of Kevlar Fibers with Gold

Electrochemical gold plating processes were examined for the metallization of Kevlar yarn. Conventional Sn(2+)/Pd(2+) surface activation coupled with electroless Ni deposition rendered the fibers conductive enough to serve as cathodes for electrochemical plating. The resulting coatings were quantified gravimetrically and characterized via adhesion tests together with XRD, SEM, TEM; the coatings effect on fiber strength was also probed. XRD data showed that metallic Pd formed during surface activation whereas amorphous phases and trace amounts of pure Ni metal were plated via the electroless process. Electrodeposition in a thiosulfate bath was the most efficient Au coating process as compared with the analogous electroless procedure, and with electroplating using a commercial cyanide method. Strongly adhering coatings resulted upon metallization with three consecutive electrodepositions, which produced conductive fibers able to sustain power outputs in the range of 1 W. On the other hand, metallization affected the tensile strength of the fiber and defects present in the metal deposits make questionable the effectiveness of the coatings as protective barriers.

Metallic Nanoparticles Deposited on Carbon Microspheres: Novel Materials for Combinatorial Electrochemistry and Electroanalysis

This review deals with the preparation of metallic nanoparticles on glassy carbon microspheres and the use of these new hybrid materials for combinatorial electrochemistry and electroanalysis. First, the preparation of gold, silver and palladium nanoparticles on glassy carbon microspheres by a simple electroless procedure is described. Then, different types of electrodes modified with glassy carbon microspheres are described. These are: (i) glassy carbon electrodes modified by a composite film of glassy carbon microspheres and multi-walled carbon nanotubes, (ii) basal plane pyrolylic graphite electrodes modified by the abrasive attachment of glassy carbon microspheres and (iii) carbon-epoxy composite electrodes loaded with glassy carbon microspheres. The three types of electrode architectures described consist of metallic nanoparticles embedded in a carbon matrix and each of the electrode macrodisc surfaces actually correspond to a random metallic nanoelectrode array. Carbon-epoxy composite electrodes have good characteristics for their use as practical sensors. Furthermore, the use of several kinds of metallic nanoparticles allows the construction of a multi-analyte electrode and the screening of electroactive materials by following a combinatorial approach.

Electroless copper deposition on aluminum-seeded ABS plastics

We report a method of converting non-conductive plastic surfaces into conductive by coating either aluminum or aluminum-carbon black containing enamel pastes onto acrylonitrile-butadiene-styrene (ABS) plastics to create aluminum-seeded surfaces for a subsequent copper deposition. Through a simple electroless procedure, copper ions were reduced on the Al seeds and deposited on the ABS surface to develop a conductive layer in about 10-min deposition time. We demonstrate that addition of carbon black particles to the pastes shorten the time to reach the maximum conductivity and enhance the adhesion of electrolessly deposited copper layer to the ABS substrate surface. The electroless copper deposition process developed in this study may open up a new route of plating on plastics (POP) for printed circuit boards, electromagnetic interference shielding, and many other applications.

Electroless Fabrication of Cobalt Alloys Nanowires within Alumina Template

A new method of nanowire fabrication based on electroless deposition process is described. The method is novel compared to the current electroless procedure used in making nanowires as it involves growing nanowires from the bottom up. The length of the nanowires was controlled at will simply by adjusting the deposition time. The nanowires were fabricated within the nanopores of an alumina template. It was accomplished by coating one side of the template by a thin layer of palladium in order to activate the electroless deposition within the nanopores from bottom up. However, prior to electroless deposition process, the template was pretreated with a suitable wetting agent in order to facilitate the penetration of the plating solution through the pores. As well, the electroless deposition process combined with oblique metal evaporation process within a prestructured silicon wafer was used in order to fabricate long nanowires along one side of the grooves within the wafer.

Synthesis of novel magnetic spheres by electroless nickel coating of polymer spheres

A grid of micrometer-sized core-shell particles was fabricated by electroless plating technique. The core-shell particles consist of a PMMA core covered with a shell of nickel–phosphorus alloy component. The morphology and structure of the as-synthesized products were characterized by OM, TEM, XRD and EDS. The magnetic property of the particles was measured by an Alternating Gradient Magnetometer (AGM). The results showed that the less uniform coverage of magnetic shell was formed as nickel–phosphorus other than pure nickel component during electroless procedure. The as-prepared particles exhibited magnetism and showed magnetic response by being formed into chain structures under an external magnetic field.

Electrochemical behavior of iodide at a nickel pentacyanonitrosylferrate film modified aluminum electrode prepared by an electroless procedure

The surface of an aluminum disk electrode was modified by a thin film of nickel pentacyanonitrosylferrate and used for electrocatalytic oxidation of iodide. The cyclic voltammogram of the modified Al electrode showed surface redox behavior due to the [Ni IIFe III/II(CN) 5NO] 0/1− redox couple. The modifying layer shows excellent catalytic activity toward the oxidation of iodide. Different supporting electrolytes containing different alkali metal cations affected the apparent formal potential of the redox films and thus, changed the thermodynamic tendency and kinetics of the modifying film toward the catalytic oxidation of iodide. This was explained by including the concept of a surface coverage normalized-catalytic current. The kinetics of the catalytic reaction were investigated by cyclic voltammetry and rotating disk electrode voltammetry in a suitable supporting electrolyte. The results were explained using the theory of electrocatalytic reactions at chemically modified electrodes. The heterogeneous rate constant for the catalytic reaction, k, diffusion coefficient of iodide in solution, D, and transfer coefficient, α, were found to be 5.8 × 10 2 M −1 s −1, 1.3 × 10 −5 cm 2 s −1 and 0.66, respectively. In addition the effect of electrode surface coverage on the dynamic range of a calibration curve was investigated. Under optimum conditions a linear calibration graph was obtained over an iodide concentration range of 2–100 mM.

Electrocatalytic oxidation of dopamine at aluminum electrode modified with nickel pentacyanonitrosylferrate films, synthesized by electroless procedure

The electrocatalytic oxidation of dopamine (DA) at a home-made aluminum electrode modified with nickel pentacyanonitrosylferrate (NiPCNF) film, has been studied by electrochemical approaches. The immobilization of NiPCNF film was performed by a simple dip-coating procedure. The cyclic voltammogram of the resulting modified Al electrode prepared under optimum conditions, shows a well-behaved redox couple due to the [Ni IIFe III/II(CN) 5NO] 0/−1 system. The NiPCNF films, formed on the Al electrode show excellent electrocatalytic activity toward the oxidation of DA. The effect of the solution pH on the voltammetric response of DA was examined using phosphate buffer solution of different pHs. Under optimum conditions a linear calibration graph was obtained over the DA concentration range 2–33 mM. The kinetics of the catalytic reaction were investigated by cyclic voltammetry and rotating disk electrode voltammetry. The results were explained using the theory of electrocatalytic reactions at chemically modified electrodes. The rate constant for the catalytic reaction k, the diffusion coefficient of DA in the solution D, the electron diffusion coefficient in the film D e and transfer coefficient α, were found to be 3.1×10 2 M −1 s −1, 3.4×10 −6 cm 2 s −1, 2.2×10 −11 cm 2 s −1 and 0.67, respectively. The interference of ascorbic acid was investigated and greatly reduced using a thin film of Nafion ® on the surface-modified electrode. Further examination of the modified electrode shows that the modifying layers (NiPCNF) on the aluminum substrate show reproducible behavior and a high level of stability during electrochemical experiments, making it interesting for analytical applications.

Electrochemical characteristics of an aluminum electrode modified by a palladium hexacyanoferrate film, synthesized by a simple electroless procedure

The use of an aluminum substrate as an electrode and the modification of its surface by means of a thin film of palladium hexacyanoferrate (PdHCF) were developed. The modification conditions of the aluminum surface including the electroless deposition of metallic palladium on the electrode surface from PdCl 2+25% ammonia solution and chemical derivatization of deposited palladium to the PdHCF film in 0.5 M K 3 [Fe(CN) 6]+0.5 M KNO 3+HNO 3 solution (pH 1–1.5), are described. The modified aluminum electrodes prepared under optimum conditions, show a well-defined redox couple due to the [Pd(II)Fe(III/II) (CN) 6] 1−/2− system. The effects of pH and the alkali metal cation of the supporting electrolyte on the electrochemical characteristics of the modified electrode were studied in detail. Diffusion coefficients of hydrated alkali metal cations in the film ( D), the transfer coefficient ( α) and the transfer rate constant for electron ( k s), were calculated in the presence of various alkali metal cations. The very high stability of the modified electrode under various experimental conditions was confirmed.

Surface modification of halogenated polymers. 2. Chloro- and fluoropolymers

Solutions of solvated electrons in the presence of magnesium make possible the surface modification of halogenated polymers such as PVDF, Viton®, PCTFE, PVC or PVDC. The magnesium treatment which is milder than that using solutions of solvated electrons in the presence of alkali metals results in defluorination and/or dechlorination of the halogenated polymers. In the case of PVDF, it was demonstrated that (i) the surface free energy and consequently the hydrophilic character of the surface increased slightly with defluorination; (ii) anion radicals could also be used as reducing species; and (iii) copper or nickel metallization of magnesium treated samples could be achieved with the electroless procedure.

Voltammetric behaviour and electrocatalytic activity of the aluminum electrode modified with nickel and nickel hexacyanoferrate films, prepared by electroless deposition

Abstract The suitability of metallic aluminum as an electrode material for the preparation of a chemically modified electrode by the simple electroless procedure is described. As a typical example of modification, metallic nickel and nickel-hexacyanoferrate (NiHCF)-coated aluminum electrodes were prepared and their electrochemical characteristics were studied. Voltammetric investigations showed that the Ni and NiHCF-modified Al electrodes were electrochemically stable over the desired potential range 0–1.2 V in 0.25 M phosphate buffer solution of pH 4–10. The cyclic voltammograms of the NiHCF films, indicate the presence of a surface redox couple at 0.44 V, which corresponds to the Fe(CN) 6 3− /Fe(CN) 6 4− system. The oxidation of ascorbic acid as a typical organic compound was examined on the modified electrodes. A well defined and reproducible anodic peak was observed. The NiHCF films, formed on the Al electrode show an excellent electrocatalytic activity towards the oxidation of ascorbic acid in phosphate buffer solution of pH 7.2. The kinetics of the catalytic reaction were investigated using a rotating disk electrode voltammetry. The results obtained for various thicknesses of the film and ascorbic acid concentrations are explained using the theory of electrocatalytic reactions at chemically modified electrodes. The rate constant for the catalytic oxidation of ascorbic acid and the diffusion coefficient of electrons in the film were calculated. Further examination of the modified electrodes shows that the modifying layers (Ni and NiHCF) on the aluminum substrate have reproducible behaviour and a high level of stability.

Surface properties of excimer-laser-irradiated sintered alumina

In this presentation, the potential of excimer laser irradiation as a tool for tailoring the physical properties of materials is demonstrated on sintered alumina. Focusing on surface versus bulk crystallographic transformations, normal incidence and low-angle X-ray diffraction analyses have been used to investigate irradiated substrates. In particular, it is shown how excimer irradiation induces melt/quench procedures which may be tuned, as a function of the irradiation parameters, to produce various degrees of ordering in the solidified material. In particular, a set of irradiation regimes are shown to induce the exclusive emergence of the alumina γ-phase at and within 10 nm from the surface of the material. The phenomenology of this γ-phase synthesis is described and further modelled taking into account the presence in its lattice of periodically distributed cationic vacancies. This presence is further demonstrated in an electroless procedure by immersing the irradiated substrates in an autocatalytic bath containing di-valent metal ions which are driven to occupy vacant sites at and close to the surface, hence demonstrating an interesting potential for the development of a novel and efficient metallization process for sintered alumina.

New Method of Preparation and Some Properties of Electrochromic MoO3 Thin Layer

A new method for large area preparation of electrochromic MoO3 thin film on ITO glass has been developed. In the electroless procedure the Cu-metal covered ITO glass was sprayed by 0.5 mol/dm3 lithium molybdate solution of 0.5-1.5 pH and blue oxide film was obtained. Experiments were carried out for the cathodically deposited films, too. The optical properties of the two layers showed the same pattern.

Electroless NiP processing for hybrid integrated circuits

Electroless methods for depositing conductive layers on insulating materials can be used in producing hybrid integrated circuits (HIC's), as alternatives to the evaporation and sputter deposition techniques. Compared with these techniques, electroless procedures are in general relatively simple and it is easy to metallize holes in substrates. Further, electroless deposited NiP layers can be used for the integration of resistors. An electroless procedure will be described for metallizing alumina and fused quartz substrates, and further a method for producing resistive layers suitable for integrated resistors. After electroless plating the desired conductive patterns are obtained by localized electroplating with gold and etching away the unwanted parts of the NiP layer. Some properties of the conductive patterns obtained in this manner have been investigated, for instance: the adhesion between the metallic pattern and substrate, microwave losses in microstrip configuration, geometrical accuracies and performance of the resistive layers. A short description of the test methods applied will be given and the results discussed. Many hybrid integrated circuits for use at frequencies up to 22 GHz already have been made by using electroless procedures.