Formation and characterization of borohydride reduced electroless nickel deposits
TL;DR: In this article, the formation of electroless Ni-B deposits and evaluation of their characteristic properties were studied. And the corrosion resistance of Ni-b deposits, in 3.5% sodium chloride solution, both in as-plated and heat-treated (450°C/1 h) conditions, was also evaluated by potentiostatic polarization and electrochemical impedance studies.
About: This article is published in Journal of Alloys and Compounds.The article was published on 2004-02-25. It has received 136 citations till now. The article focuses on the topics: Electroless nickel & Nickel boride.
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TL;DR: In this paper, the initial deposition and growth of electroless nickel-boron deposits on mild steel were studied: the films were prepared in an electroless plating bath using sodium borohydride as reducing agent.
Abstract: The initial deposition and growth of electroless nickel–boron deposits on mild steel were studied: the films were prepared in an electroless plating bath using sodium borohydride as reducing agent. Samples were immersed in the plating solution for times from 5 s to 1 h and the morphological evolution of the deposit was followed by scanning electron microscopy (SEM) observation of the surface and prepared cross sections. Energy dispersive X-ray spectrometry (EDX) and glow discharge optical electro spectroscopy (GDOES) analyses were used to obtain information about the chemistry of the deposits and their results were correlated with the morphology of the coating. The initiation mechanism of electroless deposition on mild steel was identified. The effects of substrate roughness variation on the morphology and growth rate of the coatings were investigated by reproducing the experiment on samples with various surface preparation (grinding) states. We observed that the increase of substrate roughness favors the deposit initiation: the density of nickel nodules increases with increasing roughness of the substrate. Longer immersions in the bath lead to homogenization and densification of the coating and the nodules are clearly distinguishable.
45 citations
TL;DR: In this paper, the effect of co-deposited phosphorus and sulfur atoms on corrosion resistance of electroless nickel deposits was evaluated by electrochemical impedance spectroscopy (EIS).
Abstract: The manufacture of electroless black nickel surfaces had been obtained, through etching electroless nickel deposits by oxidizing acid solution. The morphology, chemical composition and reflectance of pre-etch and post-etch coatings were compared to examine influence of phosphorus and sulfur content on preparation of black surfaces. The non-metallic elements content of electroless nickel deposits was greatly improved after black treatment. It indicated the etching treatment was a selective dissolving process. The nickel atoms can be preferentially removed during the period. Optimum phosphorus content range to produce low reflectance black surface was proposed, after reflectance measurement of black surfaces. Additionally, the effect of co-deposited phosphorus and sulfur atoms on corrosion resistance of electroless nickel deposits was evaluated by electrochemical impedance spectroscopy (EIS). The fitting results indicated that corrosion resistance of high-phosphorus electroless nickel deposits will be significantly reduced after black treatment. However, that of low-phosphorus deposits will be improved.
45 citations
TL;DR: In this paper, depth-dependent hardness variation of dimethylamine borane-reduced electroless Ni-5'wt-%B deposits has been examined using the nanoindentation technique.
Abstract: Depth-dependent hardness variation of dimethylamine borane-reduced electroless Ni–5 wt-%B deposits has been examined using the nanoindentation technique. The deposits were characterised using ICP-OES, FESEM, XRD and DSC for evaluating the composition, morphology, structure and phase transformation behaviour, respectively. Coatings were also analysed for hardness and wear resistance. The surface of the as-plated deposit exhibits a typical nodular morphology. DSC traces show the presence of a single exothermic peak at 313°C conforming to its phase transformation. X-ray diffraction pattern of as-prepared deposit contains a mixture of amorphous and sharp microcrystalline nickel peaks. Heat-treated coating exhibits improved hardness and wear resistance. Depth-dependent nanohardness profile of as-deposited film neither obeys Nix–Gao nor the Lam–Chong model of indentation.
45 citations
TL;DR: In this article, an amorphous Ni-B/TiO2 catalyst has been synthesized by silver-catalyzed electroless nickel plating, and high-resolution transmission electron microscopy (HRTEM) indicated that the Ni−B nanoparticles presented a porous and flower-like morphology, which was different from the solid sphere of conventional Ni·B particles prepared by impregnation reduction method.
Abstract: An amorphous Ni–B/TiO2 catalyst has been synthesized by silver-catalyzed electroless nickel plating. The amorphous structure of Ni–B nanoparticles was characterized by X-ray diffraction (XRD) and selected area electron diffraction (SAED). A transmission electron micrograph (TEM) of the Ni–B/TiO2 showed particles with size ranging from 30 to 50 nm were homogeneously dispersed over TiO2 support. High-resolution transmission electron microscopy (HRTEM) indicated that the Ni–B nanoparticles presented a porous and flower-like morphology, which was different from the solid sphere of conventional Ni–B particles prepared by impregnation–reduction method. To investigate the formation process of the porous Ni–B particles, the diffusion of nickel nuclei and the growth of Ni–B particles were characterized. The as-prepared porous Ni–B/TiO2 catalyst exhibited superior catalytic activities in the hydrogenation reactions to those of catalysts prepared by conventional methods.
44 citations
TL;DR: In this article, electroless Ni-B alloy and Ni-b-CeO2 nanocomposite coatings were formed on 356 aluminium alloy surfaces using ceria incorporation to reduce the average nodular grain size from 1150nm to 650nm and Ni crystallite size from 15nm to 997nm.
Abstract: Nickel-based coatings on aluminium with specific surface properties are of great interest for anti-corrosive, anti-wearing, and self-lubricating applications In the present study electroless Ni-B alloy and Ni-B-CeO2 nanocomposite coatings were formed on 356 aluminium alloy surfaces Ceria incorporation to Ni-B coating reduces the average nodular grain size from 1150 nm to 650 nm and Ni crystallite size from 15 nm to 997 nm Ni-B-CeO2 nanocomposite shows remarkable improvement in microhardness of 684 VHN compared to pure Ni-B coating with 424 VHN Enhanced wear resistance and reduction in friction coefficient are observed for the nanocomposite coatings compared to 356 Al alloy and Ni-B alloy coating Potentiodynamic polarization measurements show a remarkable reduction in the corrosion current density for ceria added nanocomposite coating (248 × 10−6 A cm−2) than that of the particle-free counterpart (1118 × 10−6 A cm−2) Uniform Ni-B-CeO2 composite coating was obtained on centrifugally cast A356 aluminium alloy cylinder liners which have potential applications in automotive systems
42 citations
References
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Book•
01 Jan 1990
TL;DR: The Electroless Plating: Fundamentals and Applications (ESPA) as discussed by the authors is a comprehensive text that covers both fundamental and applied aspects of electroless deposition, and was first introduced at SUR/FIN '91.
Abstract: Many texts have been written on surface finishing over the years that deal with electroless deposition as a sidelight. Through the talents and efforts of Glenn Mallory and Juan Hajdu, a comprehensive text, entitled Electroless Plating: Fundamentals and Applications, is available through AESF Headquarters. The editors have combined the efforts of 27 contributing authors to produce a wide-ranging text that covers both fundamental and applied aspects of the subject. Published by the AESF, the book was first introduced at SUR/FIN ‘91—Toronto.
963 citations
Patent•
23 Sep 1968
TL;DR: HIGH STABILITY, AUTOCATALYTIC ELECTROLESS NICKEL PLATING BATH COMPRISING an AQUEOUS SOLUTION CONTAINing about 0.08-016 MOLE/LITER NICKels IONS, about 019-0.38 MOLE / LITER HYPOPHOSPHITE IONS and ESSENTIALLY about 035-3.14 MOLE or Liter CITRATE IONS as discussed by the authors.
Abstract: HIGH STABILITY, AUTOCATALYTIC ELECTROLESS NICKEL PLATING BATH COMPRISING AN AQUEOUS SOLUTION CONTAINING ABOUT 0.08-016 MOLE/LITER NICKEL IONS, ABOUT 0.19-0.38 MOLE/ LITER HYPOPHOSPHITE IONS, AND ESSENTIALLY ABOUT 0.35-3.68 MOLE/LITER AMMONIUM IONS, ABOUT 0.0.-1.07 MOLE/LITER ACETATE ION AND ABOUT 0.007-0.14 MOLE/LITER CITRATE IONS, THE SOLUTION HAVING A PH IN THE RANGE OF ABOUT 7.0 TO ABOUT 9.5 THE AMMONIUM IONS COMPLEX PALLADOUS IONS INTRODUCED INTO THE PLATING BATH BY "DRAG OUT" FROM THE ACTIVATOR SOLUTION TO FORM A SOLUBLE AMMONIUM-PALLADIUM COMPLEX, WHICH INHIBITS REDUCTION OF PALLADOUS ION TO ZERO VALENT CATALYTIC PALLADIUM BY THE HYPOPHOSPHITE OF THE BATH. BY THE REMOVAL OF POTENTIAL CATALYST SITES FROM THE BATH OR BY RENDERING THE POTENTIAL SITES RELATIVELY CATALYTICALLY INACTIVE, RANDOM DEPOSITION OF THE NICKEL AND PREMATURE LOSS OF THE BATH IS AVOIDED.
154 citations
TL;DR: In this paper, the same fundamental reaction is occurring on all the coatings of the present study but over a different effective area in each case, which can be attributed to the decrease in the effective metallic area prone to corrosion.
Abstract: Electroless Ni-P composite coatings have gained a good deal of popularity and acceptance in recent years as they provide considerable improvement of desirable qualities such as hardness, wear, abrasion resistance, etc. The disagreement among researchers on the corrosion behaviour of these coatings warrants a thorough investigation. Among the various techniques available for the determination of corrosion resistance, electrochemical impedance spectroscopy (EIS) is considered to be superior as it provides not only an assessment of the corrosion resistance of different deposits but also enables the mechanistic pathway by which the deposits become corroded to be determined. The present investigation focuses on the evaluation of the corrosion resistance of electroless Ni-P and Ni-P-Si3N4, Ni-P-CeO2 and Ni-P-TiO2 composite coatings produced using an acidic hypophosphite-reduced electroless nickel bath, using EIS. The study makes evident that the same fundamental reaction is occurring on all the coatings of the present study but over a different effective area in each case. The charge transfer resistance of electroless Ni-P and Ni-P composite deposits are in the range 32,253–90,700 Ω cm2, whereas the capacitances of these coatings are in the range 11–17 µF/cm2. The improved corrosion resistance obtained for electroless Ni-P and Ni-P composite coatings is due to the enrichment of phosphorus on the electrode surface, which enables the preferential hydrolysis of phosphorus over that of nickel. The better corrosion resistance obtained for electroless Ni-P composite coatings can be ascribed to the decrease in the effective metallic area prone to corrosion. Among the three electroless Ni-P composite coatings, the corrosion resistance is in the following order: Ni-P-CeO2=Ni-P-Si3N4>Ni-P-TiO2.
119 citations
TL;DR: In this paper, the effect of phosphorus on the corrosion behavior of electroless nickel-plated mild steel in deaerated 40 w/o NaOH solution was examined using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) techniques.
Abstract: Electroless Ni-P deposits with phosphorus content ranging from 4.8 to 12.8 weight percent (w/o) were examined using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) techniques to characterize the effect of phosphorus on the corrosion behavior of electroless nickel-plated mild steel in deaerated 40 w/o NaOH solution. Anodic polarization of the electroless Ni-P alloys in caustic NaOH solution shows that the passive current density decreases with increasing phosphorus content in the deposits. At an applied potential of -1.2 V vs. saturated calomel electrode (V SCE ) (close to their E corr ), EIS data indicate that the R ct for Ni-P alloys in NaOH solution increases with increasing phosphorus content. X-ray photoelectron spectroscopy (XPS) results suggest that the primary constituent formed on the Ni-P surface after EIS measurement in 40 w/o NaOH solution at an applied potential of -0.4 V SCE (in the passive region) is Ni(OH) 2 , which is responsible for the passivity of the Ni-P alloys. The polarization resistance of Ni-P alloys in NaOH solution at -0.4 V SCE also increases with increasing phosphorus content
111 citations