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Journal ArticleDOI

Autocatalytic electroless nickel-boron plating on light alloys

21 Feb 2000-Surface & Coatings Technology (Elsevier)-Vol. 124, Iss: 2, pp 201-209
TL;DR: In this paper, the authors examined the possibility of depositing a thick autocatalytic electroless Ni-B plating on aluminium alloys and proposed an alkaline bath containing sodium borohydride as the reducing agent.
Abstract: Light alloys are more and more widely used, notably in aeronautics and the car industry. To improve their superficial properties, they can be covered with a hard and wear resistant protective layer. In this article, we examine the possibility of depositing a thick autocatalytic electroless Ni–B plating on aluminium alloys. We propose an alkaline bath containing sodium borohydride as the reducing agent. The deposition rate is held constant by a regular replenishment of the Ni–B bath allowing a rate of about 25 μm/h. The Knoop microhardness of the Ni–B deposits after the bath reaches about 750 hk100. Appropriate heat treatment can increase the deposit microhardness up to more than 1000 hk100 but must be applied with regard to the substrate properties. The study of these heat treatments will be published in a further paper.
Citations
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Journal ArticleDOI
TL;DR: In this article, the authors reviewed the tribological advancement of different electroless nickel coatings based on the bath types, structure and also the tribo testing parameters in recent years.

477 citations

Journal ArticleDOI
TL;DR: In this paper, the performance of metal oxide thin film electrodes on activated carbon has been evaluated in the context of supercapacitors, showing that metal oxide films will play a major role in super-capacitor technology and are expected to significantly develop the capabilities of these devices in the near future.
Abstract: The electrochemical capacitor (EC), also called as supercapacitor, is an energy storage device possessing a unlimited life-cycle and high power density known to store energy in the double-layer or through supercapacitance as a result of an applied potential. Fundamental values in relation to the major chemical and physical qualities of electrode materials are explained in the following review, with carbon-made electrodes, specially activated carbon highlighted in regards to their improvement of the typical power and energy densities of ECs. Supercapacitive materials, remarkably transition metal oxides are revealed by the potential to further develop EC performance through synergistic effects and asymmetric design. Recently, several chemically deposited metal oxide thin film electrodes as well as ruthenium oxide, manganese oxide, cobalt oxide, nickel oxide, iron oxide, ferrites etc., have been evaluated in supercapacitors. This review presents supercapacitor performance data of metal oxide thin film electrodes on activated carbon offered by electroless plating as a suitable, fast and economical technique. The supercapacitors demonstrated the specific capacitance (Sc) principles, which are relatively comparable with bulk electrode values; therefore, it is likely that metal oxide films will continue to play a major role in supercapacitor technology and are expected to significantly develop the capabilities of these devices in the near future.

297 citations

Journal ArticleDOI
TL;DR: This review article provides a detailed overview on how to chemically fabricate SMEs, including the material preparation, fabrication technologies, methods to characterize their key properties, and representative studies on different wearable applications.
Abstract: Flexible and wearable electronics is one major technology after smartphones. It shows remarkable application potential in displays and informatics, robotics, sports, energy harvesting and storage, and medicine. As an indispensable part and the cornerstone of these devices, soft metal electrodes (SMEs) are of great significance. Compared with conventional physical processes such as vacuum thermal deposition and sputtering, chemical approaches for preparing SMEs show significant advantages in terms of scalability, low-cost, and compatibility with the soft materials and substrates used for the devices. This review article provides a detailed overview on how to chemically fabricate SMEs, including the material preparation, fabrication technologies, methods to characterize their key properties, and representative studies on different wearable applications.

222 citations

Journal ArticleDOI
TL;DR: The results of scratch tests show that the Ni-B deposits have good tribological properties under external solicitations as discussed by the authors, they are hard, wear and abrasion resistant, and also have good adhesion to the aluminium substrate.
Abstract: Electroless nickel–boron baths reduced with sodium borohydride can be stabilized with various agents such as thallium nitrate or lead tungstate with no fundamental modification of deposition rates and stability. To improve the mechanical properties of electroless nickel–boron deposits, various heat treatments are applied. At low temperatures, no fundamental changes in the deposit structure are observed, only an improvement of adhesion on aluminium substrate. The values of the Knoop microhardness obtained on these heat-treated deposits are near 600 hk 100 . At higher temperatures, structural changes take place and the nickel–boron deposits crystallize. The microhardness rises until 1050 hk 50 for heat treatments at 350 °C for 4 h. A diffusion layer between the electroless nickel deposit and the aluminium substrate appears at high heat treatment temperatures. The results of scratch tests show that the Ni–B deposits, with or without heat treatments, have good tribological properties under external solicitations. They are hard, wear and abrasion resistant, and also have good adhesion to the aluminium substrate.

178 citations

Journal ArticleDOI
TL;DR: In this article, the effect of borohydride, thallium acetate, ethylenediamine and sodium hydroxide concentrations, and the coating bath temperature on both the coating rate and boron content of the electroless Ni-B films was investigated systematically.
Abstract: The effect of borohydride, thallium acetate, ethylenediamine and sodium hydroxide concentrations, and the coating bath temperature on both the coating rate and boron content of the electroless Ni–B films was investigated systematically. The Ni–B coating rate increased with the increase in thallium acetate and sodium hydroxide concentrations, but it was not very sensitive to the borohydride concentration. Below 90 g L − 1 ethylenediamine concentration the coating efficiency was significantly low and above this value as the ethylenediamine concentration increased the coating rate decreased slightly. Below 85 °C the coating rate was very low and above this temperature it was insensitive to the bath temperature. The boron content of Ni–B film increased with the increase in the borohydride concentration and the bath temperature, and decreased with the increase in thallium acetate and ethylenediamine concentrations. Up to 50 g L − 1 sodium hydroxide concentration, the boron content of the film increased and above this concentration it was insensitive to the sodium hydroxide concentration. As the boron content of Ni–B film increased, both the corrosion resistance and microhardness of Ni–B film increased. Heat treatment brought significant improvement in the microhardness but the corrosion resistance of Ni–B film was observed to decrease due to the disappearance of the amorphous characteristics of the as-deposited Ni–B film and the formation of the Ni–B compound phases.

138 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

Book
01 Dec 1991

406 citations

Journal ArticleDOI
TL;DR: In this article, a process was developed for the production of adherent nickel deposits of good quality on steel without the use of an electric current, which was brought about by chemical reduction of a nickel salt with hypophosphites in a hot ammoniacal solution.
Abstract: A process has been developed for the production of adherent nickel deposits of good quality on steel without the use of an electric current. The deposition of nickel is brought about by chemical reduction of a nickel salt with hypophosphites in a hot ammoniacal solution. The reaction is catalytic and, under the prescribed conditions of concentration and pH, no reduction occurs in the solution unless certain metals, such as steel or nickel, are introduced into the bath. The reduction then occurs only at the surface of the immersed metal with the production of a coating of nickel of 96 to 97 percent purity.

385 citations

Journal ArticleDOI
TL;DR: In this paper, the anodic oxidation of reductants (hypophosphite, formaldehyde, borohydride, dimethylamine borane, and hydrazine) was studied on different metal electrodes (Au, Pt, Pd, Ag, Cu, Ni and Co) at various temperatures, with special interest in the catalytic aspect of electroless plating.
Abstract: The anodic oxidation of reductants (hypophosphite, formaldehyde, borohydride, dimethylamine borane, and hydrazine) was studied on different metal electrodes (Au, Pt, Pd, Ag, Cu, Ni, and Co) at various temperatures, with special interest in the catalytic aspect of electroless plating. The rate of the anodic oxidation strongly depended on the pH value, the concentration of reductants, and the nature of the metal electrode. The catalytic activities of the metals for the anodic oxidation of different reductants were evaluated by the potentials at a reference current density. The order of the catalytic activity with metal varied depending on the nature of the reductants. The catalytic activity series thus obtained can be utilized for choosing the reductant suitable for the metal to be deposited. Arrhenius plots of the anodic currents on different metals at a reference potential yielded their respective straight lines. Some correlations were observed between the catalytic activity and the activation energy. The catalytic activity series was discussed in connection with that for hydrogen electrode reaction.

244 citations

Book ChapterDOI
01 Jan 1994

39 citations