Topic
Electroless nickel plating
About: Electroless nickel plating is a research topic. Over the lifetime, 1593 publications have been published within this topic receiving 14940 citations.
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TL;DR: In this article, a theoretical expression of the nickel deposition rate is created by envisioning the Stern−Grahame electrical double layer presumably attached to the plating frontier (the inner Helmholtz plane) as a one-dimensional potential well.
Abstract: The electroless nickel plating process involves multiple chemical reactions that interrelate mutually in intricate ways and take place almost simultaneously. This work attempts to provide a theoretical template for understanding this complicated system from the role of heavy metal stabilizers. Pb2+ ion was selected for the study because it is the most effective species in this category. A theoretical expression of the nickel deposition rate is created by envisioning the Stern−Grahame electrical double layer presumably attached to the plating frontier (the inner Helmholtz plane) as a one-dimensional potential well and the electron transfer from the Fermi level of plating frontier to Ni2+ ions at the outer Helmholtz plane as the quantum tunneling effect. The deposition of P atoms is assumed to go through the oxidative-addition of hypophosphite (H2PO2-) ions at Ni atoms on the plating frontier and on this basis its theoretical deposition rate is developed. Another adsorption state of H2PO2- on the surface Ni...
54 citations
TL;DR: In this article, a new process with zinc transition layer obtained by combining immersing zinc in an improved zinc bath containing FeCl3 and electroplating zinc, is used to plate Magnesium alloy AZ91D.
Abstract: A new process, which is characterized with zinc transition layer obtained by combining immersing zinc in an improved zinc bath containing FeCl3 and electroplating zinc, is used to plate Magnesium alloy AZ91D. Corrosion testing and SEM images indicate that the immersion zinc layers obtained in zinc immersion baths with FeCl3 are more compact. Peel testing shows that there is good adhesion to the subsequent electrodepositing layer. The electroplating zinc can further promote the coverage of zinc transition layer on the magnesium alloy substrate before electroless nickel plating and reduce the galvanic corrosion effect between Mg alloy and Ni–P alloy. The good zinc deposit can be obtained by electroplating zinc in pH 9∼10 zinc pyrophosphate bath at 40 °C under the current density of 2∼3 A/dm2. The developed new process of electroless nickel plating greatly improves the adhesion and coverage of Ni–P coating. The zinc transition layer obtained by the developed process can supersede copper transition layer obtained by cyanide plating process in electroless nickel plating on magnesium alloy.
54 citations
TL;DR: In this article, the effect of bath pH and pH stabilizers on plating rate and coating quality as well as bath life were studied in detail, and a highly uniform and dense coating was formed via EN plating in the new bath containing ammonium acetate.
Abstract: In order to develop the new bath solutions with long cycles and high stability for electroless nickel (EN) plating of magnesium alloys, effect of bath pH and pH stabilizers on plating rate and coating quality as well as bath life were studied in detail. Gravimetry was used to determine the deposition rate of coating. The coverage of coating was evaluated by 2 h of immersion test for magnesium alloys in 3.5 wt.% NaCl solution. The results showed that the bath pH not only changed the reactivity of the bath, but also had a strong impact on the microstructure and electrochemical properties of coatings. A highly uniform and dense coating was formed via EN plating in the new bath containing ammonium acetate. The bath life was extended when appropriate amount of ammonium acetate was added. It was effective for ammonium acetate to stabilize pH in the plating solution, to control coating quality and bath life.
54 citations
TL;DR: In this article, the authors used X-ray diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy characterization techniques to identify the presence of nickel deposition on the carbon nanotubes (CNTs) and the degree of graphitization.
52 citations
TL;DR: In this paper, a number of experiments designed to characterize the activation of aluminum bondpads to electroless nickel plating, focusing on the effects of solution exposure time and bondpad composition.
Abstract: Electroless nickel bumping of aluminum (Al) bond-pads followed by solder paste printing is seen as one of the lowest cost routes for the bumping of wafers prior to flip-chip assembly. However, the electroless nickel bumping of Al bondpads is not straightforward and a number of activation steps are necessary to enable the nickel deposit to form a strong, electrically conductive bond with the Al. For the electroless nickel coating of mechanical components made of aluminum, a zincate activation process has been used for many years; however, extension of these techniques to semiconductor wafers requires careful control over these pretreatments to avoid damage to the very thin bondpads. This paper reports a number of experiments designed to characterize the activation of Al bondpads to electroless nickel plating, focusing on the effects of solution exposure time and bondpad composition. In addition, the results are discussed in the context of other studies presented in the literature to provide an understanding of the mechanism of the zincate activation process applied to Al bondpads.
52 citations