Advanced Features of Electrolytic Silver-tin (AgSn20) Process

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This work describes the Silveron™ GT-820 Silver-Tin as a robust process for the electrodeposition of silver-tin alloys of composition equal to Ag3Sn and Ag4Sn. A design of experiment method was used to study the influence of process parameters on the deposit performance. It was found that the alloy composition is controlled by organics components of the bath. It is independent on the metal concentration ratio and the applied current density inside the specified process window. The silver-tin deposit is semi-crystalline directly after plating but can be converted to a fully crystalline material by a short annealing. This coating is not only ductile and tarnish resistant but also displays a good insertion and retention force needed for press-fit interconnections. The product was tested successfully under serial production conditions and shown to be suitable for tin and tin-lead replacement in solderless interconnections.

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A Study on Environmentally Friendly Electroless-Plating

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An innovative environmentally friendly electroless plating technology is proposed in this research. This innovative technology, which is a modified galvanic displacement electroless plating technology, combines a thick film aluminum conductor with the galvanic redox chemical displacement reaction. The thick film Al conductor, which has three major characteristics, including a high oxidation potential, a porous structure, and ultra-low cost, is used to define a pattern by using screen printing, where a sacrificial layer is used to carry out the galvanic displacement reaction with other metal ions. Since the existing displacement electroless plating is only reacted on the surface of metal, a porous, thick film Al conductor is used instead of a metal film to obtain entire replacement when the galvanic redox displacement reaction is carried out with low oxidation potential metal ions, such as copper, nickel, etc. In this study, the innovative environmentally friendly displacement electroless plating technique solves the environmental issues associated with electroless plating of Cu with formaldehyde and electroless plating of Ni with lead, and thus provides clean, electroless plating of Cu and Ni films with good electrical performance.

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Environmentally friendly electrolyte for the electrodeposition of Cu-Zn alloys

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Environmentally friendlier and safer alternatives are required as replacement for highly toxic cyanide baths used by electroplating industries. Glutamate has proved to be an adequate complexing agent in alkaline copper and zinc plating baths due to its capability to form anionic complexes with those metal ions. Consequently, studies with a glutamate-based electrolyte for Cu-Zn alloys deposition are presented.
In this work, cathodic polarization experiments on a rotating disk electrode in both static and rotating conditions were carried out using the novel electrolyte with and without the addition of a polymeric cationic surfactant (Polyquaternium-7). The deposits were later dissolved by anodic stripping to characterize the electrochemical processes involved in the Cu-Zn-Glutamate system. Galvanostatic experiments, using flat steel electrodes as substrate, were carried out at different current densities with and without additive. These coatings were characterised by SEM, EDS and XRD.
Cu-Zn alloys with compositions between 37-83 wt.% of copper were obtained. α, β and γ phases were obtained depending on the electrolyte composition and the applied current density.

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Investigation of nucleation mechanism and surface morphology of the crystallites in zinc-cobalt alloy coating

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  • Fig. 1: Hull cell experimental results: (a) Key, Influence of (b) Brightener (TG) (c) Zinc Sulphate (d) Cobalt Chloride (e) Sodium sulphate (f) Boric acid (g) Cetyl trimethyl ammonium bromide (CTAB) (h) pH (i) Temperature (j) Current

In present investigation, a new brightener was synthesized by condensation of 3, 4, 5-Trimethoxy benzaldehyde and Glycine (TG). Hull cell experiments were conducted to optimize the plating bath components and operating parameters. To examine the influence of TG on nucleation mechanism of Zn-Co alloy electrodeposition, cyclic voltammetry and chronoamperometry study was carried out. Schariffker and Hills model was used to analyze current transients, which in presence of TG confirmed instantaneous nucleation. Corrosion studies were done using potentiodynamic polarization and electrochemical impedance spectroscopic technique, in 3.5 wt. % NaCl for bright and dull zinc-cobalt alloy coatings. Phase structure, surface morphology and brightness of the deposit were characterized by X-ray diffraction analysis, scanning electron microscopy and reflectance studies. These studies revealed the role of TG in modifying the nucleation mechanism and surface morphology of zinc-cobalt alloy crystallites and thereby producing a bright corrosion resistant Zn-Co alloy coating on mild steel substrate.

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The need for digitalisation in electroplating - How digital approaches can help to optimize the electrodeposition of chromium from trivalent electrolytes

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  • Fig. 1: Example of an ontology for the description of the electrodeposition of chromium and the characterization of the layer properties. The scheme contains optimization loops for the chromium deposition process by ML and simulation based modelling
    Fig. 1: Example of an ontology for the description of the electrodeposition of chromium and the characterization of the layer properties. The scheme contains optimization loops for the chromium deposition process by ML and simulation based modelling

In order to make material design processes more efficient in the future, the underlying multidimensional process parameter spaces must be systematically explored using digitalisation techniques such as machine learning (ML) and digital simulation. In this paper we shortly review essential concepts for the digitalisation of electrodeposition processes with a special focus on chromium plating from trivalent electrolytes.

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