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

  • 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. Continue reading…


    

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

  • 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. Continue reading…


    

Influence of wet surface pretreatment on the electroless metallization of stereolithography resins

In the present paper, the influence of different wet pretreatment routes on the final quality of electroless layers plated on stereolithography resins is investigated. Two pretreatment methods, acidic and alkaline, are employed. Acidic etching is unable to provide acceptable results in terms of surface quality. On the contrary, alkaline etching guarantees a bright copper surface coupled with a level of adhesion high enough to pass a standard peel test. ATR FT-IR is employed to investigate the chemical reactions occurring on the resins during the pretreatment, evidencing a major role of the ester hydrolysis process on the depolymerization of the material and on the formation of new functional groups on the surface. Resin hydrolysis is linked with increase in surface roughness and wettability, parameters that strongly determine final metal adhesion. The combination of ATR FT-IT, contact angle and roughness measurement constitutes a possible combined methodology to follow the evolution of surface pretreatment on different stereolithography resins. Continue reading…


    

Electroforming with Nickel

  • Das ist ein Test


While there are a large number of written documents on nickel as a coating, there are very few dealing with nickel electroforming. This technology is an important consumer of nickel – about 5,000 tons per year worldwide – used to manufacture a wide range of articles (it is a manufacturing process, not a coating process). It is indeed the ONLY process that can produce certain very important products that are very often used in society. Most people are not aware of the process and its importance. It is a process that is indispensable for the production of compact audio discs and digital visual discs. Since the annual production of these items is estimated at about 4.000,000,000, you can see how important it is for our lifestyle today. Another very large application is the mass production of holograms. Continue reading…


    

Diverse Applications of Simultaneous Occurrence of Oxidation-Reduction Reactions

Oxidation-reduction reactions also known as redox reactions for a shorthand term are typified by any chemical process that involves transfer of electrons between two species. The ubiquitous nature of redox reactions occurs over diverse systems ranging from industrial processes to chemical reactions encountered in everyday basic life functions. Based primarily on electrochemistry, the present article reviews the science of redox reactions with applications in some specific industrial and real life cases. Continue reading…