Tartrate-Based Electrolyte for Electrodeposition of Fe–Sn Alloys

Magnetic properties of the sustainable Fe−Sn alloys are already known. However, there is lack of information in the field of Fe−Sn electrodeposition. In the present study, a novel Fe(III)−Sn(II) electrolyte with tartaric acid as a single complexing agent is introduced. The influence of the pH and the current density on the structural properties of the Fe−Sn deposit was studied. The stability of the electrolytes as a main attribute of sustainability was tested. The ferromagnetic phases Fe5Sn3 and Fe3Sn were electrodeposited for the first time, and it was found that the mechanism of the Fe−Sn deposition changes from normal to anomalous at a pH value 3.0 and a current density of approximately 30 mA/cm2. A possible reason for the anomalous deposition of Fe−Sn is the formation of Fe-hydroxides on the cathode surface. Two electrolyte stability windows exist: The first stability window is around a pH value of 1.8 where bimetallic Fe−Sn tartrate complexes were formed, and second one is around a pH value of 3.5 where most of the Sn ions were present in the form of [Sn(tart)2]2− and Fe in the form of [Fe(tart)]+ complexes

Pulse Plating

Surface Technology and in particular, Electroplating, is a key, across-the-board discipline without which the entire range of today's manufactured products would not exist. The formation of functional surfaces is a key to innovation in all branches of industry. In the realm of Electroplating, the use of pulsed deposition currents, known as "Pulse Plating" allows the production of a wider range of coating layers than those possible using DC, with extremely attractive functional properties. It is, however, the case that Pulse Plating is a knowledge-based technology. In order to exploit it to the full, a detailed knowledge of electrode kinetics and mass-transport in the electrolyte is essential. This volume, edited by two leading authorities in the field, presents the state-of-art knowledge of the science and the associated technology and equipment. Building on what was hitherto the standard work on the subject, written in the 1990's, the current understanding of the basic principles is presented together with the full range of processes now available, within its 400 pages, in the English language. Significant developments within the field of Pulse Plating both from aqueous solutions and ionic liquids include the deposition of binary and ternary alloys, composite coatings, compositionally-graded coatings and multilayer coatings. Also described are nanocrystalline deposits and selective plating which is widely used in electronics manufacture and in high-rate deposition processes for coating semiconductors (electronics, solar cells....). The technology is also used in anodic processes (oxidation, electrochemical machining, electropolishing etc). Following a forward-looking but also critical introductory chapter, the book falls into four sections covering all the basic principles and significant industrial applications of the technology. The first of these sections opens with an in-depth treatment of the thermodynamics and reaction kinetics of metal deposition at the metal-electrolyte interface. Special emphasis is laid on the kinetics of multi-step processes, on alloy deposition as well as the importance and modus operandi of additives, all of this supported with examples and documentation. Nucleation and growth processes in electrodeposition and formation of microstructure as well as nanocrystalline deposits using both DC and Pulse Plating are described. A systematic approach to the effect of additives, hitherto scarcely described in the literature, is also provided. The effect of Pulse Plating parameters on secondary current distribution (below the limiting current density) is critical. The use of simulation and modelling is also discussed, not least as used in an industrial setting. One important example of this is the modelling of copper electrodeposition for blind via filling. Of special importance in metal electrodeposition using Pulse Plating are phenomena at the electrode double layer in relation to mass transport and the effects of current pulsing on the double layer structure, which in turn, affects current efficiency. The effects of pulsed current on additives and microstructure as well as alloy deposition are also discussed. Finally, the various models used in simulation of metal and alloy electrodeposition are described. In the second section, various aspects and requirements for industrial applications of pulse electrodeposition are set out. Thanks to electronic and electrotechnical developments in modern power supplies, these can deliver any conceivable pulse regime in terms of current and rapid voltage transients such as square wave pulses. Where suitable equipment is installed, this ensures that the deposition process can be optimised. The means by which an understanding of basic principles can be harnessed to the practical electrodeposition of metals is shown with special emphasis on identification of key pulse plating parameters. Especially helpful in this respect is a systematic approach to determining these parameters for rack and barrel plating. Finally, there is a consideration of the environmental aspects of pulse plating in terms of energy consumption and the related CO2 emissions. The third section of the book covers in great depth, the industrial applications of pulse plating. Of these, the most important is currently copper electrodeposition for printed circuit board manufacture with special emphasis on Pulse Reverse Plating for through-hole contacting and filling of blind vias. It is in these particular applications that the strengths of Pulse Plating become especially evident. Also covered is the deposition of nickel and its alloys as well as the deposition of nickel-phosphorus deposits, electroforming and formation of nanocrystalline nickel layers. Other processes include electrodeposition of tin and its alloys and the broad topic of chromium plating for decorative or functional applications. The deposition of precious metals and their alloys is discussed and the section concludes with an in-depth treatment of zinc and zinc alloy deposition, especially zinc-nickel. The fourth and last section deals with special systems. This includes the use of pulsed current for anodising aluminium and its alloys, Electrochemical Machining (ECM) as well as electropolishing. Other applications include the deposition of nanostructured multilayers (CMM) and the potential applications of pulse plating for electrodeposition of composite coatings, especially those incorporating nano-sized second phase particles. The whole volume is systematically laid out with various aspects clearly classified. It leaves no doubt as to the huge potential of the method for future developments in electrochemical surface treatment and the associated equipment. This new work which will certainly become the accepted standard and is aimed not only at those researching new developments, but also at those working in an industrial setting and others seeking to acquire proficiency in the subject