Electrodeposition of Alloys Composites With Superior Corrosion Electrocatalytic Properties

摘要

Tremendous potential exists for the growth of metal finishing industry in this century through the development ofprocesses that are either environmentally friendly or are applicable at the nano scale. This talk will discuss some ofthe theoretical and experimental studies done to achieve such coatings. Nanostructured alloys and innovativecomposite materials were developed through adaptation of existing bath chemistries. Process development wasbased on techniques developed in our laboratories such as: under potential deposition (UPD) of monoatomic metallayers, autocatalytic reduction and potentiostatic pulse (PP) and pulse reversal (PR) plating of layers of amorphousand crystalline nanostructured alloys. The development process has been optimized based on obtaining superiorcorrosion and electrocatalytic properties. Further refinement of the coating process was achieved through thedevelopment of first principles based theoretical models. An example of this approach is our current focus todevelop electroless and electrodeposition based processes to synthesize secondary and ternary alloys such as Zn-Ni-X (X=Cu, Cd, Mo, or P). These materials were targeted as a replacement for Cd deposition and can inhibitcorrosion and completely eliminate hydrogen induced cracking. The talk will feature development of a novelprocess based on silicate electroless deposition from PQ solution for protection of zinc substrates. This process isdeveloped as an alternative for the conventional chrome passivation technique. A mathematical model will bepresented that explains the processes at the interface and estimates the thickness of the coating as a function of pHand concentration of electroactive species.The talk will also showcase the development of composite materials that are applicable in the next generation ofbatteries, super capacitors and fuel cell assemblies. With increasing miniaturization of electronic devices, currentfocus is on developing portable energy sources that can power these devices. To this purpose, severalnanostructured composites based on transition metals (Co/Ni/Cu) and noble metals (Pt/Pd/Ru) loaded on powderswere developed using electroless and pulse plating techniques. The talk will demonstrate that electrodeposition isan attractive method for controlling composite microstructure and morphology, thus yielding superiorelectrocatalytic properties.