Electrochemical Preparations I (Conventional Coatings and Structures)

Abstract

Traditional electrodeposition refers to cathodic formation of bulk metals, preferably in the form of film coatings or electroformed articles, and is concerned with the practical objective of obtaining these materials in a coherent, dense, and macroscopically homogeneous state. Although the majority of plated materials are the (relatively) pure metals, unfavorable chemistry limits the number of metal elements that are capable of being obtained electrochemically from aqueous solutions in an unalloyed state, to only 33 of the about 70 metallic elements in the Periodic Table; and even less are the metals that are deposited to any extent for commercial or technical purposes. Nonetheless, the number of possible alloys which can be made from these metals is very large. Furthermore, immense are the binary or multiple combinations of metals with non-metallic elements; however, electrochemical preparative techniques have not played a significant role in the development of such materials, the reason probably lying in the more complicated character of the relevant processes as compared to electrodeposition of single metal elements or metallic alloys. In any case, the unique feature of electrodeposition being an electrically driven process capable of precise control offers a prospective advantage over thermally driven deposition processes. Further, electrodeposition occurs closer to equilibrium than many vacuum deposition methods; it is more applicable to complex shapes, generally less expensive, and capable of providing very thick coatings.