Versatile electrochemical coatings and surface layers from aqueous methanesulfonic acid

Abstract

Ever tightening environmental pressure together with the continued need for coatings able to meet challenging service environments have stimulated advances in coating technology. In the case of electrochemical techniques, the classical techniques of electrodeposition and anodising are being upgraded to meet the need for modern surface engineering coatings (including nanostructured films) on metals. A major challenge is to retain conventional processing, including aqueous solutions, simple power supplies and existing electrolyte tanks while using cost effective, 'green' electrolytes. One successful direction has been the emergence of electrolytes based on methanesulfonic acid, MSA which has good electrolytic conductivity and is capable of dissolving many metals as well as acting as a useful medium for dispersion of solids prior to electrophoretic coating. A range of application methods result, including electroplating, anodising and electrophoretic deposition from a stable, aqueous sol. A diverse range of coating materials is emerging, including metals, alloys, porous metal oxide films, conductive polymers and many composites. This review illustrates the usefulness and applications of MSA electrolytes using recent examples from the authors' laboratories and others. Developing coatings, including alternating multilayers of Sn and Cu, nanostructured metals, hierarchical pores, nanotubular metal oxides and graphene composites are briefly considered. This is a review with 94 references.

Electrodeposition and pyrolysis of Mn/polypyrrole nanocomposites: a study based on soft X-ray absorption, fluorescence and photoelectron microspectroscopies

“…[35][36][37][38][39][40]57,58 Addition of small amounts of H 2 O in acetonitrile baths for PPy electrodeposition, has been reported to increase the rate of pyrrole electropolymerisation owing to a reduced electrostatic repulsion among hydrated radical cations. 58 It is worth noting that MnO 2 /PPy composites can be electrodeposited in a single-step one-pot anodic process from an electrolyte containing pyrrole and Mn(II), 65 nevertheless, the scope of the present investigation involves the co-electrodeposition of binary 36,37 and ternary 38,51 Mnbased composites and, since the elemental form of the alloying element is of interest, in this study we have concentrated on the combined anodic/cathodic process. 60,61 Basicity is further ensured by acetonitrile hydrolysis, yielding acetic acid and NH 3 .…”

Composite, multilayer and three-dimensional substrate supported tin-based electrodeposits from methanesulphonic acid

“…The extremely wide range of coatings and surface finishes possible from such electrolytes (single metals, alloys, ceramics, polymers and composites) by electroplating, electrophoresis and anodising has recently been profiled 4 .…”

Effects of the degradation of methane sulfonic acid electrolyte on the collapse failure of Sn–Ag alloy solders for flip-chip interconnections

“…[10][11][12][13][14] However, one of the most serious issues when using the MSA based electroplating bath is that the electrolyte gradually degrades with time, particularly when it is used for mass production in industrial elds, although the composition can be maintained by adding undegraded additives and inorganic components. Because the mechanical and electrical reliability of the Sn based alloy solders are highly dependent on the electroplating conditions, [15][16][17][18][19][20][21] the degradation of the electroplating bath leads to packaging problems.…”