Influence of anodic pulses and periodic current reversion on electrodeposits. (November 2014)

• Record Type: Journal Article
• Authors: Leisner, P.; Zanella, C.; Belov, I.; Edström, C.; Wang, H.
• Is Part Of: Transactions of the Institute of Metal Finishing. Volume 92:Number 6(2014:Nov.)
• Page Start: 336
• Page End: 341
• Publication Date: 2014-11
• Subjects: Pulse reverse, -- Periodic current reversion, -- Silver, -- Throwing power, -- Passivation, -- Internal stress; Metals -- Finishing -- Periodicals; Metals -- Surfaces -- Periodicals; Metallurgy -- Periodicals; 671.705
• DOI: 10.1179/0020296714Z.000000000210
• Languages: English
• ISSNs: 0020-2967

Abstract

Abstract : This paper discusses how anodic pulses and periodic current reversion influence electrodeposition. Depending on the involved metal and electrolyte, very different effects can be observed and taken advantage of. The Wagner number, Wa, describing the current distribution is shown to be useful for predicting the throwing power at low frequencies of current reversion, even in complex electrochemical systems, but is less useful at higher frequencies. Passivation can occur due to oxide formation, super-saturation of metal salts or depletion of complexing agents at the electrode surface. Furthermore, dissolution and desorption processes in the anodic period can have strong influence on the succeeding cathodic electrocrystallisation affecting preferred crystal orientation, intrinsic stress and current efficiency. A literature survey is combined with experiments from silver plating from a cyanide bath.