Hybrid Electro-Electroless Deposition (HEED)

Hybrid electro-electroless deposition (HEED) is a novel thin film metal deposition technique developed in Windsor.  The process combines both electroplating and electroless deposition within a single electrolyte.  The two deposition processes upon which HEED is based are combined such that each individual process targets a distinct metal ion for reduction.  The nature of the deposit is determined by the composition of the electrolyte and electroplating potential applied, among other well established factors for both individual techniques.  The process of HEED allows the formation of composite, alloyed, and multi-layered, or compositionally modulated alloy, deposits.  Composite HEED deposits are somewhat uncommon as one of the two techniques must produce well defined grains.  Alloyed HEED deposits are produced under two sets of conditions.   Either each individual technique comprising HEED, electroplating and electroless deposition, is made to deposit an alloy [1], or each technique deposits a thin layer for the purpose of interlayer diffusion.  Multi-layered HEED deposits are produced wherein each technique deposits pure, or nearly pure, metallic layers which nominally do not diffuse into one another [2].  The novelty of the HEED process may be illustrated with the deposition of metals of similar nobility, such as nickel and cobalt, in a multi-layered deposit [2].  The HEED multi-layers are in contrast to the standard method of electroplated multi-layers wherein the deposition potential and electrolyte support nearly pure layer deposition where the metals are of differing nobility [3].   

[1] Robert Petro and Mordechay Schlesinger, “Development of Hybrid Electro-Electroless Deposit (HEED) Coatings and Applications”, Journal of The Electrochemical Society, 161(10), (2014), p.D1-D6

[2] Robert Petro and Mordechay Schlesinger, “Deposition of Cobalt-Nickel Hybrid Electro-Electroless Deposited (HEED) Modulated Multilayers”, Journal of The Electrochemical Society, 162(4), (2015), p.D154-D158

[3] K. D. Bird, M. Schlesinger, “Giant Magnetoresistance in Electrodeposited Ni/Cu and Co/Cu Multilayers”, Journal of The Electrochemical Society, 142(4), (1995), p.L65-L66