Electrodeposition of flow-induced composition modulated nife alloys in the uniform injection cell

Abstract

NiFe thin film alloys with nanometer-scale spatially periodic composition modulations have been electrodeposited in the uniform injection cell (UIC) by oscillating the electrolyte flow rate. [See, Medina and Schwartz, J. Electrochem. Soc. 142, 451, 457, L46 (1995) for a description of the UIC.] The flow-induced composition modulated alloys were made using flow oscillation frequencies ω ≤ 0.05 Hz and galvanostatic deposition at -10 mA cm-2. Flow-induced periodicity wavelengths (Λ) as small as 55 nm were measured using stripping voltammetry. The experimental results showed that Λ had the expected inverse dependence on the flow oscillation frequency. The electrochemical response of the NiFe plating system was found to be out of phase with the low frequency (quasi-steady) flow modulations, a result that reiterates the anomalous nature of NiFe codeposition and the important role that careful hydrodynamic impedance studies could possibly play in analyzing the system. © 1997 Elsevier Science Ltd.