The influence of Polyethylene Glycol 200 (PEG(200)) or a PEG(200)/benzylideneacetone (BDA) mixture on the mechanism of Zn deposition and nucleation kinetics was studied by voltammetry, chronoamperometry and atomic force microscopy (AFM). The addition of PEG(200) or PEG(200)/BDA to the solution partially inhibited the reduction of Zn(II) at E = -1.135 V vs. SCE. In the presence of PEG(200)/BDA, an additional reduction process was observed at E = -1.24 V vs. SCE. Analysis of the nucleation processes indicated that, in all systems studied, the initial stage of Zn deposition was dominated by 3D diffusion-controlled nucleation. At E = -1.132 V vs. SCE, the addition of PEG(200) caused a reduction in the nucleation rate constant (A) and the number density of active sites (N(0)) with respect to the values obtained without additives. AFM analysis of coatings obtained at E = -1.132 V vs. SCE, showed the formation of Zn clusters with different sizes distributed randomly on the surface. At E = -1.243 V vs. SCE, both A and N(0)were higher for the solution containing the PEG(200)/BDA mixture than for the systems with PEG200 alone or without additives. AFM analysis revealed the formation of similarly sized Zn clusters uniformly distributed on the surface. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3591058] All rights reserved.