The single-phase gamma zinc-nickel alloy (gamma-Zn3Ni) nanocrystal was deposited on composite graphite electrode at a scan rate of 10,000 mV s(-1). The average particle size obtained was 11.8 +/- 3.1 nm. Transmission electron microscopy analysis indicated that codeposition applied potential, i.e., nucleation overpotential, scan rate, and codeposition time were critical on crystal sizing and Ni content in the matrix. Cyclic voltammetry and analysis of X-ray diffraction have also indicated that single-phase (gamma-phase) alloy was, indeed, obtained at the scan rate used. The results also revealed that 19.0 wt % Ni nanoparticles were uniformly dispersed in the phase compositions of the alloy coating. (C) 2008 The Electrochemical Society. [DOI: 10.1149/1.2987744] All rights reserved.