Y2O3 nanospheres were prepared by a two-step process involving cathodic deposition of yttrium hydroxide thin films in a chloride bath followed by thermal conversion of hydroxide into crystalline Y2O3 in air. Optimum conditions for an adherent and compact film of Y(OH)(3) nanospheres on steel substrates were obtained via a galvanostatic synthesis by applying a cathodic current density of 2 mA cm(-2). The morphologies and structures of as-deposited and heat-treated materials were examined by means of scanning electron microscopy and transmission electron microscopy (TEM) methods as well as X-ray diffraction. Raman and Fourier transform IR spectroscopies were used to further characterize the oxide sample. To investigate the dehydration and decomposition behaviors, thermal analysis of samples was performed by means of differential scanning calorimetery and thermogravimetric analysis. The obtained oxide comprised larger monodispersed spheroids nearly 500 nm in diameter. TEM revealed that these are composed of smaller nanoparticles with an average particle size of 50 nm. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3469574] All rights reserved.