Deposition of multifunctional titania ceramic films by aerosol routes

Aerosol coating processes were developed to deposit titania ceramic films o nto steel and silica substrates. In situ lightscattering measurements were used to understand the deposition mechanisms in different system configurat ions, The conditions that were necessary to obtain uniform, nonporous, and well-adhered titania films on steel substrates were established. The as-coa ted films had excellent anticorrosion characteristics at room temperature, as established by the standard salt-fog test. Film crystallinity and morpho logy were examined using X-ray diffractometry and scanning electron microsc opy; these analysis methods revealed an oriented, nanocrystalline anatase p hase. Film composition was established, as a function of film thickness, us ing Auger electron spectroscopy and was confirmed to be stoichiometric (Ti: O = 1:2), The optical band gap and optical phonons of the deposited films w ere probed using spectrophotometry and Raman scattering, respectively; thes e analysis methods revealed a blue shift of the gap, relative to bulk anata se, and a localization of carriers in the nanometer-sized crystallites.