Radio frequency sputtering has been used to deposit alpha-alumina (alpha-Al2O3) thin films at substrate temperatures of 280-560 degreesC. The films are shown to be single phased and hard. Nanoindentation gives values of 306 +/- 31 and 27 +/- 3 GPa for elastic modulus and hardness, respectively, for a substrate temperature of 280 degreesC. Growth of the a phase was achieved by in situ predeposition of a chromia template layer. Chromia crystallizes in the same hexagonal structure as alpha-alumina, with a lattice mismatch of 4.1% in the a- and 4.6% in the c-parameter, and is shown to nucleate readily on the amorphous substrates (silicon with a natural oxide layer). This results in local epitaxy of alpha-alumina on the chromia layer, as is shown by transmission electron microscopy. The alumina grains are columnar with grain widths increasing from 22 +/- 7 to 41 +/- 9 nm, as the temperature increases from 280 to 560 degreesC. This is consistent with a surface diffusion dominated growth mode and suggests that alpha-alumina deposition at low temperatures is possible once initial grain nucleation has occurred. Results are also presented demonstrating chromia/alpha-alumina growth on a technological substrate (Haynes230 Ni-based super alloy, Haynes International, Inc.). (C) 2004 American Vacuum Society.