The feasibility of preparing a thin layer of alpha-Al2O3 on the surface of a single-crystal, Ni-based superalloy was examined using a chloride-based chemical vapor deposition (CVD) process previously developed for cutting tool applications. A coating directly deposited by this method on the alloy surface consisted of similar to1 mum alpha-Al2O3 crystals in a matrix of amorphous Al2O3. When the alloy surface was predeposited with an electroplated Pt layer, the coating was mostly alpha-Al2O3, but with the presence of fine microcracks on the coating surface. In comparison to the results observed for pure Pt substrate, the role of the Pt interlayer was apparently to promote the rapid formation of kappa-Al2O3 nuclei, which subsequently transformed to alpha-Al2O3 during the CVD growth process.