Abstract
Using a vacuum CVD technique, alumina films were deposited on 10 mu m diameter carbon fibers, and 120 mu m diameter silicon carbide fibers. This was accomplished by exposing resistively heated microfiber substrates to a sublimate of [Al(O- super(t)Bu) sub(3)] sub(2), while the reaction chamber was maintained at 120 degree C under a pressure of 0.15 torr. The coated substrates were then sealed into glass capillaries, using an epoxy sealant, to form microelectrode devices. The quality of the alumina films was found to be dependent on the substrate temperature, with optimum film quality being obtained at substrate temperatures between 750 degree C and 800 degree C. Film thickness was controlled by deposition time, and films from 1-100 mu m were routinely produced. Films were characterized by microscopy and electrochemical techniques.