Making superior corrosion resistant aluminum oxide films using ozone-electrochemical and electron microscopy studies

Aluminum surfaces have been subjected to oxidation at 300 K, using a molecu lar beam of ozone of 97% purity. An enhancement of the kinetics of oxidatio n is found compared to oxidation by O-2. The oxide film produced exhibits e nhanced corrosion resistance as measured by several electrochemical methods compared to comparable thickness oxide films made by oxygen exposure. Tran smission electron microscopy measurements show that the ozone-grown films e xhibit small pore sizes and also increased average density as measured by t he behavior of the radial distribution function derived from electron diffr action measurements on films made from ozone and oxygen. These effects may be due to the lower oxygen vacancy defect density in films made from ozone. The special properties of ozone-grown aluminum oxide films are preserved e ven after the films are removed from vacuum and exposed to the atmosphere. (C) 2001 American Vacuum Society.