AVS 50th International Symposium
    Surface Science Thursday Sessions
       Session SS2-ThM

Paper SS2-ThM2
Chemical Inhibition of Aluminum Surface Oxidation

Thursday, November 6, 2003, 8:40 am, Room 327

Session: Catalysis III: High vs. Low Pressures
Presenter: V.J. Bellitto, Naval Surface Warfare Center
Authors: V.J. Bellitto, Naval Surface Warfare Center
J.N. Russell, Jr., Naval Research Laboratory
Correspondent: Click to Email
Aluminum powders are used to tailor the energetic content of propulsion and explosive systems. As the size of aluminum particles approach the nano-scale, the performance of the energetic materials may be enhanced by providing greater surface to volume ratios, but not if the nano-particle is largely comprised of aluminum oxide. Therefore, we are examining chemical methods for passivating aluminum surfaces and inhibiting oxidation. We report the surface chemistry of a series of perfluoro- and perhydro- carboxylic acid compounds on an Al(111) surface and their ability to inhibit aluminum surface oxidation. Using x-ray photoelectron spectroscopy and infrared reflection absorption spectroscopy we established the compounds chemisorb on the atomically clean Al(111) surface through scission of the O-H bond and formation of carboxylate species. We monitored the temperature dependent chemistry of the adsorbates, demonstrating the greater thermal stability of the fluorinated surface species. The oxidation rates of the clean, partially functionalized (0.5 ML) and fully functionalized (1ML) Al(111) surfaces were compared. The fully functionalized surface did not exhibit spectroscopic features characteristic of O@sub 2@ chemisorption or Al@sub 2@O@sub 3@ formation even after being exposed to > 1 x 105 L of O@sub 2@ at room temperature. The thermal dependence of the oxidation inhibition is under investigation.