Keith Sheppard

Air-Impregnated Nanoporous Anodic Aluminum Oxide Layers for Enhancing the Corrosion Resistance of Aluminum

Nanoporous anodic aluminum oxide layers were fabricated on aluminum substrates with systematically varied pore diameters (20-80 nm) and oxide thicknesses (150-500 nm) by controlling the anodizing voltage and time and subsequent pore-widening process conditions. The porous nanostructures were then coated with a thin (only a couple of nanometers thick) Teflon film to make the surface hydrophobic and trap air in the pores. The corrosion resistance of the aluminum substrate was evaluated by a potentiodynamic polarization measurement in 3.5 wt % NaCl solution (saltwater). Results showed that the hydrophobic nanoporous anodic aluminum oxide layer significantly enhanced the corrosion resistance of the aluminum substrate compared to a hydrophilic oxide layer of the same nanostructures, to bare (nonanodized) aluminum with only a natural oxide layer on top, and to the latter coated with a thin Teflon film. The hydrophobic nanoporous anodic aluminum oxide layer with the largest pore diameter and the thickest oxide layer (i.e., the maximized air fraction) resulted in the best corrosion resistance with a corrosion inhibition efficiency of up to 99% for up to 7 days. The results demonstrate that the air impregnating the hydrophobic nanopores can effectively inhibit the penetration of corrosive media into the pores, leading to a significant improvement in corrosion resistance.

Information technology as a bridge between engineering analysis, visual design and informal education

The creation of a new graduate program in product-architecture, that fuses the design culture normally associated with architecture and industrial design with the engineering institution, has presented the opportunity to better prepare students for a paradigm in which design, engineering and its application merge as an interdisciplinary, collaborative endeavor. In turn this graduate program has been a catalyst to draw in undergraduates in traditional engineering disciplines to this new mode in higher education that also bridges the gap between: undergraduate and graduate education, visual design and engineering disciplines and the academic and professional setting. At the heart of this new approach is the effective use of information technology. This is illustrated through a project to design a museum building and multimedia exhibition to display a supersonic Concorde aircraft. The design of the building and of the interactive, multimedia exhibit take cues and content from engineering analysis of the aircraft design as it relates to sub-sonic and supersonic flight.