Title page for ETD etd-04252003-104756


Type of Document Dissertation
Author Pugh, Dylan Vicente
Author's Email Address dypugh@vt.edu
URN etd-04252003-104756
Title Nanoporous Platinum
Degree PhD
Department Materials Science and Engineering
Advisory Committee
Advisor Name Title
Corcoran, Sean Gerald Committee Chair
Reynolds, William T. Jr. Committee Co-Chair
Farkas, Diana Committee Member
Kampe, Stephen L. Committee Member
Saraf, Ravi F. Committee Member
Keywords
  • surface diffusivities
  • selective dissolution
  • small angle neutron scattering
  • nanoporous metals
Date of Defense 2003-04-21
Availability unrestricted
Abstract
Dealloying is a corrosion process in which one or more elements are selectively removed from an alloy leading to a 3-dimensional porous structure of the more noble element(s). These porous structures have been known to cause stress corrosion cracking in noble metal alloy systems but more recent interest in using the corrosion process to produce porous metals has developed. Applications for these structures range from high surface area electrodes for biomedical sensors to use as skeletal structures for fundamental studies (e.g. low temperature heat exchangers or sensitivity of surface diffusivity to chemical environment). In this work we will review our current understanding of alloy corrosion including our most recent results demonstrating a more accurate method for calculating alloy critical potential based on potential hold experiments. The critical potentials calculated through the potential hold method were –0.030VMSE, 0.110VMSE, and 0.175VMSE for Cu80Pt20, Cu75Pt25 Cu71Pt29 respectively. We will present the use of porous metals for making surface diffusivity measurements in the Pt systems as a function of chemical environment. A review of the use of small angle neutron scattering to make accurate measurements of pore size is presented and the sensitivity of pore size to electrolyte, electrolyte composition, applied potential and temperature will be explained. The production of porous Pt with pore sizes ranging from 2-200nm is demonstrated.
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