Low energy electron diffraction study of low index platinum single crystal surfaces
Lyon, Hylan Benton, Jr.
MetadataShow full item record
The post-acceleration technique of Low Energy Electron Diffraction has been used to examine the three low index (100), (110), (111) crystal faces of platinum. The single crystal samples were subjected to ion bombardment, ultra-high vacuum anneal (p = 5Xl0(-10) torr) 25°C < T < 1450°C) and exposure to different gases (0(2), CO, H(2), CH(4), C(2)H(4), NH(3), N(2)). The changes in the diffraction features of platinum were correlated to these treatments in an attempt to explain the appearance of new surface structures. Several distinct sets of new diffraction patterns were observed as a function of these different treatments. These were characterized by the appearance of new periodicities in the diffraction pattern at well-defined ranges of electron beam energy. A high temperature anneal (T > 1000 °K) in ultra high vacuum will generally lead to the formation of a disordered, highly unreactive structure which is the same for all three faces of platinum. The specular intensity was measured as a function of beam voltage. The Debye temperatures which characterize the mean displacement of the surface atoms perpendicular to the surface planes were measured for all three faces. The average value of the surface Debye temperature is 110°K and shows little variation from face to face. The Debye temperature of bulk platinum is 234°K.
This thesis document was issued under the authority of another institution, not NPS. At the time it was written, a copy was added to the NPS Library Collection for reasons not now known. It has been included in the digital archive for its historical value to NPS. Not believed to be a CIVINS (Civilian Institutions) title.
Showing items related by title, author, creator and subject.
Lugge, John J. (Monterey, California: Naval Postgraduate School, 2013-06);Currently, carbon is the preferred support material for platinum catalyst particles used in polymer electrolyte fuel cells (PEFCs). Carbon possesses qualities needed for a fuel cell catalyst: high surface area and conductivity, ...
Livingston, Gill Frederick (Massachusetts Institute of Technology, 1968-05);The S/N fatigue life gage is a small sensor which is similar in appearance to a foil strain gage. The S/N fatigue life gage is bonded to the surface of a mechanical structure using standard strain-gage techniques. The ...
Plastic instability of platinum modified and unmodified aluminide coatings during 1100 C cyclic testing McCloskey, Margaret Ann (Monterey, California: U.S. Naval Postgraduate School, 1987-09);In a study conducted at the Naval Postgraduate School on the effect of cyclic oxidation at 1100C on platinum modified and unmodified aluminide coated nickel base superalloy (I-738), a surface deformation described as ...