Material Science

Research Programs

• Novel thermoelectric materials
  Over the past few years we have been working with the Jet Propulsion Laboratory, a branch of NASA, to study new types of thermoelectric materials.  These materials can convert a temperature gradient directly into electric power and will be a component in the energy source portfolio of the future.  To date we have investigated nanostructured silicon germanium, lanthanum telluride, and Zintl phase YMS materials.  We are beginning a study of lead telluride and skutterudites.
• Metal-hydrides
  It has been long known that hydrogen gas can insert itself into the spaces between atoms in many types of metals.  This is one approach to hydrogen storage.  A detailed knowledge of the hydrogen absorption and desorption process is crucial to the design and optimization of hydrogen storage units.  The Materials Science group at NCPA is in the process of studying the elastic constants of palladium hydride at high temperatures and hydrogen pressures.  We have plans to study non-metalic hydrogen absorbers such as graphene sheets and ways to speed hydrogen absorption/desorption rates using acoustic resonances.
• Novel ceramics for hydrogen fuel cells
  Ceramic based hydrogen fuel cells require high temperatures for operation and require strong, thermally robust structural components.  We are beginning a study into several types of novel layered ceramics at high temperatures which are being developed for next generation fuel cell technology for use in automobiles.
• Lead-free solder alloys
  New types of solder alloys avoid the use of lead for environmental and health reasons.  A current problem with these alloys however is excessive brittleness, which can lead to failure of solder joints in electronics.  We have a current study to measure the elastic moduli in polycrystalline lead-free solder alloys up to the melting point for samples at various degrees of aging.  Additionally, we are measuring crystallite growth dynamics by monitoring acoustic resonances over time.

About Materials Science Group:

• The materials science group at the NCPA has focused on characterization of mechanical properties and structure of novel materials. Elastic constants of a crystal are a measure of the curvature of the energy binding atoms together and, as such, they are sensitive probes into changes in the atomic environment.  Because elastic constants are relevant to both microscopic and macroscopic properties of a material, they are important to both fundamental solid state physics as well as materials and mechanical engineering.  Our group has focused to elastic constant measurements in extreme environments including both high temperatures (up to 1000 oC) and high pressures (vacuum to 140 atmospheres).  The types of materials we are primarily interested in are energy related materials which will eventually become components of clean, carbon free energy systems in the future.

Collaborators and Sponsors

• Jet Propulsion Laboratory
• Los Alamos National Laboratory
• Oak Ridge National Laboratory
• Cisco Systems Corp.
• Delphi Corp.
• U.S. Army