Katherine Faber Ph.D., California Institute of Technology, "Probing Pore Space: Creating and Characterizing Porous Ceramics"

Thursday, April 20, 2017 -
3:00pm to 4:30pm
101 Thomas 3:05 pm - 4:20 pm

Pores have long been regarded as undesirable in the search for the perfect ceramic. The deleterious role of pores on mechanical properties notwithstanding, porosity has now become important, even critical, in expanding the utility of ceramic materials.  In addition to lowering density, pores have become the conduits for fuels and reaction products in fuel and electrolysis cells.  They serve as the size limiter in filtration, the source of high surface area for catalysts, and the path for cell growth in biomedical implants. In this presentation, methods for producing various pore structures in oxide and carbide ceramics are explored. These approaches range from directional freeze casting, in which a fluid, upon freezing, pushes ceramic particles aside and serves as a sacrificial template for the pore network, to a fluorotopaz decomposition reaction where acicular grains form “pick-up stick”-like microstructures.  Pore size, fraction, and distribution, as well as connectivity and tortuosity of porous systems, all vital for understanding pore effects on material properties, are evaluated using 3D data sets produced using synchrotron X-rays. Pore network-property relations are also discussed.