William J. Dawson

Fuel processing catalysts based on nanoscale ceria

Abstract The water-gas shift (WGS) reactor is a key component in fuel processors, but existing WGS catalysts are unsuitable for transportation applications, since the iron-chrome catalysts used at high temperatures are relatively inactive, and the copper-based catalysts used at low temperature tend to degrade under the severe conditions encountered in an automotive system. NexTech Materials has developed hydrothermal synthesis methods for dispersed suspensions of nanoscale ceria and ceria-zirconia, to give more active WGS catalyst, as well as more efficient and rugged catalyst packaging. The resulting WGS reactors based on ceramic monoliths loaded with Pt/ceria catalysts provide a technically viable and cost-effective option for automotive fuel processors.

Development of a Templated Grain Growth System for Texturing Piezoelectric Ceramics

High strain actuation can be obtained from crystallographically textured piezoelectric ceramics. Single crystal piezoelectrics demonstrate high strain because crystal orientation can be controlled - the perfect lattice simplifies crystal orientation. Single crystals actuate better than typical ceramics, but are expensive. Highly textured ceramics offer an alternative path to easily aligned crystals. The crystallites in textured ceramics are crystallographically oriented. Textured ceramics are expected to provide improved properties, with lower processing costs. NexTech Materials is developing textured piezoelectrics via Templated Grain Growth. In this process, anisotropic template particles are oriented in a fine matrix. During heat treatment, the templates grow, resulting in a textured polycrystal.

Novel methods of powder preparation and ceramic forming for improving reliability of multilayer ceramic actuators

Critical components of many smart systems employ multilayer piezoelectric actuators based on lead zirconate titanate (PZT) ceramics. Applications include active vibration systems, noise suppression, acoustic camouflage, actuated structures, reconfigurable surfaces, and structural health monitoring. Two strategies involving novel materials processing techniques are discussed for improving the performance and reliability of PZT ceramic components. The first is the use of an advanced powder synthesis, which was recently developed for a range of DoD specification materials. The second strategy involves two improved ceramic manufacturing routes designed to replace the current tape casting and co-firing method. One is the use of roll- compaction for tape forming. The other is the application of the infiltrated electrode approach. Both of these methods provide improved electrical and mechanical performances and superior reliability.