I-Wei Chen Ph.D.
Materials science of electronic and structural ceramics including their thin films, heterostructures, and composites. Materials design, synthesis, testing and modeling.
Current Research Projects
Bulk and thin film ferroelectric oxides used for memory, sensors and actuator applications are being investigated to understand the roles of domain interfaces, lattice defects and electronic carriers in their performance. Thin films, oxide semiconductor heterostructures, single crystals and polycrystals are prepared to conduct model experiments using dielectric, ferroelectric, impedance, and mechanical spectroscopy. Computer simulation and analytical modeling are also used to gain mechanistic insight of these materials.
Silicon nitride is widely used today for turbomachinery, cutting tool, and bearing applications. Processing of silicon nitride is a classical physical chemistry problem involving liquid-solid interfaces, thin colloidal films, acid base reactions, and capillarity. The development of its unique whisker-like microstructure also allows continuing innovation by manipulating nucleation, growth and coarsening steps. We have discovered a new family of high toughness silicon nitride that is as hard as carbides and borides. This discovery opens up opportunities for new applications for structural ceramics.
Oxide Microalloys and Microlaminates:
Oxide solid solutions and microlaminates have unique properties and processing characteristics not seen in ordinary monoliths and composites. They can be developed for applications as automotive catalysts, filters, and machinery components. By using novel powder synthesis and colloidal rolling techniques, we have prepared oxide microalloys that are sinterable at one-third of the melting temperature with enhanced chemical activities. Microlaminates and cellular composites with scaling lengths down to several micrometers with exceptional strength and toughness have also been demonstrated.
EducationPh.D. Metallurgy, Massachusetts Institute of Technology, 1980; M.S. Physics, University of Pennsylvania, 1975; B.S. Physics, Tsinghua University, 1972
Important ArticlesI-W. Chen, P. Li, and Y. Wang, J. Phys. Chem. Solids, 57, 1525 (1996).
"Structural Origin of Relaxor Perovskites"
I-W. Chen and A. Rosenflanz, Nature, in press.
"A New Tough SiAlON Ceramic with a Whisker-like Microstructure"
P-L. Chen and I-W. Chen, J. Am. Ceram. Soc., 80, 637 (1997).
"Sintering of Fine Oxide Powders, II. Sintering Mechanisms"
By this Researcher