Jump to Nanostructured Materials, Bonded Abrasives, Educational Research

Most of my materials research interests focus on the effect of INTERFACES on material properties.

Nanostructured Materials

Nanostructured materials are generally defined as materials having structural elements with at least one dimension less than 100 nm. (A nm is a billionth of a meter.) Such structural elements could include second phase particles, the thickness of layers in a laminated material, the diameter of in-situ whiskers or fibers, or the grain size in a single phase crystalline material. By comparison, most conventional polycrystalline materials have grain sizes on the order of microns to tens of microns. To put this size difference in perspective, consider the width of a human hair; that dimension is the approximate grain size of some conventional polycrystalline materials. A nanocrystalline material could easily have 1000 grains across the diameter of that human hair!

My research in nanostructured materials focuses on developing a better understanding of several size-dependent phenomena: defect chemistry in oxides and grain boundary segregation, in particular. A recently completed Master's Thesis by Xinlan Shi demonstrated that nanocrystalline TiO2 has an enhanced conductivity and a wide PO2-independent regime relative to conventional TiO2. This behavior is likely due to either enhanced ionic conductivity or conduction of protons; further work is planned to distinguish between these mechanisms.

Another master's student is exploring whether there is a grain size-dependence of the anatase-rutile phase transformation in TiO2. Related research focuses on understanding the thermal stability (or lack thereof) in nanostructured ceramics. If fine grain sizes could be stabilized at elevated temperatures, these materials could see more widespread use.

Recent Publications and Presentations

My major refereed journal publications and presentations in the area of nanostructured materials are listed below, along with links to the abstracts. Send e-mail if you would like reprints of any of these papers.

Bonded Abrasives

Recent Publications

Scholarship in Teaching

Recent Publications, Presentations, and Workshops
Last modified: 28 January 1999