Chemical Routes to Ceramics with Tunable Properties and Structures: Chemical Routes to Nano and Micro-Structured Ceramics
Abstract
The goal of this completed AFOSR research program was to design, synthesize and develop the materials applications of new processible chemical precursors to technologically important nonoxide ceramics that allow the formation of these ceramics in forms that have been unattainable with conventional methods. Major achievements include demonstrations that: (1) blends of boron and silicon-based preceramic polymers can be used as excellent precursors to boron-carbide/silicon-carbide ceramic composite materials in processed forms with certain compositions showing significant oxidation resistance, (2) chemical precursor systems composed of zirconium or hafnium powders dispersed into blends of boron and silicon preceramic polymers provide simple efficient routes to new types of complex ultra high temperature ZrB2/ZrC/SiC and HfB2/HfC/SiC composites, (3) blends of the Penn poly(norbornenyldecaborane) polymer with the commercial poly(methylcarbosilane) polymer could be electrostatically spun to produce polymer fibers that could then be thermally converted to nano- to micro-scale boron-carbide/silicon-carbide composite ceramic fibers, (4) silica-bead templating techniques employing preceramic polymers enable the generation of 2-dimensional nanoporous ceramic arrays, (5) diatom-templating methods provide excellent routes to micro- and nanostructured nonoxide ceramics, and (6) preceramic polymers can be used in conjunction with templates generated by multi-beam interference lithography to produce high temperature nonoxide ceramic photonic crystals.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 20, 2009
- Accession Number
- ADA589781
Entities
People
- Larry G. Sneddon
- Shu Yang
Organizations
- University of Pennsylvania