Creep Behavior of Polymer Precursor Derived Si3N4/SiC Nanocomposites
Annual technical rept. 1 Sep 2003-31 Aug 2004
CALIFORNIA UNIV DAVIS DEPT OF CHEMICALENGINEERING AND MATERIALS SCIENCE
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Two batches of plasma sprayed zirconia-alumina-spinel powder with or without high energy ball milling HEBM were consolidated to full density by spark plasma sintering SPS. The resulting nanocomposite showed superplasticity with a high activation energy of 945 kJmol for the HEBMed batch the absence of HEBM treatment resulted in no superplastic behavior. The special grain boundary formed during SPS from nucleation and growth of new phases from metastable matrix in plasma sprayed powder is believed the key microstructure to turn this superplastic triphase ceramics into a non-superplastic one. If TEM analysis currently in process proves our postulation plasma spraying may be a potential technique to make intrinsically creep-resistant microstructures.
- Laminates and Composite Materials