| Microstructural Uniformity and Homogeneity
in Alumina Sintered by Microwave (Hybrid)
Heating at 2.45 GHz |
ARINDAM DE*, IFriKHAR AHMAD, E. Dow WmTNEY AND DAVID E. CLARK
Pages : 156-161
DOI : 10.1080/0371750X.1995.10804710 |
| Abstract |
| Microwave (hybrid) heating (MHH) is a unique combination
of microwave (MW)-material interaction and conventional
radiant heating/conduction mechanisms that facilitates
the attainment of very high heating rates in a 2.45
GHz multimode MW cavity. Microstructural uniformity
and homogeneity of cold-pressed green samples of pure,
undoped, as-received alumina, fired by MHH vis-a-vis conventional
fast firing (CFF) has been investigated. The synergism
of the twin heating mechanisms (with MHH) results
in an improved parity in temperatures across the sample
cross-sections vis-a-vis CFF and stand-alone MW (SMW)
sintering; this enhanced parity in temperatures (with
MHH) can be premised to be responsible for the better
microstructural homogeneity and enhanced mechanical
properties relative to CFF. Sintering of larger (20 gm vs 6
gm) samples with MHH shows evidence of a definitive mass
dependence on the MHH phenomenon. Larger masses show
a better parity in temperatures between the surface and the
interior of the sample. Consequently, this culminates in
further enhancements in the homogeneity of the microstructure,
and improved and more uniform mechanical
properties relative to the smaller MHH and CFF samples. |
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