ABSTRACT. The electric field distribution during microwave sintering of compacted ceramic powders is calculated and found to be very intense on a microscopic scale, close to grain boundaries and rough surfaces. The electric fields are strongly "focused" by the ceramic particles into the inter-particle contact zones. The peak fields exceed the applied fields by factors of 10 and 30 in the material and in the surrounding air, respectively. Furthermore, the electric field exhibit preferred polarization directions despite being illuminated by a randomly polarized electric field. This can lead to accelerated mass transfer and enhanced densification rates.

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