Microwave processing and properties of ceramics with different dielectric loss

Microwave sintering behaviors of three kinds of ceramics with different dielectric loss [Al2O3, Ce-Y-ZrO2 and lead-based relaxer ferroelectrics (PMZ NT)] in 2.45 GHz microwave furnace were described. Measurement of sample densities showed an enhancement of the sintering processing for all materials studied. Fo PMZNT and Ce-Y-ZrO2 with high dipolar loss or ionic conductive loss, the associated microstructure examined using scanning electron microscopy showed that microwave-sintered compacts produced much finer grain sizes at near theoretical density compared to conventional sintering. Resulting material properties, such as flexure strength and breakdown strength, were also increased due to developed microstructure in microwave processing. However, a comparable grain size and properties were observed for high pure AL(2)O(3), with low dielectric loss in microwave and conventional methods. (C) 1999 Elsevier Science Limited. All rights reserved.