Article ID Journal Published Year Pages File Type
1475040 Journal of the European Ceramic Society 2014 10 Pages PDF
Abstract

Conventional sintering of undoped Y2O3 requires temperatures above 1400 °C for a few hours. We show that it can be sintered nearly instantaneously to nearly full density at furnace temperature of 1133 °C under a DC applied field of 500 V/cm. At 1000 V/cm sintering occurs at 985 °C. The FLASH event, when sintering occurs abruptly, is preceded by gradually accelerated field-assisted sintering (FAST). This hybrid behaviour differs from earlier work on yttria-stabilized zirconia where all shrinkage occurred in the flash mode. The microstructure of flash-sintered specimens indicated that densification was accompanied by rapid grain growth. The single-phase nature of flash-sintered Y2O3 was confirmed by high-resolution transmission electron microscopy. The non-linear rise in conductivity accompanying the flash led to Joule heating. It is postulated that densification and grain growth were enhanced by accelerated solid-state diffusion, resulting from both Joule heating and the generation of defects under the applied field.

Related Topics
Physical Sciences and Engineering Materials Science Ceramics and Composites
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