Reactive flash sintering: MgO and α‐Al2O3 transform and sinter into single‐phase polycrystals of MgAl2O4
Abstract
We show that flash experiments with three phase mixed‐powders of yttria‐stabilized zirconia (8YSZ), MgO, and α‐Al2O3 not only produce polycrystals of high density, but also the transformation of magnesia and alumina into single‐phase spinel. The presence of zirconia facilitates the onset of the flash. The sintering experiments in the laboratory were extended to live experiments at the National Synchrotron Light Source II at Brookhaven National Laboratory in order to measure the time‐dependent evolution of single‐phase spinel. The phase transformation occurred in II. Later, during Stage III the cubic zirconia transformed partly into the monoclinic phase, which reverted back to the cubic phase when the flash was extinguished by turning off the current to the specimen. The results underpin a recent report on the synthesis of single‐phase bismuth ferrite from constituent oxides in reactive flash experiments, raising the specter of flash as a method for synthesis as well as sintering of complex oxide ceramics. The role of zirconia in catalyzing the flash in the present study is discussed.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 08, 2018
- Source ID
- 10.1111/jace.15974
Entities
People
- Bola Yoon
- Devinder Yadav
- Rishi Raj
- Sanjit Ghose
Organizations
- Army Research Office
- Brookhaven National Laboratory
- United States Department of Energy
- University of Colorado Boulder