Flash microwave sintering of alumina

Guillaume Riquet (1) , Sylvain Marinel (1) , Clotilde Lechevallier-Boissel (1) , Christelle Harnois (1) , Charles Manière (1)

1 CRISMAT - Laboratoire de cristallographie et sciences des matériaux

Conventional flash sintering is difficult to adapt to ceramics with a very low electrical conductivity like pure alumina. Alternatively, the latter can be heated by microwave/matter interaction due to dielectric losses. Microwave energy is also preferable as it allows a rapid contactless and volumetric heating that can be initiated by susceptors. This work presents the assembly designed for this purpose by using a 2.45 GHz single-mode microwave cavity and the original assembly of susceptors made from silicon carbide plates and a 3D printed zirconia crucible. Controlled thermal cycles ranging from 300 to 900 K/min were successfully applied while measuring the shrinkage during the flash sintering. Alumina pieces were successfully sintered up to 93-98 % in mere seconds, depending on the heating rates, and microstructures were discussed according to the microwave "flash" heating conditions originally applied.

Keywords: Flash sintering; Alumina; microwave sintering; hybrid heating

Domains: Material chemistry; Chemical and Process Engineering; Mechanics of materials [physics.class-ph]

Guillaume Riquet, Sylvain Marinel, Clotilde Lechevallier-Boissel, Christelle Harnois, Charles Manière. Flash microwave sintering of alumina. Materials Letters, 2023, 330, pp.133327. ⟨10.1016/j.matlet.2022.133327⟩. ⟨hal-03818623⟩