Lowering compaction pressure and sintering temperature of alumina using spray freeze granulation dried granules

Abstract

Spray drying (SD) and spray freeze granulation drying (SFGD) are the granulation processes of ceramic powder. Alumina green body made from SFGD granules via compaction has a relatively uniform structure without inter-granular pores, resulting in higher density and strength in the sintered body. This gives SFGD granules an advantage over SD granules. This study investigates the compaction pressure and sintering temperature of alumina granules produced by SD and SFGD. Using SFGD granules allows for the production of dense high-strength sintered alumina at lower compaction pressures and sintering temperatures. Even with higher compaction pressures applied to SD granules, the achieved sintered density falls short of that obtained with SFGD granules. These findings highlight the additional benefits of using SFGD granules over SD granules.