Sintering and microstructure evolution in highly porous yttrium iron oxide ceramics

Abstract The evolution of the microstructure in highly porous compacts was analyzed using scanning electron microscopy on yttrium iron oxide samples exhibiting densities of less than 30% of theoretical density. During grain growth in highly porous compacts, the grains initially form a mesh chain structure, followed by either elongation or the formation of ring‐like structures, and finally assembly into hollow or coarser spheres. The latter process may involve the formation of fine necks growing through the ring structure, acting as the core of a coarser sphere. Thus, YFeO 3 porous materials have macroscopic and microscopic pores, and the total porosity level as well as porous cluster sizes inside granules can be controlled by adjusting temperature or dwell time.