Liquid immersion technique coupled with infrared microscopy for direct observation of internal structure of ceramic powder compact, with alumina as an example

Infrared microscopy was applied to observe the internal structure of alumina powder compact, which was made transparent with an immersion liquid. It provided clear images of nonuniformity in the structure for a specimen as thick as 1 mm. Two types of nonuniformity found in this paper are the large pores made from the pores in powder granules and the low-density region forming network structure, which was formed by the presence of a binder. The minimum size of nonuniformity detected in a structure is under 20 μm.