Direct observation of non-uniform distribution of PVA binder in alumina green body

Influence of particles packing in granules on the particles orientation in compacts

“…These formations of pores and granules traces are related to granules properties as has been discussed in past publications. 20,21 Here, surprisingly, despite of low strength of granules, low density areas within loose granules (L1 and L2) are difficult to be eliminated even after being CIPed at a very high pressure. This explains the relatively low green density compared to compacts made from dense granules.…”

Strength‐Processing Defects Relationship Based on Micrographic Analysis and Fracture Mechanics in Alumina Ceramics

“…These three types of defect are developed from the structure of granules. The relationship between the granule structure and the slurry property and its relevance to the granulation process have been discussed 23–26 . Once formed in the green compact, these inhomogeneous structures are not eliminated in the subsequent sintering period and form the defect in sintered body 27…”

Effect of internal binder on microstructure in compacts made from granules

“…[1][2][3][4][5][6][7][8] The characteristics of binder must be carefully controlled, but may change easily in many systems, such as PVA. The granules with PVA are hard under glass transition temperature (∼25 • C) and become soft in high relative humidity over 80% and temperature above 20 • C. 9 Hard elastic granules tend to form large flaws in green compacts as well as in sintered ceramics.…”