Compaction Curves: A Tool for Qualitative Evaluation of Quasi-static Compaction Behavior of Ceramic Powders

Magnesium Aluminate, (MgAl2O4) spinel powder having average particle size 250 nm (D-50) with irregular morphology, (SP) and spray dried granules with average size of 10 mu m and spherical morphology (SG) were subjected to compressibility studies. Reliable information on the compaction behavior could be obtained from the coefficients of the equation derived for true compaction curves and further, exhibited a good correlation with the measured green densities. Diametral compression testing of SG compacts indicated tensile failure propagating the crack diagonally however, in case of SP compacts the cracks initiated from all the sides propagating throughout the body leading to the final collapse. SEM analysis of fracture surfaces of SG compacts showed a combination of inter-granular with more of intra-granular fracture however, packing flaws and inter-granular voids are evident with SP compacts. Compressibility parameters and green density are found to complement with fracture patterns and features of the fracture surfaces.