Effect of organic dispersants on structural and mechanical properties of Al2O3/ZrO2 composites

Al2O3/15%ZrO2 nanopowder is prepared via ball milling procedure. In order to select the most efficient milling strategy, both wet and dry ball milling procedures are tested. Dry milling is found to be a better choice and comminuting conditions (i.e. rotation speed and milling duration) are optimized. To understand the effect of organic dispersing agents on microstructure, physical, and mechanical properties (density, hardness, and fracture toughness), Al2O3/ZrO2 nanopowders are prepared by addition of different saccharide dispersants. Zero point charge (zpc) of Al2O3/ZrO2 powder, synthesized in the absence of dispersing agents, is determined to find the proper pH for addition of the additives. Glucose, maltose, and dextrin are selected as mono, di, and polysaccharides, respectively, to investigate the effect of chemical structure and organic chain length on dispersion quality. Results revealed that dextrin can efficiently prevent agglomeration and help to produce dense ceramic specimens with small particles, high hardness, and high fracture toughness.