Preparation of soft-agglomerated nano-sized ceramic powders by sol–gel combustion process

The soft-agglomerated Gd2BaCuO5 (Gd211) nano-powders were synthesized by sol–gel combustion process with binary ligand and the special pretreatment on gel. The mechanism of the formation of weakly agglomerated structure was studied in detail. The results showed that network structure in gelation process was found to be a decisive factor for preventing agglomeration of colloidal particles. The removal of free water, coordinated water, and most of hydroxyl groups during pretreatment further inhibited the formation of hydrogen bonds between adjacent particles. The soft-agglomeration of the particles was confirmed by isolated particles in calcined Gd211 powders and in green compact, a narrow monomodal pore size distribution of the green compact and the low agglomeration coefficient of the calcined Gd211 powder. Extension this process to synthesis of BaCeO3, BaTiO3 and Ce0.8Sm0.2O1.9 powders, also led to weakly agglomerated nano-powders. It suggests that this method represents a powerful and facile method for the creation of doped and multi-component nano-sized ceramic powders.