Improvement of sinterability of KNN ceramics by mechanochemical activation-assisted process

In order to enhance the sintered density of K0.5Na0.5NbO3 [KNN] ceramics by using fine KNN powders, mechanochemical activation-assisted process was applied for the synthesis of KNN powders. Shaker milling of K2CO3-Na2CO3-Nb2O5 raw powders mixture for 30 min could decrease the temperature of the subsequent calcination from 800-850°C of the conventional solid-state reaction to 500°C. This novel process produced KNN powders with crystallites of 50-100 nm in size. The relative density of sintered KNN prepared by mechanochemical activation-assisted process was 95.7%, which was about 2% higher than that of sintered KNN prepared by the conventional solid-state reaction process. Mechanochemical activation-assisted process also improved the P-E property of sintered KNN ceramics.