DAI Feifei, ZHANG Fan, XIAO Qian

(School of Materials Science and Engineering, Shenyang University of Chemical Technology, Shenyang 110142, Liaoning, China)

Abstract:Sb and Ta doped (K, Na)NbO₃ (KNN) lead-free piezoelectric ceramic powders were synthesized via hydrothermal method using Nb₂O₅, KOH and NaOH as the main raw materials, Sb₂O₃ as Sb source and Ta₂O₅ as Ta source. The effects of doping of Sb and Ta on the morphology and crystal structure of KNN were studied by XRD and SEM. The results show that when the Sb content changed from 2 mol % to 8 mol %, Sb could spread into the KNN lattice and form a new solid solution and the products were all of perovskite structure (K, Na) NbO₃.When the doping amount of Sb was fixed at 2 mol %, Ta content changed from 2 mol % to 4 mol %, the crystal structure changed from orthorhombic phase to tetragonal phase perovskite structure. With the increasing of Ta content, 3-4 μm –sized spherical KNN powders changed into 1-2 μm cubic shaped powders.

Key words:hydrothermal method; the potassium sodium niobate; Sb and Ta doped; lead-free piezoelectric ceramics