Electrical Properties of lead free (Na,K,Li)(Nb,Sb,Ta)O 3 Ceramics with MnO 2 Addition

Abstract - Electrical properties and microstructure were investigated on the effects of MnO 2 and the lead-free (Na 0.44 K 0.52 Li 0.04 )(Nb 0.83 Sb 0.07 Ta 0.1) O 3 ceramics with the addition of MnO 2 were fabricated by a conventional mixed oxide method. A gradual change in the crystal and microstructure was observed with the increase of MnO 2 addition. For the NKN-LST-xmol%MnO 2 sintered at 1100℃, bulk density increased with the addition of MnO 2 and showed maximum value at addition 1.0mol% of MnO 2 . Curie temperature of the NKN-LST ceramics slightly decreased with adding MnO 2 . The dielectric constant, piezoelectric constant (d 33 ) and electromechanical coupling factor (k p ) increased below 0.25mol% of MnO 2 addition, which might be due to the increase in density. The high piezoelectric properties = 145 pC/N, electromechanical coupling factor = 0.421 and dielectric constant = 2883 were obtained for the NKN-LST-0.25mol%MnO 2 sintered at 1100℃ for 4h. Key Words : Piezoelectric properties, Lead-free, NKN-LST-MnO