Dielectric and Ferroelectric Properties of Lead-Free NKN and NKN-Based Ceramics

摘要

Lead-free ceramics of Na_(0.5)K_(0.5)NbO_3 (NKN), Na_(0.5)K_(0.5)(Nb_(0.94)Sb_(0.06))O_3 (NKNS6) and Na_(0.5)K_(0.5)(Nb_(0.94)Sb_(0.06))O_3 + 0.5%MnO_2 (NKNS6 + 0.5%MnO_2) have been prepared by a solid phase hot pressing sintering process. X-ray diffraction results show that the obtained samples possess the perovskite structure. The micrograph of the fractured surface showed a dense structure in a good agreement with that of 91-94% relative density determined by the Archimedes method. An average grain size decreases with Sb andMn doping (from about 20 [imforNKNto about 5 and 2 fimforNKNS6 and NKNS6 + 0.5%MnO_2, respectively). Low frequency (100 Hz-200 kHz) investigations revealed the diffuse phase transitions. It was found that Mn or Sb doping influence dielectric and ferroelectric properties.