The presence of the Sb5+ ion increased the piezoelectric properties of the (Na0.5 K0.5) NbO3 (NKN) ceramics by enhancing the poling state as identified by the increased phase angle (θ). The increased θ value was explained by the increased ferroelectricity due to the large electronegativity of the Sb5+ ion and the increased off centering of the cation due to the small ionic size of the Sb5+ ion. The (Na0.5 K0.5) (Nb0.97 Sb0.03) O3 [NK (N0.97 S0.03)] ceramics containing CuO were well sintered even at 960 °C. A small amount of the Cu2+ ions was incorporated into the matrix of the NK (N0.97 S0.03) ceramic and behaved as a hardener. The kp, Qm, d33, and ε3T / ε0 values of the CuO-added NK (N0.97 S0.03) ceramics were much higher than those of the CuO-added NKN ceramics due to the Sb5+ ion's enhancement of the piezoelectric properties by increasing the poling state of the specimens. The high piezoelectric properties of kp =0.41, Qm =1333, d33 =111 pC/N, and ε3T / ε0 =324 were obtained from the 2.0 mol % CuO-added NK (N0.97 S0.03) ceramics sintered at 960 °C for 8 h.
ASJC Scopus subject areas
- Physics and Astronomy(all)