Effects of SiO_2 Substitution on Piezoelectric and Mechanical Properties of PMS-PZT Ternary Piezoelectric Ceramics

摘要

The effects of SiO_2 additives on microstructure, piezoelectric and mechanical properties were investigated for Pb_(0.98)Sr_(0.02)(Mn_(1/3)Sb_(2/3))_(0.05)Zr_(0.48)Ti_(0.47)O_3 (PMS-PZT) ternary system close to the morpho-tropic phase boundary. Piezoelectric coefficient (d_(33)) and electromechanical coupling factor (K_p) considerably deteriorated with the substitution of SiO_2 increased. On the other hand, the mechanical quality factor (Q_m) increased, the maximum value was 1800. Fracture strength of 1.0 wt% SiO_2 added the specimens reached to 106.54 MPa which was about 1.4 times higher than pure PMS-PZT ceramic. The rapid improvement of fracture strength probably due to the decrease of grain size, pore distribute and the second phase (redundant Si~(4+) ions) segregating on the grain boundary which enhanced the bond energy of grain boundary. The optimized concentration of SiO_2 doped PMS-PZT ceramics was 0.4 wt% for high power application: d_(33) = 300 PC/N, K_p = 0.51, Q_m = 1500, tanδ = 0.32% and the fracture strength was 88.5MPa.