Effects of ZnO nanoneedles addition on the mechanical and piezoelectric properties of hard PZT-based composites

Hard PZT (PZT4)-based composites embedded by ZnO nanoneedles (denoted as PZT/ZnOn) were fabricated by a solid state sintering technique. The characteristic diffraction peaks of the perovskite PZT and ZnO phases were identified from the studied composites, indicating the retention of ZnOn. With increasing ZnOn content, the grain size of the composites was reduced gradually. In contrast with the pure PZT, the PZT/ZnOn composites possessed more excellent mechanical properties, while the piezoelectric properties were reduced by a certain extent. The best mechanical properties of PZT/ZnOn composites were obtained by sintering at 1,150 A degrees C with 1.5 wt% ZnO nanoneedles addition: fracture toughness K (IC) similar to 2.04 MPa m(1/2), flexural strength sigma (f) similar to 105.44 MPa, compressive strength sigma (c) similar to 543.89 MPa. The piezoelectric properties of the PZT/ZnOn composites were found to be lower than that of the pure PZT with dielectric permittivity epsilon (r) of 768-893, piezoelectric coefficient d (33) of 240-260pC/N, mechanical quality factor Q (m) of 340-650 and planar electromechanical coupling k (p) of 0.5-0.55.