Enhanced mechanical properties in Ag-particle-dispersed PZT piezoelectric composites for actuator applications

Functional ceramics naturally have inferior mechanical properties. This study shows that incorporating Ag into lead zirconate titanate (PZT) piezoelectric ceramics by co-firing in air at 1200 °C is effective for mechanical property enhancement. The Ag addition has increased the fracture strength σf from 69 MPa for monolithic PZT to 129 MPa for PZT–15% Ag composite, and increased the corresponding fracture toughness KIC from 1.0 to 2.4 MPa m1/2. The Vickers hardness Hv decreased with increasing Ag concentration, from 3.8 GPa for monolithic PZT to 2.7 GPa for PZT–15% Ag composite. The strength enhancement is attributed to the combined effects of good interface bonding between Ag and PZT, ductile deformation of Ag particles and particle-dispersion strengthening. The fracture toughness enhancement is correlated to crack deflection and crack arrest due to the existence of Ag particle. The enhanced mechanical properties make the PZT/Ag composites promising candidate for piezoelectric actuator applications.