Significantly toughened PZT-based piezoelectric ceramics simultaneously keeping excellent electrical properties via incorporating trace amount of yttria-partially-stabilized zirconia

Piezoelectric ceramics are prone to cracking during functioning due to the repetitively applied high stress. Hence, toughened ceramics with robust microstructures are highly desired for resisting the potential cracks. Toughening of Lead Zirconium Titanate (PZT) based piezoelectric ceramics with high d₃₃·g₃₃ for ignition applications is investigated in this work. Yttria-partially-stabilized zirconia (YPSZ) particles were incorporated into the PZT-based piezoelectric ceramics via conventional solid state reaction. Measurements of mechanical properties of as-sintered ceramics indicate that incorporation of an appropriate amount of YPSZ significantly improves the fracture toughness of PZT-based ceramics by 38.7%, meanwhile the piezoelectric coefficient still remains at a high level with a decrease of less than 7%. When doping 0.5 wt% YPSZ, the optimal comprehensive properties can be obtained as follows: fracture toughness K_IC = 1.41 MPa·m^1/2, Vickers hardness H_V = 4.60 GPa, piezoelectric coefficient d₃₃ = 462 pC/N, planar electromechanical coupling factor k_p = 60.1%, and dielectric constant ε₃₃^T/ε₀ = 1750. This successful toughening mechanism paves a way in developing functional ceramics simultaneously possessing superior fracture toughness and electrical properties via doping an appropriate content of YPSZ submicron particles.