Concurrent optimization of piezoelectric response and mechanical quality factor through synergistic ZnO–Li2CO3 Co-doping in PMS–PZT

With the fast progress of ultrasonic transducer applications, higher and higher requirements have been put forward to the performance of the piezoelectric ceramics applied in this field. For power-type ceramics, not only high Q m is needed to reduce the heat and improve the power capacity, but also high d 33 is needed to provide the stronger driving force. In this work, a conventional ternary solid-solution ceramic system (0.05 Pb(Mn 1/3 Sb 2/3 )O 3 -0.47PbZrO 3 -0.48PbTiO 3 ) modified by ZnO and Li 2 CO 3 ( x wt % ZnO +  y wt % Li 2 CO 3 ) (designated as: 0.05PMS-0.95PZT +  x wt % ZnO +  y wt % Li 2 CO 3 ) ( x , y  = 0-0.3) was fabricated and researched. The combination of A-site doping of Li 2 CO 3 and B-site doping of ZnO was discovered to be able to enhance the piezoelectric coefficient ( d 33 ) effectively over 500 pC/N and maintain the mechanical quality factor ( Q m ) above 1000 simultaneously. The ZnO act as acceptor dopant to enhance the content of oxygen vacancies but facilitate the motion of domain walls to improve the piezoelectricity. Meanwhile, the A-site substitution of Li  +  construct an internal biased field to stabilize the domain structure leading to the relatively high Q m . Additionally, The Li 2 CO 3 also worked as sintering aid to form liquid transition phase to improve the densification process. The phase composition, microstructures of natural surfaces and fractured surfaces, electrical properties of ceramics were characterized systematically. The excellent comprehensive piezoelectric properties ( d 33  = 525 pC/N, Q m  = 1064, k p  = 0.63, T c  = 320 °C, tan δ  = 0.3% (at 25 °C), ε r  = 1344) were achieved in the 0.2 wt % ZnO and 0.2 wt % Li 2 CO 3 co-doped 0.05PMS-0.95PZT ceramic sintered at 1075 °C. These advantages make 0.05PMS-0.95PZT + 0.2 wt% (ZnO and Li 2 CO 3 ) a promising alternative for the improvement and production of high-performance ultrasonic transducers applied in power-type applications.