Multiscale Structures and Comprehensive Properties of (K,Na) NbO3-based Lead-free Piezoceramics
Driven by the growing demand for environmentally friendly materials,efforts are being made to develop high-performance lead-free piezoelectric materials. In this study,the relationship between multiscale structures and electrical properties of Li/Ta/Sb-coped (K,Na) NbO3 (KNNLTS) ceramics was unveiled. At room temperature,the presence of the polymorphic phase transition (PPT) endows the material with a complex domain morphology comprised of sub-micrometer strip-like domains and nanoscale domains. Benefiting from the combined effects of the PPT of the polycrystalline phase and nanoscale domains,the KNNLTS ceramics possess superior piezoelectricity,with a high piezoelectric coefficient of 268 pC·N-1. The complete set of elastic,dielectric,and piezoelectric constants of KNNLTS ceramics was determined by utilizing a classical resonance and anti-resonance frequency approach. After 104 cycles of bipolar electric field,slight fatigue behavior appeared in KNNLTS ceramics,which may be ascribed to the domain wall pinning by point defects. This study will inspire further development of high-performance lead-free piezoceramics by rational multiscale structure design and accelerate their applications.
NETL
NSTL
万方数据
