Sodium lithium niobate lead-free piezoceramics for high-power applications: Fundamental, progress, and perspective

Abstract

With the capability of interconversion between electrical and mechanical energy, piezoelectric materials have been revolutionized by the implementation of perovskite-piezoelectric-ceramic-based studies over 70 years. In particular, the market of piezoelectric ceramics has been dominated by lead zirconate titanate for decades. Nowadays, the research on piezoelectric ceramics is largely driven by cutting-edge technological demand as well as the consideration of a sustainable society. Hence, environmental-friendly lead-free piezoelectric materials have emerged to replace lead-based Pb(Zr,Ti)O 3 (PZT) compositions. Owing to the inherent high mechanical quality factor (Q m ) and low energy loss, (Li,Na)NbO 3 (LNN) materials have recently drawn increasing attention and brought advantages to high-power piezoelectric applications. Although the crystallographic structures of LNN materials were intensively investigated for decades, the technical strategies for electrical performance are still limited. As a result, the property enhancement appears to have approached a plateau. This review traces the progress in the development of LNN materials, starting from the polymorphism in terms of the crystal structures, phase transitions, and local structural distortions. Then, the key milestone works on the functional tunability of LNN are reviewed with emphasis on involved engineering approaches. The exceptional performance at a large vibration velocity makes LNN ceramics promising for high-power applications, such as ultrasonic welding (UW) and ultrasonic osteotomes (UOs). The remaining challenges and some strategic insights for synergistically engineering the functional performance of

Deciphering the leakage conduction mechanism of BiFeO 3–BaTiO 3 lead-free piezoelectric ceramics

“…The maximum phase angle (θ max ) is about 23.50° which is an important index to evaluate the polarization degree of piezoelectric ceramics. The Q m value is as high as 105.82, which may be related to charged defects in the ceramics [32]. A large number of charge carriers have been reported to suppress domain switching, reduce internal friction, and increase Q m [33,34].…”

Textured Potassium Sodium Niobate Lead-Free Ceramics with High d33 and Qm for Meeting High-Power Applications

“…Among the lead-free piezoceramics, KNN-based piezoceramics have emerged as the most promising contenders against their lead-based counterparts, primarily due to their high Curie temperature T c , desirable piezoelectricity, and promising application prospects. − Notably, Saito et al achieved a remarkable d 33 value of approximately 416 pC·N -1 in KNN-based ceramics, garnering significant attention within the research community. Over two decades of development, significant breakthroughs have been achieved in the piezoelectric properties of KNN lead-free ceramics, with their d 33 even surpassing that of commercialized ceramics.…”

Significantly Enhanced Electrostrain in Oriented Epitaxial Self-Assembled Aurivillius-Type Piezoelectric Films via Regulating Polarization Vectors

“…With the development of microelectromechanical system (MEMS) technology, devices are becoming miniaturized, integrated, and multifunctional. MEMS devices based on piezoelectric films have higher mechanical accuracy and stability and thus have drawn much attention. − However, piezoelectric materials with high operating temperature are needed in enormous scenarios, such as aero-engines, rocket motors, nuclear powers, etc. , At present, perovskite piezoelectric films (either lead-based or lead-free) are difficult to meet the high temperature (>500 °C) requirements, such as high-temperature MEMS actuators and acceleration vibration sensors, due to their low Curie temperature. − Aurivillius-type piezoelectric materials, which are composed of two [Bi 2 O 2 ] layers sandwiched by m perovskite-like (i.e., [BO 6 ] octahedron) layers in the c -axis direction, hold great potential for high-temperature applications in virtue of its good fatigue property and high Curie temperature ( T C ). − The study of Aurivillius-type films mainly focuses on their ferroelectric properties for FeRAMs application. However, due to its poor piezoelectric property and large anisotropy, it is quite difficult to obtain large electrostrain in Aurivillius-type piezoelectric films. , Therefore, it remains a challenge to explore Aurivillius-type piezoelectric films with excellent strain properties for the development of high-temperature piezo-MEMS devices.…”