Precipitation Hardening in Ferroelectric Ceramics. Issue 36 (24th July 2021)

• Record Type: Journal Article
• Authors: Zhao, Changhao; Gao, Shuang; Yang, Tiannan; Scherer, Michael; Schultheiß, Jan; Meier, Dennis; Tan, Xiaoli; Kleebe, Hans‐Joachim; Chen, Long‐Qing; Koruza, Jurij; Rödel, Jürgen
• Is Part Of: Advanced materials. Volume 33:Issue 36(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-07-24
• Subjects: dielectrics -- electromechanical hardening -- ferroelectrics -- mechanical quality factor -- precipitation; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202102421
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Domain wall motion in ferroics, similar to dislocation motion in metals, can be tuned by well‐concepted microstructural elements. In demanding high‐power applications of piezoelectric materials, the domain wall motion is considered as a lossy hysteretic mechanism that should be restricted. Current applications for so‐called hard piezoelectrics are abundant and hinge on the use of an acceptor‐doping scheme. However, this mechanism features severe limitations due to enhanced mobility of oxygen vacancies at moderate temperatures. By analogy with metal technology, the authors present here a new solution for electroceramics, where precipitates are utilized to pin domain walls and improve piezoelectric properties. Through a sequence of sintering, nucleation, and precipitate growth, intragranular precipitates leading to a fine domain structure are developed as shown by transmission electron microscopy, piezoresponse force microscopy, and phase‐field simulation. This structure impedes the domain wall motion as elucidated by electromechanical characterization. As a result, the mechanical quality factor is increased by ≈50% and the hysteresis in electrostrain is suppressed considerably. This is even achieved with slightly increased piezoelectric coefficient and electromechanical coupling factor. This novel process can be smoothly implemented in industrial production processes and is accessible to simple laboratory experimentation for microstructure optimization and implementation in various ferroelectric systems. Abstract : A novel ferroelectric hardening method is proposed by precipitating a secondary phase inside of the ferroelectric grains. Akin to hindered dislocation motion in metals, domain wall motion in ferroelectrics is impeded and loss is reduced. The mechanical quality factor in the model system BaTiO3 –CaTiO3 is enhanced by 1.5 times, while the piezoelectric coefficient and planar electromechanical coupling factor remain nearly unchanged.