Tailoring of unipolar strain in lead-free piezoelectrics using the ceramic/ceramic composite approach

Abstract

Local structure change evidenced by temperature-dependent elastic measurements: Case study on Bi1/2Na1/2TiO3-based lead-free relaxor piezoceramics J. Appl. Phys. 115, 084108 (2014) Tailoring of unipolar strain in lead-free piezoelectrics using the ceramic/ceramic composite approach The electric-field-induced strain response mechanism in a polycrystalline ceramic/ceramic composite of relaxor and ferroelectric materials has been studied using in situ high-energy x-ray diffraction. The addition of ferroelectric phase material in the relaxor matrix has produced a system where a small volume fraction behaves independently of the bulk under an applied electric field. Inter-and intra-grain models of the strain mechanism in the composite material consistent with the diffraction data have been proposed. The results show that such ceramic/ceramic composite microstructure has the potential for tailoring properties of future piezoelectric materials over a wider range than is possible in uniform compositions. V C 2014 AIP Publishing LLC.

Enhancing electromechanical properties of lead-free ferroelectrics with bilayer ceramic/ceramic composites

“…The first successful demonstration of this approach in lead-free materials was by Lee et al in a composite system comprised of BNKT-BA matrix with BNT as a nonergodic relaxor seed material [39]. Since then, lead-free composite systems have also been reported using BNT-BT-KNN as the ergodic relaxor matrix [40], [41]. Recently, Groh and colleagues have investigated composites of BNT-BT/BNT-BT-KNN [40]- [43].…”

Maximising electro-mechanical response by minimising grain-scale strain heterogeneity in phase-change actuator ceramics

“…3 Microstructural engineering has also been applied to enhance piezoelectric performance in lead-free systems. This can be done by crystallographic texturing 4 ceramic-ceramic composites 5,6 or core-shell grain structures. 7 Generally, these methods require more complicated processing controls than standard polycrystalline ceramic processing, and thus increase the expense of the final material.…”

Enhanced extrinsic domain switching strain in core–shell structured BaTiO 3 –KNbO 3 ceramics

“…In the ceramic-ceramic composite approach, a ferroelectric phase (e.g., BNT, BNT-BT) has been used as a particulate component in a relaxor ferroelectric matrix to modify the actuating field and maximum electric-field-induced strain in compositions of Bi 1/2 (Na 3/4 K 1/4 ) 1/2 TiO 3 -BiAlO 3 , and 0.92(Bi 1/2 Na 1/2 TiO 3 )-0.06(BaTiO 3 )-0.02(K 1/2 Na 1/2 NbO 3 ) [19,21]. It has also been shown by an in situ high-energy X-ray diffraction study that the local response of the ferroelectric phase materials in such ceramic-ceramic composites can be critical to induce/nucleate specific behaviour in the matrix phase leading to the desired bulk material properties [22]. Thus, modification at the grain length scale can also be a useful method to enhance electro-mechanical properties.…”

“…In addition to compositional modifications, microstructural modification (i.e., tailored microstructure) such as a ceramicceramic composite approach can be utilised [19][20][21][22][23]. In the ceramic-ceramic composite approach, a ferroelectric phase (e.g., BNT, BNT-BT) has been used as a particulate component in a relaxor ferroelectric matrix to modify the actuating field and maximum electric-field-induced strain in compositions of Bi 1/2 (Na 3/4 K 1/4 ) 1/2 TiO 3 -BiAlO 3 , and 0.92(Bi 1/2 Na 1/2 TiO 3 )-0.06(BaTiO 3 )-0.02(K 1/2 Na 1/2 NbO 3 ) [19,21].…”