Functional perovskite lead based and lead free ceramic/crystals for piezoelectric applications

7^th International Conference on Smart Materials and Structures

July 02-03, 2018 | Vienna, Austria

Binay Kumar

University of Delhi, India

Posters & Accepted Abstracts: J Material Sci Eng

Abstract :

Functional materials possesses typical properties like ferroelectricity, pyroelectricity, piezoelectricity, ferromagnetism, etc. which are sensitive to a change in the environment such as temperature, pressure, etc. and, therefore can be used in transducer, sensor and actuator applications. Piezoelectric binary Pb(Bâ�?�?Bâ�?)O3-PT perovskite, with proper substitution at Bâ�?�? and Bâ�? sites, leads to high performance Pb (Zn1/3 Nb2/3)0.91 Ti0.09 O3 (PZN-PT), PMN-PT, etc. systems which exhibits ultrahigh piezoelectric charge coefficient (d33 > 2000 pC/N) when properly poled (cff d33 as 450 & 18 pC/N for PZT & LiNbO3, respectively). Crystals of these systems are extensively used in high end applications. However, due to high content of lead in these materials, the industry needs environment friendly ferroelectric materials suitable for devices, which do not contain lead and still have very good dielectric, ferroelectric and mechanical properties. Alkali based perovskite systems like (1-x) NBT-xKBT (BNKT) and NKLN are front runners of this category. Recently, single crystals of these materials are grown which exhibited excellent piezoelectric behavior. High piezoelectric coefficient (d33 more than 1500 pC/N), ferroelectric remnant polarization (Pr above 40 �?µC/cm2) and pyroelectric coefficient (P upto 3300 �?¼Cm-2 oC-1) properties have been achieved with resonable high Curie temperature. These crystals were subjected to PUND test to extract true switchable polarization and shown that very small leakag current are present. Further, fatigue test establised that they these crystals can preserve the ferroelectric properties even after 107 cycles of field. Thus these crystals are suitable for high temperature devices for long duration. These ceramics and single crystals are used to demonstrate the piezoelectric ennrgy harvesting and pressure sensor applications. It has been demonstrated how the performance of these devices are enhanced with the use of high performance materials.