Studies on Structural and Physical Properties of Zr Substituted Na0.5Bi0.5TiO3 and Na0.5Bi0.5TiO3-BaTiO3 Solid Solution for Vibration Sensor Application

Gottuparthi, V (2014) Studies on Structural and Physical Properties of Zr Substituted Na0.5Bi0.5TiO3 and Na0.5Bi0.5TiO3-BaTiO3 Solid Solution for Vibration Sensor Application. Masters thesis, Indian Institute of Technology, Hyderabad.

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Abstract

In the present day modern technology scientists are more focused on lead free ferroelectric ceramics in understanding the fundamental issues, to improve the ferroelectric and piezoelectric properties of these materials. Among these lead free piezoelectric ceramics, sodium bismuth titanate (Na0.5Bi0.5) TiO3 (NBT) in recent times has attracted much more due to its high ferroelectric and piezoelectric properties. It is well known that the structural and functional properties of materials can be tuned through the elemental substitution. In this regard, at present we have focused on tuning the piezoelectric properties of NBT ceramics via Zr substitution and NBT-BT solid solution. In order to synthesize both (Na0.5Bi0.5) Ti1-xZrxO3 and NBT-BT solid solutions conventional solid-state reaction route has been used. X-ray Diffraction, phonon mode measurements have been carried out to identify the structural and phase modifications. The sintered samples were electroded and poled to measure the dielectric and piezoelectric properties. The observation of relaxor features in Zr substituted NBT ceramics i.e. frequency dispersion in Tmax along with diffused phase transition. In NBT-BT solid solution decrease in the depolarization temperature and Tmax has been reported through dielectric studies. The electromechanical coupling coefficient of these materials has been measured using resonant and antiresonant method, which revealed the decrease in the coupling coefficient with substitutions. The piezoelectric strain coefficient was measured using Piezo-test meter for Zr substituted NBT and decrement in this value observed with Zr substitution. Finally these NBT ceramic pellets have been tested for the vibrational sensor applications.

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