PhD Thesis Colloquium: : Ms.Pooja Punetha (28/07/25)
Thesis title:
Structure–Property Correlation in the Lead-Free K0.5Bi0.5TiO3-Based Piezoceramics
Faculty advisor(s):
Rajeev Ranjan and Pavan Nukala
When?
28th July, 2025 (Monday), 10:00 AM (India Standard Time)
Where
KPA Auditorium, Dept of Materials Engineering
Abstract:
Ferroelectric materials with a perovskite (ABO₃) structure exhibiting enhanced electromechanical properties are widely used in actuators, pressure sensors, electro-optic devices, and transducers across sectors such as healthcare, space, defence, and automotive industries. Among these, lead zirconate titanate (Pb(ZrₓTi₁₋ₓ)O₃ or PZT) has been the material of choice for over four decades due to its superior electromechanical performance, particularly near the morphotropic phase boundary (MPB) that separates the ferroelectric tetragonal (P4mm) and rhombohedral (R3m) phase fields. However, the toxicity of lead and its volatility during processing pose significant environmental and health risks, prompting global legislation to encourage the development of lead-free alternatives. This has driven intensive research into lead-free piezoelectrics, including (K,Na)NbO₃ (KNN), BiFeO₃ (BF), BaTiO₃ (BT), Na₀.₅Bi₀.₅TiO₃ (NBT) and K₀.₅Bi₀.₅TiO₃-based systems. KBT-based ferroelectrics have attracted attention for their distinctive properties, including high tetragonality, elevated depolarization temperature and the ability to form morphotropic phase boundary (MPB) lead-free solid solution with rhombohedral NBT. KBT has received limited attention in the literature, primarily due to challenges in a chieving high densification during synthesis, which arise from the volatile nature of K, Na, and Bi. In this thesis, we have explored KBT-based solid solutions, and a comprehensive investigation has been carried out to understand the structure–property correlations in KBT and its related solid solutions.