Solid State Refrigeration Potential in Lead-free Ferroelectric Ceramic

This book attempts to shed light on the use of various physical and chemical routes towards the systematic investigation of exploring and enhancing (electro) caloric effects in bulk lead-free Ba0.85Ca0.15Zr0.1Ti0.9O3(BCZT) ceramics composition. Caloric effects were estimated by indirect predictions using Maxwell’s relations in conjunction with experimental data. Electrocaloric(EC) effect in BCZT, Ba0.85Ca0.15Zr0.1Ti0.9-xFexO3 and Ba0.85Sr0.15Ti0.9Zr0.1O3(BSTZ) are found as 0.41K (0-21.5kV/cm), 0.86K (0-37kV/cm) and 2.4K at 303K (0-37kV/cm), respectively. Further, Ba0.85Ca0.075Sr0.075Ti0.9Zr0.1O3(BCSTZ) exhibits temperature invariant performance in spanning 60K (303K-363K). The BCSTZ and BSTZ ceramics have an improved electrocaloric behavior (1.5±0.1K and 2.4K) at an optimum sintering temperature of 1475°C and 1450°C for dwell time of 5hr and 4hr, respectively. A remarkably large elastocaloric response (ΔTmax of 1.55K) is observed in BCZT at 340K. Finally, a novel cycle was proposed for suitably combining the multicaloric response using the same material. Additionally, inverse piezocaloric, flexocaloric and barocaloric effect in BCZT, (Ba0.67Sr0.37)TiO3, and PVDF was observed.