1. Effects of Sintering Behavior on Structure and Properties of B2O3 doped (Bi0.5Na0.5)0.94Ba0.06TiO3 Lead-Free Ceramics
Ms. SUPALAK MANOTHAM
Department of Physics and Materials science, Faculty of Science, Chiang Mai University

2. Outline
Introduction
Experimental
Results and discussions
Conclusion

3. Introduction Piezoelectric Materials  Pierre and Curie (1880) Sensor
There are two different effects, direct and converse effect, which can describe this phenomenon
Sensor
Actuator
Mechanical stresses Electrical Potential
Electric Field
Mechanical Strain
Direct effect
convert effect

4. Introduction
Lead-based piezoelectric materials, represented by PZT are the most widely used for piezoelectric transformer, actuator, sensor and multilayered capacitor

5. Introduction
However, lead-based piezoelectric materials contain large amount of PbO, ( % by weight)
PbO
Highly toxic
Causes a crucial environmental problem
Strongly harmful for human health

6. Introduction The development of environment friendly lead-free
piezoelectric material has been required
LEAD –FREE
FRIENDLY To the EARTH
ENVIRONMENTAL SCIENCE
Excellent properties
 Comparable with the properties found in lead-based ceramics

7. Cause many problems during poling process
Literature Review
Bismuth Sodium Titanate  (Bi0.5Na0.5)TiO3
It displays a strong ferroelectricity at room temperature
 Large Pr  38 C/cm2
 High Curie temperature, Tc  320C
However, this material has many drawbacks
 High coercive field, Ec  73 kV/cm
 High conductivity
Cause many problems during poling process

8. In order to develop new lead-free material system
Literature review…
In order to develop new lead-free material system
(1-x)Bi0.5Na0.5TiO3–xBaTiO3
(Bi0.5Na0.5)0.94Ba0.06TiO3
2 wt. % B2O3 doped BNBT
High dielectric performance

9. Ceramics characterization
Experimental
Modified BNBT
2 wt. % B2O3 doped BNBT
(Bi0.5Na0.5)0.94Ba0.06TiO3
Conventional mixed oxide
Calcined Powders
BNKT powder  800 C/2h
Sieve and pressure
BNBT- 2 wt. % B2O3
Ceramics
Ceramics characterization
BNBT- 2 wt. % B2O3
Sintering
Temp: C
Time: 2 h
Rate: 5C/min

10. Experimental
Phase
Physical
Dielectric
Ceramics
Characterization

11. Results and discussion
XRD  BNBT doped B2O3 Ceramics
Fig. 1 X-ray diffraction patterns of the ceramics sintered at various temperatures.

12. Results and discussion
Fig. 2 Plots of density and porosity values of the ceramics sintered at different sintering temperatures.

13. Results and discussion
Dielectric Properties  BNBT doped B2O3 Ceramics
Fig. 3 Room temperature dielectric constant (εr) as a function of frequency for the samples sintered at different sintering temperatures.

14. Results and discussion
Dielectric Properties  BNBT doped B2O3 Ceramics
Fig. 4 Room temperature dielectric loss (tan δ) as a function of frequency for the samples sintered at different sintering temperatures.

15. Results and discussion
Dielectric Properties  BNBT doped B2O3 Ceramics
Fig. 5 Dielectric constant and dielectric loss as a function of temperature and frequency of the ceramics sintered at various sintering temperature.

16. Conclusion
In this work, lead-free B2O3 doped (Bi0.5Na0.5)0.94Ba0.06TiO3 ceramics were successfully synthesized by a simple conventional mixed-oxide and ordinary sintering method. The ceramic samples presented a pure perovskite structure. The optimum density was noted for the sintering temperature of 1050 °C. The dielectric constant increased with an increasing sintering temperature and showed the maximum value of 885 at the sintering temperature of 1150°C.

17. Acknowledgments My advisor Prof. Dr. Gobwute Rujijanagul
Electroceramics lab Member
The 50th Anniversary Chiang Mai University Fund for Ph.D. Program

18. Thank You …