Preparation and structure of rainbow piezoelectric ceramics

Abstract

Rainbow piezoelectric ceramics are a new type of stress-biased, oxide-reduced composite ferroelectric ceramics, which have a special dome structure. The have shown excellent properties such as ultra-high displacement under an applied electric field and enhanced load-bearing capability. In this article, their manufacture, structures and properties were discussed in detail by combining experiments and theory analysis. The resuts show that the optimal conditions for producing Rainbow samples from PLZT ceramics were determined to be 900°C for 1 to 1.5 hours. A number of different phases have been found in the reduced layer of Rainbow ceramics by XRD analyses. The phases found include metallic lead and other oxide phases, such as PbO, ZrO₂ and TiO₂. The original PLZT phase was not observed. The reduced layer was transgranularly fractured while the unreduced ceramic was intergranularly fractured. Two kinds of fracture types can be seen at the interface, which denotes the different degrees of reduction. It is shown that the Pb grains (about 0.2μm) constitute a continuous phase in the reduced layer, which accounts for the good electrical conductivity

Keywords

Rainbow / piezoelectric ceramic / stress-biased / actuating materials

References

[1] Xing Shen. Atuator of Large Displacement Rainbow Ceramics. Transaction of Nanjing University of Aeronautics & Astronautics, 2001, 18(2): 188-193.

[2] Xing Shen. Design of RAINBOW Actuators Made of PSZT. Chinese Journal of Aeronautics, 2002, 15(3): 176-180.

[3] Onitsuka K. Effects of Bonding and Geometry on the Flextensional Tranducer Moonie, 1993, PA: The Pennsylvania State University.

[4] Dogan A. Flextensional Moonie and Cymbal Actuators, 1995, PA: The Pennsylvania State University.

[5] Haertling G H. Rainbows—A New Type of Ultra-high Displacement Actuators. Am. Ceram. Soc. Bull., 1999, 73: 96-99.

[6] Hooker M W. Properties and Performance of RAINBOW Piezoelectric Actuator Stacks. SPIE, 1997, 3044: 413-420.

[7] Haasen P. Physical Metallurgy, 1996 3rd Ed. Wuhan: Cambridge University Press.

[8] Wang Qing-Ming, Cross L E. Analysis of High Temperature Reduction Processing of RAINBOW Actuator. Mater. Chem. Phys., 1999, 58: 20-25.

[9] Moon J H, Jang H M. Effects of Sintering Atmosphere on Densification Behavior and Piezoelectric Properties of Pb(Ni_1/3 Nb_2/3) O₃−PbTiO₃−PbZrO₃ Ceramics. J. Am. Ceram. Soc., 1996, 76(2): 549-552.