Non-uniform electric field in poling of structurally graded monolithic piezoactuator
- 75 Downloads
In this paper the effect of a non-uniform electric poling field and its optimisation for structurally graded piezoelectric actuators are investigated. The two compared actuator structures were both based on commercial PZT 5H bulk discs with thicknesses of 375 µm (Ø 25 mm), where one was machined into a graded structure with a step-like decrease of the thickness towards the centre and one intact. The hysteresis loops of the pre-stressed concave shaped actuators were measured under 0.5–5.0 kV/mm electric fields at 25–100°C temperatures, and the remanent polarization and coercive electric field were determined. The graded structured actuator obtained ∼10% higher coercive field compared to the non-graded actuator, when measured at 25°C and 5.0 kV/mm. On the other hand the remanent polarisation values of the graded actuator were slightly lower than non graded bulk values. However the maximum decrease was only 9.6% under 5.0 kV/mm. The results show that strain and stress gradients in the structure are generated when exposed to an electric field. Furthermore, as a consequence of the restricted dimension changes, an inherent bending of the monolithic ceramic structure was obtained which can be utilised, for example, in miniaturised micro-machined actuators or in larger pre-stressed benders.
KeywordsPiezoelectric Gradient Actuator Monolithic
J. Palosaari gratefully acknowledge the financial support of the Jenny and Antti Wihuri foundation. J. Juuti gratefully acknowledges the Hi-Piezo project (number 124011) funded by the Academy of Finland. The authors acknowledge the Micro and Nanotechnology Center (MNT) of the University of Oulu for the surface profile measurements.
- 1.J. Palosaari, E. Heinonen, J. Juuti, V.-P. Moilanen, H. Jantunen: Electromechanical performance of structurally graded monolithic piezoelectric actuator. Journal of Electroceramics. Published online (March 2008)Google Scholar
- 2.Heinonen E, Juuti J, Moilanen P, Palosaari J, Jantunen H; Structurally graded monolithic piezoelectric actuators, modelling and optimization with FEM, Journal of Intelligent Material Systems and Structures (November 2008)Google Scholar
- 5.D.H. Pearce and T.W. Button, in Proceedings of the Eleventh IEEE International Symposium on Applications of Ferroelectrics, p. 547, (IEEE, Piscataway, 1998)Google Scholar
- 7.Q. Jiang,W. Cao, and L.E. Cross, in Proceedings of the Eighth International Symposium on Applications of Ferroelectrics, p. 107, (IEEE, New York, 1992)Google Scholar
- 9.H.Wang, R.E. Newnham, L.E. Cross, andW.Y. Pan, in IEEE Seventh International Symposium on Applications of Ferroelectrics p. 422, (IEEE, New York, 1990)Google Scholar
- 10.H.-W.Wang, S.-Y. Cheng, and C.-M.Wang, in Proceedings 1989 Japan International Electronic Manufacturing Technology Symposium, p. 263, (IEEE, New York, 1989), Google Scholar
- 12.G.H. Haertling, in Proceedings of the Tenth IEEE International Symposium on Applications of Ferroelectrics, p. 65, (IEEE, Piscataway, 1996)Google Scholar