Fabrication of PMN_0.65-PT_0.35 Tubes for Transducer Applications by High Temperature Extrusion

The piezoelectric tubes with optimum inner to outer radius ratio were theoretically shown to have zero radial and large axial displacement, which is useful for transducer application. In an effort to fabricate such tubes, the powder processing, tube fabrication and characterization was carried out. PMN _0.65 -PT _0.35 precursor powders were prepared by modified solid-state method and added with 0.15 wt% Mn. Mn addition increased the d ₃₃ coefficient from 530 to 650 pC/N after sintering. Low-density polyethylene based binder was developed for these Mn added powders to fabricate ceramic discs and tubes. The tubes with different inner to outer diameter ratio were fabricated by high temperature extrusion. The samples were subjected to optimized binder burn out cycle and sintered at 1150°C to achieve 92% theoretical density ceramics. The sintered pellets, despite being processed with 50 vol% of binder, showed high piezoelectric coefficients. Preliminary characterization of the tubes indicates high longitudinal displacement.

Keywords:

• Ferroelectric
• piezoelectric
• transducer
• tube
• fabrication and PMN

Acknowledgments

Paper originally presented at AMF-4, Bangalore, India, December 12–15, 2003; received in final form April 10, 2005. The original Proceedings of the Fourth Asian Meeting on Ferroelectricity (AMF-4) are published in seven earlier volumes of FERROELECTRICS (Volumes 323–329, inclusive).