Development of tube actuators with helical electrodes using fused deposition of ceramics

Fused Deposition of Ceramics (FDC), a Solid Freeform Fabrication technique, has been used to manufacture tube actuators with helical electrodes. It is expected that the special electroding along the length of the tubes results in higher axial displacements since d₃₃ coefficient is applicable as opposed to d₃₁ in radially poled tubes. A silver-palladium electrode filament with solids loading of 55 vol.% was developed. Two different methods of deposition were used to fabricate the tubes. with helical electrodes either within the tube wall or on the outer surface of the tubes. Electrodes with different thickness and width were deposited on the tubes. Modified heating procedures for binder burnout and sintering, as well as special electrode geometries were used to minimize the damage, occurring due to the oxidation and subsequent reduction of palladium at temperatures < 800°C