Fabrication of curved ceramic/polymer composite transducer for ultrasonic imaging applications by fused deposition of ceramics

Fused Deposition of Ceramics (FDC), developed at Rutgers University, is a Solid Freeform Fabrication (SFF) technique where a three-dimensional green ceramic object is built, layer by layer, starting from a Computer Aided Design (CAD) file of the object. This technique was used to build novel piezoelectric ultrasonic transducers for medical imaging applications. Curved ceramic skeletons for 2-2 composite transducers were built by FDC. The design's curvature can be tailored in the CAD file. Therefore, the final composite requires very little machining. The FDC-built green parts were designed in order to have 30 percent volume fraction of ceramic in the composites. The FDC green samples were subjected to a slow binder burnout cycle at 550/spl deg/C for 4 hours, using a heating rate of 10/spl deg/C per hour, then sintered at 1285/spl deg/C for 1 hour. Two radii of curvature were chosen: 10 cm and 20 cm. The minimum composite thickness was 1.5 mm in both cases. The maximum thickness was 2.26 mm for the first radius of curvature and 1.88 mm for the second. Physical characterization of the samples revealed that 95% of the theoretical density was achieved. The electromechanical properties of the final composites and of FDC bulk samples are reported in this paper.