12/11/2023 0 Comments Ultrasonic piezo motorAs a result, the piezoelectric materials with these architectures exhibit piezoelectric coefficients much lower than those of their pristine ceramic counterparts and weak emission pressures when used as ultrasonic transducers. The mechanical stress caused by the machining processes results in grain pullout, reduced strength and depolarization, leading to significant degradation of the piezoelectricity of the manufactured elements 12. The manufacturing of these architectures is either dependent on conventional machining methods, including etching, dicing and hot pressing 10 due to the brittle nature of piezoelectric ceramic 11, 12, 13, 14, or limited to 3D printed composite materials containing piezoelectric nanoparticles and polymer matrices 15. Recently, the emergence of new structural designs and computations has led to the prediction that incorporating 3D microfeatures into piezoelectric materials could provide unprecedented properties or functionalities, including designed anisotropy 8 and the ability to emit tailored and localized ultrasound fields 9, as well as sensors and actuators for miniaturized robots and transducers. Owing to the capability of piezoelectric materials to convert mechanical to electrical energy and vice versa, they are widely used in sensing 1, actuation 2, energy harvesting 3, 4, cleaning 5, and ultrasound imaging 6, 7. The integrated printing of transducer packaging materials and 3D printed piezoceramics with microarchitectures create opportunities for miniaturized piezoelectric ultrasound transducers capable of acoustic focusing and localized cavitation within millimeter-sized channels, leading to miniaturized ultrasonic devices that enable a wide range of biomedical applications. The resulting piezoelectric charge constant, d 33, and coupling factor, k t, of the 3D printed piezoceramic reach 583 pC/N and 0.57, approaching the properties of pristine ceramics. The 3D printed dense piezoelectric elements achieve high piezoelectric coefficients and complex architectures. We introduce optimized piezoceramic printing and processing strategies to produce highly responsive piezoelectric microtransducers that operate at ultrasonic frequencies. While advances in additive manufacturing give rise to free-form fabrication of piezoceramics, the resultant transducers suffer from high porosity, weak piezoelectric responses, and limited geometrical flexibility. Due to the brittle nature of piezoceramics, existing processing tools for piezoelectric elements only achieve simple geometries, including flat disks, cylinders, cubes and rings. The performance of ultrasonic transducers is largely determined by the piezoelectric properties and geometries of their active elements. Nature Communications volume 14, Article number: 2418 ( 2023) 3D Printing and processing of miniaturized transducers with near-pristine piezoelectric ceramics for localized cavitation
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