Multifarious strategies for resolving the deep-curing challenges of PZT piezoceramics slurry in vat photopolymerization

The vat photopolymerization (VPP) technology offers exceptional flexibility in design and manufaction of high-performance piezoceramic structures. However, due to the high refractive index and strong UV absorption characteristics of Pb-based ceramics, ceramic slurries are required to have a low solid content in for efficient deep-curing. This limitation often results in sintering distortion, cracking, low density, and deteriorated piezoelectric properties. To address these challenges, a heat treatment process was initially employed to spheroidize the PZT powder, which effectively decreased light scattering and absorption. Subsequently, high-refractive-index and highly reactive photosensitive resins were introduced to enhance the penetration of UV light and reduce the critical exposure energy of the slurry. Additionally, a hindered amine light stabilizer is added to capture the peroxy radicals to overcome the oxygen inhibition effect and further increase the curing depth. As a result, a PZT slurry with a high solid content of 45 vol.%, was successfully formulated, facilitating the manufacturing of PZT ceramics with complex structures. The sintered samples achieved a high relative density of 96.5% and a d 33 value of 573 pC/N. These optimized strategies provide a solid foundation for the development of high-performance PZT devices with intricate geometries.