Research On Preparation Of PZT Piezoelectric Ceramics And Arrays Based On Digital Light Processing

Lead zirconate titanate（PZT）is a kind of functional ceramic which can realize the conversion of mechanical and electrical signals through piezoelectric effect,which are widely used in the manufacturing of transducer,hydrophone,medical ultrasonic probe and other devices owing to their high piezoelectric constants and electromechanical coupling coefficients.In recent years,with the maturity of micro and nano processing technology,the structural design of electronic devices has gradually developed in the direction of miniaturization and high integration,and the market demand for fine ceramic components is also increasing.The characteristic size of piezoelectric wafer in high-frequency medical sensor is often only tens of microns,and the characteristics of high hardness,brittleness and high melting point of ceramic making it difficult to be prepared by traditional technology.In this paper,based on digital light processing（DLP）,the preparation technology of photocuring PZT ceramic suspension was studied,and the near-net forming of micron ceramic array was realized by combining the photocuring technology with the soft mold method.The main research contents of this paper are as follows:（1）In view of the large particle density of PZT ceramics,which leads to difficult dispersion of the particles and poor stability of the suspension,the effects of dispersant and photoinitiator on the rheological behavior of the suspension were systematically studied,the modification mechanism of the dispersant on the ceramic particles was discussed,and the action mechanism of the photoinitiator and its influence on the curing behavior were analyzed.The results show that the surface modification of PZT particles with Triton X-100 can significantly change the viscosity and stability of the suspension.With the increase of dispersant content,the viscosity of suspension decreases first and then increases.When the dispersant content is 2 wt%,the viscosity of the suspension with 44 vol%solid content is as low as 1.02 Pa·s.The photolysis product of photoinitiator 819 contains two trimethylbenzoyl radicals and one phenylphosphonoyl radical,which have high initiating activity,but their content has a significant effect on the curing depth.When the content is low,the light intensity threshold of UV-induced photopolymerization is high,resulting in a small curing depth.However,when the initiator concentration is greater than 3 wt%,the curing layer formed by the rapid solidification of the superficial suspension blocks the transmission of ultraviolet rays,resulting in insufficient curing power and reduced curing depth of the deep suspension.（2）Considering that the absorbance of PZT particles is affected by their composition,the energy gap of PZT under different Zr/Ti ratios was systematically studied using first-principles,and the influence of PZT particle content on the curing ability of suspension under different sintering systems was analyzed.The results show that the energy gap increases first and then decreases with the increase of Zr content.When the Zr/Ti ratio is 58/42,the energy gap is 3.698 e V,which is much larger than that of the rest of the composition,and the PZT particles have the smallest absorbance.The photocuring behavior of PZT in suspension can be significantly changed by adjusting the content of PZT calcined particles and sintered particles.When the ratio of calcined particles and sintered particles is 1:9,the critical exposure energy of the suspension is 2.95 m J/cm²and the curing depth is 59μm according to the Beer-Lambert law.The ceramic obtained after solidification and sintering of the suspension has the highest density,and its piezoelectric constant d₃₃is about 365 p C/N.（3）The micron-scale silicon-based array was prepared by inductively coupled plasma etching technology.By silanizing the silicon wafer,its contact angle increased from 24.10°to73.75°,which greatly increased the success rate of structural replication and ensured the successful preparation of PDMS soft molds with fine structure.The raw ceramic array with a height to diameter ratio of more than 7 was prepared by soft molding process and light curing.The fine ceramic array with a diameter of 10μm and a height to diameter ratio of more than 6was prepared by adjusting the sintering procedure.