Study On Preparation And Properties Of PZT-based Layered Piezoelectric Ceramics

PZT layered piezoelectric ceramics have low lead volatility,high electrical performance and other advantages.In this thesis,the design of layered composite structure effectively reduces the amount of Pb volatilization during sintering,which can reduce the harm to the environment.On the other hand,the study of layered composites with different components and interface diffusion can accomplish better electrical properties of ceramics.Through the diffusion of oxygen vacancies in the soft and hard layered composite structure,the sintering process is promoted,and the sample is densified at a reduced temperature to achieve a low energy consumption effect.The results are listed as follows:(1)lwt%CuO+5SKN and 2SKN/PZT layered piezoelectric ceramics was prepareted by dry pressure molding.Due to its special layered structure,the formation of PbO-CuO liquid phase at the interface between layers promotes the sintering diffusion process,effectively inhibiting the volatilization of lead,and at the same time maintaining performance.The lead volatilization of the 1wt%CuO+5SKN and 2SKN layered composites was only 0.45%at 900°C.Even at 1000°C,the lead volatilization was only 1.42%.In addition,the lwt%CuO+5SKN and 5SKN layered composite structure not only maintains the advantages of low lead volatility,but also has good piezoelectricity and low dielectric loss.At the same time,it has a high Curie temperature(395°C)and has potential application.(2)We studied the effect of different "hard doping"(low-valent ions replace high-valent ions)on PZT-based layered piezoelectric ceramics,and found that hard doping can cause oxygen vacancies,which can will pin the domain walls,limit their mobility during polarization,and reduce the dielectric loss.When compounding with 5SKN to form layered structure,the different interface diffusion effects appeared,which is related to the concentration of oxygen vacancies.In addition,the diffusion of oxygen vacancies in the soft and hard layered composite structure promotes the sintering process,and the sample is densified at a low temperature to achieve a low energy consumption effect.(3)By studying the high-temperature sintering of layered piezoelectric ceramics with different Fe contents,we found that,the transition layer of the 4Fe-5SKN layered structure is distinct,and with the increase of temperature,the thickness of the transition layer increased from 24.80 ± 2.35 ?m to 158.42 ± 3.53 ?m.And it has a higher dielectric constant and lower dielectric loss.Compared with the research of multilayer piezoelectric ceramic devices,the study of the co-firing interface of layered piezoelectric ceramics also has a non-negligible value for industrial applications.