Preparation And Properties Of Piezoelectric Ceramic/Structural Ceramic Layered Composites

As ceramic-based functional devices become more compact,integrated,and multi-functional,single-function ceramic materials have been difficult to meet the performance requirements of existing ceramic-based devices.Based on this,a piezoelectric ceramic/structured ceramic layered composite with structural and functional integration was successfully fabricated by tape casting technology.The co-sintering behavior,electrical and mechanical properties of the composites were systematically studied.Firstly,PZT-based piezoelectric ceramic cast green sheets were successfully prepared by tape casting technology.The green sheets were laminated,hot pressed,and sintered at 1100°C for 4h to obtain compact and excellent piezoelectric ceramics.In order to achieve the co-sintering of the above piezoelectric ceramics with Al₂O₃ ceramics,the effect of sintering aid content on the sintering temperature and compactness of Al₂O₃ ceramics was studied.It was found that60wt%Al₂O₃-20wt%Bi₂O₃-10wt%SiO₂-10wt%B₂O₃ components were at 1100°C.After sintering for4h,Al₂O₃ ceramics with higher density and good grain growth can be obtained.PZT-based piezoelectric ceramic/Al₂O₃ ceramic layered composites were prepared by lamination of PZT green sheets and Al₂O₃ green sheets prepared by co-sintering technique.The solid content,layer thickness ratio and hot pressing pressure of PZT and Al₂O₃ were studied.The effect of co-sintering temperature on the microstructure and interfacial bonding strength of the composite ceramics.The results show that when the solid content of PZT green sheets and Al₂O₃ green sheets are45%and 65%,respectively,the layer thickness ratio is 2:1,the hot pressing pressure is 15MPa and the co-firing temperature is 1150°C.A PZT-based piezoelectric ceramic/Al₂O₃ ceramic layered composite with good shrinkage ratio matching and good interface can be obtained.The interfacial shear strength of the composite ceramic is 61MPa,and the dielectric constantof the piezoelectric layer after co-firing is 865.The dielectric loss tan?is 0.52,the piezoelectric constant d₃₃ is 213pC/N,the electromechanical coupling coefficient k_p is 0.43,and the friction coefficient of the structural layer is0.725.In order to avoid diffusion of PbO into the piezoelectric layer during the co-sintering process,part of the yttrium oxide is replaced by doping lead oxide in the structural layer to suppress the diffusion of PbO in the piezoelectric layer.The experimental results show that when the doping amount of PbO in the structural layer is 15wt%,the grain growth of the piezoelectric layer is uniform and the size is basically uniform after co-firing,and the relative content of Pb in the piezoelectric layer is 55%before doping.Increasing to 70%,the interfacial shear strength of the composite ceramic is 75MPa.The dielectric constantof the piezoelectric layer after co-firing is 1103,the dielectric loss tan?is 0.39,the piezoelectric constant d₃₃ is 301pC/N,and the electromechanical coupling coefficient k_p is 0.55.The coefficient of friction of the structural layer is 0.752,indicating that doping15wt%PbO in the structural layer helps to improve the interfacial bonding strength and electrical properties of the composite ceramic.Based on the PZT-based piezoelectric ceramic/Al₂O₃ ceramic layered composite prepared in this paper,it has excellent electrical properties and wear resistance,so it has potential application in the integrated connection of piezoelectric ceramic/stator elastomer of ultrasonic motor.prospect.