The Property Study Of PMS-PNN-PT Piezoelectric Thick Film Material

Piezoelectric thick film is a new functional type material develeped by 1990's. It has the merits both the block material and thin film, with excellent piezoelectric, dielectric and pyroelectric properties.In the thesis, progresses made on piezoelectric ceramics were reviewed. The piezoelectric property, principle and the main parameters of it were introduced briefly. Well, the preparation technology and the application of piezoelectric thick film were summarized in detail.In the work, PMS-PNN-PT thick film with high piezoelectric performance was prepared on Al2O3 board using Screen Printing technology. The thickness of the prepared was about 50~80μm, and main properties of it wasρ=6.0g/cm3,d33=63.5pC/N,Kt=0.52,εr=143,tgδ=0.009,Qm=734.Sintering processes including sintering temperature, heat preservation time and sintering atmosphere of piezoelectric thick film about its phases, microstructure and electricity performance were investigated and researched based on XRD and SEM technology. It was found that PMS-PNN-PT thick film had excellent microstructure and piezoelectric performance when sintered beneath PbO atmosphere at 1040℃for 60min.Poling conditions including poling temperature, poling time and poling electric field of electricity performance of PMS-PNN-PT thick film were researched. It was found that the optimum poling condition: Poling electric field 4.0 kV/mm, Poling temperature120℃, Poling time 5 min.In order to enhance the relative low mechanical quality factor and dielectic constant of PT system, to meet the need of high-power piezo-facility. A few component addition Pb(Mn1/3Sb2/3)O3 and Pb(Ni1/3Nb2/3)O3 (hereafter abbreviated as PMS and PNN) was introduced. The influences of microstructures and properties of PMS-PNN-PT piezoelectric thick film were studied following the ratio of PMS/PNN, and the phrase and microstructure were analyzed through XRD and SEM. It was found that following the rising of PMS/PNN, a little of pyrochlore phrase was found during the calcining proeess for the instability of PMS structure. The microstructure and piezoelectric both got well and then got bad following the rising of PMS/PNN. When PMS/PNN is 0.03/0.05, piezoelectric thick film had high performance.The influences of microstructures and properties of PMS-PNN-PT piezoelectric thick film using SiO2 as buffer layer were studied. The lower electrode and the piezoelectric layer of the thick film were analyzed based on SEM and the bonding strength among lower electrode, piezoelectric layer and substrate was studied by scratch test. It was found that the bonding strength with SiO2 super to the one without it , which showed that SiO2 as buffer layer prevented the diffusion between lower electrode, piezoelectric layer and the substrate effectively. In addition, it can also enhance the viscidity among them and improve the piezoelectric performance.