Preparation And Properties Of PMS-PZT Piezolectric Ceramics

In recent years, there is a trend that electronic equipments constantly becoming smaller, which requires electronic components with high-performance, miniaturization, and integration. However, the power transformers, as an important part in the equipment, mainly is electromagnetic transformers with a large volume. Thus the development of a new generation of transformers becomes a hot topic in the world, and multi-layer piezoelectric transformers come into being. The technical difficulty to develop the multi-layer piezoelectric transformer is to obtain piezoelectric ceramics with high-performance and low sintering temperature. In order to resolve this problem, investigation has beem performed in this dissertation, including:1)the effect of sintering temperature on the phase structure and electrical properties of the PMS-PZT piezoelectric ceramics; 2) the PMS-PZT of low sintering temperature using CuO-Bi2O3-Li2CO3 as sintering agents; 3)the influence of NiO and CoNb2O6 additives on the micro structure and properties of PMS-PZT ceramics sintered at low-temperature.PMS-PZT ternary piezoelectric ceramics were prepared by solid-solution processing, and the effects of different sintering temperature on the microstructure and electric properties were investigated. The experimental results indicate that pure perovskite structure was obtained in the sintering temperature range. With the increasing of the sintering temperature, phases shift from tetragonal phase to rhombohedral phase, and the mechanical quality factor Qm reduce. Dielectric constantεr, electromechanical coupling factor Kp and piezoelectric constant d33 increase with the increasing of the sintering temperature and then decrease, whereas, dielectric loss tanδdecrease and then increase. The ceramics sintered at 1200℃have the optimized properties of Qm=1500,εr=1866,KP=0.56, d33=326 pC/N and tandδ=0.4%.CuO-Bi2O3-Li2CO3 was used as the additives, the phase structure and electric properties were studied for PMS-PZT ceramics with different Li2CO3 content. Results show that phase structure, piezoelectric and dielectric properties of PMS-PZT ceramics are much influenced by the content of Li2CO3. It was found that when added right amount of Li2CO3, at the earlier period of sintering process, the transition liquid phase was formed and promoted sintering.The sintering temperature of the ceramics with 0.2wt.% Li2CO3 aid could be lowed from 1200℃to 980℃, while the piezoelectric properties has declined:Qm=932,εr=1586, KP=0.52, d33=301 pC/N and tanδ=6.9%.The effects of NiO-doped on the microstructure and piezoelectric properties of PMS-PZT ceramics were investigated. The experimental results indicate that pure perovskite structure was obtained in the doping range. With the increasing of doping amounts, phases shift from tetragonal phase to rhombohedral phase. The mechanical quality factor Qm, Dielectric constantεr,electromechanical coupling factor Kp and piezoelectric constant d33 increase and then decrease, whereas, dielectric loss tanδdecrease and then increase. The ceramics with doping amount of 0.1wt.% sintered at 980℃have the optimal properties of Qm=1345,εr,=1853, KP=0.62, d33=375 pC/N and tanδ=0.21%.