Study on Liquid Phase Low Temperature Sintering PZT Piezoelectric Ceramics
Publish Time: 2019-09-10 Origin: Site
4.1 Cooling by adding a low melting point substance
3. 2 cooling by forming a solid solution
It is prepared a conventional solid phase synthesis method using Pb0. 94 Sr0. 06 (Ni1P2 W1P2 ) 0. 02 (Mn1P3 Nb 2P3) 0. 07 ( Zr0. Ti0. 49 ) 0. 91 ( 0. 02PNW - 0. 07PMnN - 0. 91PZT) piezoelectric disc crystal. By adding low-melting BiFeO3 to introduce soft doping ions such as Fe3 + and Bi3 + , since the ion size, lattice type and electricity price are not much different from those of PZT piezo crystal phase A, they can be mutually dissolved to form a solid solution. A liquid phase is formed during sintering to promote sintering. At the same time, the introduction of soft ions can also improve the properties of piezoelectric ceramics. When the doping amount of BiFeO3 is 10% (mol), the PNW-PMnN-PZT ceramic sintered at 950 °C has the best piezoelectric properties. It is obtained a ternary compound of PZT-PCN by adding Pb (Cu0. 33Nb0. 67) O3 to PZT by a conventional solid phase method. When the relative content of PCN is 0.08, at 1050 The density of sintering for 2 h can reach 7.8 to 7. 9 gPcm3, which is 98% of the theoretical density. Sintering at 950 °C for 2 h gave better electrical properties: d33 = 473 pCPN, εr = 1636, Kp = 0.64. The authors believe that PCN and PZT form a solid solution, in which the initial melting of CuO contributes to the doping modification of Nb5 + , and the liquid phase formed simultaneously reduces the sintering temperature. Waited for the case where MnO2 is doped with PZT-PZN. When the doping amount of MnO2 is 0.4 wt%, the PZT-PZN ceramic can be completely densified after sintering at 930 °C for 4 h. The best electrical properties available are Qm = 1000, Kp = 0.62, d33 = 330 pCPN. The mechanism is as follows PZT forms a solid solution with PZN, which reduces the sintering temperature and improves the electrical properties of the piezo ceramic. By adding MnO2, it plays the role of thickening and sintering, making the material denser and easier to sinter, and improving the Qm value of the material. Further, a solid solution capable of forming a solid solution with PZT ceramics is BaCu0. 5W0. 5 O3 (BCW) , NaNbO3 [20 ], Sr (Cu1P2 W1P2 ) O3 , BiFeO3 (BF), and the like.These additives not only reduce the sintering temperature, but also maintain and improve their performance, which is of great significance for energy saving and environmental pollution reduction.
In general, improperly lowering the sintering temperature of the piezoceramic tube transducer material results in a decrease of performance. Therefore, while the temperature is greatly reduced, the density and good performance of the ceramic body can be ensured to achieve the low temperature sintering of the piezoelectric ceramic material. Of course, low-temperature sintering is not only achieved by a single route, but requires a combination of various methods, coordination, and long-term complement to achieve the best results. Due to the simple process of liquid phase sintering, low cost, and good performance of piezo ceramics at lower temperatures, it has become a hot research topic at home and abroad, and has broad application prospects in industrial production. At present, in order to reduce the cost of preparing multilayer piezo ceramic chip devices and realize the purpose of using co-fired internal electrodes of silver and copper as chip devices, it is particularly important to study the low-temperature sintering technology of PZT piezoelectric ceramics..