Electric Properties And Performance Of BiScO₃-PbTiO₃ Based Piezoelectric Ceramics

Nowadays, with the rapid development of the aerospace industry, weapons, automotive industry and high-tech electronics, piezoelectric materials with highCurie temperature and large piezoelectric constant become badly in need. Compared with displacive ferroelectrics, relaxors have a series of merits including aspects of piezoelectricity, dielectricity and electrostriction.(1-x)BiScO3-xPbTiO3(BS-PT) ternary solution exists high Curie temperature(Tc=450?) and large piezoelectric constant at MPB. However, the costly Sc2O3 material and great attanchment to components restrict its commercial production. To overcome these shortcomings, LiNbO3(LN) and Pb(Yb1/2Nb1/2)O3(PYN) were selected as the third end materials to form novel ternary systems with BS-PT. The phases, microstructures, electric properties and temperature stability were studied systematically in this paper.36BS-64 PT piezoelectric ceramics were prepared by conventional solid state synthesis. Searching for the optimum calcined temperature, sintered temperature and the processing parameters. The results indicate that when the ceramics calcined and sintered at 750? and 1100? respectively, then poled at 4.2kV/mm, 100? and last 15 min, the samples possess optimum combination properties: d33=401pC/N, kp=0.42, tan?=0.017.(95-x)BS-xPT-5LN(x=28, 30, 32, 34, 36, 38, 40, 42) ceramics were synthesized by conventional solid-state method. Testing results indicate that the MPB of this system locates in 32?x?36. The best room-temperature properties were observed at x=34: d33=530pC/N, kp=0.47, Pr=42.5C/cm2, ?r=2268. The d33* reached 1177pm/V at 140? with x=36. This system possesses excellent temperature stability. Meanwhile, with the increasing content of BS, a transformation from displacive ferroelectric to relaxor has been detected. By fitting the Curie temperature of each content, a linear relation: Tc=-10x+615(?) has been detected.(1-x-y)BS-xPT-yPYN(y=0.1, 0.15, 0.2, 0.3) ceramics were prepared by columbite precursor method. The ternary system shows homogeneous microstructure. Searching for the MPB and the points with best properties in different PYN contents. Analysing the temperature stability of the system by temperature dependence tests. The results indicate that the relaxor properties and temperature stability have been enhanced with increasing PYN content. The MPB locate nearby 0.32BS-0.58PT-0.1PYN, 0.33BS-0.52PT-0.15 PYN, 0.32BS-0.48PT-0.2PYN and 0.3BS-0.4PT-0.3PYN.