Effects of sintering temperature on electrical properties of La/Ce rare-earth ions modified CBN ceramics
PENG Zhihang1*, ZENG Xiangxiong2,XIANG Yang1,CAO Feng1
(1 College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073, Hunan, China; 2 Northwest Institute of Nuclear Technology, Xi′an 710024, Shaanxi, China)
Abstract:
Multi-rare-earth La/Ce ions modified CaBi2Nb2O9（CBN）ceramics were prepared by a conventional solid state sintering method. The effects of different sinter temperatures on crystal structure, microstructure and electrical properties were investigated. The X-ray analysis data show that the specimens sintered in the temperature range of 1 000-1 150 ℃ have a single bismuth-layered structural phase. A secondary phase corresponding Ca2Nb2O7 was detected for the ceramics sintered at 1 200 ℃. The grain size significantly increases with an increase of sinter temperatures. The microstructure of ceramic grains changes from spherical to disk like morphologies. Moreover, the dielectric, dc resistivity and piezoelectric properties at different sintering temperature were studied. The Curie temperature of modified-CBN ceramics decreases from 935 ℃ to 915 ℃ with increasing sinter temperatures. Meanwhile, the dc resistivity at 500 ℃ decreases from 3 MΩ·cm to 0.76 MΩ·cm. La/Ce-CBN ceramics sintered at 1 150 ℃ for 2 h possess good piezoelectric properties, with piezoelectric coefficient d33 of 16.6 pC/N. The d33 value decreases to 15.1 pC/N after annealing at 850 for 2 h, exhibiting a good piezoelectric temperature stability.
KeyWords:
CaBi2Nb2O9; piezoelectric; sinter; rare-earth ions doping
