摘要
Calcium bismuth niobate(CaBi_(2)Nb_(2)O_(9))is regarded as one of the most potential high-temperature piezoelectric materials owing to its highest Curie point in bismuth layer-structured ferroelectrics.Nevertheless,low piezoelectric coefficient and low resistivity at high temperature considerably restrict its development as key electronic components.Herein,markedly improved piezoelectric properties and DC resistivity of CaBi_(2)Nb_(2)O_(9) ceramics through Naþand Sm^(3+)þco-doping are reported.The nominal compositions Ca_(1-2x)(Na,Sm)_(x)Bi_(2)Nb_(2)O_(9)(x=0,0.01,0.025,and 0.05)ceramics have been prepared via the conventional solid state method.An optimum composition of Ca_(0.95)(Na,Sm)_(0.025)Bi_(2)Nb_(2)O_(9) is obtained,which possesses a high Curie point of~949℃,a piezoelectric coefficient of~12.8 pC/N,and a DC electrical resistivity at 500℃ of~4×10^(7)Ω⋅cm.The improved d33 is probably ascribed to the reduction in domain size and the increase in domain wall density caused by the reduced grain size.More importantly,after annealing at 900℃ for 2 h,the piezoelectric coefficient still maintains about 90%of the initial d33 value,which displays a significant improvement compared to pure CaBi_(2)Nb_(2)O_(9) ceramic with only 44%of the initial d33 value.This work exhibits a feasible approach to simultaneously obtain high piezoelectric property and thermal stability in CaBi_(2)Nb_(2)O_(9) ceramics by Naþ/Sm^(3+)þco-doping.
基金
supported by the National Key R&D Program of China(Grant No.2021YFB2012100)
National Natural Science Foundation of China(Grant No.U19A2087)
the Special Funding Support for the Construction of Innovative Provinces in Hunan Province of China(Grant No.2020GK2062)
the Fundamental Research Funds for the Central Universities of Central South University,and the State Key Laboratory of Powder Metallurgy,Central South University,Changsha,China.Xuefan Zhou(Postdoc)is particularly grateful for the support from the China National Postdoctoral Program for Innovative Talents(Grant No.BX2021377).
