摘要
采用常压烧结方法制备了Mn掺杂的(K0．5Na0．5)0．96Sr0．02Nb1-xMnxO3无铅压电陶瓷．研究了Mn含量对该体系材料的相组成、微观结构、介电、压电和热稳定性能的影响．XRD表明随着Mn含量的增加,体系由正交相过渡到赝四方相;而且,富Na的第二相消失,得到纯净的钙钛矿相结构．在Mn含量为x=0．03和0．04时,观察到了两个温度(200和390℃)处的介电反常,这和晶格畸变引起的复晶胞结构有关．Mn含量为x=0．02时,得到综合性能优良的压电超声换能器用材料:介电常数ε33 7／ε0=479,压电常数d33=121pC／N,机电耦合系数Kp=41％,机械品质因子Qm=298,介电损耗tanδ=1．6％,居里温度Tc=391℃,谐振频率fr和机电耦合系数Kp随温度的变化率αfr(80℃)和αKp(80℃)分别为-1．85％和1．19％．
Dense lead free ceramics of （Ko.sNa0.5）0.96Sr0.02Nb1-xMnxO3 （z=0,0.01,0.02,0.03,0.04）were successfully prepared by a conventional mixed oxide method. The X-ray diffraction patterns revealed pure peroveskite structure after Mn doping as compared to the original composition. This was attributed to the inhibition of K^＋ volatility during sintering process. Dielectric anomaly was observed and explained by multiple-cell structure resulting from Mn-induced lattice distortion. Low loss tangent and relatively high planar electromechanical coupling factor were obtained at x=0.02. The main parameters for the composition of x=0.02 are：ε^T33/ε0=479,d33=121pC/N Kp=41%,Qm=298,tanδ=1.6%,Tc=391℃The rates of resonant frequency variation,αfr and planar coupling factor variation,αKp with temperature are 1.85% and 1.19% at 80℃, respectively. This material may be suitable for applications in ultrasonic transducers.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第3期469-473,共5页
Journal of Inorganic Materials
基金
国家自然科学基金(50577065)
关键词
无铅
压电陶瓷
介电
换能器
lead free
piezoelectric ceramics
dielectric
transducer
